Search

Highlights • Definition of passive envelope indexes and caracterization of libraries in La Plata. • Environmental monitoring: achievement of preventive conservation indexes. • Correlation between passive envelope indexes and preventive conservation indexes. • Determination of the most influential passive envelope indexes for the achievement of preventive conservation indexes. Abstract The common approach for libraries to preserve their paper-based collections from irreversible deterioration is by controlling quantitative parameters, such as temperature and relative humidity. Variations of these parameters for preventive conservation can be expressed by the "performance index" (PI) and the "amplitude index" (AI). Building envelope is the first filter of the external climate, buffering the external weather fluctuations and maintaining the building's indoor climate stable. Its shape, window areas and envelope materials are the most influential parameters. As they capture the relationship of a few geometric and physical variables with the building's performance, the envelope characteristics can be expressed as certain passive envelope indexes. This paper studies the relationship of certain passive envelope indexes and the preventive conservation indexes for books for several libraries and archives located in La Plata, Argentina. The results show the impact of every passive envelope index upon the preventive conservation indexes. The compactness, heaviness, adjacency to spaces and adjacency to ground have a positive linear correlation meanwhile transparency and global transmittance are parameters with a negative correlation. In general, the most influential parameter is the relative area adjacent to other spaces, followed by global transmittance, transparency, heaviness, relative area adjacent to ground and compactness. [ABSTRACT FROM AUTHOR]

Much research has been focused on maintaining stable humidity conditions in buildings housing heritage collections while reducing energy use. Moisture buffering by collections themselves can have a marked effect on the stabilisation of relative humidity (RH), the key parameter for preservation. Modelling of moisture transport using COMSOL Multiphysics was applied to transform three-dimensional paper and wooden objects into their one-dimensional representations, without changing the moisture uptake and release characteristics. The results were coupled to the modelling of indoor microclimate and energy consumption in collection storage spaces with the use of WUFI ® Plus software. The study revealed the crucial impact of air exchange rate of the building on the stability of indoor RH and the humidification and dehumidification loads required to maintain it. In the adequately air-tight library store, a sizeable paper collection was found to reduce the RH fluctuations from ±9% to ±6% around the yearly average and the energy consumption due to the humidification and dehumidification load by 38% when compared with the empty space, for a high-quality climate control scenario. In turn, a wooden collection, occupying a realistic fraction of a museum store was not large enough to significantly narrow down the RH variations and reduce the energy consumption. [ABSTRACT FROM AUTHOR]

• Automatic MiC envelopes and layout generation by a novel SSG-MOO method. • Multi-objective optimization formulation for passive MiC design. • A pilot MiC study in Hong Kong produced 5 selected Pareto optima out of 625. • Up to 0.42% energy savings and 9.71% spatial daylight autonomy improvement against the baseline. • A multi-level analysis of results and design strategies for practitioners. Modular-integrated Construction (MiC) is an emerging construction technique promoted in the building sector for high productivity and low waste emission in the construction phase; yet, the standardized modules also bring new challenges, such as balancing passive energy efficiency and spatial daylight autonomy, to the operational phase. This paper proposes a Symmetric Skeleton Grammar-based Multi-Objective Optimization (SSG-MOO) method to formulate parametric MiC envelopes and detailed layout, with the two objective functions being energy efficiency and interior daylight performance in the operational phase. Pareto optima of the SSG-MOO, computed by the Non-dominated Sorting Genetic Algorithm II, are generally verified and analyzed in three levels, i.e., MOO's solution space, SSG layout, and MiC design parameters. A case study of MiC residential building in Hong Kong demonstrated the SSG-MOO method through five new passive MiC designs (i.e., spatial reorganization of three architectural modules, and parameter tuning of the envelops and corridors), achieving up to 0.42% energy savings and 9.71% spatial daylight autonomy improvement compared to the baseline design. The contribution of this paper is two-fold, including a novel and sound SSG-MOO formulation for parametric MiC designs, and offering time-efficient and evidence-based design tactics for MiC designers and industrial practitioners to push boundaries of MiC. [ABSTRACT FROM AUTHOR]

• Renewable energy assessment methods used in 12 GBRSs are analysed and compared. • Methods used in green neighbourhood rating system are also introduced. • Evaluation way, renewable energy types, building characteristics, etc. are analyzed. • The effects by using different methods in one building are analysed. • Suggestions are provided to improve the renewable energy assessment. Green buildings and neighborhoods can help mitigate impacts of buildings on the environment, society and economy. Many rating systems or tools have been developed worldwide to assess and certificate green buildings or green neighborhoods. Renewable energy plays an important role in achieving green buildings/neighborhoods or zero energy buildings/neighborhoods by reducing fuel consumption and pollution emissions. However, substantial differences exist in assessing or quantifying the renewable energy in green building/neighborhood rating systems. This paper therefore provides a comprehensive review on renewable energy assessment methods adopted in green building/neighborhood rating systems, which would be very helpful to understand and then improve the rating systems. These methods are analyzed and discussed regarding to the calculation way, involved renewable energy types, building characteristics and energy conversion. Then a case study is conducted to quantitatively illustrate the difference of typical renewable energy assessment. Suggestions are summarized to improve the assessment methods. This paper will help investors, users and policy makers understand the rating systems more thoroughly and promote the development of green buildings and green neighborhoods. [ABSTRACT FROM AUTHOR]

Abstract In 2011, the Danish government published an energy strategy for Denmark where one of the main targets are that Denmark should be a fossil-free society by 2050. Calculations show, that in order to reach this goal it is necessary to reduce the energy consumption of the existing building stock by 50% on average. Since a 50% reduction is obviously not possible for all buildings, those that can should aim for a so-called "deep energy renovation", i.e. reducing the energy consumption to a level corresponding to that of new buildings or even more. This paper describes two case studies where multi-story apartment buildings have undergone deep energy renovation. "Traneparken" where the expected energy use after renovation aimed at a level corresponding to that of a new building according to the Danish Building Regulations from 2015. "Sems Have" where the aim was to go even further and meet the requirements expected for new buildings in 2020, i.e. corresponding to the Danish "nearly zero energy"-definition according to the EPBD. The paper reports on calculations and measurements of energy savings, the economy of the projects and looks at the added benefits or co-benefits that residents, housing association and society in general have achieved in addition to significant energy savings. [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]

Highlights • A pre and post renovation energy use analysis of almost 90,000 renovated dwellings. • The (p)rebound effects explain only partly disappointing energy renovation results. • Effectiveness of renovations are dependent on state of building prior to renovation. • Effectiveness of renovations are dependent on type of occupant. • Deep renovations often save less energy than expected but are the most effective. Abstract Energy renovations often result in lower energy savings than expected. Therefore, in this study we investigate nearly 90,000 renovated dwellings in the Netherlands with pre and post renovation data of actual and calculated energy consumption. One of the main additions of this paper, compared to previous studies on thermal renovation, is that it only takes dwellings into account with the same occupants before and after renovation, using a large longitudinal dataset. Overall this paper shows new insights towards the influence of the energy efficiency state of a building prior to energy renovation, the type of building, the number of occupants, the income level of the occupants and the occupancy time on the actual energy savings, the energy saving gap and on the probability of lower energy savings than expected. We also investigate if the influence is different per type of thermal renovation measure. Some of the findings are: it is impossible to conclude which single thermal renovation measure is the most effective because this is dependent on the energy efficiency of the building prior to the energy renovation, type of building, income level and occupancy; occupants with a high income save more energy than occupants with low income; dwellings with employed occupants benefit more from improved building installations than dwellings occupied by unemployed occupants; The prebound and rebound effects are only part of the explanations for lower than expected energy savings; Deep renovations result more often in lower than expected energy savings than single renovation measures but nevertheless they result in the highest average energy saving compared to other thermal renovation measures. The results could be used for more realistic expectations of the energy reduction achieved by thermal renovations, which is important for (amongst others) policy makers, clients and contractors who make use of energy performance contracting, home owners, landlords and (social) housing associations and as a starting point to improve the energy calculation method. [ABSTRACT FROM AUTHOR]

When modeling the energy performance of existing buildings, model calibration always serves as an essential and necessary step to ensure the accuracy and applicability of building models. Model calibration for detailed energy models, which is also known as calibrated simulation (CS), refers to the process of tuning model's input parameters to narrow down the mismatch between the simulation result and the real-monitored data of building energy consumptions. Two major problems of current CS are: (1) a successful calibration requires HVAC domain knowledge of modelers. (2) Traditional building calibration process is labor-intensive and time-consuming. To solve these problems, a normative energy modeling based quick auto-calibration approach is proposed in this study. This approach is able to reduce the modeling time and simplify the calibration procedures. Firstly, this paper demonstrates the working principles and the credibility of Normative Energy Modeling (NEM). Then, the methodology of the proposed quick auto-calibration approach is elaborated. The energy performance model of a large hotel located in Shanghai, China with NEM is used as a case study to investigate the effectiveness of the proposed quick auto-calibration approach. The simulation result of the case study suggests that the proposed approach can significantly simplify the procedures of model calibrations while still achieve a good accuracy specified by ASHRAE Guideline 14 [1]. Besides, the results further confirm that such method requires much less time and computational power for modeling, compared with other counterparts (e.g., “Autotune” calibration [2]). With the advantage of speed and accuracy, the auto-calibration proposed in this paper is promising to be applied in both engineering and research field. [ABSTRACT FROM AUTHOR]

In Sweden, approximately 1.4 million dwellings were built 1946–1975. Today, a considerable part of these are in need of renovation for various reasons. Research results, as well as experiences and outcomes from renovation projects could facilitate in performing more efficient renovations. As an aid for further research, this paper aims to compile and review relevant literature that may support in choosing a renovation strategy as well as decisions on renovation measures. The focus of this paper is research on status determinations, renovation strategies and renovation measures. Differences and similarities within these areas are presented through the analysis of 234 relevant references. The results show that renovation of multifamily buildings in temperate climate conditions is widely researched. The included research has a strong energy focus, and while other aspects of renovation are researched as well, they are not as strongly represented. Status determinations are often based on data from national databases that include useful information that could help alleviate decision making in the renovation process. This study suggests that future research should be conducted on the effect of such databases on the renovation process. This study also shows that there are numerous renovation strategies, and while there are both in-depth and broader strategies, these are seldom connected. Finally, there are many references evaluating various effects of the application of renovation measures, but some effects and measures are more widely researched than others. This study lays a strong foundation for further in-depth research on the reviewed articles, reports, and theses. [ABSTRACT FROM AUTHOR]

A simple way to reduce energy consumption is to minimize heating use during unoccupied periods. This implies the possibility of adjusting the room temperature setpoint. However, systems with a large thermal capacity cannot follow sudden setpoint changes because of their thermal inertia. A model predictive control (MPC) allows the harnessing of this inertia in order to reduce heating costs and improve comfort. This advanced control technique is based on disturbances anticipation (occupation, weather conditions) and requires a model of the system which has to be controlled. Therefore, the use of such controller needs a reliable model that describes well the dynamics of the room on upcoming days. This paper presents a method for the selection of the model (type, level of complexity) to be implemented in a MPC controller to anticipate the control of a long time response floor heating system on a real building. The demonstration room and embedded systems serving as experimental support are presented. Short measurement periods are carried out to identify the model parameter values minimizing the gap between model output and measurement. Gray-box models based on electrical analogy and state-space representation are proposed. They are constructed from physical knowledge and then identified by choosing the most appropriate measurement series. A sensitivity analysis method (Morris) is used to improve the quality of the identified model which satisfies control criteria with two specific validation measurement series. In a complementary paper, the predictive controller integrating the selected model is compared to more conventional management strategies in simulation and on-site with the experimental building. [ABSTRACT FROM AUTHOR]

The main purpose of this research is to evaluate the thermal-comfort environment in an office building served by a liquid-desiccant and indirect-and-direct evaporative-cooler-assisted 100% outdoor-air system (LD-IDECOAS). This research presents a method for evaluating the thermal environment via a series of energy simulations using the TRNSYS 17 program, integrated with an engineering equation-solver (EES) program. The supply air (SA) temperature is estimated according to the LD-IDECOAS seasonal operation modes proposed in previous research. The indoor-air conditions are estimated under the assumption that the relative humidity of room air was maintained at the set values by auxiliary humidification systems. Then, the predicted mean vote (PMV) values are estimated using the given indoor environment conditions. In this paper, the indoor-air conditions and PMV values for each LD-IDECOAS operation mode are represented. A detailed analysis of the impact of the indoor-air conditions on the PMV is provided in this paper. Furthermore, the simulation results for LD-IDECOAS were compared with those for a conventional variable-air-volume (VAV) system to evaluate the thermal environment in a building served by LD-IDECOAS. The PMV values with LD-IDECOAS showed that the thermal environment in a conditioned space is generally in compliance with ASHRAE Standard 55. Consequently, it is concluded that using LD-IDECOAS in an office building can produce energy savings with an acceptable level of thermal comfort. [ABSTRACT FROM AUTHOR]

Buildings are responsible for about 92% of the total energy end-use in Hong Kong, of which above 70% is from the commercial sector. Most of the buildings in Hong Kong are high-rise, and approximately 15% of the total building stock is commercial buildings. Despite the considerable improvement in the understanding of the life cycle energy use of office buildings, there is still a lack of research into the life cycle energy demand of high-rise office buildings. Such knowledge is however essential for facilitating building energy conservation in the high-rise urban environment. The aim of this paper is to investigate the life cycle energy use of high-rise office buildings. The research was carried out through a critical literature review and case studies of ten real-life high-rise office buildings in Hong Kong. Results show that the life cycle energy consumption is 51.78–73.64 GJ/m 2 over the 50-year study period. Building operation consumes 78–89% and the rest (i.e. 11–22%) is taken by the embodied energy. Despite the distinction in terms of the amount of embodied energy between high-rise buildings and low-rise counterparts, no clear correlation is found between building height and embodied energy intensity. Moreover, energy use for material manufacturing and transport should be prioritised in reducing the embodied energy, of which the transport energy needs to be taken into extra consideration for the case of Hong Kong. The findings should inform construction industry participants of the significant potential in reducing the embodied energy of high-rise office buildings. The paper profiles the life cycle energy use of high-rise office buildings and should be important for the policy formulation towards the holistic energy conservation in high-rise buildings over their lifespans. [ABSTRACT FROM AUTHOR]

This paper explored the application of model predictive control (MPC) technology to the TBSs hybrid free cooling system with latent heat thermal energy storage (LHTES) unit for minimizing the building operational cost without sacrificing temperature requirements. First, the system was briefly introduced and the dynamic thermal process models of building structure and LHTES unit were developed. Then, a hierarchical control structure with dynamic multi-swarm particle swarm optimization was presented to address the dimensional challenge and discontinuities in control variables. Due to the considerable decrease of optimization variable space, the method presented in this paper enables long-term simulation and application in a real controller. Simulations were carried out based on a typical TBS building located in Beijing, China. The total energy consumption of the cooling system and the control quality of indoor air temperature were used as the criteria to evaluate the performance. Compared to a defined baseline case, the optimal control method can achieve significant energy saving, i.e. up to 18%. The impacts of the size of LHTES unit and the type of building structure were discussed, as well. The active and passive heat capacity both played a catalytic role in performance of MPC. Additionally, an uncertainty analysis demonstrated that the proposed approach has strong robustness and can handle quite high errors in forecasting building disturbances from energy consumption level. In summary, the knowledge and use of the plant system and future disturbances make MPC a powerful control tool for TBS buildings for maximizing the use of renewable energy sources. [ABSTRACT FROM AUTHOR]

Occupant behavior is viewed as a main source causing the building energy performance gap between the predicted and the actual consumption. The nature of occupants’ energy behavior research requires a combination of social science and natural science, which indicates that a mixed methods design would be useful. However, researchers often do not know when and how mixed methods approach should be used. To fill this gap, this paper first reviewed the research methods adopted in 230 relevant articles published in the past decade. The results show that 83.48% of articles applied quantitative methods, followed by mixed methods (5.22%) and qualitative methods (0.87%) with rest being pure review or conceptual papers. This shows that researchers in the field of occupant behavior mainly adopt the objectivist philosophical position. Subsequently, an in-depth analysis of research methodologies was conducted in relation to worldviews and philosophical assumptions, and the advantages and disadvantages of qualitative and quantitative methods were discussed. Finally, a mixed methods research design framework was proposed as a point of departure for researchers to gain a comprehensive understanding of mixed methods design. It is expected that this framework could help researchers develop a proper mixed methods research design according to the nature of their research problem. [ABSTRACT FROM AUTHOR]

Humidity is an important factor that influences both thermal comfort and indoor air quality. Air-conditioning (A/C) systems in large-scale buildings can employ different equipment to control temperature and humidity independently. However, A/C systems commonly seen in small- and medium-sized buildings have no specific device to deal with moisture due to space limitations, which may leave humidity in these buildings without regulation. This paper summarizes two methods applied to control temperature and humidity in these buildings using A/C systems. One is to modify the structure of A/C systems or to introduce an additional dehumidifying equipment that is adaptive in small- and medium-sized buildings to decouple temperature and humidity control loops. The other is to develop advanced control algorithms to realize simultaneous temperature and humidity control in a variable speed direct expansion air-conditioning unit. Principles, merits, and obstacles of these two methods are presented. Since the paths for development of the two methods were totally separated before, potential benefits of energy saving and better control performance brought by combining the two methods are discussed. It is expected that this paper could promote relevant studies and applications. [ABSTRACT FROM AUTHOR]

The development of innovative materials aiming to achieve energy savings is a main focus in the building technology sector. In this context, aerogel-enhanced products are often indicated as promising materials for increasing the thermal resistance of the building envelope. In particular, aerogel blankets have already started showing their effectiveness in retrofitting projects, while the development and adoption of aerogel-enhanced renders and aerogel-incorporating glazing systems is progressing. Based on the state of the art, this paper describes several new aerogel-enhanced systems that have been developed over the last few years at Ryerson University in Toronto, ON. In particular, the paper presents the recent results regarding aerogel-enhanced plasters, lightweight concretes, blankets, and glazing systems. Thermal characterization tests of these new materials confirm the superior performance for building retrofits. For example, the thermal conductivity of plasters with more than 80%vol. aerogel is below 0.025 W/(mK), a tenth of the respective value for traditional plasters, while mortars with more than 30%vol. aerogel show a thermal conductivity as low as 0.23 W/(mK). The newly presented aerogel-based systems are then assessed for the retrofitting project of an educational building located in Toronto. An extensive energy audit was conducted through measurements of the envelope thermal characteristics, the building airtightness, and several indoor environmental parameters. The audit helped to build an accurate energy model that was used for analyzing the energy consumptions of the building and assessing several energy saving measures. The study showed that high thermal resistance values could be obtained installing thin aerogel-enhanced products in the opaque and transparent envelope, with overall building energy savings up to 34%, with limited impacts and interruptions on the building functionality and internal usable space. However, the high costs of aerogel-enhanced products made their payback times of several decades and represented a barrier for the adoption of most of the systems presented in this paper. [ABSTRACT FROM AUTHOR]

The need for improved building performance is global and has led to numerous international collaborations. Since 2000, the International Energy Agency (IEA) Energy in Buildings and Communities Program (EBC, formerly ECBCS ) has completed two building commissioning research annexes, recognizing the role of the building commissioning process in meeting energy conservation goals. Annex 40 established a common understanding of the commissioning process and initiated research that became the basis for the development of national guidelines and automated tools. Subsequently, Annex 47 focused on advancing the use of technology in commissioning and the work developed and ideas exchanged in Annex 47 were foundational in enabling numerous positive impacts internationally. This paper describes research results from these annexes 1 1 Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. and discusses the impact of both in four areas: 1) commissioning support software tools, 2) cost-benefit methodology, 3) guidelines and standards, and 4) industry associations and research conferences. The paper concludes with a discussion of current commissioning industry research and policy needs. [ABSTRACT FROM AUTHOR]

Whilst new nearly Zero Energy (nZE) concepts have been the first priority in the previous decade, in more recent years it has become widely acknowledged that renovating dwellings will have a large impact on the energy use in buildings. Using a simplified calculation method, this paper illustrates the high-energy consumption in several building types within the housing stock in Bologna. Among these, a specific building has been selected as the worst-case for an in-depth investigation. For this building the paper analyses a large set of possible scenarios for renovation –from the more standard operations up to higher levels of façade components’ transformation- as technically feasible solutions to achieve a nearly Zero Energy Building (nZEB). By discussing the economic/energy impact of each scenario, this paper aims at contributing to the debate on deep-versus-shallow renovation in existing buildings. In particular, it attempts at answering the following important research issues: whether the technical feasibility is associated to the economic feasibility in the retrofitting towards nZEBs; to what extent deep renovation and high transformation of buildings is competitive with respect to shallow retrofit; whether non-energy related factors can be considered to properly assess the economic competitiveness. Energy and economic benefits are the main renovation’s objectives in building renovation; nonetheless, non-energy related aspects are also helpful to expand the feasibility of nZEBs retrofit in the current building practises. [ABSTRACT FROM AUTHOR]

While IEA EBC Annexes usually are focused on R&D about single energy technologies, their broad scale use in practice is of even higher importance to contribute to global energy goals. This practical application of low-carbon technologies on community scale has been the subject of Annex 51, carried out from 2010 to 2013. In this Annex, evaluating 25 community energy case studies of the 10 participating countries, a ‘Guidebook on Successful Urban Energy Planning’ has been extracted from these evaluations to directly address practical urban/energy planners and municipal decision makers. The main content of the Guidebook with respect to planning approaches is summarized in this paper, distinguishing between the different planning fields of ‘urban energy planning’, which is addressing whole cities and communities, and ‘local energy planning’, oriented to neighbourhoods or building clusters. The necessary link between both is emphasized, considering a city as an interconnected energy system requiring a holistic approach rather than a compartmented consideration. As a side effect, a general method to calculate the primary energy performance of buildings and neighbourhoods employing different energy systems, including energy efficiency or energy conservation technologies, was derived. Using appropriate system characteristics, such as seasonal performances, this approach can be applied for every energy system, and for every building or neighbourhood. It is presented in this paper supplying an example from one of the case studies. [ABSTRACT FROM AUTHOR]

Green construction is gaining foothold among professionals, decision makers and the broader public. However, its success depends on a clear minded analysis of its pros and cons based on critical assessment, including cost-benefit analysis. This paper makes a first attempt at such an analysis of some of the first green sustainable schools in Israel. It deals with a limited sample available, as well as diverse rating systems which the different architects have chosen to comply with. By identifying and isolating the “green premium” of those schools which are comparable, and by analyzing actual direct benefits for the schools through energy and water bills (23% and 24% lower consumption respectively per year), the paper concludes that for the time being the payback period of green schools in Israel may prove counterproductive and prohibitive if calculated only on the basis of these two direct and immediate benefits. However, including in the analysis additional benefits, e.g. staff satisfaction (included in this paper), student achievements, user and broader public health issues and other public benefits (not included in this paper) can change the cost-benefit analysis outcome significantly. [ABSTRACT FROM AUTHOR]

Since the heating substation plays a key role in transferring the thermal energy from the primary network to the secondary network and controlling the heat output of district heating system to meet the thermal load, high operation performance of heating substation is essential for energy conservation, cost saving and emission reduction. The dynamic operation stability of heating substation is a very important dynamic characteristic of heating substation and largely affects the operation efficiency of district heating system. The operation instability of heating substation mainly manifest as flow rate and pressure oscillations, which will deteriorate the network hydraulic condition, break the network thermal balance, reduce the consumer comfort and increase the energy cost of the pumping system. Since heating substations will easily operate unstably under some conditions, this paper presents a theoretical method to analyze the stability and retune the feedback controller for operation stability of heating substation. Mathematical model of the plate heat exchanger was established and the feedback control theory was adopted to study the operation stability of heating substation. Based on the mathematical model and feedback control theory, a stability criterion was proposed for analyzing the operation stability of district heating substation effectively. The dynamic model of plate heat exchanger was validated with measured data. Simulation results show that controller tuned at certain operating condition can’t ensure operation stability of heating substation, when operating condition varies in large range. The stability analysis method proposed in this paper can be applied to analyzing the operation stability and tuning the controller of heating substation to enhance the operation stability. [ABSTRACT FROM AUTHOR]

There has been general recognition within the construction industry that there is a discrepancy between the amount of energy that buildings actually use and what designers considered that they should use. This phenomenon is termed “The Performance Gap” and is normally associated with new buildings. However, existing and older buildings contribute a greater amount of operational carbon. In response to the Performance Gap, CIBSE have developed the TM54 process which is aimed at improving energy estimates at design stage. This paper considers how the TM54 process can also be used to develop energy management procedures for existing buildings. The paper describes an exercise carried out for a university workshop building in which design energy use has been compared with the actual building energy use and standard benchmarks. Moreover, a sensitivity assessment has been carried out using different scenarios based on operation hours of building/equipment, boiler efficiency and impact of climate change. The analysis of these results showed high uncertainty in estimates of energy consumption. If carbon challenges are to be met then improved energy management techniques will require a more systematic approach so that facilities managers can identify energy streams and pinpoint problems, particularly where they have assumed responsibility for existing buildings which often have a legacy of poorly metered fuel consumption. [ABSTRACT FROM AUTHOR]

In recent decades there has been a growing awareness regarding energy consumption in buildings. Unfortunately, at a time when all building actors should get involved in the challenge to reduce energy consumption, designers cannot rely on effective tools to help them in their decision making process concerning airtightness. This literature review allows the identification of two important issues: new airtightness predictive models are complex to develop and existing airtightness predictive models do not meet the needs of designers and contractors. This paper is divided into three main parts in addition to the introduction and the conclusion. The first part deals with the key concepts of infiltration and airtightness, the second part with influencing factors and the third part with airtightness predictive models. These different chapters highlight a need for standardization regarding the metrics used for data presentation, parameters definition and statistical quantification. The lack of standardization hinders the development of a new airtightness predictive tool for designers and contractors. Along with the problem of standardization, supervision and workmanship are parameters that are difficult to model. Their significant impact can explain why designers and contractors find some existing models unreliable. This paper concludes that none of the existing models can be used in their present form as design tools. Further work should focus on the standardization of data presentation and on the development of a new airtightness predictive model. The first step in the development of such a model is to draw an appropriate classification of “air paths.” [ABSTRACT FROM AUTHOR]

Extensive research works have been carried out over the past few decades in the development of simulation tools to predict the thermal performance of buildings. These validated tools have been used in the design of the building and its components. However, limited simulation tools have been developed for modeling of district energy systems, which can potentially be a very laborious and time-consuming process. Besides many associated limitations, providing a realistic demand profile of the district energy systems is not a straightforward task due to high number of parameters involved in predicting a detail demand profile. This paper reports the development of a simplified model for predicting the thermal demand profile of a district heating system. The paper describes the method used to develop two types of simplified models to predict the thermal load of a variety of buildings (residential, office, attached, detached, etc.). The predictions were also compared with those made by the detailed simulation models. The simplified model was then utilized to predict the energy demand of a variety of districts types (residential, commercial or mix), and its prediction accuracy was compared with those made by detailed model: good agreement was observed between the results. [ABSTRACT FROM AUTHOR]

HVAC systems in buildings are composed of many subcomponents which consume energy in huge amounts. In recent years, energy consumption becomes very important aspect due to the lack of energy resources and environmental reasons. In terms of energy consumption, the components of HVAC systems account for large portion of total energy used in buildings. Therefore optimization of energy consumption in HVAC applications is an essential requirement in terms of thermodynamic and economic point of views. Besides, the efforts for decreasing energy consumption turn into economic recovery. It also provides benefits for human health and cleaner environment. In this paper, as originality, thermodynamic and economic analyses of an existing social and cultural building which has a heating and cooling area of 8852 m 2 are presented by comparing of a conventional HVAC and a VRF system. A novel contribution is given to the open literature by comparing two systems with actual data measured from the existing system. The other originality is to apply and test a VRF system to a complex-structured building. This study is a rare one which contains insulation, heating and cooling accounts of a building together. In this paper, VRF system is modelled to the existing building for the comparison of the conventional HVAC system. Both systems have been compared in terms of heating and cooling capacity, initial, operation and maintenance costs. It is found that the VRF system is more economic and efficient such that the VRF system is found to have 44% cost profit when compared with the conventional HVAC system. [ABSTRACT FROM AUTHOR]

Many retrofit projects are being carried out in existing buildings to reduce energy consumption. However, the energy consumptions before and after retrofit need to be known in order to evaluate such retrofit projects. Even though the energy consumption after retrofit can be determined through measurement, the energy consumption before retrofit cannot be known. This study is to more easily estimate energy usage prior to the retrofit. Generally, dynamic simulation or regression model should be used to estimate the energy consumption of buildings before retrofit. However, existing regression models have no way to calibrate the model if it is inaccurate. In this paper, we use a clustering technique to improve the accuracy of the regression model. The estimation of energy consumption before retrofit is referred to as “baseline model” and the inverse model is used to create this baseline model. The inverse model is created through monthly data, daily data, and other similar data. In this study, the inverse model was created through daily data and the baseline model was derived from it. The conventional change-point Model and the cluster inverse model presented in this paper were compared and evaluated with the criteria presented through M&V (Measurement and Verification). The results suggest that the cluster inverse model which reflects the characteristics of data is more appropriate when the baseline model is derived from daily data. [ABSTRACT FROM AUTHOR]

Lowering the embodied carbon dioxide equivalent (embodied CO 2 e) of buildings is an essential response to national and global targets for carbon reduction. Globally, construction industry is developing tools, databases and practices for measuring embodied CO 2 e in buildings and recommending routes to reduction. While the TC350 developed standardized methods for the assessment of sustainability aspects in construction works and Environmental Product Declarations, there is no consensus on how this should be carried out in practice. This paper evaluates the current construction industry practice through a review of both academic and professional literature, and through focus groups and interviews with industry experts in the field. Incentives in the available building codes, standards, and benchmarks are also analysed, as are the existing methodologies, tools and datasets. The multiple data sources are used to identify the barriers to the effective measurement and reduction of embodied CO 2 e in practice. This paper recommends that Governments mandate for improved data quality and support the development of a transparent and simplified methodology. [ABSTRACT FROM AUTHOR]

Application of building integrated photovoltaic (BIPV) technology in the building envelope gives an aesthetical and modern appearance. BIPV is a practical, innovative and promising technology for net zero emission buildings. This paper introduces the best in class of the BIPV products and their properties along with international guidelines and testing standards. BIPV products for rooftops, façades and windows have been highlighted in this paper. The properties of BIPV products incorporate solar PV efficiency, V oc , I sc , P max and fill factor (FF). The life cycle sustainable assessment of BIPV module has been reviewed by examining energy payback time and GHG emission. [ABSTRACT FROM AUTHOR]

• A data-informed building energy management (DiBEM) framework was proposed. • It was demonstrated in an office/laboratory building with two-years' experimental data. • The impacts of energy efficient interventions were quantified through data-driven models. • The energy use intensity was reduced from 54.1 kWh/m2 to 42.8 kWh/m2. To support building operations in reaching ultra-low energy targets, this paper proposes a data-informed building energy management (DiBEM) framework to improve energy efficiency systematically and continuously at the operation stage. Specifically, it has two key features including data-informed energy-saving potential identification and data-driven model-based energy savings evaluation. The paper demonstrates the proposed DiBEM with a detailed case study of an office and living laboratory building located in Cambridge, Massachusetts called HouseZero. It focuses on revealing the performance of the energy-efficient interventions from two-years' building performance monitoring data, as well as evaluating energy savings from the interventions based on the data-driven approach. With Year 1 as baseline, several interventions are proposed for Year 2 including improvements to controls and operation settings, encouragement of occupants' behavior for energy savings, and hardware retrofitting. These were deployed to heating/cooling, domestic hot water, lighting, plug and other loads, and photovoltaic (PV) systems. To quantify the impacts of different interventions on energy end uses, several data-driven models are developed. These models utilize linear regression, condition model, and machine learning techniques. Consequently, the heating/cooling energy consumption that was already ultra-low in Year 1 (12.8 kWh/m2) is further reduced to 9.7 kWh/m2 in Year 2, while the indoor thermal environment is well maintained. The domestic hot water energy is reduced from 2.3 kWh/m2 to 1.2 kWh/m2. The lighting energy is only increased from 0.3 kWh/m2 in pandemic operations without occupancy in Year 1 to 0.8 kWh/m2 in partial normal operations in Year 2, while the indoor illuminance level meets occupants' requirements. Combined with other relatively constant loads and the reduction of plug and other loads due to COVID building operation restrictions, the total energy use intensity is thereby reduced from 54.1 kWh/m2 to 42.8 kWh/m2, where 5.4 kWh/m2 of energy reduction for Year 2 is estimated to be contributed by the energy-efficient interventions. PV generation is 36.1 kWh/m2, with an increase of 1.4 kWh/m2 from a new inverter. In summary, this paper demonstrates the use of DiBEM through a detailed case study and long-term monitoring data as evidence to achieve ultra-low energy operations. [ABSTRACT FROM AUTHOR]

Facing the challage of energy conservation and emission reduction in the building sector, most energy saving strategies of central heating only focus on the performance improvement of building envelope, ignoring the impact of energy use behavior. This paper proposed a building energy conservation strategy based on energy use behavior analysis, which provides a perspective for in-depth exploration of building energy conservation. After investigating a typical university in the northern China, the energy use behaviors were characterized and two different DeST energy consumption models before or after considering energy use behavior were established. By comparing the results calculated by these two models, the impact of energy use behavior analysis on building energy consumption was quantitatively analyzed. The results show that the heating energy consumption and carbon emission can be reduced by 23.28% and 23% respectively through the proposed strategy based on energy use behavior. Therefore, the analysis of energy use behavior can provide a theoretical basis for heating operators to make decisions on energy supply regulation. With central cooling and heating further popularizing in the future, the research methodology of this paper has more extensive reference value for energy conservation and emission reduction strategies in the building sector. [ABSTRACT FROM AUTHOR]

The use of active thermal energy storage can provide energy savings, cost reduction and CO 2 mitigation by reducing energy demand for heating and cooling, allowing the use of peak load shifting strategies and enhancing the introduction of renewable energies in the sector. The high investment cost of these systems makes mandatory an appropriate control in order to maximize the energy benefits during its operation. Within this context artificial intelligence techniques have been successfully used to control active thermal energy storage units. This paper uses an experimentally validated numerical tool to study the effect of different control strategies on the performance of one TES system applied to the building sector, a ventilated facade with PCM which uses free cooling. Three different strategies were designed to control the ventilated facade based on cost savings, energy reduction and CO 2 mitigation, under different climatic conditions. Results show robust benefits in the three tested control strategies, achieving average savings in comparison to a manual operation of the system of 4.3%, 7.8%, and 16.7%. Moreover, the paper shows that when the control strategy is focused on optimizing cost, the other two benefits claimed by TES systems (energy and CO 2 mitigation) are significantly reduced. [ABSTRACT FROM AUTHOR]

This paper reviews occupancy based model predictive control (MPC) for building indoor climate control. Occupancy behavior in buildings is stochastic and complex in nature. With better understanding of occupancy presence in rooms and spaces, advanced controls, such as MPC, can be designed to achieve a more energy efficient operation, compared to more traditional control methods, while comfort is maintained. This paper starts with an overview of traditional controls implemented in buildings, and importance of occupancy based controls. Various control-oriented building modeling methods including physics-based and data-driven models are reviewed. Later on, a comprehensive review of MPC in terms of control theory, objective functions, constrains, optimization methods, system characteristics and various types of MPC is presented conducted. In principle, MPC finds an optimal sequence of control commands to optimize an objective function, considering system model, disturbances, predictions and actuation constraints. Lastly, occupancy based controls including commonly used rule-based and latest model-based controls are reviewed. In addition, a few experimental studies are presented and discussed. The paper presents a holistic overview of occupancy-based MPC for building heating, ventilation, and air conditioning (HVAC) systems, and discusses current status and future challenges. The purpose of this paper is to provide a guideline forresearchers who would like to conduct similar studies to have a better understanding of established research methods. [ABSTRACT FROM AUTHOR]

Abstracts Energy conservation and emission reduction issues in the construction phase of buildings are increasingly important to meet the challenges of sustainable building. Technological advancement is considered as one of the essential driving forces for green and sustainable construction. But, it is not as effective as expected because the anticipated energy conservation from efficiency improvement would be partially or even totally offset if energy rebound effect exists. This paper fills the research gap by quantitatively investigating the impacts of technological advancement on energy consumption in China’s building construction industry by incorporating direct rebound effect. First, technological advancement rate in terms of energy efficiency is measured by constructing an energy-environmental non-radial directional distance function (ENNDF), which provides a strong support for the Porter hypothesis. Second, by incorporating asymmetric energy price decomposition into a framework of translog cost function, it is estimated that 21.8% energy savings from energy efficiency improvement in China’s construction industry are offset due to rebound effect. Based on the measured results of technological advancement rate and rebound effect, further counterfactual analyses find that technological advancement contributes 27.11 million tons of standard coal equivalent (Mtce) of energy conservation for the construction industry over the period 2003–2012, and 7.57 Mtce of energy would have been saved in the sector if there were no rebound effect. Empirical findings in this paper reveal that technological innovation as well as energy pricing reforms, tax policies and other environmental regulations should be further implemented to achieve effective energy conservation for green building construction. [ABSTRACT FROM AUTHOR]

Abstract To achieve energy efficient Heating, Ventilation and Air Conditioning (HVAC) systems in buildings it is essential to enhance the designs of their various integrated mechanical and electrical components and to control and operate plant optimally. More efficient HVAC systems lead to a significant reduction in power consumption in buildings, which is significant bearing in mind that buildings consume over 40% of the total power consumption in many developed countries. This Special Issue on energy efficient HVAC systems was open to all contributors in the field of heating, ventilation and air conditioning systems in buildings. The invitation was for novel and original papers which extend and advance our scientific and technical understanding of efficient energy HVAC systems including Heat Pumps, water heating and cooling systems in buildings, efficient air conditioning systems, efficient component designs, energy storage (heating and cooling) and regenerative processes. In the event, all these topics were covered in the very wide-ranging submissions accepted but interesting papers on other aspects of HVAC systems and operation were also received. [ABSTRACT FROM AUTHOR]

Harvesting daylight for improving building energy performance has become an important issue in recent years. Most energy simulation tools use a Daylight Factor (DF) based algorithm to capture the complexity of daylight behaviors. However, DF has a limitation for fully accounting realistic daylight conditions, and several modifications or integrations with other supporting tools were developed to compensate for this limitation. This paper uses the Kriging method to predict daylight conditions for a whole year, and couples this method with energy simulation tools. Kriging is a group of geo-statistical techniques used to interpolate the value of a random field at an unobserved location from discrete observed values at nearby locations. In previous research, the Kriging method showed promising outcomes; that result was significantly better than current daylight modeling in energy simulation tool, and very close to the results from advanced physics-based daylight simulation tool. However, Kriging also comes with certain limitations that require further investigation. One major hurdle was Kriging’s long computational time compared to current daylight models in energy simulation tools. For this reason, this paper aims to find possibilities to reduce computational time to realistic levels that can be applicable in practice. Furthermore, it proposes a method to integrate Kriging-based daylight model with an energy simulation tool that can plot hourly indoor light distribution. This proposal obtains more realistic results than current energy simulation daylight models, while reducing computational expense. [ABSTRACT FROM AUTHOR]

Buildings are responsible for 40% of global energy use and contribute towards 30% of the total CO 2 emissions. The drive to reduce energy consumption and associated greenhouse gas emissions from buildings has acted as a catalyst in the increasing installation of meters and sensors for monitoring energy use and indoor environmental conditions in buildings. This paper reviews the state-of-the-art in building energy metering and environmental monitoring, including their social, economic, environmental and legislative drivers. The integration of meters and sensors with existing building energy management systems (BEMS) is critically appraised, especially with regard to communication technologies and protocols such as ModBus, M-Bus, Ethernet, Cellular, ZigBee, WiFi and BACnet. Findings suggest that energy metering is covered in existing policies and regulations in only a handful of countries. Most of the legislations and policies on energy metering in Europe are in response to the Energy Performance of Buildings Directive (EPBD), 2002/91/EC. However, recent developments in policy are pointing towards more stringent metering requirements in future, moving away from voluntary to mandatory compliance. With regards to metering equipment, significant developments have been made in the recent past on miniaturisation, accuracy, robustness, data storage, ability to connect using multiple communication protocols, and the integration with BEMS and the Cloud – resulting in a range of available solutions, selection of which can be challenging. Developments in communication technologies, in particular in low-power wireless such as ZigBee and Bluetooth LE (BLE), are enabling cost-effective machine to machine (M2M) and internet of things (IoT) implementation of sensor networks. Privacy and data protection, however, remain a concern for data aggregators and end-users. The standardization of network protocols and device functionalities remains an active area of research and development, especially due to the prevalence of many protocols in the BEMS industry. Available solutions often lack interoperability between hardware and software systems, resulting in vendor lock-in. The paper provides a comprehensive understanding of available technologies for energy metering and environmental monitoring; their drivers, advantages and limitations; factors affecting their selection and future directions of research and development – for use a reference, as well as for generating further interest in this expanding research area. [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]

Occupants account for a significant impact on building performance through their interactions with zone level building components. Empirically-derived occupant models, despite their potential to represent occupants’ impact in building performance simulation (BPS), have minimal penetration in design and code compliance processes. Instead, occupants are represented with static schedules or simple deterministic triggers. The objective of this paper is to better understand the influence of assumptions made in representing occupant interactions with building components over a BPS model's energy use and comfort predictions, as well as their ability to promote better design decisions. To this end, the energy and daylight performance of a generic perimeter office space in Ottawa, Canada were evaluated using a set of comprehensive performance metrics. Results indicate that representing dynamic occupant–building interactions lead to different energy predictions from the static schedules. The maximum difference in the total electricity use was for window-to-wall area ratios (WWR) of 20%, which was about 30% higher with the stochastic cases than the blind-open static cases. WWR 60% and 40% generally yielded the lowest lighting electricity use with the static and stochastic cases, respectively. This paper emphasizes the importance of incorporating empirically-derived dynamic occupant models for simulation-aided design and code compliance. [ABSTRACT FROM AUTHOR]

This paper deals with the quantification of the uncertainties due to wind in building pressurisation tests. The steady wind model error stems from the heterogeneous pressure distribution around the building. We have analysed this error based on a simplified one-zone building model with one leak on the windward side and one on the leeward side of the building. Our model gives an analytical expression of this error that depends on the leakage distribution and pressure coefficients. Using test and reference pressures at 50 Pa in this model, standard measurement protocol constraints contain the steady wind model error within about 3% and 11% with wind speeds below 6 m s −1 and 10 m s −1 , respectively. At 10 Pa, the error is in the range of 35% and 60% at 6 m s −1 and 10 m s −1 , respectively. This paper also includes an estimate of the combined uncertainty including other sources of errors which can be used to assess the relevance of measurement protocols. Under idealised conditions, using 50 Pa as reference pressure and a default flow exponent, it can be expected a combined expanded uncertainty of 6%–12% for wind speeds of 6–10 m s −1 , respectively. [ABSTRACT FROM AUTHOR]

Whole-house ventilation, which is defined as systems that supply and exhaust or relieve ventilation air for a residence, has been a mandatory provision since the announcement of IECC 2012. As a result, an increasing numbers of publications and standards are now addressing residential ventilation in terms of performance and efficiency. In addition, loudness is increasingly addressed in standards and guidelines, especially in the last decade as it is now considered to be a significant factor for certified performance ratings of ventilation fans. Because of the above interest in fan performance, this paper provides statistics of bathroom ventilation fan tests and their results for an almost decade-long period from 2005 to 2013. Also, the paper interprets these statistics with regards to the recent development of residential ventilation standards and guidelines. In order to investigate year-to-year changes, this paper first evaluates changes in loudness ratings for the test period 2005–2013, and its relevance to applicable standards, including ASHRAE 62.2. Then, noticeable transitions in loudness and efficacy in specific time frames are investigated. The test results of DC-motor high-efficiency bathroom fans are also compared to AC-motor fans. Relationships between performance variables and loudness are investigated, and formulated by developing regression models. [ABSTRACT FROM AUTHOR]

Smart building systems are opening up new markets, nevertheless the implementation of these novel technologies still lacks suitable and proven whole engineering solutions in complex buildings. This paper presents a detailed approach for the ventilation control of an underground space, as an example of application of the developed solution to a very harsh environment but also highly demanding in terms of energy consumption. The underground spaces are characterized by a particular thermal behavior, because of the continuous and huge thermal exchange they have with the outside, via the openings and the ground surrounding the majority of the building. The main objective of the developed methodology is to reduce energy consumption of ventilation control while maintaining acceptable comfort levels: succeeding in achieving this twofold goal in a real station and the generalization of the approach are the most relevant contributions of the paper. The developed solution is based on a Model-based Predictive Control algorithm used together with a proper monitoring platform. The model predictive control is based on a Bayesian environmental prediction model, which works in cooperation with a weather forecast web service, schedule-based predictions about trains and external fans and an occupancy detection system to appraise the real amount of people. The prediction model develops scenarios useful to allow the controller acting in advance in order to adapt the system to the current and future conditions of use, taking profit of the knowledge of the real ventilation demand. Finally, the proposed control architecture is applied to the Passeig de Gràcia metro station in Barcelona as a case study, validating the usefulness of the proposed approach and obtaining more than 30% of energy savings in the ventilation system, while maintaining the pre-existing comfort levels. The saving percentage values estimated by simulation are confirmed by the direct measures continuously taken on site through energy-meters. [ABSTRACT FROM AUTHOR]

Current trend in the field of civil engineering is building energy-saving and environmentally friendly constructions. One of ways of achieving these trends is using new, progressive construction materials, which are friendly to the environment, have good end-use properties and which are also for reasonable price. Another way is building plant facades and roofs. Plants are capable of regulating temperature and humidity in such constructions. Their advantage is positive influence on healthy living in large cities, where the beneficial properties of plants can be used, like capability of retaining fine dust particles, reducing the level of noise and protecting the structure from weather effects. The paper describes possible connection of both above mentioned modern technologies and gives results of research and development of insulation materials based on natural fibers; in particular technical hemp, flax and jute and their application into buildings with plant facades and roofs. The paper also mentions hydrothermal behavior of the developed materials, including computational simulation of behavior of the optimal hemp fiber based material after building into a structure with plant facade. [ABSTRACT FROM AUTHOR]

The smart grids are modern electric power grid infrastructure for enhanced efficiency and reliability through automated control, high-power converters, modern communications infrastructure, sensing and metering technologies, and modern energy management techniques based on the optimization of demand, energy and network availability. The role of buildings in this framework is very crucial. This paper addresses critical issues on smart grid technologies and the integration of buildings in this new power grid framework. The main objective of this paper is to provide a contemporary look at the current state of the art in the potential of buildings and communities to be integrated in smart grids as well as to discuss the still-open research issues in this field. The challenges for the building sector are discussed and future research prospects are analysed. [ABSTRACT FROM AUTHOR]

In this paper, a phase change material (PCM) to air rectangular heat exchanger is studied for an objective of electricity peak shaving. First, a set of dimensionless numbers are derived from physical equations to understand the storage device behaviour: 1/ BiFo , Bi / St and Ste . Second, these numbers are used to select the PCM based on the thermophysical properties of the material. Finally, the storage device is pre-designed by a proper analysis of the remaining dimensionless numbers. With the methodology developed in this paper, it is possible to efficiently design solutions from the specification requirements of the storage system. [ABSTRACT FROM AUTHOR]

The selection of a thermal comfort model for establishing indoor optimal hygrothermal conditions during the hot period has a major impact on energy consumption of Net Zero Energy Buildings in hot climates. The objective of this paper is to compare the influence of using different thermal comfort models for zero energy buildings in hot climates. The paper compares the impact of applying Fanger's model, Givoni's model, the ASHRAE 55 adaptive comfort model and the EN 15251 adaptive comfort model on energy consumption and comfort performance. Using both the building performance simulation tools ZEBO and EnergyPlus for energy simulation, an existing prototype of a residential apartment module is used to evaluate energy performance and thermal comfort in two parametric series. The first one is the result of coupling natural ventilation and mechanical cooling and the second one is guided coupling natural ventilation, mechanical cooling and ceiling fans. This study shows that the percentage of energy consumption difference meeting the comfort criteria according to ISO 7730 in comparison to EN 15251, ASHRAE 55 or Givoni's model varied up to 16%, 21% and 24.7%, respectively for the presented case study. More energy savings can be expected for buildings in hot climates with greater cooling demands. [ABSTRACT FROM AUTHOR]

One major obstacle encountered in building energy conservation and retrofit is the lack of detailed energy submetering data. Direct submetering is expensive and sometime very difficult to be installed in real practice. For example, the HVAC terminal end-use electricity consumption is extremely difficult to measure, because its data is always mixed together with lighting-plug or power submeter. This paper presents a new approach to solve this problem, which is based on a Fourier series model (FSM) for calculating the lighting-plug and power submeters in commercial buildings, and then disaggregate the HVAC terminal end-use hourly electricity consumption from them. Compared with black-box models, such as ANN, SVM and so on, FSM as a grey-box model has two key advantages (1) the application is convenient because of its simple model structure and (2) once a model is developed, it can be used in other same type commercial buildings directly. Measured data from two office buildings and two shopping malls located in Shanghai are analyzed in this paper. The disaggregation results demonstrate that the method is accuracy within a reasonable degree. The calculated hourly HVAC terminal end-use electricial consumption is close to the real measured data. The MRE (mean relative error) and CV (coefficient of variability) both can be controlled within 10%, and in some special cases they are almost within 1%. [ABSTRACT FROM AUTHOR]

The aim of this paper is twofold: to investigate the applicability of a building-stock modelling methodology to assess the potential of Energy Conservation Measures (ECMs) and their associated effects on carbon dioxide (CO 2 ) emissions for a building stock in a South European climate, with Spain being used as an example; and to analyse the technical potentials and costs of the ECMs when applied both individually and as packages of multiple ECMs for the entire Spanish building stock, including residential and non-residential buildings. The modelling methodology, which has been designed to be applicable to any European country, is fully dynamic and based on an aggregated description of the building stock. This paper updates and validates the methodology to account for the climate and technical characteristics of the region under study. Applying all ECMs as a package gives a potential technical reduction in final energy demand of 55% and a 65% reduction in CO 2 emissions, while the corresponding techno-economical potentials are 33% and 37%. Nevertheless, the market potentials estimated are substantially lower (5–10%), which indicate that policy shifts are needed if the techno-economic potentials identified in this work are to be realized. [ABSTRACT FROM AUTHOR]

Do energy efficient buildings save energy or spare it for other uses? Cost-effective energy efficiency improvements increase the available income of a household, or business. The increase of household income may be re-spent on the same energy service or elsewhere in the economy, or invested. This problematic, termed “rebound effect”, receives renewed attention. Its micro- and macroeconomic implications can in part explain why governmental energy efficiency programmes failed to reduce total energy needs in our societies. This paper identifies zero energy buildings (ZEBs) as both a solution and a contributor to this energy efficiency paradox. The E2 (economy–environment) vector is used to qualitatively illustrate the rebound effect link to energy efficient and zero energy buildings. The paper argues that a robust energy balance, one that shall ensure ZEBs effectively contribute to the global mitigation of greenhouse gas emissions, needs to address this paradox of energy efficiency. The paper proposes ways to do so. [ABSTRACT FROM AUTHOR]

Global warming has drawn great attention in recent years because of its large impact on many aspects of the environment and human activities in buildings. One area directly affected by climate change is the energy consumption for heating and cooling. To quantify the impact, this study used the HadCM3 Global Circulation Model (GCM) to generate weather data for future typical meteorological years, such as 2020, 2050, and 2080, for 15 cities in the U.S. based on three CO 2 emission scenarios. The method was validated by comparing the projected TMY3 data using HadCM3 with the actual TMY3 data. By morphing method, the weather data was downscaled to hourly data for use in building energy simulations by EnergyPlus. Two types of residential buildings and seven types of commercial buildings were simulated for each of the 15 cities. This paper is the first to systematically study the climate change impact on various types of residential and commercial buildings in all seven climate zones in the U.S. through EnergyPlus simulations and provide weighted averaged results for national-wide building stock. We also identified geographical dependency of the impact of climate change on future energy uses. There would be a net increase in source energy consumption by the 2080s for climate zones 1–4 and net decrease in climate zones 6–7 based on the HadCM3 weather projection. Furthermore, this paper investigated natural ventilation performance in San Francisco, San Diego, and Seattle with improved natural ventilation model. We found that by the 2080s passive cooling would not be suitable for San Diego because of global warming, but it would still be acceptable for San Francisco and Seattle. [ABSTRACT FROM AUTHOR]

Thermal comfort is one of the most important aspects of the indoor environmental quality due to its effects on well-being, people's performance and building energy requirements. Its attainment is not an easy task requiring advanced design and operation of building and HVAC systems, taking into account all parameters involved. Even though thermal comfort fundamentals are consolidated topics for more than forty years, often designers seem to ignore or apply them in a wrong way. Design input values from standards are often considered as universal values rather than recommended values to be used under specific conditions. At operation level, only few variables are taken into account with unpredictable effects on the assessment of comfort indices. In this paper, the main criteria for the design and assessment of thermal comfort are discussed in order to help building and HVAC systems designers and operators to navigate the complex and varied world of standards in the field of thermal environment for improving indoor environmental quality and energy saving. The examples discussed in the paper will also be useful for the standardization, leading to harmonized documents more readable for all users. [ABSTRACT FROM AUTHOR]