Building Simulation Applications BSA 2015

x This keynote address offers a number of critical observations with regard to the representation of occupants' presence and behaviour in building performance simulation applications, tools, and processes. The objective is to contribute to a more reflective attitude and to further productive discussions of the subject in the relevant research community.

x The prediction of daylight availability in indoor environments is nowadays an extremely relevant topic in the design practice for many reasons: it affects the design of the electric lighting system and therefore the calculation of the related energy consumption; it also has an impact on evaluation of comfort. Dynamic daylight simulations are a helpful tool to predict daylight availability in indoor environments and consequently to evaluate the possible reduction in energy consumptions. However, there are different software packages that perform dynamic daylight simulations and they use different engines and calculation methods which may be a source of differences in the results. Moreover this type of analysis requires a weather data file of the building's location to be performed. Since there are many of them available, which are developed from historical sets of weather measurements using different methods, the use of one or another can affect the simulations' results. Therefore in this paper an example of the impact on dynamic daylight simulations' results of different weather data files (IWEC, Meteonorm, TRY and Satel-Light) and different software (Daysim and 3ds Max Design®) will be reported.

x Studies on Outdoor Comfort in urban open spaces adopt several tools and software to simulate a microclimate model, energy performance and the fluid-dynamics of winds. The output data, therefore, of these software solutions, e.g. temperature, wind velocity, relative humidity, should be the input data to evaluate the comfort indexes. In the present paper, we describe ENVI-BUG, an ENVI-met algorithmic app developed by Grasshopper, that uses the LadyBug method to rapidly calculate the distribution of local PMV.

x Recently, increased efforts have been invested to enhance the sophistication of occupancy modelling approaches in building performance simulation. However, the effectiveness of such approaches depends on the robustness of the underlying empirical information. Thereby, an important question pertains to the existence and level of inter-individual differences in occupancy patterns. In the present contribution, we use a repository of monitored occupancy data in an office building to address this problem empirically. The results of the study facilitate a discussion of the diversity in observed occupancy profiles and the implications for relevant occupancy models in building performance simulation.

x Computational assessment of buildings' thermal and visual performance as well as the estimation of building-integrated solar-thermal and photovoltaic collectors require detailed boundary condition information regarding sky conditions. Advanced building performance simulation tools for energy and daylight modelling typically rely on high-resolution sky models that provide radiance and luminance values of discrete sky patches. Perez et al. (1993) and CIE (1996) represent instances of such models, incorporated, for instance, in the RADIANCE lighting simulation application. The performance of such models needs to be examined against measured data in various locations. In this paper, we used the RADIANCE application to compute irradiance values on vertical surfaces facing four cardinal for a location in Vienna, Austria. Thereby, both Perez et al. and CIE models were deployed. The simulated vertical irradiance values were compared with corresponding measurement results. The statistical appraisal of the comparison points to limits in the predictive accuracy of both models. The results are discussed to address potential contributing factors and future research needs.

x The ongoing EU-funded project RESSEEPE explores, in addition to the hardware-centric solutions, the potential for the enhancement of energy efficiency in public edification through the optimization of buildings' operational regime. For the purpose of this contribution, we report on the simulation-based studies on three public buildings across Europe within the framework of the RESSEEPE project: A secondary School in Skellefteå, Sweden, a hospital in Terrassa, Spain, and a university building in Coventry, UK. The case studies provide a basis for the formulation of a general modelling and analysis process for the implementation of advanced control scenarios, as well as an evaluation of the extent to which these measures can contribute to enhancing the building performance in different European climates.

x The main focus of this work was the simulation and optimization of a BIPV-façade-system configuration through the development of simulations using the ”TRNSYS” software. First, several limitations and constraints within the TRNSYS framework needed to be solved to develop a reliable simulation environment. Various parameters were detected which influence the temperature distribution over a BiPV-system and thus the PV-efficiency. Several configurations were selected and optimized in order to maximize the energy yield of the system by varying the air gap between the building structure and the external pane of the BiPV-installation. Furthermore, the impact on the building behavior was examined. The achieved results showed the positive contribution of the integration of PV in a façade system to the building energy balance.

x There is extensive pressure on sustainable buildings to deliver energy efficiency, but in practice, designs often fail to achieve the expected level of in-use energy consumption. One of the main factors behind this discrepancy between designed and real total energy use in buildings is the window opening behaviour. Towards nearly zero energy building (NZEB), building performance simulation is being increasingly deployed beyond the building design phase. With the aim to investigate how the climate affects the probabilistic model of window behaviour, the case study is simulated in different locations, i.e. Continental (Turin) and Mediterranean (Athens). Moreover, each simulated model refers to three comfort category heating and cooling set point conditions (Category I, II, III) as defined in Standard EN 15251:2006. Comparing the results, the influence of window behaviour on energy consumption in different climates generates energetically different outcomes. The present study highlights the importance of users’ interaction with window control systems in order to design sustainable and energy-efficient office buildings in a more realistic way.

x This paper explores the reliability of acoustical simulation for the prediction of the sound insulation of double leaf facades with openings for natural ventilation. The subject of the study is an experimental modular double-leaf wall with multiple opening possibilities. Different elements can be opened in both (i.e., internal and external) layers, so that multiple opening configurations can be studied both empirically and computationally. The actual acoustical performance of the wall was captured through parametric laboratory measurements. The respective configurations were then modelled using a state-of-the-art room acoustics simulation program. Thereby, alternative representations of the double leaf facade were considered. In one representation, the facade layers were explicitly modelled in terms of two separate entities with the facade cavity as an interstitial space. In other representations, the sound transmission through the wall and the acoustical coupling between openings on the two layers were modelled as separate processes. The initial acoustical model was calibrated by comparing the measured and the simulated reverberation times in the laboratory's two chambers. Specifically, the calibration involved the adjustment of the absorption properties of surfaces of the laboratory chambers so that an improved match between the measured and simulated reverberation times could be achieved. Computer simulation and laboratory measurement results pertaining to the sound insulation of the experimental wall were compared for multiple opening configurations. The results illustrate the potential as well as the considerable limitations of acoustical performance simulation toward prediction of the sound insulation of double-leaf wall systems. Likely reasons for this circumstance as well as potential improvements are discussed.

x Soil-cement blocks generally comprise graded soil, cement and sand to varying proportions to achieve desired structural performance and durability. In their actual integration as part of a building masonry element (envelope), the thermal performance of these blocks determines the climate-responsiveness of the building. However, little study has been done in discerning the influence of varying mix-proportion on the thermal performance of these blocks. The current study examines the role of physio-chemical properties, determined by the varying mix-proportions, on the thermal performance of soil-cement blocks. The paper discerns the influence of the clay content, cement content and dry density on the thermal conductivity of the soil-cement blocks. For this study, soil-cement blocks casted with locally available materials been adopted. Preliminary results revealed that as the clay content increases from 10.5 to 31.6% the thermal conductivity value increases. Further, with an increase in cement content from 5 to 16% the thermal conductivity values also increases. The thermal conductivity tests conducted using QTM-500 thermal conductivity testing instrument. Further investigation included the influence of soil-cement blocks’ thermal properties on dynamic building thermal performance such as time lag and decrement factor. The results of the study are expected to support design of climate-responsive building envelopes for various climatic conditions.

x As part of a Scientific Planning and Support (SPS) initiative for designing buildings, a team of researchers from the Energy Research Institute @ Nanyang Technological University (ERI@N) in Singapore helped design a high performance building using extensive benchmarking, modelling and simulation studies. The building is designed to perform well beyond Singapore’s highest energy efficiency standard – The Green Mark Platinum rating. Designing high performance buildings in the tropics poses a unique set of challenges. Typical to the region, all non-residential buildings require robust air-conditioning and ventilation systems to fulfil high cooling demands (which typically comprises close to 50% of the building’s total energy demand). The SPS team organized a Design Charrette to address problems such as (i) efficient cooling solutions, (ii) developing tropic-specific standards and schedules, (iii) separating latent and sensible cooling loads, (iv) increasing indoor thermal comfort, (v) passive air-distribution, (vi) centralized water cooling, (vii) intelligent chiller sizing and optimization, (viii) maximizing of natural ventilation and (ix) maximizing of natural lighting. This paper presents the modelling and simulation results which were used to design energy efficient solutions specific to the problems faced in the tropics, as mentioned above.

x A micro-heat pump in combination with a mechanical ventilation with heat recovery (MVHR) unit is developed and integrated in the façade in the framework of the iNSPiRe project. The heat pump uses the exhaust air of the MVHR unit as a source and provides heat to the supply air of the ventilation system. Thus, one compact unit can be used for combined ventilation and heating (and/or cooling). Fresh outdoor air flows into the MVHR unit, where it is heated with a heat recovery efficiency of up to 90%. It is then further heated by the micro-heat pump up to a maximum of 52 °C in order to supply space heating (reverse operation for cooling possible in future versions). A simulation study has been performed to investigate the energy performance of the micro-heat pump. A detailed physical model of the µHP is developed within the Matlab simulation environment and validated against measurements of two functional models in so-called PASSYS test cells. The performance of the system is investigated for different renovation standards (EnerPHit with 25 kWh/(m2·a) and PH with 15 kWh/(m2·a)) at 7 different climatic conditions.

x Energy efficiency issues are being integrated into Building Information Modeling (BIM) quickly by the InnovANCE Italian research project which provides the creation of the first Italian open-source construction "unified database", shared by all stakeholders: public and private clients, construction companies, professionals and manufacturers. The aim of this research is to define a methodology by which to obtain data flows and information exchanges, with as small as possible data losses, from architectural software (as Revit Architecture) and energy analysis software, mainly those based on transient-state. The transient-state tool analyzed for this study was the EnergyPlus simulation engine, which represents the state of the art tool in building energy simulation. As the process of exchanging data from Revit to EnergyPlus is not direct, “Space Boundary Tool” (SBT) middle-ware was used as an “interoperable bridge” with good results passing through the Industry Foundation Classes (IFC) format, analysing problems and possible solutions. Up to now, SBT is used for three different purposes: (i) To apply needed geometric transformations in order to transform an architectural model into a two-dimensional surfaces model; (ii) To assign thermal boundary conditions to model surfaces and adding materials thermal properties; (iii) To get an .idf file that can be processed by EnergyPlus simulation engine. The correct data exchange obtained makes the energy optimization process easier, mostly if applied in preliminary design phases (when energy analysis can be more effective in driving to the “zero energy building” goal), by avoiding building a new energy model for each architectural design variation.

x The Urban Heat Island effect has been widely studied in large cities around the world, more rarely in medium-size ones. The paper reports on the study of the UHI phenomenon in Padua, a medium-size city in the northeast of Italy, one of the most industrialized and developed parts of the country. Experimental measurements were carried out during summer2012, recording the main thermo-hygrometric variables by mobile surveys along an exact path crossing different zones of the city area (urban, sub-urban and rural). Some measurements in situ in characteristic sites of the city area (like the city centre, high and low density populated residential zones, industrial zone, rural zone) were carried out in order to evaluate thermal comfort indexes. The analysis of the data highlights the presence of the UHI effect with different magnitudes depending on the function of the zone of the city. In the city centre, a historical zone, the effect was up to 7 °C. The ENVImet simulation model was used in order to quantify possible increases in thermal comfort as a consequence of some mitigation strategies. In particular, a very famous square of the city (Prato della Valle) was analysed: it can be considered representative of the phenomenon because of the size and so the very different characteristics from the UHI effect point of view. Two scenarios were analysed besides the actual one (“AsIs” scenario): “Green ground” (halving the asphalt surface and doubling the green and plants surface) and “Cool Pavements” (increasing the albedo of impervious horizontal surfaces). The simulations results are presented both in terms of UHI intensity (difference in air dry-bulb temperature between Prato della Valle and a reference rural site) and in terms of mean radiant temperature and thermal comfort sensation. The results are presented both in spatial and temporal terms for a typical summer day. The “Green ground” scenario allows up to a 1.4 °C and 3 °C decrease in air temperature, respectively during the night and the day. The same items for the “Cool Pavements” scenario are, respectively, 1.8 and 4 °C.

x This paper presents a novel dynamic simulation model for the analysis of multi-zone buildings’ thermal response and the assessment of building energy performance and indoor comfort. In this new release of the code, called DETECt 2.3, two important innovations are implemented. They regard the simulation model of multi-zone buildings, consisting of thermal zones totally enclosed in others, and the design of a novel temperature-humidity control algorithm. The developed innovative control strategy is based on a reference adaptive control scheme for the online adaptation of the control gains, with the aim of overcoming the well-known problems of classical fixed gain control algorithms. This feature will be a key tool for the next generation of building performance simulation codes (also toward NZEB analyses). Both the innovations embedded in the code can be exploited to simulate special indoor environments of hospitals / laboratories, rooms or museum halls. With the aim of showing the features and the potentialities of the simulation code coupled with the new control scheme, a suitable case study related to an expo indoor space of a museum building, including a display case with an accurate climate control, was developed. Details about heating and cooling demands and loads are provided. Good tracking performance for both the temperature and humidity control are obtained through the presented control scheme.

x The paper stems from the benefits of the application of energy analysis in the early-stage building design combined with the difficulties that prevent this integration due to the complexity of the needed simulations. The most common solution to overtake this obstacle is to simplify the building energy model, but not enough attention is paid to understand or predict the consequences of this action. The paper focuses on discussing the difference in results evaluated comparing the simulation of a detailed building model, based on all information available on the building during operation, and a simplified one, suitable for the application in early stage design. This result is achieved by defining a methodology, which consists in developing a simplification protocol and applying it to a suitable number of case studies starting from a detailed model and ending in the simplified one after the application of said protocol. The protocol is based on the use of EnergyPlus software both to develop a detailed model of the building, under various system hypothesis, and the simplified models. Three different case studies, featuring large non-residential buildings each with specific peculiarities, are discussed in this paper and simulated under three different system hypotheses each, resulting in nine different simplified models. Simulations are performed for the duration of a solar year, the differences registered between a fully simplified model and the corresponding detailed models are discussed both in term of total energy needs and peak loads, both for heating and cooling. Lastly, based on the results of the case studies, the possibility of integrating the presented simplification protocol into a simplified simulation tool is evaluated, discussing the possible advantages said tool would bring to the integration of energy simulation in early stage building design.

x The contribution of the solar heat gains to the cooling load is usually calculated through accurate procedures implemented in several simulation programs. Some simplified methods, such as the ASHRAE method, are also available for hand calculations, but they are based on tabular data that apply only to specific conditions. This paper discusses a newly introduced parameter for the evaluation of the cooling load due to the solar radiation incident on the glazed surface of a building. This is the Solar Response Factor (SRF): it is a complex number, and can be rigorously defined and calculated as a combination of the thermal and the optical properties of walls and glazing. In particular, the usefulness of the SRF is twofold. First, it allows us to classify the response of the enclosure to the solar radiation by means of a couple of parameters (amplitude and phase), which makes it easy to perform comparisons amongst different envelope solutions. Then, it allows for an easy analytical estimation of the cooling load in dynamic conditions, starting from the decomposition of the cyclic solar gains in a series of sinusoidal functions. The paper discusses how the Solar Response Factor depends on the main thermo-physical and geometrical properties of the opaque and the glazed envelope. Moreover, an example is discussed to show how the use of the SRF allows us to evaluate the effectiveness of a series of solutions to limit the cooling load. The outcomes of this analysis provide very useful information for a conscious design of buildings, oriented to the limitation of the cooling load and the overheating of indoor spaces.

x This work defines a methodology aimed at the creation of a simplified energy model able to simulate a residential building with a reasonable workload. The simulation results should have a sufficient accuracy at any stage of a building design, by exploiting the benefits of a modular approach with increasing detail rendition. The idea is to verify the accuracy of the simulations comparing different methodologies, from stationary simulations, using a Italian software called TERMUS, to more sophisticated, even if standard, dynamic simulations, using TRNSYS. Such comparisons have already been carried out in the past in different papers, but a thorough analysis of the envelope-plant system using progressive simplification steps has not yet been done, especially for a residential test case in an on-going retrofit process. The results indicate that with the proper simplification steps, shown in the analysis, the accuracy in terms of energy needs and power curves is very high (the difference with the most complete analysis is always below 12% for all the output parameters) with a workload of a few hours for the preparation of the model and the simulations. The fact of having considered a case in northern Italy does not limit the universality of the procedure, which may be applied for a very large number of built environments in residential areas.

x In this paper the theoretical concept of modelling complex fenestration systems is shown firstly by the development of two simplified modelling approaches and secondly by a newly developed model in TRNSYS17 based on BSDF-data and the ISO15099 standard. Final results of a comparison between the more detailed BSDF model and the simplified models based on the bi-directional SHGC will be worked out and described. By simulating two different blind systems incorporated in the façade of a standard office room (Fig. 1), the capabilities and restrictions of the simplified approaches in modelling conventional, diffuse shading blinds and daylight deflecting, specular blinds are shown. Depending on the external boundary conditions and pre-defined settings to be done for the simplified model approaches by parameter studies, the results show satisfying correlations between all models for static and dynamic boundary conditions.

x Daylight performance metrics are moving away from the traditional daylight factor and average illuminance to more climatic-based metrics such as Daylight Autonomy (DA) and Useful Daylight Index (UDI). These metrics offer a better measure of the daylight performance throughout the year and incorporate the varying weather conditions and as such are dubbed climatic-based metrics. However, in hot climates where the ratio of direct to diffuse is highest, achieving these metrics may result in over-heating the spaces. Achieving acceptable climatic-based metrics for the space may result in unacceptable heat gains. The Daylight Autonomy and the Useful Daylight Index do not account for the total amount of lux-hours achieved throughout the year. The solution thus far has been to run coupled-energy and daylight simulations in order to assess the effect of achieving certain climatic-based metrics on the heat gain and thermal performance of the space. In this paper a new metric is proposed that takes into account the total amount of lux-hours achieved throughout the year and the irradiation for different time steps into a single measure. Details about the measure and sample test cases are presented.

x Simulating daylight in building spaces is becoming an increasingly important task to achieve sustainable and healthy building designs. However, accurate modeling of daylight necessitates the inclusion of environmental conditions as well as accurately modeling the buildings’ surroundings, including obstructions. Obstructions in the form of vegetation such as trees and shrubs can significantly impact the daylight performance. This paper presents a parametric study of the effect of vegetation on the daylight performance of the building spaces. RADIANCE is used to simulate the effect of the vegetation obstructions on the daylighting. A routine is developed to parametrically create vegetation and outputs geometric descriptions that in the rad format, so that they can be easily incorporated into the RADIANCE scene description file. The developed routine allows for parametric variations of the tree shapes and configuration so that these values can be studied. A standard office space is used and the daylight performance is assessed using a daylight climate-based metrics namely daylight availability. The results demonstrate the importance of taking vegetation obstructions into account when modeling daylight performance.

x The awareness about environmental problems due to fossil fuel consumption is increasing widely; therefore, efforts are being made to develop energy efficient and environmentally friendly systems by utilisation of non-polluting renewable energy sources. Ground source heat pumps (GSHPs) belong to this category. Many variations of geothermal system typologies exist, with different configurations suitable in different situations and most locations around the world. One emergent configuration is the solar assisted GSHP (SAGSHP). The paper focuses on different control strategies of a solar assisted ground source heat pump (SAGSHP) for different Italian locations. Dynamic simulation approach has been used through TRNSYS software. The impact of the considered strategies on the seasonal performance factor has been evaluated. Results have shown that the strategy strongly affects the system consumption; therefore, it needs to be chosen appropriately in the design phase. Furthermore, when solar energy is driven into the ground, the temperature difference between solar collectors and the ground, which has to be a positive value to charge the ground, plays a fundamental role. In particular, solar thermal energy injected into the ground decreases to zero moving from a humid sub-tropical (Cfa) to a dry-summer subtropical (Csa) climate. Therefore, a compromise between the operation of the circulation pumps used for supplying free cooling energy and for driving solar thermal energy into the ground has to be found for each climate.

x The article illustrates the results of a study regarding occupancy profiles and energy needs of residential buildings located in a Mediterranean climate (southern Italy). Different parameters are collected by using surveys: data from bills, characteristics of buildings, family composition and practices, heating, cooling and DHW systems, control strategies. The data processing is used in order to identify occupancy scenarios and representative case studies. The influence of the occupancy profiles on thermal performances of selected buildings is investigated by energy simulations comparing thermal losses and gains obtained by means of the application of Standard procedures contained in UNI/TS 11300-1 and real patterns. Heating energy needs and comfort parameters are studied considering the variables influenced by occupant behavior: set point temperature, ventilation, lighting, appliances and shading systems.

x Energy retrofit of historic buildings is a complex activity, which requires a multidisciplinary approach. Interventions should limit energy consumption, consider users’ comfort and preserve cultural and aesthetic values. While the impacts of interventions on energy performance and comfort can be quantified in advance using simulation software, conservation aspects are less tangible. In this paper, we propose a method to identify retrofit strategies that are optimal from an energy, comfort and conservation point of view. The first step is to choose a set of interventions and conservation aspects to consider. This requires a multidisciplinary team of experts. Next, quantitative metrics for assessing energy performance, comfort and conservation are defined. Through a multi-objective optimization, the combinations of interventions that yield the best tradeoffs among these objectives are found. We demonstrate the method on a calibrated EnergyPlus model of the “Waaghaus” (weigh house), a medieval building in Bolzano located in the north of Italy. The aim is to transform this currently vacant building into a cultural center. We considered the following interventions: external and internal envelope insulation with varying materials and thicknesses, airtightness improvements, replacement of windows and summer ventilation availability. Conservation aspects taken into account were visual, physical and spatial impact of the interventions on the building’s heritage significance. We selected the hourly sum of all sensible and latent ideal loads for heating and cooling over a year as energy performance metric. All internal loads were modelled according to the planned future use of the building. We assigned a score to each intervention equal to the number of conservation aspects met. The yearly average of the absolute values of the predicted mean vote was used as a proxy for comfort. We performed the multi-objective optimization with the C code NSGA-II, which implements a genetic algorithm based on non-dominated sorting. As a result, we obtained solutions with an absolute mean PMV of 0.5, an annual ideal load for heating and cooling of 20 kWh/m2 and a good level of conservation.

x An energetic analysis of an office building located in southern Italy and properly designed to have energy consumption almost zero, has been carried out by means of the Design Builder simulation software. The choices of opaque surfaces, glazed surfaces and appropriate external shading devices have been made to reconcile the different and conflicting needs of the investigated building. Several simulations of different opaque surfaces have allowed the choice of adequate materials for the dispersing walls, to reduce thermal losses and attenuate summer thermal waves. Glazed surfaces have been conveniently selected, to exploit their optical properties both in winter and in summer. Finally, an appropriate sizing of unmovable external shading devices has allowed the optimization of winter solar gain and the reduction of summer solar load. These choices have demonstrated that, in Mediterranean climate conditions, the design process of the building envelope follows a completely different approach compared to the method typically used for the realization of passive houses conceived for continental climates. With reference to the primary energy requirements, simulation results have been used to design a proper generation system coupled with active solar systems in order to obtain a NZEB building.

x Building thermal simulation based parametric methods are computationally intensive for optimizing the building design. This work uses experimental design techniques, i.e. fractional factorial design and response surface methodology, for sensitivity analysis and surrogate modeling respectively. These techniques find the solution in a reasonable time. Their application for building design optimization has not been found in the literature before. Fractional factorial design has been used to identify the significant design variables. These variables are used to form a correlation for annual cooling load prediction, using response surface methodology. These methods are illustrated using two cases to minimize the life cycle cost of a single-storeyed, air-conditioned, solar powered, detached home, with 64 sq. m. floor area, for the warm and humid Mumbai climate. For this climate, window solar heat gain coefficient, window to wall ratio, overhang depth and roof reflective coatings turn out to be the most important among the design variables used for this case study. The created response surface models show an error of less than 5% for more than 99% of the test data, which is comparable to other such models. Strategies are suggested to bring the error for the entire search space to less than 10%. Life cycle cost minimization using the model for case 2 does 12 million iterations as opposed to 250 iterations using a parametric EnergyPlus simulation run at the same time. The solution is better and the design achieved is also different. The optimum design has a cooling load of 55 kWh m-2 yr-1, while it varies from 46 to 118 kWh m-2 yr-1. This work adds an intuitive method for building design and opens up possibilities for optimization.

x This paper presents a verification of CitySim, a large-scale building energy simulation tool based on a simplified thermal model. First, the main assumptions behind the simplified model are presented. Then, CitySim is compared to other detailed simulation tools on case studies defined in the Building Energy Simulation Test (BESTEST) validation procedure. Finally, the predictions of CitySim regarding the annual heating load are compared with the monitored consumption of a building located on the campus of the Swiss Federal Institute of Technology Lausanne (EPFL). Regarding the BESTEST, CitySim gives annual heating and cooling results together with peak heating and cooling loads that are within the acceptable range defined by reference simulation tools except for the annual heating load of case 960 and the peak cooling of case 610 but the differences are rather small (less than 1%). Regarding the EPFL campus building, CitySim gives an annual heating consumption within a 5% range of the monitored consumption of two reference years. The paper concludes that despite its simplified thermal model, CitySim results remain consistent with more detailed programs and the monitored heating consumption of an office building. These results reinforce the confidence in the tool to predict annual and peak load energy needs for conditioning buildings.

x The European Directive 2010/31/EU on the energy performance of buildings introduces the nearly zero-energy requirement, by 2020 and 2018 for new buildings in general and for public buildings respectively. This challenging target requires a complete assessment and optimization of the integration of efficient systems and renewable energy technologies in the building design. Dynamic energy simulation represents an essential tool in this regard. In this context, we present an integrated approach applied to the design of a new university building in Milan, in northern Italy. This case study consists of a four-storey building dedicated to offices, laboratories and classrooms. The building envelope design was formerly optimized, adopting passive strategies, like thermal insulation, solar control, daylighting and night natural ventilation, to reduce heating, cooling and lighting needs. In order to meet the net zero energy requirement, locally available renewable energy sources and energy efficient systems have to be taken into account. Therefore in this case dynamic energy simulations in EnergyPlus are used to compare different heating and cooling plants options. A reference plant consists of a condensing boiler and a chiller coupled to a cooling tower, and an alternative system is based on a Ground Source Heat Pump coupled to a vertical ground heat exchanger. A VAV distribution system is assumed. Finally, PV devices are integrated in the building roof. The simulation allows to choose the most efficient plant and to assess the overall strategy. Finally, the net zero energy target is tested and critically related to the different uses available in the building and to the climatic context.

x The typical architecture of countries in a hot arid climate is a valuable source of principles that today we call bioclimatic and sustainable. Ancient people knew very well how to avoid the harshness of the desert and their knowledge came from centuries of experience and attempts. Among these principles, we can remember the typical narrow winding alleys, the courtyard houses, the domes and the large thermal mass of the walls. It was decided to combine this knowledge with computer techniques to try to parameterize these aspects in order to optimize and make them as effective as possible, allowing us to add something to what had been handed down. The project was born from a practical need, creating new settlements in places far from civilization, but close to important human activities. The first aim of the project is to design self-sufficient houses, using the sustainable desert principles, and the second aim is to use the concept of folding architecture to build a village as soon as possible. From an energetic point of view, the patio has a crucial role to enhance the inner environment: producing shade, it supports natural ventilation. Starting from a “zero organism”, through generative algorithms made in Rhino/Grasshopper, this effect is optimized by maximizing the area of the shadow produced by the roof inside the patio, during the hottest hours. By classifying the various organisms obtained, through structural (i.e.: length, compressive stress) and energetic parameters (i.e.: radiation analysis, cooling loads), a ranking open to various solutions has come out.

x Rhinoceros and Grasshopper have the extensibility which makes architects able to study forms, structures, acoustic behaviour, energy consumption, etc. as well as daylight availability: the most important aspect in this study. The software described has been useful to evaluate running costs including heating, cooling, electrical devices and lighting systems. The software used includes Ladybug and Honeybee; they connect the Radiance and Daysim engines to Grasshopper and Rhinoceros. The building analyzed in this study is a competition proposal for the New Town Hall in Remseck Am Neckar (Germany). The simulation started by designing the electric lighting system while the daylight availability was evaluated afterwards. The core study is the critical investigation of the daylight contribution necessary to satisfy the lighting demand. Two simulations were run: the first one followed the European Regulation EN 15193, the second one was based on Daysim. If these methodologies gave two equivalent results for the north-exposed offices, on the other hand the south-exposed rooms obtained slightly different values. The idea consists in developing a third method to use opposed to the others described before, called the ‘Octopus method’ (OM) and based on Octopus, a multi-objective evolutionary algorithm integrated within Grasshopper. The new feature the OM introduces is the annual illuminance data computation being different from Daysim. The latter just makes a multiplication between the illuminance deficiency and the required comfort level. The OM considers the comfort level throughout the year simulating the real illuminance distribution within the ambient of study and the effect of electric light system installed.

x This study focuses on the application of system identification to estimate the flow rate and the heating consumption in a central heating system in an office building in San Michele all’Adige, Italy. The study was done within the European ICT PSP project Smart Build with the aim of reducing the energy consumption of existing public buildings through the application of ICT systems. The installed monitoring system, designed after an early energy auditing, foresaw the use of permanent temperature sensors coupled with a portable flow rate meter, to estimate thermal consumption. The flow rate varied with time depending on several factors therefore making it challenging to monitor it for only a short period. To overcome this obstacle, we monitored the flow rate for four workdays and one weekend to identify a mathematical model which could explain the real system behaviour. A statistical analysis was performed at first to assess the reliability of the monitored data. Subsequently, we focused on the identification of autoregressive models with exogenous inputs with a varying complexity and level of confidence. Different tests were performed on the hourly data to assess the reliability of the models. The best model was subsequently used to estimate the time-varying heating consumption for available monitoring periods with the aim to understand the impact of the ICT system as a function of the floor of the building and in order to show how system identification can reliably estimate the water flow rate in a central heating system and consequently be used to calculate the heating consumption. The calculated monthly average deviated from the bills by 20%, attributable to the heating consumption of the non-monitored ground floor.

x Air-source heat pumps in heating mode are characterized by performances strongly dependent on the value of the outdoor air temperature. The Italian standard UNI/TS 11300-4 indicates, for the evaluation of a heat pump seasonal efficiency, a method based on the local bin distribution of the external air temperature. The aim of this paper is to test the bin-method proposed by UNI/TS 11300-4 by comparing the results obtained through this method with the results deducted by using a more accurate dynamic simulation of the system. The heat pump Seasonal Coefficient Of Performance (SCOP) is calculated by means of a dynamic simulation code, written in MATLAB, in which hourly climate data distributions defined by CTI for different Italian towns are introduced as input data together with the thermal characteristics of the building. The thermal winter behaviour of the building is introduced in the models by using the Building Energy Signature. In the paper the values of the seasonal indexes SCOPon and SCOPnet obtained by means of the bin-method and the dynamic hourly simulation, both for mono-compressor and inverter-driven heat pumps, in the service of several buildings placed in different Italian climates, are evaluated and compared to each other. Different buildings and different climate data are used in order to highlight the main conditions which are responsible for the difference between the predictions obtained with the bin-method and the results obtained by using the dynamic hourly simulation. The results presented in this paper show that the predictions of the bin-method tend to be in agreement with the results of the dynamic simulations based on the Test Reference Year only in particular conditions. The observed discrepancies in terms of SCOP between these two approaches can reach 23%, varying with the climate data and with the type of heat pump considered.

x In this study, four different small-scale biomass-based cogeneration heat and power (CHP) technologies along with three conventional energy generation systems serving an office building in Helsinki, Finland are investigated to find the local cost-optimal solutions for minimum energy performance for each as well as the global cost optimal solution. The Energy Performance of Building Directive (EPBD) comparative framework methodology is followed. All building combinations are simulated by IDA-ICE 4.5 software including building energy efficiency measures/packages; external wall insulation, window type, and envelope air-tightness, and building service system packages including ventilation system, and daylight control. The reference case is defined consisting of a reference building built in accordance with the current building code served by district heating and vapor compression cycle cooling system (DH-VCR). The results show that the pellet boiler with vapor compression refrigeration system (PB-VCR) has global cost-optimal solution. When the CHP capacities are sized to cover the peak thermal demands, the low power-to-heat (P/H) ratio CHP technologies have life cycle cost (LCC) less than the reference case, while the CHP technologies with high P/H have higher LCC. The reason for that is the high investment cost relating to higher associated electrical capacities as well as high operational energy costs due to lower thermal efficiency. However, optimizing the CHP capacity and installing an auxiliary pellet boiler means that all investigated CHP technologies have LCC less than the reference case. Furthermore, the net zero energy building (NZEB) solutions extended - by implementing photovoltaic system (PV) - for the cost-optimal solutions have lower LCC than those extended based minimum energy performance solutions.

x Currently the value and the appeal of a house are deeply influenced by its own energy performance and its comfort. As a consequence, several examples of net zero energy buildings have been realized worldwide in the last decade, using renewable energy sources for their moderate energy consumption. An architectural experiment of this kind of buildings is represented by shipping container houses that could be used not only in emergency situations but also as alternative guestrooms or also low-cost houses. The paper presents the results of software simulations carried out to evaluate the energy and lighting performance of three kinds of shipping container houses characterized by different floor areas and usage. The bigger one is a typical shipping container having a surface of about 14 m2 and a height of 2.4 m; the others have the same height but smaller surfaces, respectively of about 7 and 5.6 m2. The furniture was designed to be moved thanks to upper runners in order to use the same area for different domestic activities during the day. Each one of them was planned to be a net zero energy building obtaining energy from solar panels and clean water from rainfall. The lighting design was carried out using DIALux while energy performance was studied through Energy Plus. The first one allowed us to optimize the selection and the position of LED lighting systems in order to assure the recommended values of the Illuminance E. Moreover, some graphical renderings were realized in order to have a clear and simple evaluation of the visual performance of the internal spaces, also taking into account the contribution of daylighting. The characteristics of the lighting systems were used for the evaluation of the whole energy performance of the building. Energy Plus is the dynamic simulation software used to determine the energy demand of each container, taking into account the heating and cooling facilities, the insulation properties of the building envelope, windows and doors included. The results of this theoretical study show that this solution is technically feasible, cheap and also comfortable not only for emergency housing.

x Building retrofitting is the most feasible and cost-effective method to improve building energy efficiency. To this aim, the building envelope should be equipped with new windows having low thermal transmission coefficients and/or with insulation material in the external partitions. This approach leads to considerable energy saving, but at the same time if the users do not properly ventilate the occupied spaces, it results in a worsening of indoor air quality. The paper presents a comparative analysis of two different strategies to enhance the energy performance of an existing building. The first is to reduce the heat transfer by transmission (i.e. use of low-emissivity glass) and the second to decrease the heat transfer by ventilation (i.e. installation of a heat recovery). The study has been applied to an office block, located in the city of Bologna, Italy. Potential energy savings were calculated by dynamic simulation using Trnsys software. To this purpose, a reference office was selected and then the following cases were studied. The first one took into account the replacement of all the windows, the second one consisted in installing a total energy ventilation recovery system and the last one contemplated both the solutions. Finally, an evaluation of the simple payback time and the net present value was performed.

x A new tool for energy and daylighting analysis of complex fenestration systems (CFS) is presented. The tool couples the daylighting simulation engine Radiance with the dynamic building simulation engine TRNSYS and performs integrated simulations using the bidirectional scattering distribution function (BSDF) that characterizes the CFS. The use of the tool allows us to implement flexible shading controls based on thermal and daylighting comfort parameters. In order to demonstrate the tool functionality two different control strategies for a shading device, composed of movable venetian blinds, are compared and analyzed.

x In tropical developing countries, the considerations of energy efficiency and quality of school buildings are minimal, compromising the minimum internal comfort. This paper explores the effects on thermal comfort and energy generated by performing parametric variations on the typical configuration of naturally ventilated classrooms in tropical Costa Rica. Using dynamic simulations by the software Design Builder, weather data and surveys of comfort, classrooms with the same design pattern in three locations prone to overheating were analysed. Effects on energy demand and the operative temperature of the enclosure by varying bioclimatic parameters of passive cooling and solar control were reviewed. The results indicate that certain configurations can optimize the performance of the typology of the cases studied, generating the possibility of applying these design parameters to new configurations of classrooms to be built in the area. The impact of choosing appropriate design considerations and the use of simulation tools to verify building performance is demonstrated. In addition the combined potential of using passive cooling and solar control to achieve favourable thermal conditions for the user and to solve an energy demand improvement of school buildings was proved.

x In recent years, there has been a gradual growth in the adoption of the new EU directives related to different topics in the field of construction. Consequently, professionals are forced to take care of different aspects in projects, which are related to limit performance requirements that the new buildings must ensure from the points of view of energy, acoustics, lighting and more in general of environmental and economic impacts. The present work deals with a new computational model (GEAR) dedicated to the multi-task simulation of buildings. GEAR is integrated with ARCHLine.XP (3D architectural cad) so that the several configurations encountered are more easily implemented.

x Among the different adoptable solutions for building envelopes, of particular interest is the green roof which allows us to obtain, at the same time, energy, economic and environmental benefits using solar energy as a source for its operation. The aim of the proposed study is to evaluate the energy and economic savings achievable through the installation of an additional green roof stratigraphy on a variety of traditional roofs. The analysis was carried out with reference to the climatic conditions of the Calabria region (Italy), classified as Mediterranean. Such assessment has been achieved by the use of a thermal model in dynamic regime formulated by the authors that allows us to determine the heat transfer in roofs with a green cover. The model is based on two energy balance equations for the vegetation and soil layer. The model has been implemented into the software tool ThermoGR that allows us to evaluate the thermal exchanges of a green roof with indoor and outdoor environments and the seasonal energy savings due to the presence of the green stratigraphy. The reduction of the thermal load through the roof, due to the green roof, is used to perform an economic analysis based on the calculation of the cost of the energy saved per square meter of roof surface during the air-conditioning period both in summer and in winter. This analysis is used to identify the constructive typologies on which the application of the green roof is more advantageous.

x The energy renovation of existing building stock has been widely acknowledged as having a key role to tackle the 20-20-20 European targets (EuroACE, 2014). However, many open challenges characterize the effectiveness of building renovations, for instance, procedural methods that consider the interaction of multiple variables and their influence on a specific building are still inadequate. The aim of the paper is to investigate a holistic method (Eriksen et al., 2013) that, if used during the diagnostic pre-renovation phase, allows for the evaluation and planning of strategic renovations. To achieve the aim, the holistic method was applied on a multi-storey building for social housing that must be renovated. Thus, investigations about economic, architectural, technical, user and legislative aspects were carried out to create an overview of the building’s features and needs. Thanks to the holistic diagnosis, the users’ involvement and active participation was found to be a challenge. Therefore, TRNSYS simulation software was employed to specifically assess how much users can influence the success of the renovation project. Specifically, the first step was the creation of a baseline model for the existing building. The baseline model calibration was based on the current thermal performance, which was derived from data collected during the holistic method application. Afterwards, two borderline renovation scenarios were developed: on one hand, a model conforming to a pre-feasibility study that does not entail users’ habits, and on the other a model that can be representative also of users’ behaviour. The rationale behind is to quantify the impact of users in case they are not considered or they are not willing to be part of the project and, hence, they do not modify their habits accordingly. Research results showed that the holistic method can contribute to optimizing the design that will be used in the renovation as it effectively assesses the multiple effects of the variables and it incorporates the users’ perspectives. Users are a crucial component to take into consideration from the beginning of a project. The paper represents other evidence of the importance of using building performance simulations (BPS) early in the design process to both assess the influence of users’ habits on the energy consumption and become a system check for subsequent further design phases.

x Energy consumption strongly depends on the occupants’ behavior for all types of buildings. However, the impact is greatly increased in high performance building, in which users can freely interact with the envelope system (opening widows and shading management) and with the HVAC control systems. The robustness of a design solution to suboptimal user´s behaviors can thus become a distinguishing factor among different design alternatives. One of the main issues regards the predictability of user choices and actions and its codification into a plausible simulating algorithm. Several strategies are presented in the literature, however energy modelers adopted to a large extent the schedule approach, to take into account users in energy simulations. This paper describes two stochastic methods implemented in EnergyPlus to simulate the users’ behaviors in managing opening surfaces and thermostat setpoint temperatures. Using these methods, the impact of different user behavior on the energy performance of a multistory building is investigated. The aim of this work is to quantify the impact of users´ behavior modeling on the results of dynamic energy simulations.

x In this paper we describe how simulation is used to support HVAC operational strategies within the context of the CASCADE project: a comprehensive platform that integrates Fault Detection and Diagnosis (FDD) techniques into an Energy Management System (EMS) that follows ISO-50001 guidelines. The CASCADE solution is conceived as an on-line application that combines a number of data intensive services using the internet as a data exchange medium. Among these services are an ontology-driven database, FDD engines, front-end visualization software and energy management tools. The project constantly monitors HVAC data and executes FDD routines that translate to specific actions rendered by the EMS software. The project is currently being implemented in two main EU airports: Rome Fiumicino (FCO) and Milan Malpensa (MXP). The ultimate intent of this research is to explore Whole Building Performance Simulation (WBPS) as a potential service to be integrated within the overall CASCADE solution. From a facility management perspective, models are commonly used as a test-bed to assess energy conservation measures before their implementation, to provide a fault free reference for recommissioning and a baseline for measurement and verification purposes. This theoretical perspective is confronted in this paper with the practical experience and lessons learned from one of the project’s demonstrator buildings.

x This study focuses on the dynamic building simulation of a low energy house, situated in the region of Lower Austria. The pre-fabricated single family house has highly insulated lightweight walls and triple glazed windows. The house is heated by a 6 kW pellet boiler supplying hot water to a floor heating system. The boiler is also used for domestic hot water production, in combination with solar collectors, thus forming a combined solar-pellet system. The house was monitored in the frame of the BioMaxEff project (funded by FP 7), aiming at the demonstration of biomass boilers in real life conditions. Parameters describing the boiler operation as well as outdoor and indoor temperatures were monitored continuously for one year. The aim of this study is to develop a coupled simulation of the house and its heating and hot water supply systems has been set up in the TRNSYS simulation suite. System components have been simulated using both standard and non-standard TRNSYS Types. A new component was developed within this study to simulate the system’s control unit. The comparison of monitoring data of the year 2013 and simulation results showed that the boiler operation in field conditions was accurately reproduced in the simulation environment.

x This paper focuses on parametric design-based visualization methods to represent building performance at the neighborhood scale in the perspective of an integrated design-support system. The goal of the developed methodology is to convey the relative effectiveness of different design alternatives according to a wide range of building performance indicators, including the potential for active solar applications, the energy need for space heating/cooling and (spatial) daylight autonomy. The proposed methodology is applied to a case study of a typical urban renewal project in Switzerland for which several design variants were analyzed using validated climate-based simulation engines. For each design variant, simulation results are represented qualitatively using multiple false-color maps and quantitatively through comprehensive plots. We conclude by showing the applicability of this methodology to a large number of neighborhood-scale design variants as well as the complementarity of the proposed visualization methods. On the basis of the case study application, a possible implementation as a design-support tool is finally discussed.

x The representation of people's presence and control-oriented behaviour in building performance representation requires a large empirical database for model development and evaluation. Toward this end, empirical case studies in different buildings and different locations are necessary. In this context, this contribution presents the results of a study of user behaviour regarding building systems operation in an office building located in the south of Vienna, Austria, ventilated by mechanical means only. Moreover, users' perception of the indoor climate conditions at their workspaces was assessed. Empirical data concerning indoor climate conditions were collected by measuring the inside temperature, relative humidity, and illuminance levels over a period of ten months. Data regarding external weather conditions were obtained from the Central Institute for Meteorology and Geodynamics, Vienna. Occupancy data and the status of the user-controlled building's systems (thermostat, electrical lighting and shades) were additionally collected via hourly observations over a period of six months. The main objective of the study was to explore the general patterns of occupant’s control-orientated behaviour at their workplaces in relation to the indoor/outdoor conditions. The results contribute to a better understanding of user behaviour in office buildings and the evaluation of the influence of occupancy on building energy use. The results also support the efforts toward integrating behavioural models in building performance simulation applications and improving building management and automation.

x Currently, there is no methodical procedure for selecting solar-optical properties of roller shades, which affect the energy and indoor environmental performance of perimeter building zones. This paper presents a new systematic methodology for identifying the range of shading properties (openness factor and visible transmittance) that can significantly reduce the risk of glare. A model that calculates angular beam-beam and beam-diffuse shading optical properties using minimum inputs is used within a hybrid ray-tracing and radiosity daylighting model, validated with full-scale experiments. The temporal variation of beam and total vertical illuminance is used to define the annual visual discomfort frequency and establish a process for selecting the range of acceptable shading properties for each set of external parameters (location, orientation, glazing visible transmittance, and buffer zone). Recommendations for openness factors and visible transmittance values are made for different scenarios. Selecting the upper limits of suggested ranges can provide more daylight into the space and reduce the probability of high contrast. These guidelines may be used for selection of shading products, followed by considerations about energy savings and provision of outside view.

x Since 2002 the CasaClima building quality certification system has been a widely recognized method. Certification of buildings is carried out with standard parameters of calculation. For this reason the results obtained do not show the real consumption, but they are indexes that allow us to compare different buildings from each other. However, the CasaClima Program has been developed in order to guarantee a high level of quality of the construction process for low-energy buildings. Looking not only at the certification, but also at a proper building design, CasaClima has integrated into its software a dynamic simulation of the building, whose characteristics and results will be presented in this paper. Having to deal with technicians, whose work is focused on the rapidity of the design, the goal, from the beginning of the development, was to allow these professionals to make the calculation for energy certification and at the same time, without further additional working, offer them the results of a dynamic simulation. For this reason some input of the calculation is fixed and unchangeable. In the CasaClima philosophy, the energy efficiency starts from the building envelope, which is associated with a system that is simple, but efficient, and able to cover the small energy needs required. For this reason, the building envelope plays a leading role and CasaClima dynamic simulation serves mainly to its design. Thus, the results show the air and operating temperature within the environment, without any air conditioning system, from which it is also possible to obtain an evaluation of the indoor comfort.

x In this paper we developed a simplified graphical visualization to provide a preliminary understanding of aerodynamic pressure distributions around tall buildings and to estimate the best positions for ventilation openings. This graphical model is based on a database of pressure coefficients hold by parametrical two-dimensional CFD (Computational Fluid Dynamics) simulations over several rectangular shape profiles. The pressure values are obtained by CFD simulations of a stationary flow (High Reynolds), with a K-epsilon turbulence model coupled with Navier-Stokes equations, by using Finite Elements Methods. Whilst turbulence model is well-known, the innovative application is the parameterization of the CFD simulations. The parameters considered here are the ratio between length and width of a rectangular shape and the wind direction (degrees azimuth). Our model adapts automatically to different shapes and various wind directions. Though not able to capture the same level of detail as the three-dimensional CFD simulations or experimental tests, it provides a rapid and intuitive guidance for architects at the preliminary design stage of a natural ventilation system. The final graphical visualizations, together with some simple recommendations, can be exploited by designers having no knowledge in aerodynamics.

x In order to promote its readability, modularity and maintainability, a new Object Oriented (OO) tool for the simulation of buildings performance, has been developed in the last years. The first results of a comparative validation done on our tool, following the BESTEST standard, have been published in the 2013 IBPSA International Conference. The chosen development methodology aims to achieve efficient and high quality software development in the field of Building Performance Simulation tools (BPSts) and is based on an Open Source (OS) development approach. Given the selected approach, the contribution of volunteer developers should be encouraged and supported. To effectively support the work of an OS community, key aspects are tasks automation, traceability and communication in the developing phase. The implemented development methodology is then based on: 1) the use of a Software Forge (SF) to promote communication between community members and to help in the management of the software development life-cycle, 2) the use of UML diagrams to describe community-agreed architectural decisions and enforce their implementation into the project, in a way that their implementation can be automatically checked, 3) the ability to group single tests of different modules in one automatic test session of validation, which also simplifies final reporting, 4) the use of inheritance, offered by Object Oriented Programming (OOP), to specialize existing classes which, avoiding rewriting, partially automate code writing. Regarding the quality of the tool, the definition of specific standards for programming, documenting and validating is also important. In particular, the validation phase has to be carried out in a well-documented pool of verifiers, and provided as an integral part of the documentation available to the user.

x It is well known that an appropriate daylighting design can influence the global energy performance of a building as well as the visual and thermal comfort for the occupants. Furthermore the increasing awareness of the potential benefits of daylight has resulted in an increased need for objective information and data on the impact that different design solutions can have on the daylighting condition within a space, in relation with the architectural features. This kind of analysis is becoming more and more requested, during all stages of the design process. The purpose of this paper is to describe a reliable simulation approach to consider daylight when assessing the energy performance of a building. The methodology is based on the use of both Daysim and EnergyPlus which were employed in synergy for a parametric study to assess lighting and energy performances of rooms with different architectural features: orientation, window size and glazing visible transmittance, room depth, external obstruction angle and site. Daysim was chosen to perform daylighting analyses since it allows us to accurately estimate the annual amount of daylight in a space and calculating climate-based daylight metrics as well as the annual electric lighting use for different lighting controls. The Daysim output file that describes the status of all lighting and shading groups in the space during the year was then used as input in EnergyPlus to estimate the influence of the daylighting and artificial lighting design on the global energy performance of a space. The paper presents some considerations on the simulation approach adopted in the study and the most important results that were obtained in terms of daylighting conditions and energy demand for lighting, heating and cooling, to demonstrate the substantial influence of daylight harvesting on the reduction of the global energy performance.

x Building Information Modelling (BIM) aims to promote collaboration between project partners by providing a single model with the required relevant information. BIM data is meant to be provided to multiple domain-specific applications in an effective manner. We consider two data formats used to facilitate this interoperability: (i) gbXML format, developed by Green Building Studio and (ii) IFC format, developed by buildingSMART. Both of these formats can be used to provide geometry information and other data to Building Performance Simulation (BPS) applications. However, gbXML and IFC have unique data structures, which has consequences for how the original geometrical and spatial data from the BIM model is translated. In this context, the present contribution aims to assess and compare the usage of IFC and gbXML data formats in separate workflows, thereby observing consistency of building data and efficiency of the process. First, the main differences and specifics of the two formats are investigated and several case models are developed. Using a BIM authoring tool both formats are then tested in a typical workflow including the use of a BPS tool. To explore the implications of the quality of the BIM model, a second workflow (with the same case models) was set up in a different BIM authoring tool. These workflows and their outcome with regard to BPS were analyzed and the capabilities and differences of the two formats were studied in detail. The results of this study show that both data formats are capable of extracting and transferring geometrical information from BIM models. However, the successful transfer of this information is strongly related to the quality of the BIM representation. Demonstrative simulation runs show that incorrect BIM-based building geometry data can produce misleading results. Moreover, the overall approach to using gbXML and IFC to perform BPS is currently rather cumbersome and difficult to validate.

x An integrated energy concept of a building should include not only its energy consumption but also the quality of the indoor environment in terms of thermal, visual comfort and indoor air quality. Shadings, window construction materials and ventilation strategies have a significant impact on the “health” of the building and of its occupants; they should be studied carefully during the pre-design phase of the building. Evaluating thermal, visual comfort or IAQ individually is quite easy thanks to reference standards and simulation tools but it can imply non-optimised solutions or even design errors. Conversely, an integrated approach should include a simultaneous analysis of all these aspects of the indoor environmental comfort in order to propose optimised technical solutions or design strategies. Previous studies have proposed statistical indicators to manage thermal and visual comfort simultaneously. In the present study further indicators of IAQ (here CO2 was considered) were included in order to achieve a global environmental quality. This integrated approach was used for the optimisation of a new large office building in Switzerland. A parametric multi-objective analysis was carried out by means of EnergyPlus. This approach allowed for the optimization of design strategies (shadings, window materials, ventilation) for both energy savings and indoor environmental quality of the building.

x This paper presents a case study with an aim to examine the indoor impact of fine particles with a maximum aerodynamic diameter of 2.5 microns (PM2.5) and evaluate its main sources of generation within one typical residential dwelling of Beijing’s housing stock in order to define optimal mitigation measures. Based upon available data, through the validated multi-zone indoor air quality (IAQ) model the relationship between impact of indoor/outdoor factors and indoor mass concentration of PM2.5 was examined. As a referent dwelling, one of Beijing's housing stock representatives was selected. Its key parameters were combined and modelled in order to create the universal framework consisted of five baseline typical housing stock cases. The main modelling drive parameters were physical and mechanical dwelling performances: five envelope’s permeability (p) values (10, 20, 30, 40 and 50 m³/m²/h @50Pa) and different types of ventilating, throughout the year (heating and non-heating period). The simulation results suggest that under present day conditions, average indoor concentrations of PM2.5 are appreciably higher than the outdoor annual average value of 102µgm-3 because of indoor sources. In the case of naturally ventilated dwellings during heating period, cooking represents the largest contributor, generating particulate matter at concentrations four times greater than annual average outdoor mass concentration of PM2.5. Modelling demonstrated that removal of PM2.5 generated by cooking activity depends on the type of ventilation and most important on its use pattern. Furthermore, modelling provided fundamental data for evaluating indoor pollutant reduction measures. Based on previous analysis, following mitigation measures are analysed: increased EF capacity and its period of use, kitchen isolation (by closing the door) from the rest of dwellings and change of occupant behaviour regarding smoking activity. Compared to the naturally ventilated dwelling in winter period, analysed measures could decrease average indoor PM2.5 mass concentrations by almost 50%. This kind of method was found to be suitable for questioning different measures of improvement and the way for this framework to be easily broadened to the bigger scale, at the urban level.

x The retrofit of historical facades of the building stock has grown in importance due to energy efficiency considerations in the building sector. Among other recent new construction technologies, aerogel-based plaster systems with high thermal insulation have been developed in the past few years by the AEC-industry. Although still rather expensive, these systems offer opportunities to insulate highly-articulated historical facades in compliance with the principles of heritage protection. This contribution analyses the effect of the application of such aerogel-based plasters on historical building facades in terms of thermal bridges. Thermal bridges are considered to be of high importance for both the building’s overall energy performance and the quality assurance in terms of healthy indoor environment. The latter includes aspects of interior surface temperatures, condensation risk, and mould growth. Typical construction details of historical building facades were selected based on relevant literature. These details were analysed and evaluated with the help of a numeric thermal bridge simulation tool. A set of scenarios including original state and different retrofit measures were applied to these details and their effect was evaluated in view of thermal bridge calculation. This contribution includes – along with basic information about the aerogel-plaster systems and related background – description of the methodology and a discussion of the results.

x The building façades, as a boundary between external and internal environments, play a central role in energy reduction and suitable comfort conditions maintenance. Their evaluation requires an integrated assessment approach, focused on occupants’ thermal and visual comfort, in time and space, as well as on maximizing daylight and achieving energy saving goals. In this paper, dynamic simulation is used to evaluate the integrated performance of different fenestration systems in an open space office located in Rome. The illuminating analysis has been performed using DIVA, and the results, processed by means of a Matlab code, have been used as an input for Energy Plus thermal and energy analysis. Then, the Energy Plus outputs have been post processed to calculate the solar radiation influence on occupants' thermal comfort. Some new metrics have been introduced in such a way that it is possible to assess the comfort performance with comprehensive indicators.

x The Commission Delegated Regulation No. 244/2012 supplementing Directive 2010/31/EU on the comparative methodology framework for calculating cost-optimal levels of minimum energy performance requirements enforces Member States to perform an analysis to determine the sensitivity of the calculation outcomes to changes in the energy price developments and the discount rates, as well as other parameters which are expected to have a significant impact on the outcome of the calculations. In Italy the cost optimal methodology has been performed by using a simulation tool enforced on a quasi-steady state numerical model (UNI/TS 11300) while the cost optimisation procedure is based on a sequential search-optimisation technique considering discrete options, as introduced in a previous work (Corrado et al., 2014). Packages of energy efficiency measures giving optimal EP levels have been found for different buildings and climatic conditions (Italian Ministry of Economic Development, 2013; Corrado et al., 2013). Results show that the optimal solutions are strongly influenced by energy costs of the different energy wares, and this can affect the suitable technical solutions for refurbishment. The present work is focused on the definition of different economic scenarios. The aim is to assess a wide economic framework as to determine the influence of the energy cost and discount rate on the costs/benefits analysis and how cost optimal solutions can change according to these trends. Different energy cost variations are considered for electricity and natural gas, which are the most used energy carriers in Italy. The economic framework is applied to four Italian reference buildings to emphasize its influence when different building uses and climatic boundary conditions are considered. Discrepancies in results are then discussed.

x The residential sector contributes largely to energy consumption in Europe: around 40% of the EU energy use (RHC-ETP, 2011). For a massive reduction of the energy consumption in the European residential sector, a common practice is the retrofitting of existing buildings. In this context, multifamily houses (MFHs) are considered to be easier to retrofit, partly because their exteriors are more uniform than single-family houses’ - which makes external insulation and glazing replacement easier to install - and partly because each building contains multiple dwellings - therefore a single action can affect more living area. The purpose of this paper is to report on the design phase of a multifamily house located in Madrid, Spain. The refurbishment concerns the installation of both passive and active solutions. In particular, transmissions through the envelope are reduced by the addition of an insulation layer and new windows. DHW production, space heating and cooling are guaranteed by an air-to-water heat pump. Heating demand and Domestic Hot Water (DHW) production are also partially covered by solar thermal panels installed on the parapet of the building. The impact of the retrofitting measures on the energy consumption have been assessed starting from energy audit data, going through modelling and simulating the building’s envelope before and after the retrofit, and finally analysing the building and energy plant together. The simulation work shows a set of integrated measures suitable to achieve a primary energy consumption for heating, cooling and domestic hot water, lower than 50 kWh/m²y.

x Reduction of energy consumption and the use of energy from renewable sources constitute important measures needed to reduce energy needs for existing buildings. Among all different options, the use of biomass could be an efficient strategy worthy of being explored during the refurbishment design. Although their use has been limited in the Italian legislation for environmental issues (particulate and fine dust emissions), the promising low primary energy conversion factor and their low cost (in comparison with other fossil fuels) allow us to investigate this option. A technical and economic analysis of different system refurbishment, framed in the cost-optimal context, has been addressed, in order to evaluate the feasibility of such interventions. Several case studies (single family house, apartment block, a school and a district made of several single and multi-family houses, served by a district heating system based on biomass) and different strategies have been analyzed: - No interventions on building envelope (installation of a biomass heating system); - Deep renovation of building envelope, with a “traditional” heating system (condensing boiler or heat pump); - A standard renovation of the building envelope and the installation of a biomass heating system. An analysis of the cost of intervention and operation (in terms of euro per kilowatt and euro per kilowatt-hour) is presented, so that it is possible to estimate what the cost-optimal levels are for the different case studies analyzed.

x This paper aims to analyse in existing building refurbishments the complex relation between natural ventilation systems (single sided and cross ventilation, thermal chimney, evaporative cooling tower and earth pipes) and thermal inertia (medium-light and heavy) in the Mediterrean climate represented by three locations, Rome, Naples and Messina. Results show that, assuming equal comfort, the energy reduction potential is 67.7% with single-sided ventilation, 76.5% with cross ventilation, 30.2 with a thermal chimney, 20.1% with a cooling tower and 95.5% with earth pipes (where the consumption is due to the fan). In combination with the above-mentioned cooling strategies, the 30 cm thick wall maintains its role of thermal flywheel, while the 18 cm thick wall shows an excessive reactivity to climatic stresses, resulting in an average of 2.8% greater energy consumption. The scenario in Rome reaches the highest average energy consumption reduction for all the analysed systems (88.0%). Naples follows (83.1%) because of poor performance of the cool tower system (- 23.4%), while the scenario in Messina is last (71.4%) because of the low thermal range that limits the efficiency of all the systems without the pre-treatment of the outside air (-37.4%).

x In developing countries, the phenomenon of informal settlements has increased significantly. For instance, Cairo is considered to have four out of the thirty biggest “mega-slums” in the world, with a total of 11.8 million inhabitants. These settlements occupy 62% of the Greater Cairo area. Sustainable development is urgently needed to ensure better quality of life for now and the following generations. One of the characteristics of informal settlements is having narrow streets and dense urban fabric. Thus, only a small amount of natural lighting enters indoor spaces, which has adverse effects on the physical and psychological health of the inhabitants. This paper aims to identify the most reasonable window ratios in relatively narrow street widths (4, 6 and 8 meters) based on the amount of light reaching the ground floor levels. This paper utilizes brute force procedure based on daylighting performance criterion. The parametric daylighting simulations were conducted using the Diva-for-Rhino, a plug-in for Rhinoceros 3D modeling software, which is used to interface Radiance and Daysim daylighting simulation engines. For the parametric tool, Grasshopper was used to generate the parametric urban model based on a generic case study taken in Cairo, Egypt. This paper presents quantitative results and measurements aiming to help decision makers address development strategies for informal settlements and to provide essential data for setting regulations for newly built urban spaces.

x CFD models have several advantages in comparison with zonal-models, due to the more accurate calculation of the airflow distribution within the built environment. Nevertheless, in currently available CFD software the simulation of mass transfer cannot be directly extended from the fluid region to the solid region. In the whole-building moisture transport studies, the mass coupling between the indoor environment and the wall system is usually achieved by third party programming. The Annex 41 research project of the International Energy Agency (IEA) was carried out to explore the complex physics governing the whole building heat, air and moisture (HAM) transfer, by developing several models to couple 3-D CFD simulations with hygrothermal models of walls. The objective of this study is to develop a coupled CFD model able to simulate the HAM transport in a single environment (i.e. a simple test room), influenced by the room factors. A numerical method was utilized to model the indoor environment and the moisture transport process in the simple room and inside the wall system as influenced by the moisture loads and ventilation conditions. The comparison between the CFD and a lumped model allows us to demonstrate how a simplified model can be reliable in predicting the RH variation inside a room, also taking into account the indoor material buffering effect.

x This paper investigates the effects of altering the glazing size of lounge spaces in Tehran city houses. The magnitude of effects is demonstrated through comparing the energy consumption of various models. A great portion of the global energy consumption and resource depletion is dedicated to the construction sector. Considering the low thermal resistance of windows and their role in a building’s aesthetic, optimizing window to wall ratio is a key factor in the design process. This research attempts to find the optimum glazing area of lounge spaces while monitoring energy consumption and daylight factor simultaneously. A total of 16 samples with different width to length ratios are studied by exploring the minimum satisfactory daylight factor according to BREEAM regulations. Considering the importance of south facades in Tehran city’s urban texture, this paper is concentrated on south façade glazing proportions. Final results indicate that increasing the glazing area of a south façade after meeting the minimum required daylight factor may double the annual energy consumption of a living space. Results also show that altering the window to wall ratio of the south façade has a liner impact on the annual energy consumption of lounge spaces.

x The buildings dating back to the Italian economic boom of the 60s and 70s are the biggest part of the national building heritage. In general they have an envelope with very poor thermal insulation and a central heating system with high energy consumption, sometimes due to the lack of a proper control system, obsolete components and a not balance pipe network. This group of buildings is one of the first targets to be addressed through building renovation and improving plant. Energy retrofitting actions is the main direction not only to provide a reduction in CO2 emissions and money saving but also to achieve thermal comfort for a large number of families. In order to reach both these objectives, a pipe balancing and proper control systems must accompany every kind of envelope upgrading. This paper deals with the interaction between the envelope refurbishment and the optimization of the plant control system in a typical 60s-70s Italian residential multi-floor building served by a central heating system, focusing on a single flat. After a proper calibration of the model, based on experimental measurements of the internal temperature and operating conditions of the heating plant, the dynamic simulation assessed through EnergyPlus was used to analyze the efficiency of different control systems to improve the energy performances: use of climatic curve control, zone control with ambient thermostat or thermostatic valves, and different proportional bands. Simulation results indicate high energy savings.

x The energy saving potential of existing buildings in highly urbanized world areas stimulates interest in the introduction of renovation measures. Due to the high economic impact of those interventions, special attention has to be paid to balance energy and economic performance, leading to the definition of the best combination through multi-objective approach. The recourse to building simulation, to improve the resolution and discrimination capability between different renovation configurations, forces us to consider the quality of the input data and leads to robustness issues for the optimal solution. In this regard, a reliable estimation of the global irradiation incident on various tilted surfaces is essential in order to account for the solar heat gains. Nonetheless, many meteorological stations monitor only global solar radiation on a horizontal plane. As a consequence, a variety of mathematical and empirical models have been proposed in the literature for both the subdivision of horizontal solar irradiation into direct and diffuse components and for the calculation of irradiation on tilted surfaces. Besides introducing inter-model uncertainty, no pair of diffuse and tilt irradiation models can provide results with the same reliability for worldwide localities different from those considered for the definition of each model. This research work investigates the extent to which the choice of solar irradiation models affects the confidence levels of the optimal solutions provided by multi-objective optimizations. With this purpose, several multi-objective optimizations are carried out with different solar irradiation models. Semi-detached houses, penthouses and intermediate flat in multi-storey buildings are analyzed with the purpose of broadening the representativeness of the conclusions.

x The European Committee is encouraging the Member States to adopt the so-called “cost optimal approach” to define new energy performance requirements for new and existing buildings. However, the cost-optimal should not neglect the indoor thermal comfort. The improvement of the building energy performance, especially if related to the addition of high insulation thickness, can increase the risk of overheating. A small energy input raises the internal temperature considerably. Therefore, in order to move beyond the mere economic optimization of retrofit interventions, it is important to understand what the solutions able to enhance the performance of the buildings are, also in terms of thermal comfort. In this paper, this problem has been investigated. The analysis has been carried out on a set of different residential building modules, representative of different building typologies and construction periods, located in two different climatic contexts. By means of a multi-objective optimization approach, the best combination of EEMs has been defined first optimizing only the energy and economic aspects, then the indoor thermal comfort has been added and the optimization re-run. A Genetic Algorithm (NSGA-II) coupled with a simulation tool has been used to optimize the different objectives.

x The European energy policy is strongly promoting the refurbishment of buildings and this affects the energy and economic performance of the district heating (DH) systems. The refurbishment of buildings connected to a DH system leads to the under-utilization of the DH capacity. This paper aims to define the energy and economic performance of a district heating (DH) considering the impact of cost-optimal refurbishment solutions of the connected buildings. For this purpose, an integrated model for both buildings and network has been developed. Several refurbishment measures for the existing buildings have been investigated and a multi-objective (energy and economic) optimization has been conducted, by means of a genetic algorithm. The possibility to shift to a low-temperature DH and the implementation of a CHP system have been investigated as feasible solutions to compensate for the loss of performance of the network. The results highlight that the building refurbishment strongly influence both the energy and economic performance of the DH system. The DH performance is considerably low when a high number of refurbished buildings is considered in the district. The implementation of the minimum network temperature allows for a partial compensation for both the energy and the economic losses deriving from the refurbishment. However, this measure is not sufficient for a profitable DH. The installation of a CHP system in the network, thanks to the revenue from the electricity trade, allows for a profitable operation of DH network with a heat density of 0.15 MWh (m year)-1. Although the installation of a CHP system is economically convenient, its primary energy saving (PES) index is negative for such a micro DH networks.

x A modified hotbox facility has been used at the Free University of Bozen-Bolzano to measure heat fluxes under a periodic pulse solicitation for some timber structures with different number and kind of layers. The simplest one – a single layer timber structure, has also been modelled with ANSYS Fluent® and the results compared to the experimental data for validation. Then, the numerical model has been used to study different forcing signals and boundary conditions. In order to characterize the response to a periodic dynamic solicitation with simple indexes, the EN ISO 13786:2007 (CEN, 2007) dynamic parameters have also been calculated.

x The aim of this paper is to present the conceptual framework of a TUBİTAK funded project titled “Developing a New Methodology to Improve Housing Quality in Turkey Based on Effects of Occupant Behavior on Energy and Comfort of the Dwellings”. Although the objective of the project is the development of new methodologies and tools to be used for the definition of effects of behavior profiles of housing occupants on the energy consumption and usage of this knowledge for building new houses and renovation of existing buildings, here the first step of research has been executed. By defining sensitivity of occupant behavior on energy consumption, it is planned to classify different models of occupant behavior. With data provided, the aim is to develop an “occupant behavior labeling” which rates occupants instead of buildings. To provide the mentioned data, sensitivity analysis of existing occupant behavior will be analysed based on the Monte Carlo Methodology. This methodology is one of the most used methodologies to analyse accurate distribution of possible outputs relied on inputs based on probability. Inputs for this research are (1) number of occupants for each space (for weekdays and weekend) (2) behaviour for ventilation (Window open/closed and mechanical ventilation on/off) (3) control of heating systems (radiator on/off and/or thermostat degree). These data will be provided with survey and data logging of chosen a house occupant group. As a consequence of the research, the aim is not only to rate the behavior of housing occupants but also determine occupancy groups/labels. With this approach, based on occupant’s behavior labeling, the aim is to realize fast and affective applications for renovation of existing buildings. Moreover, by evaluation/assessment of houses which will be designed in the future based on determined occupant profiles allow to produce high performance dwellings.