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• A novel MOF-based paper sheet was developed for passive indoor moisture control. • The MOF paper sheet has excellent moisture buffer capacity and mechanical properties. • A numerical model was developed to find the optimal thickness of the MOF paper sheet. • The energy-saving potential of wallpaper made of MOF paper sheet was investigated. Passive indoor moisture control is a meaningful way to reduce HVAC operation and improve building energy efficiency. Metal-organic frameworks (MOFs) have been considered one of the most promising sorbent materials for passive indoor moisture control. However, the powder form of MOF is challenging to use in the built environment. Typical shaping methods like pellets, beads, and coating can lead to problems like partial pore blocking, insufficient mechanical stability, amorphization, and low material utilization. Here, we report a new sustainable MOF paper sheet comprising 25% cellulosic fibers and 75% MOF MIL-100(Fe) powder. The porous polymer matrix provides good support and fixation for MOF particles, so it's more applicable in the built environment. The crystalline and pore structure characteristics of the MOF in the membrane are well preserved. Hydro characteristic test results show that MIL-100(Fe) paper sheet has high water vapor uptake, S-shape isotherm, mild regeneration condition, and high MBV. Then, a numerical model was developed to calculate the relation between a material's MBV and its thickness. MIL-100(Fe) paper sheet with the most efficient thickness was applied as wallpaper in a building energy simulation model. The simulation result shows that the MIL-100(Fe) paper sheet is promising for passive indoor moisture control. It can remove about 45%-55% of the latent cooling load in most European climate types. [ABSTRACT FROM AUTHOR]

As the built environment is among the main contributing sectors to climate change, it is needed to investigate new paradigms to push decarbonization efforts towards the ambitious objectives defined internationally. It is a shared understanding that shifting the perspective from the single building to the district perspective is required to fully take into consideration the complexity of all interactions undergoing within the built environment, thus the concept of Positive Energy District emerged as a district with annual net zero energy import and net zero CO 2 emission working towards an annual local surplus production of renewable energy. In this framework, this paper explores the investigation of the potential for achieving the level of Positive Energy District in a group of non-residential buildings in Balaguer, Catalonia, Spain. These buildings, occupying 8,825 m2 in the city centre, require significant refurbishment for improved energy performance. The analysis includes building energy modelling and simulation, renovation studies, several alternative balance calculations, and carbon emissions assessment. The paper also considers mobility and embodied energy and their impact on energy/carbon balances. The results show that Positive Energy Districts carbon and primary energy balances are not met with rooftop PV installations when retrofitting an existing district towards the Positive energy target but further significant PV areas (roughly + 50%) are required to meet merely the use stage balances: negative results are traced when mobility and embodied energy are computed. A formulation alternative to the simple mathematical balance to facilitate the diffusion of Positive Energy District as catalyst of urban decarbonisation could be needed, including context factors and alternative systems (e.g., rating systems). [ABSTRACT FROM AUTHOR]

Highlights • A new experimental procedure to test PCM-enhanced components is presented. • A modified Dynamic Heat Flow Meter Apparatus is used to perform the tests. • The thermal conductivity of PCMs is measured in different phases (solid-liquid). • Indications to solve the issues related to building PCM-specimens are provided. Abstract The implementation, in Building Performance Simulations (BPS) tools, of robust models capable of simulating the thermophysical behaviour of a Phase Change Material (PCM) represents a fundamental step for an appropriate thermal evaluation of buildings that adopt PCM-enhanced envelope components. Reliable and robust measuring procedures are essential, at a material and component level, to provide experimental data for the empirical validation of software tools. The traditional laboratory tests that are generally used for the validation of models present some limitations, because PCMs are usually subjected to conditions that may be very different from the real boundary conditions of the building components in which PCMs are applied. Furthermore, in many experimental full-scale mockups, the relatively small quantity of installed PCM and the combination of several thermal phenomena do not allow software tools to be tested in a reliable way. In this paper, an experimental procedure, based on a modified Heat Flow Meter Apparatus, has been developed to test the behaviour of PCM-enhanced components; the procedure, which is based on the measurement of the sinusoidal response, has been set up to provide data for the comparison and testing of numerical models and of BPS tools. Moreover, general indications and guidelines are provided to solve some issues related to building specimens that contain bulk PCM in order to obtain a more accurate measurement of their performance. The experimental results presented in this paper were obtained from two different bulk PCMs (organic and inorganic). It was found that it is important to evaluate different PCM typologies and different thermophysical boundary conditions, including partial and full phase transitions, to test simulation codes that implement PCM modelling functions. In fact, some phenomena, such as hysteresis and subcooling effects are more evident when partial phase transition takes place. The results related to the characterization of the thermal conductivity of a paraffin-based PCM have shown a significant increase (up to 42%) of the equivalent thermal conductivity from a solid to a liquid state, with an upward heat flux, thus highlighting that further investigations and improvements are needed to measure the equivalent thermal conductivity in the different PCM phases. [ABSTRACT FROM AUTHOR]

Occupancy is one of the main factors affecting building energy consumption. The occupancy data, which refer to the occupancy number in this paper, has been widely used in the building simulation field. However, due to the stochastic nature of occupant behavior, it is hard to predict and measure how many people stay in a given building. The rapid development of mobile Internet technology provides an efficient and convenient option for occupancy detection. This paper proposes a concept of typical occupancy data (TOD), which are extracted from real-time occupancy data collected by mobile devices. K -means algorithm is employed to generate the TOD data through cluster analysis. An energy performance model of an office building is used as a case study to demonstrate the effectiveness of the TOD data. [ABSTRACT FROM AUTHOR]

The paper presents an energy simulation-based study to investigate the impacts of climate change on energy consumptions of an office building located in five different cities, United States. Annual energy consumption of a medium-size office building was predicted by building energy simulation software—EnergyPlus using TMY3 weather data and future climate data. In this study, we have used two sets of further climate data with different climate models including (1) Hadley Centre Coupled Model, version 3 (HadCM3), and (2) NCAR Community Earth System Model version 1 (CESM1) with the Community Atmosphere Model version 5 (CAM5). A morphing method was applied to downscale the monthly weather forecast to hourly forecast for use in building energy simulation for the two General Circulation Models (GCMs): HadCM3 and CESM1. Using the generated future weather files, HVAC operation related mitigation measures including adjustment of thermostat setpoints, reduced HVAC operation hours, reduced VAV box minimum flow setting, and mixed-mode ventilation were simulated to compare with ASHRAE Standard 90.1 baseline simulated using TMY3 weather data. Simulation results on predicted whole building, heating and cooling energy consumptions were examined. The paper highlighted the importance of efficiently operating mechanical systems in buildings to ensure a more sustainable future. [ABSTRACT FROM AUTHOR]

In this paper we propose an algorithm to find optimal design of skylight for a one-storey office building while saving source energy consumption. The algorithm simultaneously couples daylighting with energy performance and compares different ratios of skylight to floor area based on both lighting and HVAC loads. Our method integrates different simulation tools with numeric optimization and exhaustive search to find the optimal ratio. More specifically we implemented EnergyPlus as a thermal engine and Radiance as a daylight engine, both of which are embedded in Ladybug and Honeybee. As Ladybug and Honeybee is a plugin for Grasshopper, we developed the algorithm in Grasshopper environment. We used Python and Grasshopper to integrate different simulation tools and implemented two methods of numeric optimization (gradient descent) and exhaustive search (parametric analysis) in order to validate the final result. After applying the proposed algorithm for a small office building in San Francisco, both methods coincide that the optimal skylight to floor ratio is 5.5–6% while decreasing the energy demand by 19%. The experiments show that the energy efficiency only occurs for skylight ratios of 3–14%. In addition, we used sDA and UDI metrics to analyze daylighting performance of each parametric scenario. We infer that only a specific range of skylight ratios that are energy efficient (5–10%) provide adequate daylight and avoid glare. The integrative process and optimization method proposed in this paper enable designers to find a robust energy efficient skylight design. [ABSTRACT FROM AUTHOR]

Building simulation tools have been widely used for performance assessment. However, many studies [1] have reported that a performance gap exists between the reality and simulation output, mainly caused by unknown simulation inputs. Therefore, model calibration needs to be introduced. Calibration attempts can fail for the following reasons: coarse initial simulation model, long sampling time, uncertainty in the model, and sensor errors. The aim of this paper is to address the abovementioned issues. For this study, an existing office building was selected and two calibration approaches were presented: deterministic vs. stochastic. For stochastic calibration, a Gaussian Process Emulator (GPE) was introduced as a surrogate of the EnergyPlus model. The stochastically calibrated model performs better than the deterministically calibrated model. It is concluded in the paper that (1) the calibration quality is influenced by the degree of the details of the initial model, (2) the accumulated measured data under a sampling time of up to one day (e.g. gas energy consumption) might be unsuitable for calibration work due to the lack of ‘time-series trend’, and (3) the calibration quality is also influenced by sensor errors and further calibration needs to take these into account. [ABSTRACT FROM AUTHOR]

Building energy models (BEMs) are typically used for design and code compliance for new buildings and in the renovation of existing buildings to predict energy use. The increasing adoption of BEM as standard practice in the building industry presents an opportunity to extend the use of BEMs into construction, commissioning and operation. In 2009, the authors developed a real-time simulation framework to execute an EnergyPlus model in real time to improve building operation. This paper reports an enhancement of that real-time energy simulation framework. The previous version only works with software tools that implement the custom co-simulation interface of the Building Controls Virtual Test Bed (BCVTB), such as EnergyPlus, Dymola and TRNSYS. The new version uses an open standard interface, the Functional Mockup Interface (FMI), to provide a generic interface to any application that supports the FMI protocol. In addition, the new version utilizes the Simple Measurement and Actuation Profile (sMAP) tool as the data acquisition system to acquire, store and present data. This paper introduces the updated architecture of the real-time simulation framework using FMI and presents proof-of-concept demonstration results which validate the new framework. [ABSTRACT FROM AUTHOR]

Bayesian calibration of building energy simulation (BES) has gained growing attention for its capability to tackle uncertainties and narrow the gap between simulated and measured results using expert knowledge. However, how output or parameter correlations influence single-output Bayesian calibration (SOBC) and multiple-output Bayesian calibration (MOBC) for BES has not been investigated and compared. Hence, this paper intends to determine the impacts of output or parameter correlations and data informativeness on BC of BES. Aiming to leverage multiple outputs' correlations while comparing with traditional SOBC in calibration performance and computation cost, we also developed the MOBC model. Compared to including weakly correlated outputs or parameters, the results show that strongly correlated outputs or parameters in MOBC reduce the Coefficient of Variation of the Root Mean Squared Error (CVRMSE) by 5.56% and 4.729% respectively and bring notably better Continuous Ranked Probability Score (CRPS) results. Conversely, including strongly correlated parameters in SOBC causes worse model performance. These results reflect that SOBC has parameter identifiability issues that MOBC can solve. The findings contribute to our better understanding of the impacts of (1) output or parameter correlations and (2) different data streams' informativeness on the calibration performance of SOBC and our developed MOBC for BES. • Employed multiple-output Bayesian calibration (MOBC) on building simulation. • Quantified the impacts of parameter and output correlations separately. • More data does not mean better building energy model calibration performance. • The single-output has parameter identifiability issues, which MOBC can ease. • Output/Parameter correlations can be exploited by MOBC for better performance. [ABSTRACT FROM AUTHOR]

In the era of post-Coronavirus Disease 2019, the dedicated outdoor air system (DOAS), which provides 100% outdoor air for the building, is widely acknowledged as it can ensure acceptable indoor air quality by delivering fresh outdoor air to occupied space. The DOAS with a proper design and operation can provide sufficient ventilation and dehumidification while achieving energy efficiency. Nonetheless, there is limited guidance in determining the optimal control sequence of the DOAS for the designers and operators to implement in practice. Accordingly, in practice, a number of issues have been acknowledged in the design and control phases of DOAS, including insufficient ventilation and dehumidification, and increasing supply air dry-bulb temperature in fear of over-cooling, which might cause significant discomfort and energy waste. There have been efforts to develop high-performing DOAS controls for better energy efficiency. However, such controls are often complex, or difficult to interpret, for building designers and operators to consider in practice. In this regard, this paper explores a simulation-based framework for generating a supply air temperature control sequence of the DOAS not only to ensure improved energy-saving potential but also to guarantee the implement-ability of the control logic. The U.S. Department of Energy prototype primary school with dynamic occupancy profiles was modeled with a whole building simulation program, EnergyPlus. The model consists of a DOAS with an exhaust air energy recovery system for ventilation and fan-coil units for space cooling and heating. Then, a Genetic Algorithm was adopted to find the true optimal supply air temperature control sequence in terms of minimizing the energy cost of the heating, ventilation, and air conditioning system operation. Lastly, Decision Tree was adopted to extract rules out of the optimums to derive an implementable sequence of operation for the DOAS supply air temperature. A total of 12 week-simulation including four weeks of heating, cooling, and shoulder seasons, separately, under the weather condition of New York City was conducted for the case study. This case study identified that the optimization-informed rule extraction-based control, when compared to conventional outdoor air temperature-based reset control, could save about 13% of energy cost and 25% of energy consumption throughout the heating, cooling, and shoulder seasons. It is notable that the energy-saving was mainly achieved by reducing the heating energy consumption. Importantly, it nearly corresponds to the true optimal control result, which reduces approximately 14% of energy cost and 27% of energy consumption. From the results, it can be highlighted that the optimization-informed rule extraction can be as energy effective as the optimal control, while significantly reducing the complexity of the control. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the key factors methodology that supports energy managers in determining the optimal building operation strategy in relation to both energy consumption and thermal comfort. The methodology is supported by the utilization of calibrated building energy simulation models that match measured data gathered by an extensive measurement framework. Building management systems, do not allow energy managers to test the impact of changes in control settings of energy systems on energy consumption and thermal comfort. The proposed methodology and prototype tool chain enables energy managers to virtually develop and test the impact of proposed changes to the control settings in the building energy systems prior to their implementation in the physical building. The paper outlines the proposed methodology defining the underpinning concepts and illustrating the performance metrics required to capture the effect of different building operation strategies. A case study is discussed to demonstrate the application of the methodology. [Copyright &y& Elsevier]

Abstract: This paper reports the use of an internationally recognized validation and diagnostics procedure to test the fidelity of a simplified calculation method. The case study is the simplified model for calculation of energy performance of building envelopes, introduced by the Brazilian regulation for energy efficiency in commercial buildings. The first step of the assessment consisted on evaluating the simplified model results using the BESTEST. This paper presents a straightforward approach to apply the BESTEST in other climates than the original one (Denver, USA). The second step of the assessment consisted on applying the simplified model to evaluate four building typologies, and compare the results with those obtained using a state of the art building energy simulation (BES) program. For some BESTEST cases, the simplified model presented results inside of a confidence interval calculated by the authors. However, the simplified model was found to yield significant difference in the four building typologies analysed. Moreover, in all four building typologies analysed, the simplified model led to a lower energy efficiency label when compared to the label obtained using BES. The paper concludes that the simplified model may require improvements to properly indicate the actual energy performance of commercial building envelopes. [Copyright &y& Elsevier]

Highlights • Our equivalent wall method uses the structure factors and harmonic heat fluxes. • The method is tested on three 2-D thermal bridges. • The comparison is based on numerical simulations results. • For a realistic, severe or step evolution of outside temperature, results are precise. • Equivalent walls results are much better than those for a classic 1-D evaluation. Abstract This paper presents a mixed method to determine a 1-D three-layer wall having the same static and dynamic behaviours as a multidimensional thermal bridge. It is based on the calculations of thermal resistance, heat capacity, structure factors and an objective function using harmonic heat fluxes features. This mixed method is applied to three 2-D details. The heat flux through inner surface is analysed over time for a step solicitation and for given boundary conditions: a sinus evolution of the inside temperature and a severe or a more realistic evolution of the outside temperature. Results are really satisfactory, evolution of heat flux through the thermal bridge is close to that of the corresponding equivalent wall. For an outside temperature profile (T e) close to real data, the error on integral value of heat flux is less than 1% in each case. The results for equivalent walls are significantly better than for a classic 1-D evaluation: for a severe evolution of T e the average error is 6 to 28 times lower in the tested cases. [ABSTRACT FROM AUTHOR]

Abstract: Building energy simulations are key to studying energy efficiency in buildings. The state-of-the art building energy simulation tools requires a high level of multi disciplinary domain expertise from the user and many technical data inputs that curb the usability of such programs. In this paper an IT tool is presented, which has the capability of predicting a building''s energy utilization configuration based on the reported annual energy and a few non-technical inputs from the user; and correspondingly generates cost effective energy conservation measures for the intended savings. The approach first identifies the system variables that are critical to a building''s energy consumption and searches for the combination of these parameters that would give rise to the annual energy consumption as reported by the facility. Genetic algorithms are utilized to generate this database. A statistical fit is formulated between the system variables and the annual energy consumption from the database. Using this correlation, system configuration for the target energy efficiency is determined with corresponding energy conservation measures. A cost analysis is carried out to prescribe the most cost effective energy conservation measures. Competency of the tool is demonstrated in the paper through case studies on three geographies with different climate conditions. [Copyright &y& Elsevier]

Abstract Parallel fan-powered terminal units (FPTUs) are widely considered more energy efficient compared with series FPTUs because of the intermittent terminal unit fan operation. Recent studies found that the energy savings potential of parallel FPTUs may be overestimated due to the primary air leakage through the backdraft dampers when terminal unit fans are not operating. However, the lack of an effective modeling approach in building simulation programs has prevented the thorough investigation of how the primary air leakage from parallel FPTUs affects the energy consumption of variable air volume (VAV) systems. In this paper, a modeling approach was developed and implemented in EnergyPlus using the Energy Management System (EMS) for the comparative analysis of energy impact of primary air leakage from parallel FPTUs. A series of building energy simulations were also conducted at four air leakage levels under five different U.S. climates. Although the percentage energy increases caused by the primary air leakage vary with local climates and leakage levels, simulation results show consistent increases in the energy consumption of central cooling coil, central supply fan, and FPTU supplemental heating throughout all the climates as the air leakage level increases. Compared with series FPTUs, the energy savings potential of parallel units significantly decreases as air leakage level increases. At the highest air leakage level of 15% simulated in this study, series FPTUs may use less energy than parallel FPTUs. [ABSTRACT FROM AUTHOR]

A building influences its surrounding external environment, and its indoor environment is usually sensitive to its surroundings. In order to obtain a more accurate prediction of the indoor thermal behaviour of a building or a building stock, it is necessary to consider the interactions between the indoor and outdoor thermal environments. The modelling approach presented in this paper is based on a building energy model and the urban modelling tool SOLENE-Microclimat. A sensitivity analysis is undertaken to highlight the parameters which influence the performance of the building model. Then, the thermal indoor behaviour of a building is compared to in situ experimental measurements and the outdoor thermal environment is evaluated in terms of external surface temperatures. The model's accuracy and behaviour is evaluated and a crossover approach with the sensitivity analysis results is proposed. The model obtains a good level of performance for almost all variables, unless some external surface temperatures intervals. [ABSTRACT FROM AUTHOR]

Greenhouse gas emissions have been recognized as one of the major cause of the global warming phenomena. The built environment accounts for more than 40% of the overall energy consumption and 36% of the overall CO2 emissions in Europe. Recent studies show that housing is one of the most responsible sector for world ecological impacts. The European Parliament developed the concept of Nearly Zero Energy Buildings (NZEB), characterized by a very low energy demand and a high renewable energy on-site production. In fact, energy efficiency is the first step towards the ambitious aim to reduce of 80% by 2050 the EU carbon emissions. The zero-energy building target is an achievable goal, which relies on a careful design that encompasses a synergy between passive and low-energy strategies. However, considering the whole life cycle of buildings, NZEBs reduce the operational energy close to zero, increasing the relevancy of the embodied energy, which occurs during the construction phase. Balancing the values of the operational and embodied energy is necessary to minimize buildings footprint on the environment. In this paper the renovation and re-use of the Atika building, a demonstrative energy-efficient building, is presented as case study of an environmental efficient methodology for energy retrofitting. The case relies on the methodology developed by Active House, a holistic vision for sustainable buildings labeling. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of the open literature on motivations, methods and applications of linking stratified airflow simulation to building energy simulation (BES). First, we reviewed the motivations for coupling prediction models for building energy and indoor environment. This review classified various exchanged data in different applications as interface data and state data , and found that choosing different data sets may lead to varying performance of stability, convergence, and speed for the co-simulation. Second, our review shows that an external coupling scheme is substantially more popular in implementations of co-simulation than an internal coupling scheme. The external coupling is shown to be generally faster in computational speed, as well as easier to implement, maintain and expand than the internal coupling. Third, the external coupling can be carried out in different data synchronization schemes, including static coupling and dynamic coupling. In comparison, the static coupling that performs data exchange only once is computationally faster and more stable than the dynamic coupling. However, concerning accuracy, the dynamic coupling that requires multiple times of data exchange is more accurate than the static coupling. Furthermore, the review identified that the implementation of the external coupling can be achieved through customized interfaces, middleware, and standard interfaces. The customized interface is straightforward but may be limited to a specific coupling application. The middleware is versatile and user-friendly but usually limited in data synchronization schemes. The standard interface is versatile and promising, but may be difficult to implement. Current applications of the co-simulation are mainly energy performance evaluation and control studies. Finally, we discussed the limitations of the current research and provided an overview for future research. [ABSTRACT FROM AUTHOR]

Increasingly compact high density urban development in cities has allowed urban heat island effect to take root and increase the energy consumption of commercial buildings to cool its interior. Although the extensive use of glass façade has allowed these buildings to harness daylight to light up the building interior, it has also allowed substantial solar energy to enter and heat up the building. This is especially critical in hot and humid tropical regions, where reducing solar heat gain, while minimizing heat loss are equally important. The evaluation of glass performance is often conducted using active measurement, which make use of known radiant source. However, this type of setup cannot be applied for testing under non-controlled weather. Though a passive test procedure can be conducted under actual weather conditions using the outdoor test chamber, it is not suitable for a large-scale testing and fast on-site characterization. In addition, this test is limited to the fabricated glazing and thus could not predict potential issues in the design stage. Advances in simulation techniques have enabled building professionals to evaluate the glass façade of a building at the design phase. However, the typical simulation tools are unable to integrate the high performance glazing description, which is generated thanks to advances in coating technology, using the existing glass models. Furthermore, these tools are often lack of local weather models that plays an important role in accurately assess the solar heat gain admitted into the building. This paper provides useful information on different high performance glass façades and assesses their applicability for green building in a tropical country like Singapore. The research effort encompasses an improvement in the methodology used to predict solar irradiance through building glass that incorporates seamlessly the advanced glass models into the solar irradiance simulation. In addition, this will show how to effectively estimate the actual sky behavior via a measured data-based optimization process. A comparison of the simulation results with the measurements from an outdoor climatic test chamber under tropical climate will be performed. An assessment based on the typical glass performance metrics (e.g. U-value and Solar-Factor) together with measured energy savings obtained with the use of different high performance glass façade compared to clear float glass as a control will also be presented. [ABSTRACT FROM AUTHOR]

An urban energy use map that illustrates the building energy consumption of a city can facilitate the formulation of energy policies. This paper used dynamic simulations of building energy consumption and building information from a geographic information system were used to develop urban energy use maps with high spatial resolutions for two urban areas in southern Taiwan. 4000 models for typical residential layouts in Taiwan were generated through the Monte Carlo method and the benchmark values of the buildings’ energy use intensity (EUI) were identified through building energy simulation and uncertainty analysis. Accordingly, the benchmark EUI values, building data, and population data were used as input parameters to derive a convenient equation for predicting energy consumption in each grid of the urban energy use maps. A comparison of the measured and predicted energy consumptions confirmed the precision of this equation. To sum up, relevant data are readily available and can be exploited to prepare urban energy use maps for other large cities in Taiwan. Moreover, the urban energy use map with high spatial resolution can present the differences in small areas, making it an important reference aid for determining energy policies [ABSTRACT FROM AUTHOR]

This paper evaluates a parametric analysis towards compliance with the nZEB standard, which in Spain is defined by the latest update of the Technical Building Code. This regulation is critically assessed regarding its ability to promote the concept of cost optimization, promote renewable energy sources and minimize primary energy consumption in the residential sector. To this end, a virtual building was defined and multiple designs were evaluated using DesignBuilder software. A set of 170 alternative scenarios was established and parametrically evaluated for five cities representing the five climatic zones of inland Spain (Bilbao, Burgos, Seville, Madrid and Almeria). The results were evaluated focusing on cost-cost effectiveness and primary energy consumption values for the different scenarios, evaluating them in relation to the minimum requirements set by the regulation. The great potential of photovoltaic energy is highlighted, which allows negative values to be obtained for the two Equivalent Uniform Annual Costs due to the cost avoided through self-consumption. This fact makes the optimal designs tend to electrification, specifically through air and ground source heat pumps. It is worth mentioning that the new Code has only established a minimum target for renewable self-consumption in the residential sector, which should be reinforced in future updates. [ABSTRACT FROM AUTHOR]

School buildings have a great potential for carbon emission reduction since their annual emission is about 72 million metric tons. Currently, more than 30 % of school buildings were built before 1960 and are underperforming. To effectively reduce carbon emissions via school building retrofits, it is critical for policymakers to understand the carbon intensity reduction potential of retrofitting school buildings in different regions. Hence, this study develops a method to comprehensively assess the long-term carbon intensity reduction potential of aggregated commercial buildings on a county-by-county basis in the continental U.S. We apply this method to the K-12 school buildings including primary and secondary school buildings. This paper predicts the carbon intensity reduction potential of K-12 school buildings with eight building retrofit measures from 2022 to 2050 in the continental U.S. The results reveal several interesting findings: (1) In the approximately 3,000 counties of the U.S. from 2022 to 2050, the carbon intensity reduction potential of retrofitting K-12 school buildings in each county ranges from 0.41 kg/m2 to 40.00 kg/m2. (2) Even in the same climate zone, the trends of carbon intensity reduction potential from 2022 to 2050 are different depending on their electricity sources. For example, in a hot and humid climate zone, the carbon intensity reduction potential in Florida will decrease from 2044 to 2048. However, in Mississippi, the carbon intensity reduction potential from 2044 to 2046 will increase due to the termination of the nuclear energy usage. (3) Generally, reducing lighting power density leads to more carbon intensity reduction in most states, but it might not be applicable for states with high clean energy penetration, such as Washington. [ABSTRACT FROM AUTHOR]

In residential buildings, occupant behavior and occupancy status have a significant impact on energy consumption variation. Although the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recommends a uniform occupancy schedule for building energy assessment, occupant behavior patterns and schedules could be different for each building due to occupants’ lifestyles, preferences, occupations, and other differences. Existing occupant behavior models focus on analyzing occupants’ sociodemographic characteristics to predict their energy consumption with statistical approaches. This paper proposes to identify and classify occupants’ behavior with direct energy consumption outcomes and energy time use data through unsupervised clustering. Based on the American Time Use Survey (ATUS), the proposed approach integrates k-modes clustering and demographic-based probability neural networks and identifies 10 distinctive behavior patterns. With the results of the behavior classification and simulation, a bottom-up engineering model reveals that the proposed behavior model offers a more accurate and reliable prediction than the ASHRAE standard schedule. With qualified and sufficient time use data, the model is capable of automatically estimating energy consumption on even larger geographic scales. [ABSTRACT FROM AUTHOR]

Several studies analyze the thermal performance of vegetated roofs, presenting either mathematical models or experimental quantifications of heat transfer process through them, also showing the effect of vegetation and soil parameters on the thermal and energy performance of this type of roofing system. However, presently the level of availability of these parameters, has not been enough considered. This work intends to investigate this underestimated issue of the green roofs’ thermal modeling, through the consideration of the availability of parameters pertinent to the shortwave radiation exchange, which are adopted by models based on leaf area index (LAI) and on the fractional vegetation coverage (σ f ). From the analysis of these models, the importance of a precise knowledge of such parameters arises, despite the availability of their values is still limited. In addition, the absence of a proper database including several green roof plant species and information on their stage of growth, to which a technician possibly will refer in the case of lack of field data, represents quite a worthwhile matter because it may lead to inaccurate estimations of the thermal loads for climatization of buildings equipped with green roofs. In this respect, the manuscript reports an estimation of the errors potentially occurring when not specific vegetation data are used. This evaluation is based on simulations, performed with the DesignBuilder © software, showing the energy effects produced by different assumptions in the green parameters (that is by adopting experimental data revealed by authors and a potential mix of the literature available parameters). Thus, the mission of the paper is to enlighten a difficulty that a technician possibly will encounter when performing an energy and thermal simulation of a green roof; therefore a strong call for making the current database more tailored on green roofs has also arisen. [ABSTRACT FROM AUTHOR]

• Development of energy signature method using data before and after deep renovation of a multi-family building. • Comparison of the proposed energy signature method with building energy simulation program IDA ICE. • Prediction of domestic hot water circulation losses using energy signature method. • Prediction of heat loss coefficient using energy signature method. Building energy use constitutes a large part of total energy use, both in the European Union and Sweden. Due to this energy use, and the resulting emissions, several goals for energy efficiency and emissions have been set. In Sweden, a large portion of multi-family buildings were built between 1960 and 1980, which have major energy savings potential. The purpose of this paper is further development and validation of previously introduced energy signature method and its inherent parameters. The method was applied on a multi-family building where thermal energy data supplied by the district heating company was available before and after deep renovation. Using IDA ICE, a building energy simulation (BES) software model was created of the building, to aid in validation of the energy signature method. The paper highlighted the accuracy of the proposed energy signature (PES) method and a sensitivity analysis on the inherent parameters have been performed. The results showed new ways of treatment of the thermal energy data and revealed how more information can be extracted from this data. [ABSTRACT FROM AUTHOR]

• A systematic literature review on the SA for building application was provided. • Key information about the SA case studies was extracted, summarized, and analyzed. • Pros and cons of the mainstream methods for SA and sampling were summarized. • Practical advice on the selection of the sampling and SA methods were given. A building system is highly nonlinear and commonly includes a variety of parameters ranging from the architectural design to the building mechanical and energy system. Serving as a powerful tool to understand the complicated building system, sensitivity analysis (SA) has been receiving increasing attention in the recent decade. This review paper focused on the application of SA in the building performance analysis (BPA). First, the existing review papers on the application of SA for BPA were briefly reviewed and summarized. Then, a large amount of recent SA case studies in BPA were reviewed. The critical information regarding the implementation of a SA, such as the sampling method, the SA method, etc., were extracted and summarized. Next, an extensive analysis was performed to evaluate the role of the SA in the BPA. This includes: 1) The typical selection of the input and output parameters for the SA were visualized; 2) The uncertainty level and sampling strategies for the input parameters were investigated; 3) The principles, benefits, and drawbacks of the SA methods were analyzed and summarized; and 4) The various tools used in the SA, including the simulation software, sampling tools, and SA tools were introduced to facilitate the practitioners. Lastly, several conclusions were summarized on the role of the SA in the BPA. Suggestions were also provided to offer practical solutions to the current challenges. [ABSTRACT FROM AUTHOR]

Occupant behavior is a major contributing factor to building energy consumption. Large discrepancies might occur when occupants with diverse types in terms of behavior patterns reside in an identical building. Moreover, it is vital to derive several kinds of typical occupant behavior that represent the assemblage of occupants in a simplified way as the reference for building designers and energy policy makers. This paper presents a preliminary research on occupant behavior categorization through the building energy simulation, where some typical occupant air-conditioning behavior patterns use in Chengdu, China have been derived from a large-scale questionnaire survey based on the energy consumption levels. These typical occupant behavior patterns could be used as the context for an overview of building energy in a community, as well as the evaluation of building energy-saving technology where occupants are involved. Further efforts are required in the algorithm of dividing occupant behavior into typical patterns, the validation of the classification results, and the analysis of other behaviors. [ABSTRACT FROM AUTHOR]

Since some years, dense cities and compact buildings are promoted as sustainable and energy efficient designs. Nevertheless, urban planning strategies should take into account the interactions between buildings and the microclimate because the Urban Heat Island (UHI) phenomenon can increase the cooling load of buildings and is strongly influenced by urban morphology, urban landscaping and the thermal properties of buildings and soil. The modification of these parameters, such as building density, can mitigate UHI, with direct and indirect improvement of building energy performances. The case study presented in this paper concerns a new district in La Rochelle (France) named Atlantech. Currently at the design stage, the goal is to transform this old military camp into a zero carbon district. This study was performed in parallel with urban planning using EnviBatE and SOLENE-Microclimate simulation. Two building densities are compared through the impacts on solar irradiance, wind airflows, building indoor temperatures and energy demand. Analysis of reference and densified district highlights various impacts such as the wind velocity decrease, up to 80%, and the effect on an existing nearby building solar irradiation, reduced by 7%. These results underline the potential usefulness of these simulation tools for urban planners at the design stage. [ABSTRACT FROM AUTHOR]

The objective of this study is to understand the role of life cycle analysis (LCA) in building system design process based on survey inputs from building system designers and a numerical sensitivity analysis. This paper first presents findings on the perceived importance of building life cycle assessment completed by 96 practicing designers from August 2012 to April 2013. The majority of respondents, approximately 70%, work as building system designers in the U.S. The building system designers are divided into three categories: (1) enclosure system designers, (2) mechanical system designers, and (3) designers working on both systems. One of the major survey findings is that life cycle assessments are much less used in building system design than energy simulations. The primary reason for performing a life cycle analysis for a building design project is a requirement from a building owner. Furthermore, Fisher's test shows that respondents’ profession, company size, and work experience have significant correlations with the deployment of energy simulations and life cycle assessments in building design projects. ANOVA-based analyses demonstrate that there is no statically significant difference among the three categories of system designer responses on the importance of building components and design selection criteria. Interestingly, the sensitivity analyses performed for the medium size DOE (Department of Energy) reference building indicate that wall assemblies have a much larger impact on building life cycle costs than window properties. The comparison between sensitivity analysis and survey results indicates that the influence of window properties on life cycle cost is over estimated by most of the surveyed participants. Overall, this study revealed that LCA is still not widely used in the building industry even though it would help address design biases toward building systems that do not deliver the expected performance. [ABSTRACT FROM AUTHOR]

Control strategies of building shading devices can achieve important savings in the air conditioning and lighting energy consumption of a building. Calculation procedures of the different solar control devices (overhangs, side fins, etc.) are of special interest in annual energy performance simulation programs, which have to obtain solar gains in hourly time-steps and, more recently, in five minute time-steps. A common approach used to overcome this problem in the past was to select a representative day of a certain period of time and maintain the same results of shading calculations for the rest of the period. Nowadays, the new generation computers have drastically reduced computational costs, but some programs still use the former approach. The present paper assesses the error made by the use of it. Different overhang and side fin typologies and orientations, location latitudes and simulation time-steps have been analysed. 25% of the studied cases have shown annual average relative errors of 5% or greater in the incident solar radiation over the glazing surface. Common configurations, such as south oriented overhangs, show daily deviations of incident solar energy up to 0.48 kW h/m 2 , with a relative error of 17%, having hourly errors as high as 26%. [ABSTRACT FROM AUTHOR]

The paper describes a study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. To evaluate thermal performance and energy consumption, simulations were carried out using FLUENT and EnergyPlus software, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building using a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a Dedicated Outside Air System (DOAS) was used as an alternative to Fan Coil Unit (FCU) that was installed in conjunction with the radiant cooling system. A comparison of energy consumption calculated that the radiant system was 17.5% more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. The Computational Fluid Dynamics (CFD) simulation showed that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. [ABSTRACT FROM AUTHOR]

Building energy assessment methods, used in a regulatory context, impose a calculation procedure under restricted and predefined conditions to check preset energy performance levels. Standardized boundary conditions and input data are implemented allowing for objective evaluation of various building designs. Focusing on school buildings in particular, these specific boundary conditions are however often inaccurate or even unavailable. Therefore, throughout this paper, typical school characteristics and their uncertainty are studied. The impact on the energy demand calculations is then demonstrated in an uncertainty analysis using the Monte Carlo analysis method combined with the Latin Hypercube sampling technique. A sensitivity analysis, using the elementary effect method of Morris, reveals the set point temperature, load and users’ profiles of lighting and equipment in class rooms as the most dominant input parameters on which additional surveys and questioning are focused to determine possible inaccuracies and to define, where necessary, new, more realistic boundary conditions. As a final result, a list of representative boundary conditions for Flemish schools is determined which can be used directly or can be converted into averaged input data for simplified calculation methods. [ABSTRACT FROM AUTHOR]

The integration of buildings in a Smart Grid, enabling demand-side management and thermal storage, requires robust reduced-order building models that allow for the development and evaluation of demand-side management control strategies. To develop such models for existing buildings, with often unknown the thermal properties, data-driven system identification methods are proposed. In this paper, system identification is carried out to identify suitable reduced-order models. Therefore, grey-box models of increasing complexity are identified on results from simulations with a detailed physical model, deployed in the integrated district energy assessment simulation (IDEAS) package in Modelica. Firstly, the robustness of identified grey-box models for day-ahead predictions and simulations of the thermal response of a dwelling, as well as the physical interpretation of the identified parameters, are analyzed. The influence of the identification dataset is quantified, comparing the added value of dedicated identification experiments against identification on data from in use buildings. Secondly, the influence of the data used for identification on model performance and the reliability of the parameter estimates is quantified. Both alternative measurements and the influence of noise on the data are considered. [ABSTRACT FROM AUTHOR]

• Time Use Survey data used profiles of occupancy and energy behaviours. • Patterns were time-dependent and affected by household size. • Behaviour patterns were aggregated to produce hourly energy demand profiles. Occupants' interactions with building components determine the timing and magnitude of energy demand. Therefore a more realistic representation of energy-related occupant behaviours in energy simulations will enhance the accuracy of predicted building energy demand. The aim of this paper was to assess occupancy and behavioural patterns in Australian households based on a detailed time use survey, which collected daily activities from 6,902 persons in 3,626 households. Profiles of occupancy state and energy-related activities were analysed for different seasons, day of the week, and household compositions. The activity sequences were further aggregated to reproduce the total time use for the activities and occupancy states. The results showed that occupancy and the timing of energy related activities were time dependent and were also affected by season, day of week, and household composition. The outcomes can be used as input to simulation tools where realistic occupant behaviour should be taken into account. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a ray-tracing method is developed to describe the global solar transmittance of louver shading devices. The method is integrated in the dynamic building energy simulation program TRNSYS to assess the cooling demand and required peak cooling power in a south oriented office room. The proposed integrated approach allows calculating the solar transmittance for each time step. As the method is quite complex and requires an important computational effort, this research contrasts the results against the performance of simplified modeling and implementation approaches to assess the performance of louver shading devices. The use of view factor models not accounting for reflections in the shading device underestimates the cooling demand and the peak cooling power. It is shown that representing the shading device as a fixed reduction factor, independent of orientation and shading typology is an unacceptable simplification. However, the use of a simplified implementation of shading factors based on ray-tracing calculations is possible within acceptable margins of error. Best results are achieved by implementing solar radiation weighted monthly averages allowing to estimate the cooling demand and peak cooling power within 3%. [Copyright &y& Elsevier]

Abstract: Current building energy simulation technology requires extensive labor, time and expertise to create building energy models, substantial computational time for accurate simulations, and generates data in formats that make results difficult to interpret. These deficiencies can be ameliorated using modern graphical user interfaces and algorithms which take advantage of modern computer architectures and display capabilities. This paper describes a novel test bed environment which offers an interactive graphical interface, provides access to simulation modules that run at accelerated computational speeds, and presents new graphic visualization methods for the interpretation of simulation results. Its modular structure makes it suitable for use in early stage building design, for use as a research platform for the investigation of new simulation methods, and for use as a tool for teaching concepts of sustainable design. Improvements in the accuracy and execution speed of many of the simulation modules are based on the modification of advanced computer graphics rendering algorithms. Significant performance improvements are illustrated in several computationally expensive energy simulation modules. [Copyright &y& Elsevier]

Abstract: In recent years, calibrated energy modeling of residential and commercial buildings has gained importance in a retrofit-dominated market. Accurate weather data play an important role in this calibration process and projected energy savings. It would be ideal to measure weather data at the building location to capture relevant microclimate variation but this is generally considered cost-prohibitive. There are data sources publicly available with high temporal sampling rates but at relatively poor geospatial sampling locations. To overcome this limitation, there are a growing number of service providers that claim to provide real time and historical weather data necessary for building modeling at 15–40km2 grid across the globe; common variables such as temperature and precipitation have been constructed on ∼1km2 grids . Unfortunately, there is limited documentation from 3rd-party sources attesting to the accuracy of this data. This paper compares provided weather characteristics with data collected from a weather station inaccessible to the service providers. Monthly average dry bulb temperature; relative humidity; direct normal, diffuse and global solar radiation; wind speed and wind direction are statistically compared. Moreover, we ascertain the relative contribution of each weather variable and its impact on building loads. Annual simulations are performed for three different building types, including a closely monitored and automated energy efficient research building. The comparison shows that the difference for an individual variable can be as high as 90%. In addition, annual building energy consumption can vary by ±7% while monthly building loads can vary by ±40% as a function of the provided location''s weather data. [Copyright &y& Elsevier]

Abstract: Energy use in the built environment represents a large part of total energy use in Sweden and is one important sector where energy conservation needs to be significantly improved in order to meet the national implementation of the European goals. One key question that needs to be investigated in relation to these goals is the performance and implementation of passive or low-energy houses. This paper presents results and an evaluation of a newly built house in an area with passive houses in Linköping, Sweden. Nine passive houses were built with the aim to be energy efficient, with an annual space heating demand of 21kWh/m2, and at the same time to have the same visual appearance as any other building in the surrounding area. This study evaluates the energy performance of a residential area with low-energy buildings based on Building Energy Simulation (BES) (IDA ICE 4), and measurements from the real object. Both annual and hourly validation is performed using room by room modeling and internal heat gains. A novel approach to internal heat gain modeling is presented using time-use data (TUD). The results show possible improvements in the design, the building envelope and in the heating control. [Copyright &y& Elsevier]

Abstract: The concern on climate change leads to growing demand for minimization of energy use. As building is one of the largest energy consuming sectors, it is essential to study the impact of climate change on building energy performance. In this regard, building energy simulation software is a useful tool. A set of appropriate typical weather files is one of the key factors towards successful building energy simulation. This paper reports the work of developing a set of weather data files for subtropical Hong Kong, taking into the effect of future climate change. Projected monthly mean climate changes from a selected General Circulation Model for three future periods under two emission scenarios were integrated into an existing typical meteorological year weather file by a morphing method. Through this work, six sets of future weather files for subtropical Hong Kong were produced. A typical office building and a residential flat were modeled using building simulation program EnergyPlus. Hourly building energy simulations were carried out. The simulated results indicate that there will be substantial increase in A/C energy consumption under the impact of future climate change, ranging from 2.6% to 14.3% and from 3.7% to 24% for office building and residential flat, respectively. [Copyright &y& Elsevier]

Abstract: The potential of night cooling, a passive cooling technique of growing interest, is typically investigated by numerical means. In particular multi-zone energy simulation is currently appraised for building design. Unfortunately, in addition to the inaccurate approximation of an ideally mixed room, the implemented empirical convective heat transfer coefficients (CHTCs) only apply to specific flow regimes – forcing to use arbitrary correlations and, thus, possibly limiting the usefulness of the simulation results. Therefore, the authors of this paper investigate the sensitivity of the night cooling performance to convection algorithms. First, the authors examine the applicability of convection correlations for real building enclosures, extracted from literature. Subsequently, simulations of a night cooled office room during summertime of a moderate climate (Belgium) are carried out in TRNSYS, using different convection correlations in addition to varying design parameters. The results show that the choice of the convection algorithm strongly affects the energy and thermal comfort predictions. More importantly, the convection algorithm is of the same importance as the design parameters – making an exact definition of the CHTC crucial. Therefore, additional research by experiments or airflow codes, based on fluid dynamics, is regarded necessary. [Copyright &y& Elsevier]

Abstract: The reliable estimation of buildings energy needs for cooling is a crucial issue in the implementation of the EPB Directive 2010/31/EU (formerly 2002/91/EC), especially in central and southern Europe climates. On this purpose one of the main topics is to predict the behavior of the opaque envelope subjected to variable boundary conditions. The EN ISO 13786:2007 technical standard assumes sinusoidal boundary conditions and introduces dynamic thermal characteristics. The aim of this paper is to assess the deviation arising by the use of different approaches for the calculation of the dynamic thermal characteristics of an opaque envelope element under periodic non sinusoidal boundary conditions. The EN ISO 13786 procedure has been firstly applied by decomposing the external forcing temperature by means of the Fast Fourier Transform (FFT) analysis. A comparison with different approaches, such as Finite Difference Methods (FDM) and Transfer Function Methods (TFM), has been carried out. The predictions of the EN ISO 13786 with a sinusoidal forcing temperature (i.e., standard approach) have also been assessed, comparing the results to the ones obtained through the FFT analysis. Furthermore, corrections to the periodic thermal transmittance and to the time shift have been proposed, in order to improve the explicative worth of those parameters. [Copyright &y& Elsevier]

Abstract: Double skin façade can be defined as a building façade covering one or several stories with multiple skins. The skins may be air tight or ventilated. With sophisticated study and design, buildings constructed with double skin façade can have better thermal performance than the conventional single skin façade. This paper reports the findings on the energy performance of double skin façade applied to a typical office building under the climatic condition in Hong Kong. An experimental setup was established and the measured data were used to verify the theoretical model developed via the EnergyPlus simulation program. The validated model was then used to evaluate the energy performance of double skin façade with various configurations including glazing type (clear, absorptive or reflective glass), glazing position (inner or outer pane) and glazing layers (single or double glazing material). The results indicate that a double skin façade system with single clear glazing as the inner pane and double reflective glazing as the outer pane can provide an annual saving of around 26% in building cooling energy, as compared to a conventional single skin façade with single absorptive glazing. However, the long payback period of 81 years makes the double skin façade system economically infeasible. Support and motivation are needed from the local government in order to foster successful and widespread application of the double skin façade system in buildings. [Copyright &y& Elsevier]

Outdoor thermal comfort (OTC) directly impacts on health and wellbeing of inhabitants while it increases cooling energy demand of buildings. In this regards, different computational models and tools are developed to investigate the impact of built environments on pedestrian thermal comfort. However, in most of these models, the coeffects of solar radiation and local wind velocity are not simultaneously investigated where models are either simplified on solar calculations when are focused on wind or vice versa. This paper proposes a novel simulation framework to develop a high-resolution, but computationally efficient procedure, to couple radiative and convective fluxes in outdoor environments using computational fluid dynamics (CFD) and building energy simulation (BES) approaches. The workflow is implemented in Grasshopper platform fed by outputs of ANSYS-Fluent as the CFD tool and EnergyPlus as the BES tool. The performance of the framework is evaluated using a case study, representing a simplified neighbourhood on a typical hot day. In comparison with the traditional models, results highlight on a considerable change in the OTC values using the proposed model. Results show that the alteration is highly related to the temporal aspects and OTC results experience changes from 5% to 40% in compared to the original OTC values. [ABSTRACT FROM AUTHOR]

[Display omitted] Improving the performance of building envelope is essential to energy conservation and emission reduction. Adaptive building envelope (ABE) has the potential to effectively reduce building energy consumption at a lower cost. Movable window insulation is an instantiation of the ABE with great application potential in buildings, but it has not been systematically studied. Trying to fill this gap, this paper proposes an automatic control system and a manual control rule for movable window insulation. The energy consumption of double-glazed windows, triple-glazed windows, movable insulation with automatic/manual control, and electrochromic windows is compared in different scenarios using building energy simulation (BES). In some scenarios, the optimal solar heat gain coefficient (SHGC) for windows with movable insulation is higher than that required by the building code. Triple-glazed windows are only effective in reducing the heating energy, while electrochromic windows are only effective in reducing the cooling energy. Infiltration has a great impact on the performance of movable insulation. The net preset value (NPV) analysis shows that movable insulation has a great application potential in Minneapolis, Atlanta, and Phoenix, while triple-glazed windows are only viable in some cases in Minneapolis. Electrochromic windows are not a profitable investment at their current prices. [ABSTRACT FROM AUTHOR]

Abstract: This paper briefly reviews the primary parameters for a double skin façade (DSF) design. The research presents an integrated and iterative modeling process for analyzing the thermal performance of DSF cavities with buoyancy-driven airflow by using a building energy simulation program (BESP) along with a computational fluid dynamics (CFD) package. A typical DSF cavity model has been established and simulated. The model and the modeling process have been calibrated and validated against the experimental data. The validated model was used to develop correlations that can be implemented in a BESP, allowing users to take advantage of the accuracy gained from CFD simulations without the required computation time. Correlations were developed for airflow rate through cavity, average and peak cavity air temperature, cavity air pressure, and interior convection coefficient. The correlations are valuable for “back of the envelope” calculation and for examining accuracy of zonal-model-based energy and airflow simulation programs. [Copyright &y& Elsevier]

Abstract: ParaSol is a computer program for calculating the solar and thermal properties of windows with sunshades and the energy demands of a room with a window/shading system. The program has three main features. One of them is a calculation of g, T and U for normal incidence of beam irradiation, which is performed as soon as a window or an internal/interpane sunshade is selected. The other two are based on yearly simulations, using DEROB-LTH, a building energy simulation program on which ParaSol is based. One of the applications gives the monthly average of g and T for the window glazing and the glazing/sunshade system. The other application gives the heating and cooling demands for a room with a window, with and without a sunshade, where input data are given for the internal heat, ventilation settings, shading control and temperature set-points. Version 3.0 of ParaSol, which has some new and improved models, is described in this paper. The g-values obtained with this program version are compared with measurements on windows with internal/interpane screens/venetian blinds. The absolute deviation is less than 0.03 for the venetian blinds. The measured values of dark internal screens with closed air gaps exceed those simulated by Parasol, but are lower than the ones simulated with open air gaps. [Copyright &y& Elsevier]

Abstract: This paper stresses the importance of a proper estimate of ground reflectivity in building energy simulation, particularly in the presence of snow. Several factors influencing ground reflectivity are reviewed. Two models for estimating ground reflectivity in the presence of snow are developed. The first one is based on the number of days with snow depth greater than 5cm, and is appropriate for use with ‘typical’ meteorological years. The second makes use of actual records of snow depth, and takes into account snow accumulation, ageing and melting to calculate reflectivity values. The algorithms were implemented in ESP-r and tested by simulating a passive solar house for six Canadian locations. The sensible heating load calculated by the simulations is reduced by up to 10.9% on a yearly basis, and 23.3% on a monthly basis, when the ground reflectivity takes into account the presence of snow. [Copyright &y& Elsevier]

Abstract: This paper reports an experimental and simulation study of application of radiant cooling using natural air for ventilation under hot and humid climate of Thailand. To avoid condensation of moisture on the cooling panel, the temperature of water supplied to the panel was limited to 24°C. This led to the expectation that the low heat reception capacity of the panel would limit its use only to situations when loads were low. Experiments were conducted in an experimental room over the hot and dry period of March, the humid period of May, and the cool period of December. The results generally confirm the good potential for application of radiant cooling. However, the room was served by radiant panels with a total area of 7.5m2. Its capacity was grossly inadequate during the hot period, even for night time application only. A special configuration was devised to achieve thermal comfort for the area served by the panel. The well-known TRNSYS program was used to simulate the use of cooling panels and conventional air-conditioning in the experimental room. Simulation results match experimental results very well. Using comfort criterion adopted by ASHRAE and International Standards Organization, results from experiments and simulation show that thermal comfort could be obtained with application of radiant cooling. [Copyright &y& Elsevier]

Abstract: Highly glazed commercial buildings with double-skin façades may overheat during summertime due to a coincidence of high outside temperatures, solar gains and internal heat gains. To optimize thermal comfort and minimize cooling loads, the thermal behaviour of this type of building, therefore, requires careful investigation at the design stage. However, complex physical phenomena—notably optical, thermodynamic and fluid dynamic processes—are involved and as yet, no single simulation tool is able to handle all these processes while remaining an efficient design tool. This paper presents a method based on the coupling of three different types of simulation models that is economical in terms of computing time, and thereby, suitable for design purposes. These models are: spectral optical model, computational fluid dynamics model and building energy simulation model. Various tools are available at each modelling level. The method is demonstrated on a commercial building with double-skin façades and additionally, night-time ventilation. [Copyright &y& Elsevier]

[Display omitted] • Developed an R package that integrates EnergyPlus with data-driven analytics. • Structured inputs/outputs format that can be easily piped into data analytics workflows. • Facilitates reproducible simulations through Docker. • Enables flexible and extensible parametric simulations. Building energy simulation (BES) has been widely adopted for the investigation of building environmental and energy performance for different design and retrofit alternatives. Data-driven analytics is vital for interpreting and analyzing BES results to reveal trends and provide useful insights. However, seamless integration between BES and data-driven analytics current does not exist. This paper presents eplusr, an R package for conducting data-driven analytics with EnergyPlus. The R package is cross-platform and distributed using CRAN (The Comprehensive R Archive Network). With a data-centric design philosophy, the proposed framework focuses on better and more seamless integration between BES and data-driven analytics. It provides structured inputs/outputs format that can be easily piped into data analytics workflows. The R package also provides an infrastructure to bring portable and reusable computational environment for building energy modeling to facilitate reproducibility research. [ABSTRACT FROM AUTHOR]