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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]

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]

Abstract: Directive 2010/31/EU adopted that by the end of 2020 all new buildings should be nearly Zero-Energy Buildings (nZEB) and Member States should achieve cost-optimal levels by ensuring minimum energy performance requirements for buildings. This paper discusses how low should be the energy required by a nZEB, in the context of housing energy consumption in a Mediterranean climate (Lisbon). For selected houses built after 1990, the calculated primary energy loads for regulated uses – heating, cooling and domestic hot water – are found to be below 90kWh/(m2 year). Applying the cost-optimal solutions of thermal insulation and glazing type and considering energy efficiency improved systems, this study concludes that housing energy loads are ‘low’ for the indicative range of 70kWh/(m2 year) for regulated uses or 100–110kWh/(m2 year) for total uses, taking primary energy indicators (PEI) from EN 15603. Assuming PEI from Passive House Planning Package or those to be assumed in Portugal for 2013, the threshold decreases to 60kWh/(m2 year) for regulated uses or 90–100kWh/(m2 year) for total uses. Only the first nZEB condition is explored by this paper. The second condition requires that the nZEB energy load is covered by a ‘significant’ part of renewable energy sources produced on-site or ‘nearby’. [Copyright &y& Elsevier]

Highlights • A methodology is introduced to rank a set of buildings based on energetic performance of occupants. • Ranking is done in two levels, each one gives specific information about occupants of a single building. • The underlying factors that create the ranks are examined to give occupants clues on how to improve their rank and reduce energy consumption. Abstract Identifying the impacts of occupants on building energy consumption has become an important issue in recent years. This is due to the interrelationship of influencing factors such as urban climate, building characteristics, occupant behavior, and building services and operation, which makes it challenging to identify the role of occupants in energy consumption. The research problem in this study lies in the fact that the occupants of a building may not be cautious regarding energy savings, and there exists no ground to assess their energy consumption behavior. One solution is the development of a systematic comparison procedure between similar buildings. This paper introduces a new procedure for comparison between occupants of several buildings to show the rank of each building among others and suggest occupants on reducing their energy consumption and improving their rank. The proposed framework is developed based on multiple data-mining methods, including clustering, association rules mining, and neural networks. The proposed methodology is composed of two levels. The first considers the amount of energy usage by occupants after filtering effects unrelated to the occupant behavior. The second ranks the buildings in terms of achieved and potential savings during the time under investigation. To demonstrate the application, the methodology was applied on a set of monitored residential buildings in Japan. Results suggest that the proposed method enhances the evaluation of buildings' energy-saving potential by revealing the occupants' contribution. It also provides diverse and prioritized strategies to help occupants manage their energy consumption by revealing the building energy end-use patterns. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Buildings consume a significant amount of energy worldwide in maintaining comfort for occupants. Building energy management systems (BEMS) are employed to ensure that the energy consumed is used efficiently. However these systems often do not adequately perform in minimising energy use. This is due to a number of reasons, including poor configuration or a lack of information such as being able to anticipate changes in weather conditions. We are now at the stage that building behaviour can be simulated, whereby computer programs can be used to predict building conditions, and therefore enable buildings to use energy more efficiently, when integrated with BEMS (i.e. simulation assisted control [1]). In this paper we demonstrate a low cost BEMS that uses building simulation to predict optimised electrical heating startup control points. Those that use electricity for heating in Scotland, where this study was based, tend to be fuel-poor, hence there is a strong case for optimisation, particularly when electricity costs nearly three times as much as the equivalent unit of gas for heating applications. The proposed system demonstrated a 50% energy saving in the reduced heating time compared to scheduling when retrospectively evaluated. [ABSTRACT FROM AUTHOR]

The hollow block ventilated wall is a new kind of ventilated wall, the exhaust air of HVAC system is used as the supply air to flow through the cavity of this wall in this paper. The heat or cool storage in the wall is reduced by using the heat recovery technology; the temperature of internal surface is lowered in summer and increased in winter, and the human thermal comfort is enhanced. A semi-dynamic heat transfer model of the ventilated wall is presented for thermal performance prediction. The dynamic optimized resistance-capacitance (ORC) model and the number of transfer units (NTU) model are joined together to develop the semi-dynamic heat transfer model of this ventilated wall. The experimental study is carried out for validating the semi-dynamic heat transfer model. The maximum relative error is 4.3% for mean internal and external surface temperatures, and it is 2.6% for the outlet air temperature of the cavity. The heat transfer model established for hollow block ventilated wall is fairly reasonable and possesses high accuracy. This model can be used to predict the surface temperature of the hollow block ventilated wall and the heat flux removed by the airflow in the cavity for performance evaluation. [ABSTRACT FROM AUTHOR]

This paper discusses the performance of CO 2 adsorption device and its utilization to save energy in buildings. This new device adsorbs CO 2 and a small amount of moisture in the CO 2 capture process, and it evaporates pure CO 2 by thermal energy in the desorption process. This study shows the possibility of implementing a CO 2 capture device in the operation of an air ventilation system for high performance air cooling and heating of buildings. This innovative strategy provides a means to recirculate indoor air to save energy for a certain period of time and the potential for an energy-efficient operation of buildings. This study presents the analysis of CO 2 adsorption performance measurements and evaluates the application of the device by numerical calculations. The results of simulations for the tropical summer and Central European winter season show that 30–60% of air ventilation energy for cooling and heating can be saved competed to conventional systems. Based on these results, this study describes the possibility of using this system to recirculate indoor air using the CO 2 capture device to save energy and minimize air cooling and heating loads. This novel strategy introduces a new paradigm of air ventilation and can replace conventional air ventilation systems for certain period of time. [ABSTRACT FROM AUTHOR]

High performance simulation of low energy building requires ever more accurate descriptions of the systems under study to improve the building's performance. This paper describes a numerical model to simulate a single room, using a three-dimensional description of heat conduction in the envelope with environmental conditions that vary over short time-steps are described. The simulation considers the projection of solar radiation through a window onto interior walls. The indoor air temperature is assumed to be uniform. The temperature of the inner and outer surface of the walls are calculated at each time step using a variable-step solver. Validation of the model was carried out using experimental data from a low energy cell operating in a natural climate. A set of well-calibrated temperature sensors and an infrared camera have been used to accurately measure the cell's thermal behavior. Comparison between experimental data and numerical results for free varying conditions shows good agreement and the reliability of the model is proven. These validated results were found for a highly insulated cell. Future studies for different thermal mass cells, with new materials, will be realized to show the contribution of this model. Thermal comfort will also be studied. [ABSTRACT FROM AUTHOR]

As one form of passive cooling, night ventilation (NV) has been proven effective to improve the building energy performance. In previous studies, however, fixed NV operating strategies were usually pre-defined, ignoring the weather condition variations over the whole operation process, the influence of outdoor humidity on NV's efficiency, and NV's integrated performance with active air conditioning systems. Such strategies may have potentials for further improvements. This paper presents a systematic approach to address the dynamic optimization of integrated operation of NV and active building air conditioning using typical variable–air–volume (VAV) systems as the case. In the optimization scheme, the physical model is developed per differential algebraic equations (DAEs). The simultaneous collocation method is introduced to translate the dynamic optimization into a nonlinear program, which is then implemented in the GAMS platform and handled by IPOPT solver. The study results indicate that the optimized strategies lead to a remarkable energy saving of 23.19–49.31% in different climate conditions compared to the traditional local control scheme without NV, and a saving of 14.97–39.70% compared to that with pre-defined NV. [ABSTRACT FROM AUTHOR]

The increase of complexity in school buildings to ensure for users comfort and social and functional demands are changing energy consumption patterns. In the Portuguese context, a recent rise in energy consumption, after a major national refurbishment programme, confirms the need to improve energy management in schools in order to reduce their environmental impact. Besides building design and systems, users are also a determining factor impacting energy consumption in buildings. However, behavioural issues are still among the areas least covered by scientific literature. The present paper analyses the energy consumption patterns of eight Portuguese case-study schools, with a methodological approach that integrates quantitative and qualitative data analysis. The approach made it possible to link the energy consumption patterns of the schools (selected as Key Performance Indicators) with the user behaviour and management strategies. As a result, six Key Performance Strategies (KPS) were identified so as potentially to enhance the energy performance of school buildings through use and management. Some of the identified KPS can be implemented directly through school management policies to reduce energy use and enhance efficiency. Others can be incorporated in future building design strategies. Some have the potential for being hereafter integrated into the simulation models of buildings’ energy performance. [ABSTRACT FROM AUTHOR]

In this paper is presented methodological approach to the energy efficiency optimization of high density data centre, in a synergy with relevant performance analysis of corresponding case study. Related case study goal—to optimize energy efficiency to the level characterized by the power usage effectiveness nearly equal 1 (PUE ≈ 1), has been successfully realized, tracing an energy efficiency optimization road to a hyper energy efficient data centre of the superb IT and energy performance. In addition to the corresponding energy densities, and energy efficient removal of extremely high heat dissipation, to reach superb IT performance very special focus is to be devoted to finally controlling indoor air temperature and humidity conditions. It has been shown that, by an integrated approach to the optimization of building construction, data centre's intrinsic IT systems and equipment selection is to be done also with the reference to its specific energy efficiency and the most recent breakthroughs in IT infrastructure fields, as well as in data centre's high performance air-conditioning and infrastructure's high precision cooling. Finally, data centre greening, implementing renewable energy sources has been analysed. [ABSTRACT FROM AUTHOR]

Liquid desiccant dehumidification system has received much attention in recent years for its important economic benefits in energy saving of buildings. Furthermore, the specific surface area of desiccant solution can be expanded dramatically by the ultrasonic atomization technology, which generates numerous tiny droplets with diameter about 50 μm. However, the tiny atomized droplets are found to be easily captured by the wall of dehumidifier chamber, resulting in the poor performance of this type of system. In this paper, a new criterion called “droplets suspension rate” together with an optimized design method was proposed to improve the performance of ultrasonic atomization liquid desiccant dehumidification system via optimizing its dehumidifier chamber. Experiments were carried out to verify the improvement, where the dehumidification effectiveness, desiccant consumption rate and the air temperature rise were adopted as indicators to evaluate the performance of the system. The results showed that the performance of ultrasonic atomization liquid desiccant dehumidification system was enhanced significantly and the desiccant consumption was reduced markedly after the improvement. Moreover, the improved system was found to be able to utilize lower-grade desiccant solution. The criterion and the method proposed may build a foundation for the better design of ultrasonic atomization liquid desiccant dehumidification system. [ABSTRACT FROM AUTHOR]

Vacuum insulation panels (VIPs) have thermal resistance values, at the center of the panel, up to 10 times or more than those of conventional thermal insulation materials. In Canada, known for its predominantly extreme cold climate, the potential to apply VIPs in the building construction industry is estimated to be enormous, particularly with the introduction of the new 2011 National Energy Code of Canada for Buildings (NECB 2011). VIPs can play a major role in Canadian buildings to meet energy requirements of the NECB 2011. However, the lack of long-term performance credentials and various constructability issues are among the major barriers for mass application of VIPs in the Canadian construction industry. This paper presents the design strategy, construction details, instrumentation and thermal performance monitoring observations of a VIP retrofitted wall system in Yukon, located in Northern Canada. Experience gained from the construction process and available thermal performance data over a period of three years provide encouraging indicators for the constructability and long-term thermal performance of VIPs in Canadian subarctic weather. [ABSTRACT FROM AUTHOR]

Abstract: Chiller sequencing control plays an important role in achieving air-conditioning system energy efficiency since chillers usually account for major part of system overall energy consumption in commercial buildings. This paper compares and evaluates the in situ performances of three commonly used chiller sequencing control strategies. These three control strategies are operating online in parallel on a management and communication platform in a super high-rise building in Hong Kong. The comparison and evaluation focus on the perspectives of chiller switch number, electrical peak demand and overall energy consumption in one week. Meanwhile, the different impacts of two systematic errors (i.e. positive errors which cause direct measurement larger than true value and negative errors which cause measurement smaller than true value) on each control strategy are also analyzed. The performance comparison demonstrates that the strategy, using fused cooling load measurement, achieved the best performance. The applications of the online computed chiller maximum cooling capacity and the advanced data fusion technique, which removes the negative impacts of sensor measurement uncertainties, can significantly improve the performance of chiller sequencing control. [Copyright &y& Elsevier]

Abstract: This paper reports investigations of energy, environmental, and economic performances of floor, wall, ceiling, and floor–ceiling heating. It is found that the floor–ceiling heating has the best performances: the lowest energy and exergy consumption, exergy destruction, CO2 emissions (compound, direct, and avoidable), and operation costs. In addition, it uses boiler of the lowest power. The worst system by all these parameters is the classical ceiling heating. The comparison of the room operative air temperatures and the operative air temperatures set by thermostats shows that all systems give satisfactory results without significant deviations. The largest deviation and the lowest values of the surrounding inner surfaces of the exterior walls are found for the floor–ceiling ceiling panel system. [Copyright &y& Elsevier]

Abstract: The increasing attention to energy saving in buildings has led to more accurate analysis of the thermal performance of windows. In particular, the use of aluminum frames has known a rapid development; thanks to the installation of thermal break systems, the performance of aluminum frames is nowadays comparable to the one wooden frames. The numerous air cavities inside aluminum frames suggest a deep investigation of the heat exchange process; the paper, therefore, analyzes the effect of the geometric and surface characteristics of the cavities on the overall performance of the profile. The attention was focused on the emissivity properties of the cavity inner surfaces, since they play a fundamental role on radiation heat transfer; furthermore, the frame thermal performance was evaluated when the geometries of some cavities are changed with the insertion of rubber gaskets. All the analysis were conducted with two different approaches: numerical and experimental, obtaining a good match between the methods; the validation of the CFD model makes it a quick and user-friendly tool for the preliminary design and optimization of aluminum window frames with a high thermal resistance. [Copyright &y& Elsevier]

Abstract: Energy efficiency in buildings is essential for economic, social, and environmental reasons. Under current European legislation, buildings have to be certified with an energy efficiency index. To provide a fair comparison of the energy performance in buildings we need a global and unified representation. In this paper we propose the Energy Efficiency Ontology (EEOnt) to provide a foundation upon which this requirement can be built. EEOnt extends the applicability of other ontological models of buildings incorporating energy efficiency data and knowledge that can be calculated with high spatial and temporal resolution in what we call an Energy Efficiency Landscape (EELB). These EELB''s provide significant information which allows a detailed diagnosis of the energy efficiency within the building. Consequently, EEOnt is capable of representing buildings and energy efficiency in a unified way. Furthermore, it supplies a tool for managing the energy efficiency in buildings and constructing national inventories. These two features link the global and particular needs of governments and users, thus becoming key to both improve the energy efficiency in buildings and to implement viable certification schemes. [Copyright &y& Elsevier]