Building Simulation Applications BSA 2017

x This contribution describes an urban energy modelling method that enables the use of dynamic performance simulation for urban-scale energy inquiries. The associated framework involves two components. The first component is tasked with the systematic reduction of the computation domain through clustering based sampling of the urban building stock. The second component recovers part of the lost diversity (due to the reductive procedure) via stochastic variation of selected model parameters such as thermal properties of building components and occupancy-related factors.

x Plastic waste is a growing issue that needs to be addressed, multiple solutions are established to reduce its impact on the environment. The aim of this research is to make use of the plastic waste piling up and, at the same time, to create a convenient daylighting solution. The research proposes a sustainable fenestration system to be used in hot-arid climates, particularly in Egypt, where it is common to use tinted glass to lower the heat gain. First, a recycling process was carried out to create samples, the samples were then tested to obtain their optical properties and lastly Radiance, a daylighting simulation tool, was used to test the performance of recycled plastics as a window glazing material. In the recycling process, three plastic types were used to create the samples: polypropylene PP (number 5), polystyrene PS (number 6), and polycarbonate PC (number 7). It was concluded that the use of recycled plastics as a glazing material is indeed possible. Polycarbonate ranked as the most transparent, yet its impurities were the most visible. Polystyrene was also observed to be quite transparent, however its transparency was inversely related to its thickness. Polypropylene was the least transparent under the selected settings. Nonetheless, further research is required regarding the recycling process settings, to determine the possibility of obtaining more transparent results.

x The analysis of 11 shopping centres in Europe reveals a lack of availability of indoor natural daylight, especially in shops and sales areas. The aim of this paper is to investigate the consequences on energy consumption and electricity use for lighting that novel retrofitting measures have when applied to Norwegian shopping centres (Haase et al., 2015a). Internal daylight and internal illuminance levels were measured in two shopping centre buildings in Trondheim and Modena together with detailed monitoring of energy use and indoor air quality. Scenarios were modelled to simulate the artificial lighting use patterns and control strategies in the shopping centres by considering occupancy hours and type of activity (illuminance levels), in order to cover different possible com-binations used in the energy and daylight simulations. Existing conditions of shopping centres (pre-retrofitting) in Trondheim, Norway were modelled based on drawings and validated with energy use measurements. Energy and daylighting simulations were performed and combinations of use pattern scenarios and facade variables were used to evaluate the influence on the electricity use for lighting and energy use for heating and cooling of the different scenario combinations. There is a trade-off, which is quantified in terms of reduction in electricity use and cooling demand as well as an increase in heating demand. The implications of lighting retrofitting on heating and cooling (aside from the end energy use savings) make the application complicated in shopping centres. Modelling and simulation of a shopping centre can help us understand the holistic consequences of single energy retrofitting measures.

x The paper describes the implementation of a 1-dimensional transient model based on the enthalpy method to analyse the thermal behaviour of a Phase Change Material (PCM) layer integrated in a window. The model and algorithm have been validated by comparison with experimental data. The model has then been expanded to couple a PV layer with the PCM layer. The complete model is implemented in MATLAB and linked to TRNSYS in order to estimate the dynamic thermal energy demand of a building equipped with a double skin façade with a PV-PCM layer in a ventilated cavity. A parametric study was carried out, investigating three different cavity ventilation strategies for two European cities (Venice and Helsinki). The results show that, when the PCM layer is coupled with the PV layer, in Venice the cooling energy demand is 60 % lower, while in Helsinki the heating demand during the winter season is 36 % lower.

x During the last decade, the application of electronics to the different components of HVAC systems has offered new and sophisticated control systems capable of adapting the behaviour of each single device and of the whole plant to design specifications. These sophisticated finely-tuned control systems are, in principle, able to play an important role in reducing energy consumption and in improving thermal comfort. At the same time, there has been a marked increase in the complexity of the HVAC plant layout. By combining the complexity of the plants with that of the control systems and by taking into account the possibility of equipping each component of the plant with its own control system, the result is a new generation of energy systems with many possible interactions between controllers. Hence, it becomes impossible for a designer to evaluate, in an easy way, the effects of such interactions. As a consequence, it is difficult to know, at the design-stage, how the overall control system will operate. Nowadays, the dynamic simulation of the complete HVAC system makes it possible to emulate the system in which the controllers operate. In this paper, the dynamic model of a basic HVAC system involving a condensing boiler, radiators with thermostatic valves and an inverter driven hydraulic pump is presented. Each element of the circuit is equipped with its own control. The model of the system was built by using a custom-made library of Simulink blocks specifically created for the dynamic simulation of controlled HVAC systems. The dynamic model will be used in order to underline the strong influence of the control system on the HVAC energy efficiency and thermal comfort conditions. Specific design rules limiting the negative interaction among the activated control systems are inferred by the results shown in this paper.

x Nowadays, the complexity of the interactions between thermal plants and buildings for NZEB buildings is increasing. The decrease in primary energy consumption by NZEB is generally pursued by maximizing the use of renewable energy which gives a discontinuous contribution during the season; it becomes important to study in detail the dynamic interactions between the building and the adopted HVAC systems, by taking into account unsteady state behaviour of walls, roofs, windows, and so on. This kind of analysis can be carried out with conventional dynamic simulation software (i.e. TRNSYS, ESP-r, Energy Plus, DesignBuilder). It has been demonstrated that a detailed analysis of controlled HVAC systems can also be carried out by using SIMULINK, and in the past open block libraries made in SIMULINK were proposed for HVAC system analysis, like in the case of the CARNOT blockset. However, besides its completeness, the building modelling is still considered a weak point of CARNOT due to its limited flexibility. For this reason, a new specific library named ALMABuild based on SIMULINK blocks for the dynamic modelling of a building is presented in this paper with the aim to integrate and improve the blocks already available in CARNOT. In ALMABuild, the modelling of a building with SIMULINK is driven by means of a series of Graphical User Interfaces (GUI). In this paper a benchmark of ALMABuild is shown by using TRNSYS as a reference. The comparison evidenced a good agreement between the two methods. However, differences were present each time that the procedure indicated by the European Standard EN ISO 13790:2008 (and integrally followed by ALMABuild) was not in agreement with the procedure followed by TRNSYS (based on American standards).

x In recent years, there has been a proliferation of air-conditioning in both residential and commercial buildings in India. Mixed-mode buildings are buildings in which a combination of air-conditioning and natural ventilation is used to provide comfortable indoor environments. These buildings are likely to be less energy consuming than fully air-conditioned buildings, and further energy savings can be achieved by using air movement to increase the cooling setpoint temperature without jeopardizing the occupants’ thermal comfort. The aim of this research was to develop and test on a typical Indian apartment a methodology to quantify these energy savings using dynamic thermal simulations. The core of this method is the definition of the cooling setpoint, which varies monthly according to the ASHRAE 55-2013 adaptive model. The results show that the annual energy demand for space cooling can be reduced by as much as up to 70 percent by using air motion devices. Moreover, the indoor thermal conditions during the occupied periods predicted by the model are closer to the values measured in field studies in India.

x During the last decade, computational fluid dynamic simulation tools have been widely applied for accurately modelling outdoor airflows and local microclimate conditions. In fact, a complete understanding of heat transfer phenomena occurring within the built urban environment is needed to properly predict the energy balance, both on a single-building and on an inter-building scale. In this scenario, several research studies have been carried out to evaluate the impact of local passive solutions on buildings indoor environment, especially by means of dynamic simulation tools. However, only a few investigations were performed by considering the local distribution and spatial variability of the indoor building physics generated by the application of passive cooling strategies. The present research is aimed at bridging this gap by modelling the indoor thermal environment of a case study prototype building, i.e. square cavity, located in central Italy, by considering indoor heat transfer phenomena. A calibrated and experimentally validated CFD model of the building was elaborated to predict the indoor temperature distribution and profile generated by the application of an innovative highly-reflective cool façade painting and cool roofing membrane on the building envelope, compared to a more traditional “non-cool” envelope finishing. So far, the authors have produced only one work about cool roofs in buildings that concerned sloped roofs in a non-insulated building envelope. Here, we deal with insulated architectures, designed according to the recent energy efficiency regulation, and a combined cool roof and cool façade indoor effect. The experimental validation of the model is carried out by means of experimental data that are continuously monitored both inside and outside the case study building by means of dedicated microclimate and weather stations. Simulation results were therefore post-processed in terms of (i) indoor temperature and (ii) indoor airflows. Main findings confirmed the huge potentiality of the model in realistically reproducing the indoor behavior of the case study building and therefore the urgent need for a CFD-based approach in investigating thermal-comfort conditions. In fact, a non-negligible and positive impact of the cool building envelope on the local indoor thermal comfort conditions is detected with respect to the more traditional non-reflective component.

x A key research effort has been dedicated toward zero energy buildings in the last decades. Recent interest is currently switching its focus from single-building scale to the inter-building scale, by enlarging the thermal-energy balance up to the settlement level, with the purpose to optimize the whole district energy efficiency and its environmental sustainability. This scale enlargement up to the district size leads to further optimization opportunities that must be considered when performing building thermal-energy dynamic simulations. In this view, buildings within net Zero-Energy Settlements (nZES) can improve their performance thanks to outdoor microclimate improvement techniques that could succeed in mitigating both winter thermal losses and summer overheating risks. In this work, microclimate modeling and building dynamic simulation tools are integrated to assess the impact of varying microclimate conditions on the building energy performance at a settlement level. The case study is performed on a residential district in Italy. In particular, microclimate simulations are carried out to predict the mitigation potential of specific strategies applied at settlement scale, i.e. cool materials, greenery, and their combination. Therefore, starting from the results of the microclimate optimization, new microclimate boundary conditions are generated to be used within the dynamic simulation environment. The final aim is to quantify the impact of such optimized microclimate boundary conditions on the buildings energy performance. The results from the microclimate simulations, supported by the European funded Horizon 2020 project ZERO-PLUS, highlighted how microclimate can play a key role in affecting outdoor thermal comfort conditions. Moreover, the dynamic simulations carried out by using the results from a microclimate optimization as input weather files, always show a decrease on the final energy needs of the building in the nZES. The highest and non-negligible reduction is reached in the final cooling need of the optimized scenario by coupling both cool and green optimization strategies, i.e. about 12 % of the initial value.

x Energy efficient buildings, besides saving energy, should provide adequate indoor thermal comfort. Hence, to maximize advantages, a balance between different energy efficient technologies and solutions must be found. In this sense, the European directives on the energy performance of buildings have defined a high standard of thermal insulation for buildings in order to comply with strict energy performance limits. However, several studies have highlighted that such an approach can have negative effects in summer, especially in the Mediterranean area, thus inducing an increase in the energy needs for cooling and a remarkable overheating. In this context, the main objective of this study is to investigate the thermal performance of Vacuum Insulation Panels (VIPs) and Phase Change Materials (PCMs) when applied to the building envelope, and their ability to improve the building thermal behavior in the Mediterranean area. To this aim, a numerical model of a test room with standard construction technologies was implemented on Design Builder. This model was validated against experimental measurements available in the literature. Once the model was calibrated, a further series of simulations was performed by applying to the same test room the above-mentioned innovative building envelope systems. The simulations were run both in free-running conditions, in order to assess thermal comfort and thermal inertia of walls, and by assuming the presence of an HVAC system, to calculate the energy needs for space heating and cooling on a yearly basis. The results highlight that, in summer, thermal discomfort and remarkable increases in the energy needs for cooling may occur when the building is retrofitted with VIPs, whereas better conditions are achieved with PCMs.

x The use of simulation for building design and performance assessment is becoming mandatory if NZEB requirements have to be met. As a matter of fact, only dynamic simulations are able to correctly account for renewable energy exploitation on the building site. Dealing with solar energy source conversion, the correct use of available standard weather data files is still more important than solar gains through the transparent envelope. When using such statistically derived weather data, however, different pitfalls might arise. In fact, when performing sub-hourly simulation, the information provided by hourly-based climatic data is insufficient. Interpolation algorithms are implemented in Building Performance Simulation tools (BPSts) to provide intermediate weather data, which can affect the quality of the results. Specifically, solar radiation data are insufficiently represented by hourly-based values when dealing with short time-step simulations of complex building systems. In this article, a review of radiation algorithms and weather data management algorithms at sub-hourly simulation time steps will be introduced, as implemented by two well-known software, such as TRNSYS 17 and EnergyPlus 8.6.0. Further considerations will be made upon information exchange among simulation components during the simulation, and upon the possibilities offered or denied by different data management-implementations when multiple actors are involved in the simulation.

x The concept of green building plays a role of primary importance in the reduction of the use of resources, water, and materials, as well as on the reduction of impacts on human health and the environment, during the building lifecycle. A large number of countries has already developed energy certification procedures in order to rate the building energy performance; furthermore, a range of green building assessment tools and protocols has been developed in the past 20 years, with the aim of reducing energy consumption and the environmental impact in both the building construction and management phases. This paper compares the results of the application of three green building assessment methods on both the energy and environmental performance. Some of the most spread rating systems were chosen: Istituto per l'innovazione e Trasparenza degli Appalti e la Compatibilità Ambientale (ITACA, Italy), Comprehensive Assessment System for Built Environment Efficiency (CASBEE, Japan), and Green Star (Australia). The analysis was developed on a residential building located in central Italy, constructed by taking into account the international principles of sustainability and bioclimatic architecture. Starting from previous studies developed by the Authors, by which these protocols were compared and their scores normalized, the proposed study assesses the sustainability of the case-study building thanks to a point-based methodological approach. It is based on the identification of six common macro-areas that allow the homogeneous comparison of the three green building assessment tools. The study aims to assess the impact of these new normalized categories on the overall sustainability performance of the building.

x The use of numerical simulation applied to heritage buildings triggers a tremendous increase in complexity and at the present time, few studies focus on this issue and the problems of their calibrations. The difficulties are affected by many factors: the complex geometry involved, the non-standardization of building elements, the inertial behaviour of the wall masses, the importance of moisture transport; in short, the complexity of managing the design workflows in a conservation project of historical buildings. The integration of numerical simulation and Building Information Modeling is not yet automated and relies heavily on the manual steps and the individual experience. The research analyses the high potential of the use of the simulation of building performance, and the computational design along with Heritage Building Information Modeling, with the aim of pushing the three technologies to their potential limits, and promote their evolution towards an easier practical application. The paper presents an experimental HBIM workflow applied to a case study of a building located in an Italian historic centre and discusses a number of problems that still exist in the application of these workflows. They range from finding a correct set of information necessary for the analysis to the lack of interoperability that still exists between the software, up to the difficulties of the methodological approach. The results show that through a combination of recent open source software constantly evolving, it is possible to overcome some of the obstacles that prevent an effective interoperability between individual software, paving the way for an increasing number of useful solutions in the built heritage conservation.

x Conventional building energy simulation utilizes characteristic locational weather data to illustrate the typical operation of the modeled facility, generally to provide design or capital investment insight. Because of the uncertainty in the weather, the assumptions behind typical meteorological year (TMY) data tend to perform poorly in building energy modeling applications for real-time control such as model predictive control (MPC) of passive building thermal mass. To account for weather uncertainty in such operational context, we present a strategy for creating an arbitrary number of plausible near-future weather scenarios via a vector autoregressive (VAR) time-series prediction framework. This approach allows us to preserve the relationships between several spatiotemporally interrelated weather variables, for example dry-bulb temperature and absolute humidity, by capturing the variance in the joint time-series. Results from several climates are presented for 24-hour predictions of psychrometric and solar weather variables for a range of samples sizes and the application to stochastic MPC is highlighted.

x Historic and traditional buildings, including rural ones, are a territorial resource in Europe and constitute an integral part of the European cultural heritage. However, they are often characterized by poor energy performance and a large potential for energy retrofit actions. On the other hand, the hardest part in retrofitting such buildings is the limited invasiveness that such actions need to have on the historical and heritage value of the building itself. The paper describes an experience of re-design of an existing rural building located in Sicily, inside the ancient Greek Valley of the Temples. An energy audit was performed on the building, its energy uses thoroughly investigated. A building model was developed in the TRNSYS environment and its performances validated. The validated model was used for redesign studies aimed towards the improvement of the energy performances of the building in compliance with the legislation. The best performing solutions to be applied to a case-study like the Sanfilippo House are those regarding the management of the building, as in the case of the natural ventilation and the HVAC setpoints that would allow a large impact (up to a 10 % reduction in energy uses) on the energy performances of the building with no invasiveness, and those with very limited invasiveness and high impact on the energy efficiency of the building, as in the lighting scenario (up to 30 % energy use reduction). The most invasive actions can only be justified in case of high energy savings as with the insulation of the roof, otherwise they should be disregarded.

x The Directive 2010/31/EU promotes the improvement of the energy performance of buildings within the European Union, by taking into account indoor climate requirements and cost-effectiveness. Thus, the cost optimisation is one of the main objectives of the EU regulatory framework concerning the energy performance of both new buildings and existing buildings subject to refurbishment actions. When assessing the cost-optimal levels of energy performance, the calculation of the energy needs is usually carried out by means of CEN standards or equivalent national calculation methods, based either on steady-state or on dynamic simplified models. However, many research studies have pointed out the limitations of the steady-state approach, especially for high performance buildings. The aim of this work is to study how the calculation method – quasi-steady or dynamic - of the energy needs for heating and cooling, impacts on the final optimal design. This is done through the application of a cost-optimal procedure to a single-family house located in Milan. The building energy needs for space heating and cooling are calculated by means of the quasi-steady-state monthly method specified by the Italian standards and the simplified hourly dynamic model of ISO 13790. The performance of the thermal systems is then assessed by means of the national standards (UNI/TS 11300), while the global cost is evaluated by means of EN 15459. Several design options with increasing levels of energy efficiency are applied to the case study. We compare the cost-optimal solutions derived from the application of the two methods, and discuss the reasons for the deviations.

x Daylight plays a very important role in educational buildings, as it allows to create a pleasant environment, to enhance students’ performance and to provide better health conditions to the occupants. For these reasons, and also to save energy in artificial lighting, a great body of literature has dealt with the study of daylight in schools in the past years. Although some quantitative criteria are already in use for assessing daylight effectiveness for several visual tasks – e.g. minimum illuminance values and daylight factors – the distinction between well and badly daylit spaces very often rely on qualitative issues, such as the avoidance of discomfort glare conditions. Moreover, current design practices rely on standard sky patterns, and neglect the specific climate-related issues, and the time varying appraisal of the indoor space. The present paper contributes to this research field by exploring the use of different strategies to enhance daylight levels in a school located in Sicily and selected as a case study. The building is mainly made up of side-lit classrooms, exposed to different orientations. The strategies that are investigated rely both on traditional static devices (e.g. light shelves and reflective glazing) and on more advanced dynamic concepts (e.g. sensor-controlled blinds and electrochromic glazing). All the selected devices are already available on the market. The daylight performance is assessed in the Radiance-based environment provided by DAYSIM 4.0; the model is calibrated upon a measurement campaign. To this aim several Climate Based Daylight Metrics (CBDM) are used to provide a deeper insight of the potentialities of each solution. Further developments are discussed in the conclusions.

x When dealing with models, a key factor to consider when selecting their features is the context in which the models will be used: for example, they could be used for design or for control purposes. If we focus on the second case, the model should be accurate enough to capture the principal dynamics of interest and simple enough to minimize the computational effort. In building modelling for control, a promising paradigm seems to be the use of simplified grey-box models. This paper presents a case study in which the existing temperature control strategy can be im-proved with the resulting possibility of considerable energy saving. More in detail, we introduce here the first step of the entire process: the choice of the model of the system. We decided to investigate the use of a grey-box model, the parameters of which were estimated using a parametric identification process. Thanks to this approach, full knowledge of the system is not required but this lack of information needs to be balanced with the use of measured data. We decided to use only measured data during the standard operation mode of the system for the parameter identification process. Thus we did not perform targeted experiments on the real system, because of all the restrictions in the specific context. Using this approach, it was still possible to achieve good results in terms of deviation between model simulation and data (indoor air: RMSE = 0.31 and R2 = 0.92).

x BiPV (Building integrated photovoltaics) stands on the bridge between architecture and energy production, some photovoltaic companies in the last decade are engaging in the design and production of non conventional PV technologies (Céron et al., 2013). BiPV industry aims to transform PV from power plant to building material, thus the need for features such as freedom of color and dimensions, and flexibility is coming up. In this paper a method is presented for the estimation of power production on curved active surfaces, the performance of two samples of flexible thin film photovoltaic modules are evaluated as a validation. Because of its curved application, the electrical layout and a non-uniform temperature issue affect the performance of the modules under study. The work shows a method to simulate the performance of curved photovoltaic modules subject to uneven irradiation. For the experimental set-up, a curved shelter was built (of those typically used to shield market carts outside supermarkets). Two different flexible photovoltaic modules are glued onto the curved roof of the structure, each module is equipped with an MPPT tracker connected to a data logger, and there are then 2 thermocouples to measure temperatures in the two different modules. Because of the curved shape of the photovoltaic surface the incoming irradiation cannot be measured with a pyranometer, and should therefore be accessed by geometry based computer simulation. The irradiation is simulated through ray-tracing computations (Ward, 1996). The simulation uses weather data retrieved from the weather station located at the ABD airport in Bozen (less then 1 km away). The main result is the comparison between the simulated and the measured power production. Both simulated and measured power point to a better performance linked to one electrical layout over the other. More values are of interest such as Ross coefficient on the module for this particular type of shape and integration. The study shows an acceptable level of agreement between the simulated power production and the measured one provided that some parameters are calibrated. The possibility of simulating this technology opens the path for economic analysis and feasibility studies to access the real potential of this technology in non-flat application cases.

x This work aims to provide a method to validate a PCM tool implemented in a whole building dynamic simulation software (IDA ICE) using outdoor measurements coming from Solar Test Boxes (STB). The STB method was originally conceived by ESTER lab at the University of Rome Tor Vergata, to evaluate thermal characteristics of transparent and semi transparent mate-rials in outdoor conditions. In the approach presented here, two boxes (reference and test) were equipped with a standard double glass pane. A PCM pane, provided by RUBITHERM®, was put on the floor of the test box. Two monitoring campaigns were carried out and the thermal behaviour of the box with PCM was analyzed and compared with the thermal behaviour of the reference box. Temperature trends measured inside the “PCM box” were used to validate the PCM behaviour provided by the IDA ICE tool, comparing measured and simulated data.

x Water heating for domestic needs contributes significantly to energy demands in the residential sector. The paper reports an energetic analysis of a solar hot water system performed on a dwelling located in Rome, Italy. The study is focused on a group of apartments, where the domestic hot water is provided by a solar system coupled with a storage tank. A recirculation loop, composed by a pump and a system of pipes from the tank to the more distant apartment is also considered in the study. The loop overcomes the problem of long waiting times for hot water for the user by keeping it flowing inside the system. Since the recirculation loop is compulsory in this kind of plants, a dynamic energetic analysis is performed in order to analyse the pipe heat loss influence on the solar fraction. Dynamic simulations are performed using TRNSYS by setting different parameters (insulation thickness, pipe length, mass flow rate) and by interrupting the flow in the recirculation loop during the night. The study shows the sizing process of the whole system, the variation of the solar fraction and heat loss fraction for all the analysed cases.

x It is well known that the calibration of building energy models is an under-determined problem, whether subjected to hourly or monthly calibration criteria. In fact, while it is possible to identify a large number of calibrated models, it is not clear which offer a good representation of the building behaviour. For a calibration methodology of building energy models to be effective, it should automate and speed-up calibration processes. This is especially important when the number of model parameters is too large to tune manually. Moreover, when the number of model parameters is too large, the probability to find the real parameter combination using statistical sampling methods is very small. Instead, we suggest performing a guided search of the parameter space, e.g. solving a parameter optimization problem. Since Tikhonov-type regularization has been applied successfully to many ill-posed inverse problems, we propose adopting the same methodology to find optimal parameters for building energy models. The regularization term can be interpreted as imposing certain a-priori distributions on model parameters as identified by an energy audit. As an illustration, the study case of a residential apartment is calibrated and we show that regularization more accurately predicts the energy demand estimate after the retrofit of the study case.

x In this study the capability of a BDFWall model (IDA Indoor Climate and Energy software) is assessed in a semi-confined site for the conservation of works of art. The case under study is the paleontological deposit of “La Polledrara di Cecanibbio” (Rome, Italy), where many valuable faunal remains from the Middle Pleistocene are preserved. The thermo-hygrometric data collected from 2009 to 2013 have allowed for a thorough investigation of the environmental conditions of the site. The calibration of the simulation-building model was performed in two phases. First, a sensitivity analysis was conducted to identify which input parameters significantly affect the discrepancy, if any, between measured and modelled hourly indoor temperature (T) data (from September to December 2013). Second, the calibration of the model was carried out by taking into account the most effective parameters. The dual approach, given by both experimental and simulation data, can support the preventive measures of risk analysis for artworks in the case of retrofit solutions of a building used for conservation purposes.

x Climate control (heating, cooling, and ventilation) is an important aspect of animal production, since the zootechnical performance and the health of reared animals are strongly related to their comfort conditions. Currently, there are neither specific protocols nor commercial tools to estimate the energy use for climate control in a livestock housing. In this work (in the context of a funded project called EPAnHaus) three different energy simulation methods (QS: quasi-steady-state method, SH: simple hourly dynamic method, DD: detailed dynamic method), in compliance with the ISO 13790 standard, are applied to a broiler house. The aim of the work is to verify which method is more suitable to be applied for the estimation of heating and cooling energy needs of the animal house. A study was carried out to make consistent boundary conditions between the analysed models. In the comparison of the results, the variability of the boundary conditions is not represented in QS model, resulting in considerable overestimations of the heating energy needs in the colder months (January, February, and December), it does not consider the simultaneity of heating and cooling needs during some months (February and March). Dynamic models (SH and DD models) correctly describe the thermal behavior of the analyzed building, in particular the trend of heating and cooling loads during the production cycles, and the temperature trend during empty periods. It should be noted that the energy need for cooling is only theoretical since usually free cooling is provided by increased ventilation instead of mechanical cooling. Further analysis and comparison with measured data may therefore be carried out once the performance and the energy use of ventilation fans in the house are modelled.

x The total energy demand of buildings consisting of heating, cooling, and artificial light demand is strongly depends on solar gains resp. daylight passing the façade. To prevent glare issues and overheating in summer, shading systems are widely used especially in office buildings. The majority of such systems involve venetian blinds. To provide a satisfying operation of the blind systems, the decision whether the façade should be opened or closed has to be based on live measurements of the external situation in terms of solar radiation, illuminance, and ambient temperature. The most commonly used control strategies operate rudimentarily, and often choose only between the two façade states, retracted blinds and deployed at a certain angle, mostly around 45°, based on simple criteria depending on single values of external sensors. This paper introduces a novel control strategy, which simulates the necessary artificial light and heating or cooling demand for each possible blind position in real time depending on external boundary conditions. This allows the determination of the best blind angle in terms of minimal total energy demand. The results show that these elaborate strategies can have a remarkable influence on the total energy demand of buildings. The evaluated test scene shows 30 % savings in terms of total primary energy demand could be achieved compared to conventional sun protection control strategies. In addition, daylight exposure of the occupants’ faces can be improved and this represents an important factor for the melanopic effect. Two new strategies are applied to three different façade setups for a single office scenario and compared to a hypothetical reference system, which represents the state of the art.

x As in the past, urban morphology plays an important role for the livability of the city and for both outdoor and indoor human comfort. Nowadays, the relationship between the urban form and energy consumption has been estimated by many researchers, showing how the morphological aspects influence the energy consumption of the buildings, the thermal comfort of the urban spaces and the district air quality. Conversely, in recent urban planning processes, these morphological aspects are undervalued or not considered, any more. To reinforce their importance, this paper presents an optimization of a previous statistical model made by the complementary use of bottom-up and top-down models to evaluate the energy-use of residential buildings. The average intensity of energy-use data for residential buildings with a different age, shape, and heated volume has been corrected using the urban energy-modelling tool CitySim Pro. This hybrid approach describes how the urban form, the solar exposure of the buildings, the outdoor spaces and the material characteristics of the urban surfaces impact the energy performance of the buildings. This research analyzed a case study in the city of Turin (Italy) to quantify the space heating energy-use of residential buildings. To estimate the buildings heating energy-use, the urban energy simulation tool CitySim Pro was used, and the building information model of Turin was validated with the real consumptions data based on two years of monitoring data. The results of this research show a direct correlation between the buildings energy-use and the following five urban variables: Building Coverage Ratio, Aspect ratio, Main Orientation of the Streets, Solar factor, and albedo coefficients of outdoor surfaces. The building density and the urban canyon phenomenon play an important role, as they reduce the heating energy-demand in medium density urban contexts. Furthermore, the solar exposure strongly influences energy demands, especially for high buildings density contexts, as well as the presence of green surfaces. The proposed methodology, based on a multi-variate compensative approach, can support urban planning to improve the energy sustainability of the cities.

x A new generation building energy performance simulation program, OpenBPS™, is currently under development. It overcomes some of the drawbacks typical of many of the popular building energy simulation programs around the world. This Building Performance Simulation Tool is primarily a set of libraries dedicated to building energy analysis and performance simulation, which can be included in any user-oriented interface or commercial software that aims to perform such analysis. The basic goal of the project is to provide a robust, validated, and high-performing calculation engine that can be shared, and grow with the contribution of a community of developers and users. To maximize its possible deployment and to facilitate its development and extension by a growing community, it has been built as an open source cross-platform (Windows, Mac, and Linux) software library. For this reason, OpenBPS™ will be distributed under a Copyleft Software License (EUPL) and is coded with a cross-platform object oriented programming language, C#, which is an open source language for .NET Framework based on ECMA standards. The main features of this tool are the object-oriented modelling of physical phenomena and building and HVAC system components, the native code parallelization to take advantage of multi-thread/multi-core processors today available, the multi-scale calculation time step (each object can work using its own time step, scaling down or up with respect to the chosen simulation time step), etc. Not only the technical systems are described and simulated modularly, being their components objects, but also the building fabric is natively modular. Any building envelope component is an object that interacts with other objects, which represent the world around it (air node included). This allows the use of different modelling approaches for different wall components during the same simulation (linear, non-linear, with phase-change, ventilated, etc.). The input and output data structures are tailored to facilitate third party integration with high efficiency, using today’s technologies. Other planned capabilities include multi-zone airflow simulation and dynamic models for HVAC system components.

x In indoor thermal environment modelling applications where dynamic local effects of fluid flows are critical, classic zonal models are not always suitable. On the other hand, CFD simulations can give accurate solutions at very high computational cost. Reduced-order models (ROMs), extracted from CFD simulations, can preserve CFD model accuracy while being characteristically of low computational cost. The authors propose a method, known as CFD-ROM, capable of rapidly and automatically generating, from CFD simulations, zones, mass, and heat flows, and boundary conditions (BCs) for ROMs. This paper presents a comparative study of automatic zone generation algorithms as a necessary initial step to developing the CFD-ROM method. Zone generation algorithms compared in this paper are: (1) Mean Values Segmentation; (2) Classic Watershed; and (3) Coarse Grid Interpolation. The methods were compared on the bases of their accuracy against the original validated CFD simulation results, and their time to zone generation. The Mean Values Segmentation method yields promising results, providing a mean error below 0.2 K for 15-zone models generated in under 28 seconds. The next immediate steps for the development of CFD-ROM are (i) construction of a ROM solver, and (ii) testing its ability to predict thermal conditions when CFD BCs and ROM BCs differ.

x Direct normal radiation (DNI) has great importance for both energy building simulations and solar energy systems. The data is seldom available from measurements but usually is recovered from global radiation data using split algorithms. The present paper analyses the performance of 33 different split radiation models and the error which arises when applied to building energy simulations using generated hourly weather files. The split models have been applied to an observed dataset composed by 525888 points, which comprises global and diffuse radiation on the horizontal plane, related to -year measurements, starting from 2001 with 10-minute time steps. The generated weather files have been employed as input for energy simulations with EnergyPlus on a building generated using DesignBuilder software. We investigated the impact of the weather files in building energy simulation highlighting the performances of four models selected among the 33 models by means of statistical indicators, during different periods of the dataset, since its amplitude allowed us to decompose and analyse 10 different years.

x The paper introduces a newly designed dynamic building energy simulation screening tool to help integrate the use of advanced simulation techniques to early stage building design and feasibility studies. The tool will help the design process to move toward an integrated design approach, including energy analyses and expertise from the first stages of design when time constraints and information requirements are still a hindrance for the use of other existing simulation tools. The paper focuses on the inte-gration of the user input and output interfaces and automatic model generation algorithms while referring to previously existing papers in term of model definition, case studies and validation. The tool is able to simulate building energy performances starting from a limited number of inputs received through a specifically designed user interface supported by databases and suggested values. Based on those inputs, a simplified building model is generated and simulated in EnergyPlus and results are post processed and visualized on the user interface. The tool is fully web based and can be used through any web-enabled device as only the input and output interfaces are man-aged by the user device, with all other components being allocated to the server. The tool is able to run building performance simulations based on a simplified building model description with a limited number of inputs and in a short span of time, ranging from minutes to less than an hour. Nonetheless, the simulations are still returning results with an acceptable margin of accuracy compared to a detailed simulation, considered to generate useful information during early stage design and still higher compared to the use of traditional stationary models. The proposed tool will help the design process evolve toward an integrated approach and adapt to the foreseeable changes in regulations and market demand of low- and zero-carbon buildings.

x Air-source heat pumps can be coupled with photovoltaic panels, a water storage tank and low temperature hydronic terminals (radiant floor) with the purpose of using renewable sources for domestic heating. Some kind of storage solution is required since the availability of solar energy is most of the time out of sync with the heating needs. In principle the energy storage could take place in water filled storage tanks, acid-lead batteries, and in the building envelope. The thermal capacity of the storage tank depends on the tank size and it could affect the performance of the system. Hence, the system management strategy should consider such inertia in order to correctly control the system, also by taking into account the current availability of solar energy. This work investigates whether the correct sizing of the water storage tank and its correct management can increase the energy self-consumption and, consequently, the renewable share of the primary energy used. The work analyses the behaviour of such a system configuration during the heating season in different climate conditions. Four European climates and two types of building envelopes, with different thermal capacities (timber and concrete), were considered. Results show that a control logic oriented to self-consumption can significantly reduce the energy taken from the power grid, with respect to the more typical control systems that reset the supply temperature based on the outdoor temperature. However, increasing the tank size in the range of the typical installations has only a slight effect on the percentage of self-consumed energy. In the case of the control strategy that includes outdoor temperature reset, it was found that this percentage does not change, regardless of the tank size.

x In the period from the ‘40s to the late ‘70s, Italy implemented an extensive public social housing plan (INA-CASA and GESCAL) that is widely representative of the national residential building stock. Obviously, its energy performance is extremely poor and its refurbishment plays a key role in the national targets of GHG emissions reduction. For these reasons, through historical research and survey of 145 social housing buildings, a building typology matrix with six-reference buildings has been developed following the IEE TABULA project method. Some typical refurbishment measures have been analysed, in term of global costs and total primary energy demand, considering different economics and climate change scenarios. The research has been carried out for Tuscany, central Italy, using both weather data sets for inland (Florence) and seaside (San Vincenzo). The input assumptions consider a constant thermal comfort level, in order to identify the measures that can provide comfort conditions to the occupants with the lowest value of energy demand. The results of this study, taking into account the impact of global warming on the Mediterranean climate, the high thermal inertia of typical buildings, and different user’s behaviours, show that the combination of measures with advanced and standard performance level can be considered optimal in terms of global costs reduction.

x Lumped-capacitance models for the simulation of the dynamic thermal behaviour of buildings have recently received growing attention due to their low computational cost and ease of implementation in city district simulation models. This work looks at two simplified dynamic models to evaluate the energy performance of buildings in both heating and cooling. In particular, the xRyC models proposed by the International Standard ISO 13790 and the German Guideline VDI 6007 are analysed in detail and compared with TRNSYS, in both long- and short-term, under the same boundary conditions. The analysis has been carried out considering an apartment with different types of building structures (high-low thermal capacitance, high-low thermal insulation). Four European climates (Helsinki, Venice, Vienna and Palermo) have been taken into account. The comparison has been done in terms of energy need, peak load, and hourly heating/cooling load profile during both seasons. The simulation results show that the simplified 7R2C model of the VDI 6007 is in good agreement with TRNSYS, in terms of both energy needs and transient behaviour. The improvement over the 5R1C model of the Standard EN 13790 increases when the cooling season is considered.

x A meteorological tower was installed on the EPFL campus in a semi-urban environment for the high frequency monitoring of the microclimate. This project was done in the larger framework of the measurement of the meteorological profiles, and also for a quantification of the energy consumption and the outdoor human comfort. A long-term monitoring of various meteorological variables like wind speed, air temperature, turbulence, humidity is realized by the use of 3D sonic anemometers, surface temperature sensor, and a meteorological station so as to analyse the micro-climate in an urban context. The preliminary results from the experimental setup confirm that the wind speed is considerably modified in the urban canopy. We show that the decrease in the wind speed will have a significant effect on the heat convection coefficient. Furthermore, we demonstrate that it is possible to reconstruct the air temperature along the vertical axis with a correction using the data from the meteorological station. In the near future, a net radiometer will be installed to analyse the influence of the incoming and out-going radiation in the urban setup on the energy balance of the district.

x Blinds are usually installed on building façades to improve the visual and thermal comfort of the occupants. They are now often linked to an automated system that helps control the glare and decrease overheating. These automated systems are linked to a weather station that is located on top of the buildings in which they are installed. In the current study, we show that the use of such stations does not provide accurate and reliable information to the control algorithm. It is proposed to couple a model that can calculate wind speed and direction in an urban canopy to the control algorithm. The model is compared to data from an experimental setup on the EPFL campus, Switzerland. We demonstrate that there is very good agreement between the models and the data that have been collected. Furthermore, a new control algorithm is proposed in order to improve the response of the system during strong gusts and to prevent an erratic behaviour of the automated system.

x This paper shows comparative results between simulated and measured values on a complex façade system. The simulation was carried out with the newly implemented model in TRNSYS for complex glazing systems based on the ISO 15099 standard and using BSDF data. Long-term measurements were done on a test façade under real weather conditions. Investigations were made on a major diffuse-reflecting and a highly specular blind system to examine the model capabilities. We compared modelled and simulated layers and air gap temperatures. The overall model results show a satisfying correlation. Nevertheless, model simplifications are reflected in the results and discussed in the conclusion of the paper.

x With the Italian Interministerial Decree of 25 June 2015, the evaluation of the cooling energy requirements for residential and non-residential buildings has become mandatory. In Italy the UNI TS 11300-1 is the reference standard for the calculation of cooling energy requirements, by integrating the quasi-steady models of the international standard EN ISO 13790. The Italian standard takes into account some corrections in order to obtain even more precise results, but the deviances are still evident for non-residential buildings equipped with large glazed surfaces. Therefore, these models have to be calibrated further for Mediterranean climatic characteristics because the results are still discordant with those obtained by dynamic simulation codes. With reference to Mediterranean climatic conditions, a new correlation to use in the quasi-steady calculation procedure, derived from summer gain utilization factors, is proposed. The latter were calculated by means of TRNSYS simulations, varying the percentages and the typologies of the windowed surface and the time constant class of a reference non-residential building. The main factors causing the divergences in the results were identified and a proper calibration of the quasi-steady procedure contextualized to the summer Italian climatic conditions is proposed, in order to obtain cooling requirements closer to those provided by TRNSYS.

x Radiant heating generally addresses all heat emission systems that have a share of radiant heat emission greater than 50 %, compared to a convector or fan coil where the heat is transferred mainly by means of convection. Recently, so-called infrared-heating systems are increasingly discussed as a cost-effective heating system. Relative small areas with high surface temperatures of typically up to 120 °C are used. In order to investigate in detail radiant heating systems, building models able to reproduce accurately the occurring physics phenomena are required. Physics-detailed steady state and transient room models have been developed in Matlab®. The required view factors for the radiative exchange between all surfaces and between each surface and a sphere representing a person are calculated using COMSOL®. Moreover, the thermal comfort in different positions of the room has been evaluated.

x Living in multi-family buildings is very common in Italy. Towards the implementation of economic sustainability principles, it is important to consider the effect of the design strategies in the energy demand of these buildings and their related operational costs. This is particularly important for low-income tenants, and is pursued by many social housing developments by which a good energy performance design is reached. In this work, a simulation-based optimization methodology that combines the use of TRNSYS® with GenOpt® is applied in order to minimize two different objective functions, one related to the primary energy demand and the other related to the operational energy cost, and to verify the extent to which an energy-optimized design differs from a cost-optimized design in the northern Italian climate. The study is performed on a 7-flat typical floor of a real multi-family building for social housing. The design of the building envelope is optimized, leading to reduce the primary energy demand for heating and cooling of the floor by 36 % and the energy costs by 35 %. Higher equality between the energy performances of the flats is also reached. Both objectives lead to very close values of primary energy and costs, but the resulting optimal building design is different according to optimization objective. The comparison between the energy-optimized and the cost-optimized scenarios leads to the conclusion that, in order to reduce the risk of energy poverty, the design solution that minimizes the energy cost can be preferred, as it can minimize the energy bill of low-income tenants while being close to the environmental optimum.

x Energy Performance Contracts (EPC) are contractual agreements between beneficiaries and energy service providers, where budgets are established in relation to a determined level of energy performance. Hence, the problem of forecasting the energy performance of buildings in the EPC tendering phase becomes relevant for the reliability of the overall contract. Unfortunately, fuzziness and incompleteness often characterize the technical information supporting EPC call for tenders. Furthermore, buildings that are the subjects of EPCs are normally quite complex public buildings (hospitals, schools, etc.) usually relatively old and not technically well known. Gathering information about such buildings is a time consuming and expensive process within the usually short time frame of EPC call for tenders. This paper investigates the application of Grey-Box modelling to the energy performance forecast of complex buildings, in perfectly and poorly informed operational cases. The proposed methodology offers a potential solution to the EPC operational requirements since it requires a substantially reduced parameter set. Results show that the proposed Grey-Box modelling can be used to arrange a calibration set-up with good forecasting performance. Furthermore, Grey-Box modelling allows an effective management of the information uncertainty usually present in the EPC context.

x In a district cooling system different kinds of cooling production can be combined (e.g., vapour compression chillers, absorption chillers, and free cooling). Controlling those systems in an efficient way is a complex problem: the cooling demand is much more difficult to predict than the heat demand and, as for absorption chillers, heat sources such as the solar energy and the waste heat are not predetermined by the designers. The EU project INDIGO deals with the improvement of District Cooling (DC) systems. Its main goal is the development of a more efficient, intelligent, and cheaper generation of DC systems. The results of INDIGO will include the development of: predictive controllers; system management algorithms; an open-source planning tool. To validate the results, the consortium is analysing some case studies. The proposed solutions for DC systems will be installed in the Basurto Hospital campus in Bilbao. Different parts of models that regard the buildings and all the relevant components of the DC system are being developed: 1) generation systems; 2) distribution and storage systems; 3) HVAC systems; 4) thermal behaviour of the buildings, considering also internal loads and building use. The first three parts are being simulated by means of Modelica, an open-source object-oriented modeling language that provides dynamic simulation models for building energy and control systems. The fourth part is being modelled with EnergyPlus. They are going to be integrated through the Functional Mock-up Interface (FMI) for co-simulation.

x The present paper presents a tool for the assessment of the visual performance of spaces, especially with regard to the requirements of visually impaired people. This tool was one of the key deliverables of a recently completed project (ViDeA) addressing the special architecturally relevant needs of the visually impaired building users. Implementation of building regulations related to visual accessibility in a reliable manner (during design process) requires expert knowledge and the use of sophisticated visual simulation software. Toward this end, the tool attempts to facilitate the accurate evaluation of visual conditions in the proposed designs. The paper describes the general structure and implementation details. It also documents the preliminary verification of the tool based on a case study of an underground metro station.

x This contribution is concerned with a number of basic questions regarding inhabitants' presence in buildings: How diverse are office inhabitants' presence patterns? Aside from the differences in the absolute values of the defining markers of such patterns (e.g. arrival and departure times), to which extent do the respective distributions of the marker values differ from inhabitant to inhabitant? Are tendencies regarding presence patterns in one location transferrable to other locations? Can the diversity of presence patterns among the inhabitants be reproduced via the randomisation of the markers' mean values? To explore these questions, we use monitored presence data from two offices in two different locations. The findings point to considerable differences amongst inhabitants and locations. Moreover, an empirically observable diversity of the office workers' presence patterns cannot be simply reproduced based on the randomisation of generic presence patterns.

x This paper explores the relationship between inhabitants’ presence, the installed power for office equipment, and the resulting electrical energy use. This exploration is based on long-term observational data obtained from a continuously monitored office area in Vienna, Austria. The findings facilitate the formulation of both simplified and probabilistic models to estimate annual and peak office plug loads. Aside from a general comparison of the performance of simple and stochastic models, the present contribution focuses on the question if and to which extent consideration of the diversity of the inhabitants influences the reliability of plug load predictions.

x Ground coupled heat pumps are increasingly used for HVAC systems. The difficulty in sizing and predicting their behaviour and performance is well known. A suitable simulation is often advisable to help in the design choices. The code EnergyPlus is widely used in the field of building simulation and, since it includes a routine dealing with borehole heat exchangers, based on the well-known concept of g-functions, it can be profitably used for the considered purpose. On the other hand a numerical tool, namely CaRM, based on a detailed finite difference model of both the ground and borehole heat exchangers has been developed. A comparison between the use and the results of the EnergyPlus g-functions approach and CaRM in ground subsystem modelling was carried out with particular reference to an office building with quite a critical unbalance between heat extracted from and heat injected into the ground.

x Recent developments in building planning and delivery processes point to an increased deployment of BIM (Building Information Modelling) and corresponding tools in the AEC (Architecture-Engineering-Construction) domain. BIM is understood as the digital representation of the physical and functional characteristics of a facility that can offer a reliable informational basis for decision-making throughout a building’s life cycle in different domains. Given this context, the present contribution addresses data transfer from commonly used BIM-software environments and a specialized simulation tool for thermal bridge analysis in view of heat flow, surface temperatures, condensation, and mould growth risk. Interestingly, much of the input data required for such in-depth assessments is already available in basic design models. However, there is a paucity of related fully functional data transfer solutions. This paper documents and evaluates data transfer issues based on sample building details. The objective is thereby to support software developers toward a better integration of state-of-the-art assessment methods in building design.

x The consideration of thermal bridges in building envelopes has gained importance in recent years. This is due to their potential impact on the overall thermal building performance of highly insulated buildings. Moreover, energy-efficient buildings tend to be more sensitive to problems associated with thermal bridges, such as surface condensation, mould growth, and thermal comfort issues. Therefore, planners must minimize the negative impact of thermal bridges. Although user-friendly thermal bridge simulation tools are available, they are not yet widely used in practice. Instead, planners often rely on generic details from the building construction literature. The thermal performance of such details often remains unknown given the wide range of possible building materials (and their thermal properties). In this contribution, we present the results of a thermal bridge simulation of a set of such standard details. Thereby, we assessed vertical sections through typical constructions via 2D thermal bridge simulation, as well as 3D corner situations constituted by such 2D sections. The aim was to address two research questions: i. How do typical details perform, given the large range of thermal properties of applied materials? ii. How does the performance of the 3D-thermal bridges compare to their constituent 2D-details, and is it possible to use 2D results to approximate the results of 3D thermal bridges?

x Classrooms acoustics can affect students´ speech intelligibility and learning performance depending on its background noise level and/or reverberation. Speech intelligibility is usually assessed in real classrooms through a subjective approach, by performing speech intelligibility tests, or through an objective approach, by evaluating speech transmission index (STI) from impulse response, speech and noise level measurements. An acoustic simulation technique makes it possible to assess acoustical conditions for speech reception in virtual environments, thus allowing for predicting intelligibility before a classroom is built or renovated. However, in order to obtain reliable results, the simulation model needs to be calibrated and validated with in-situ measurements. The aim of this work is to compare tests performed in-situ on a group of people, with tests performed on the same people by reproducing the auralized test signal through headphones, in terms of intelligibility scores (IS), response times (RT), listening efficiency values (DE) and related STI values. Simulations have been carried out using the room acoustic software Odeon version 14.01. The investigation focused on a university classroom, which is part of the Classroom Spaces Living Lab of the Free University of Bozen-Bolzano, currently equipped with devices for monitoring energy and indoor comfort conditions, as well as detailed external weather conditions. By exploiting the bilingual context in South Tyrol, Diagnostic Rhyme Tests (DRT) in the Italian language were administered to both Italian and German native speaker students, the latter with an Italian level at least equal to B2, according to the common European framework of reference for languages. In this way, speech reception performance of the two groups has been investigated and compared.

x In this contribution, we describe ongoing research efforts to assess the performance of a number of buildings by the Austrian architect Konrad Frey, a pioneer of energy-efficient architecture. A number of his buildings, planned in the 1970s, adapted the principles of modern solar houses. These key projects are the subject of an ongoing nationally funded research project. Thereby, we deploy building simulation to assess the energy performance of one of his buildings (Kindergarten Pachern, located in Hart, close to Graz, Styria, completed in 1997). Moreover, the object was subjected to detailed performance monitoring. The building implements two design strategies: On the one hand, its envelope design is optimized for solar gains, on the other, the building is embedded in the local landscape’s morphology, utilizing the benefits of reduced transmission losses via ground-adjacent building components. The building contains standard facilities for kindergarten usage (three group rooms, a gym, a kitchen, and sanitary facilities). The intensive monitoring phase started in summer 2016. The monitored data is expected to support the documentation of the building's actual performance. Moreover, a simulation model of the current state of the building will be calibrated via the collected data. Based on this calibrated model, previous states of the building (subtracting later adaptions) can be simulated. We thus can virtually reconstruct the building's originally intended state and assess its performance.

x Energy efficiency and Greenhouse Gases emission reduction are actual key issues in all the economic sectors and, in particular, in the building sector that is one of the most energy-consuming. This paper reports on the performance of sustainable materials produced from natural resources as hemp-concrete or from recycled-waste non-biodegradable materials including Recycled PolyEthylene Terephthalate (R-PET). Three façades employing three different materials (hemp-concrete, hemp-concrete with brick and R-PET) were investigated in three cities in France (Nancy and Carpentras) and in Italy (Perugia) with different climates. The energy performance of each façade was assessed in terms of cooling and heating demands, electrical consumptions and indoor thermal comfort including in-door temperature and relative humidity. The effects of two ventilation modes were tested using a constant airflow rate or humidity sensitive flow rate.

x The energy efficiency of existing buildings is one of the challenges launched by the EPBD recast. The RWTH Aachen University accepted this challenge and started the project EnEff: Campus - Roadmap aiming at reducing the specific primary energy consumption of the university campus building stock (about 300 buildings) by 50 % until 2025. For the estimation of refurbishments for this kind of big data, data mining techniques can be used like the CART method (Classification and Regression Tree). In this investigation, the method applied on the RWTH Aachen buildings stock and the estimated results will be compared to results from a simple data mining technique, called visual method. The comparison is performed by using low-order dynamic building model (LOM) performance simulation through the Modelica AixLib. The determined results of the recommendation of the CART method will be discussed and evaluated in this paper.

x Urban populations continue to increase in parallel with global temperatures. The result is an increasing number of people affected by increasingly severe urban heat conditions. Understanding these effects and being able to accurately account for the effects of the urban climate on building energy use is important for urban and architectural design decision making. This paper presents part of an on-going research effort to evaluate the Weather Research and Forecasting (WRF) model as a tool for improving prediction of boundary conditions in urban climates. WRF is a regional climate model that is capable of down-scaling global weather data to a fine resolution and includes detailed urban canopy models. The use of a numerical model in urban climate studies would allow for computational experiments involving changes to the urban fabric and future climate scenarios. In this study, Vienna, Austria, was used as a test case. The weather was simulated over five 48-hour periods, which were selected using cluster analysis to best represent typical weather conditions in Vienna. The model results were then compared to data collected from a network of 170 weather stations throughout the region of interest. Additionally, the land-use classification and urban parameterization in the model domain were improved using high-resolution GIS data from the city of Vienna. Results show a great deal of variation in the accuracy of the model under different weather conditions. Although individual problems can be identified during specific intervals, there is no obvious trend or bias to the variation across all time periods. The extent of the variation indicates the model results are not suitable for use as boundary conditions for building performance models throughout an entire year.

x Complex fenestration systems influence indoor comfort conditions and energy consumption in a complex way. If all the involved aspects are not considered jointly since the design phase, buildings can show a deep gap between their planned and real performance, especially when dealing with low energy buildings (Vanhoutteghem et al., 2015). This can be avoided by identifying the design configurations able to provide a trade-off between contrasting requisites: improving comfort conditions while minimizing energy use. This work analyzes and compares different design solutions for an open space office from a global performance perspective. Dependence on the building characteristics and operation strategy has been assessed by comparing two different windows sizes, three glazing systems, and three different approaches to control the shading devices, for a South oriented façade in the climate of Rome. The study has been conducted combining a RADIANCE/DAYSIM lighting simulation with EnergyPlus for the thermal comfort and energy analysis. A set of metrics, able to express both the time constancy and the spatial uniformity of visual and thermal comfort conditions, has been evaluated together with the energy demand for heating, cooling, and lighting. The results show how a global approach allows obtaining a more comprehensive building performance evaluation and, consequently, identifying design solutions capable of enhancing both energy efficiency and occupant comfort.

x The recent progress in numerical weather prediction modelling, and in particular the possibility to reach increasingly finer spatial resolutions, allowed researchers to re-produce building-atmosphere interactions in a more accurate and realistic way, especially in urban areas. The present work aims at evaluating the impact of high-resolution gridded datasets of urban morphology parameters on the results of numerical simulations of atmospheric processes performed with the WRF/Urban suite in the city of Bolzano (Italy), and to analyze how they affect near-ground temperature fields. A sensitivity test was carried out, combining the WRF model with the Building Effect Parameterization (BEP) scheme to simulate two typical clear-sky summer days, respectively with and without the input gridded data of urban morphology. The structure and the morphology of the city of Bolzano were carefully reproduced through several fine-scale morphometric parameters from surface and terrain models (0.5 m resolution). The results highlight that urban morphological parameters display a high spatial variability, moderately affecting the distribution of the temperature field near the ground. High-resolution meteorological fields inside urban areas can be valuable information for building energy simulations. Accordingly, a scheme of model chain coupling WRF and TRNSYS codes is proposed, in order to enhance the future assessment of urbanization effects and in the same way to provide more realistic and accurate building energy simulations.

x Thermal bridges play a significant role in the heat loss of nearly Zero Energy Buildings (nZEB). In the case of existing buildings, the underestimation of thermal bridges can lead to errors of about 20 % in the assessment of their energy requirements. Nowadays, proper simulation tools for evaluating the building energy performance in dynamic conditions are increasingly needed. Their outputs are important inputs for life cycle costs (LCC) and life cycle assessment (LCA) as well as for energy audits. A weak point is that the tools which are currently well established on the market, do not consider the contribution given by thermal bridges to the overall building energy balance as they rely on a one-dimensional approach to recreate heat flows. Several scientific studies deal with different methods that can be applied to evaluate the dynamic behaviour of thermal bridges, but they disregard the wall capacity to accumulate/release heat loads and the role played by internal temperatures. This work analyses some numerical methods proposed by different authors based on the discretization of thermal bridges and their characterization in dynamic regime. A calculation procedure is evaluated to underline its potential as a rapid dynamic calculation algorithm to be integrated in the current software for dynamic analyses. The surface temperatures and the heat fluxes are taken into account. In the present work, the method of the equivalent thermal wall has been implemented to get the input parameters required to dynamically assess the thermal bridges energy contribution. Afterwards a finite volume analysis is developed to compare the outputs coming from different methods in terms of crossing fluxes, surface temperatures and thermal storage capacities.

x In this paper, the energy performance of a façade open loop Building Integrated Photovoltaic/Thermal (BIPV/T) system with air as working thermal fluid is investigated. For this aim a new dynamic simulation model based on a detailed transient finite difference thermal network is developed. For a complete building energy performance analysis, such model was implemented in a suitable computer tool written in MatLab (called DETECt 2.3, suitably modified). The presented simulation model includes a parametric analysis tool useful to minimize the building energy demand. In order to show the potential of the developed code, a comprehensive case study related to a multi-floor office building located in several climate zones is developed. In particular, with the aim to identify the design and operating parameters minimizing the overall energy consumptions, while guaranteeing the comfort of occupants, a suitable optimization procedure is carried out. Results show that through the produced electricity and thermal energy it is possible to balance the overall building energy demand approaching the NZEB goal.

x In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase the thermal inertia of building envelopes and to assess the effects/ weight of several design parameters (e.g. PCMs melting temperature, etc.) on the building heating and cooling energy demand and on the related thermal comfort. In order to show the potentiality of the presented simulation model, suitable case studies referred to residential and office buildings, to three different weather conditions and to two alternative PCM layouts in the building envelope, are developed.

x The energy audit on the existing buildings has become a priority in the last years, as a consequence of the adoption of the European Directives on building energy efficiency. In particular in Italy, public buildings are often the most inefficient among the stock and, thus, those with the high-est potential for improvements. Many methods can be applied to perform an energy diagnosis; one of them is “Energy Signature” simplified method, ES, described in the Annex B of the technical standard EN 15603:2008. The ES can actually be seen as a very simplified model of the building, based on a linear regression between energy consumption and degree-days in a set of reference periods. If applied year after year, the ES allows a fast detection of system faults, changes of use patterns, and to assess the efficacy of different energy management strategies or retrofitting interventions, discounting the effect of weather variations. When the stock of buildings is large, individual energy audits can be too onerous and time consuming and building simulation impracticable. For this reason, ES can be combined with clustering techniques in order to identify groups of buildings with similar behaviour among which a reference case can be identified and deeply investigated either experimentally or through detailed building energy simulation (BES). In this respect, ES and clustering can be seen as the key element to allow the extension of BES also to the analysis of building stocks. In this work, ES and different clustering techniques have been used to analyse a set of 41 schools in the province of Treviso, north of Italy, pointing out the buildings features that most affect their energy signatures through multiple linear regressions. A comparison between two non-hierarchical clustering algorithms, K-means and K-medoids, has been conducted. Particular attention has been paid to the approaches for the evaluation of closeness of schools in the same group and the identification of the reference school for each set. As the final outcome of this research, the impact of the clustering algorithms is discussed, in order to assess to which extent the selection of the schools with the most representative energy signatures can be affected by the choice of the data mining techniques.

x The new European Directive 2014/24/EU requires the use of BIM procedures in the construction of public buildings for all member States. The countries belonging to the European Union shall be obliged to transpose the Directive and adapt their procedures to that effect. The paper analyzes the IFC format, the only one recognized by the Euro-pean Directive Standards for BIM procedures, to assess its use for simulations of buildings. IFC, described by the ISO 16739:2013 standard (ISO, 2013), is a standard that describes the topology of the constructive elements of the building and what belongs to it, overall. The format includes geometrical information on the rooms and on all building components, including details of the type of performance (transmittance, fire resistance, sound insulation), in other words it is an independent object file for the software producers to which, according to the European Directive, it will be compulsory to refer in the near future, during the different stages of the life of a building from the design phase, to management, and the possible demolition at the end of its life. The present study aims at carrying out a first analysis on the IFC data format, which will be further studied in-depth in the following phases. The study will compare the information and data contained in it, with those in other formats already used for energy simulations of buildings such as the gbXML (Green Building XML), highlighting the required information missing, and proposing the inclusion of new data for energetic and acoustic simulation. More generally the attention is focused on the building physics simulation software which is implemented to exploit the BIM model potential enabling interoperability.

x Sensible (SHR) and total heat recovery (THR) can play a significant role in energy savings in mechanical ventilation usage. Apart from the technical characteristics of the heat exchangers, the savings on the ventilation load depend on the air conditions for the two airstreams, namely the conditions maintained for the indoor air and the actual outside conditions, and on the proper control strategies deployed to minimize the impact on the air processes required after the heat recovery device. In this respect, humidity control can conflict with heat recovery whenever excessive humidity requires dehumidification of the ventilation air. In particular, SHR in heating mode should be preferably by-passed if the outside humidity exceeds the supply conditions required to compensate internal latent loads. For THR, moreover, the control strategy has also to account for the device’s latent effectiveness, which may require an even earlier limitation of heat recovery or a by-pass if the system effectiveness cannot be controlled. Depending on the specific climate, the actual heat recovery can be much lower than the expected one and needs to be evaluated in order to avoid overestimating its energy and economic performance. The humidity supply limit required in the analysis of the actual recovery can be defined considering the target indoor humidity ratio (corresponding to the relative humidity setpoints of 50 %) reduced by the amount needed to compensate any indoor humidity source. This reduction can be expressed in terms of a specific latent load, SLL, calculated as the ratio between the mass rate of water vapor produced indoor, and the mass rate of the ventilation air, no matter whether some recirculation exists or not. Since both vapor production and ventilation air mass rate depend on sources and occupants’ density inside the conditioned space (0.8, 1.2, 1.6, 2.0 or 2.4 gv/kgda), SLL is largely independent of the remaining building characteristics. In this research, we studied the savings from ventilation heat recovery in different European climatic zones and countries by applying different control strategies to avoid excess humidity. Only the ventilation system had to be modelled through a simplified effectiveness model, considering different SLL as the only relevant building characteristic. Savings were expressed in terms of energy demand per flow rate, averaged over climatic Köppen-Geiger classes.

x Design activity on healthcare buildings cannot be limited to the energy aspects and must account also for the indoor thermal comfort conditions. Indeed, the occupants of this category of buildings are affected by different kinds of unhealthy statuses and particular attention is required in order to ensure conditions adequate to therapies and medical treatments. Even if simulation can be a helpful tool in designing new buildings, also in case of complex clinics and hospitals, a proper calibration is a necessary step for the existing building stock. In this way, discrepancies between simulated and measured building energy performance and thermal behavior can be reduced, improving the reliability of the model itself and allowing its use for many purposes, from the assessment of energy performance to the evaluation of indoor thermal comfort. In this work, experimental and numerical modelling activities have been performed in order to develop a calibrated model of part of a healthcare building in Vienna, Austria, for the assessment of both thermal performances and comfort conditions. The facility was built in the early ‘90s, with later expansions, and is composed of many environments characterized by different therapeutic activities. Many properties of the building envelope and system are unknown and initial values have been assumed from direct inspections and documentation on construction standards. After zoning the healthcare, for each ambient, long-term measurements of the air temperature were recorded every 10 minutes from March to June 2015 and used to calibrate the model. During the same period, occupants were interviewed about their thermal comfort sensations and detailed short-term measurements were collected to calculate Fanger’s Predicted Mean Votes and Percentages of Dissatisfies. The simulated air temperature and internal surface temperature profiles have been used to evaluate the same indexes by comparing them with those calculated from the measured data and people’s votes.

x Although it has been widely acknowledged that occupants play a critical role in building energy consumption, the characteristics of the occupants’ presences and actions are not accurately represented in building simulation tools. In this study, the authors aim to identify the temporal and spatial difference in the characteristics of the occupants’ presences in a library building located in South Korea. The data of each individual entering and leaving rooms in the building were recorded for weeks from 15 to 31 January by Radio-Frequency Identification (RFID) tags. Based on the data, the periodicity and predictability of the occupants’ presences were investigated in terms of (1) spatial variation (individual room vs. entire floor vs. entire building), and (2) temporal variation (5 minutes vs. 30 minutes vs. 1 hour sampling times). The periodicity and predictability of the occupants’ presences were quantified using a Normalized Cumulative Periodogram (NCP). The occupants’ presences in an individual room were less periodic or less predictable than those in the entire building. The predictability of the occupants’ presences was influenced by the sampling time. The greater the sampling time (5 minutes vs. 1 hour), the better predictable the occupants’ presences were. In other words, it is much easier to predict the aggregated number of occu-pants over the entire building with a longer sampling time (e.g. a couple of hours) than to predict the number of people in individual rooms with a shorter sampling time (e.g. 10 minutes). These findings could be further applied to an energy simulation study of the building and its relevance to energy prediction will be studied.

x Recently, an Energy Recovery Ventilator (ERV) in a residential building was seen as an attractive ventilation option in terms of energy saving and indoor air quality. In order to identify a feasible set among many ventilation strategies in this situation, various decision-making approaches (deterministic or stochastic) using Building Performance Simulation (BPS) tools have been suggested. As a simulation-based decision-making approach, a Stochastic Multi-Criteria Decision Making (SMCDM) method based on Cumulative Prospect Theory (CPT) is presented in this paper to find the best ventilation strategy under model uncertainties. For this study, two ventilation strategies, considering air inlet positions and CO2 sensor positions, were chosen and modelled using two simulation tools: CONTAMW 3.1 for the airflow model and EnergyPlus for the thermal model. In addition, Latin Hypercube Sampling (LHS) was used to reflect the model uncertainties. In this study, it is shown that CPT can provide a more realistic and trustworthy framework than the Bayesian decision theory.

x In this paper, a new method is presented to compare different scenarios of insulation by assigning a Life Cycle Energy Efficiency (LCEE) index, which includes operational energy use and embodied energy of materials. For this purpose, a sensitivity analysis has been performed to determine the relation between insulation thickness and total energy consumption, then the new method to assign the LCEE index has been used and the results have been compared. Our methodological approach consists of the following steps: (i) Simulate a 27 m3 cubic simple zone with a double glazed air filled window on south surface in EnergyPlus 8.3 software; (ii) Determine the thermal comfort boundaries for each studied city including Tehran, Bandar Abbas, Tabriz and Kerman; (iii) Vary installation materials and insulation thickness and calculate the total energy demand for heating and cooling in each city that includes 128 insulating scenarios; (iv) Calculate the embodied energy of different insulating alternatives based on LCI databases; (v) Perform a sensitivity analysis for each insulation material in each city to figure out the relationship between thickness of insulation materials and total energy demand in each city; (vi) Use the new method to assign the LCEE index in order to compare different scenarios. The analysis showed that both operational energy and embodied energy have considerable impacts in decision-making processes in order to select the best insulation type and thickness. Moreover, the new method to assign the LCEE index was used as a useful method to assign a concise comparative index in order to compare different decisions by building designers.

x This paper presents the development of the numerical model of a hybrid cooler. It is based on a modular and generic coil geometry that deals with any staggered coil and pipe arrangement. Particular attention is given to model the spray water system and to the calculation of water evaporation on the coil surface. It is validated by monitored data from a pilot system installation in which a commercial hybrid cooler is operated under typical summer south European working conditions. The numerical model has an average error of 7 % for the rejected heat and 0.1 % for the fan power consumption. The model is compatible with TRNSYS simulation software. It can be used for design and product development purposes by HVAC manufactures and thermal engineers.

x Visual comfort is one of the main priorities in designing working and living environments. Several indicators have been developed to quantify the degree of visual discomfort; however, there is a lack of studies in spaces with roller shades on the windows, commonly used in North America. Roller shades transmit direct and diffuse daylight and therefore their effect on visual comfort is complex. A recent study with human subjects proposed two alternative approaches in quantifying visual discomfort for the case of roller shades, based on (i) a modification of the Daylight Glare Probability (DGP) and (ii) an index based on the direct and the total portion of vertical illuminance on the eye of the observer. This paper uses a methodology based on the newly developed indices in an inverse way in order to propose suitable ranges for optical properties of the shade fabrics, in terms of openness factor and visible transmittance. A complex fenestration model that calculates the angular beam–beam and beam–diffuse shading optical properties is implemented within an advanced hybrid ray-tracing and radiosity daylighting model. Then, the concepts of annual discomfort frequency (Chan et al., 2015) and View Clarity Index (Konstantzos et al., 2015b) are used as a basis for the extraction of ranges of shade optical properties with respect to glare mitigation, energy performance and connection to the outdoors, for different sets of input parameters (location, orientation, glazing visible transmittance and distance from the window). The use of these extracted ranges can help architects select the most suitable shading products for their designs, minimizing glare complaints with the minimum cost in terms of lighting energy use and connection to the outdoors.

x Dynamic simulation allows us to foresee the actual behavior of a building as a whole, namely of the envelope, its occupants, and HVAC equipments. This approach requires a huge amount of data of current in-homogeneous variables related to local climate, shelter’s shapes and materials, fenestration and lighting technologies, mechanical and electrical facilities, air quality needs, etc. Consistency and accuracy of input data, together with a comprehensive and integrated knowledge of the performance of all the parts involved, act as the crucial points of the process. The paper, by means of a proprietary simulation SW proposed and used in the past by one of the Authors, shows first results in terms of impact of different degrees of buildings fenestration on needs of energy for either lighting and air conditioning. Conflicting opportunities when comparing locations in Southern (Rome) and in Northern (Berlin) Europe are found. A focus on crucial points is made using a case study as a reference.

x In the US, more than 45 % of the building primary energy is used for space cooling, space heating, and water heating. Advanced HVAC systems are key to building energy consumption reduction. A variable refrigerant flow (VRF) system is a promising solution to this problem, because it can precisely provide space cooling and/or space heating for different zones. A literature review of previous VRF modeling studies shows that the use of existing simulation tools, such as EnergyPlus, can result in more than 20 % deviation in both capacity and energy consumption. In this study, a new VRF model is proposed to improve the accuracy over conventional models. Simulation results show that the proposed model agrees with experimental field test data within a 10 % deviation in hourly capacity and 5 % in hourly energy consumption. After the validation of the VRF system model, a new VRF control strategy was proposed based upon evaporating/condensing temperature controls. The seasonal performance of VRF system with the new control strategy was simulated for the same building design in four different climates representing these US cities: Miami, Houston, Baltimore, and Chicago.

x Building energy benchmarking is a system to evaluate and compare the energy performance of a building over time, relatively to other similar buildings, or to a reference building, which can be used to continuously manage the energy performance of the building. An energy-benchmarking model is a mechanism to develop the benchmarks necessary for the benchmarking process. It should be selected appropriately considering the availability of building energy performance information and building specification data. The purpose of this study is to develop an energy performance-benchmarking model for existing office buildings by analysing energy consumption data from the national building energy consumption database (DB) in Korea. The results of this study can be used as the energy performance evaluation and diagnostic criteria for existing office buildings.

x Thermal comfort is an important aspect to occupants’ well-being and productivity in a workplace. Indeed, as observed by some authors in the literature, a high thermal comfort can improve workers’ productivity and progressively reduce the number of accidents as well as occupational diseases. This paper aims at investigating to what extent the level of thermal comfort in workplace influences productivity, estimated according to Roelofsen model (2001). In particular, the study analyses the economic benefits of investing in additional air-conditioning systems to improve thermal comfort conditions, considering the impact of insulation of the envelope, internal gains and climate.