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This paper shows development of a simple, cheap “Building Energy Management System” (BEMS) to monitor energy consumption, and an application to measure energy consumption, including electricity and gas consumption in buildings. The system uses current transformers to measure electric consumption at each distribution box. Web cameras monitor lighting in each room, as well as air conditioning status by recognizing the movement of a ribbon at the outlet. Web cameras can also monitor gas consumption at the meter through character recognition. The data is sent via network to a computer for monitoring and analysis. As an example, key components of this BEMS were tested to measure building energy consumption of Osaka City University Sugimoto Campus in Japan for a period of 2 years (2013, 2014). The electric consumption of campus as well as the electric and gas consumption for air conditioning use was measured. Web cameras were installed in several rooms in one section of the campus to record lighting and air conditioning use data. The data was analyzed to reveal a correlation between hourly outdoor temperature and hourly electric consumption, with a stronger correlation between hourly outdoor temperature and hourly electric consumption for air conditioning. [ABSTRACT FROM AUTHOR]

Commercial and residential buildings account for 40% of total energy usage in the United Sates. Efforts have been made to better manage energy through the implementation of building energy management systems. In particular, heating, ventilating, and air conditioning consume 50% of energy used in buildings. The system air-conditioner, an individually as well as centrally controlled HVAC system, is widely used across Asia. As energy cost increases, building managers often take building-wide energy saving measures, such as intermittent indoor unit shut-down and setting units to uncomfortable temperatures. In this paper, we argue that a smarter approach is possible. Analyzing a large amount of data collected from indoor units, we see that these units have varying levels of energy consumption and that we can identify those that consume more energy than others, resulting in individual measures for each. We propose a business intelligence framework that allows us to see why certain rooms consume more energy than others through three variables: hours of power-on, hours of thermo-on, and a timeframe of power-on. All variables are visualized, providing building managers with an intuitive understanding of their buildings’ energy consumption. We used real-world data to validate the framework and received positive feedbacks from domain experts. [ABSTRACT FROM AUTHOR]

There is evidence that occupants’ energy use holds a large fraction of the total energy consumed at the office. Our work, motivated by a relevant study investigating the effect of individual feedback on energy use at the workdesk, exploits earlier findings to design a six-month field trial that monitors occupants’ energy use and provides individual feedback to 18 office employees in a university setting. This paper presents the research design and methods used, employing data analysis to assess how office workers responded to the feedback provided, and to examine their impact on the energy consumption of their desktop computers. The main findings were: the behavior of occupants affected the energy consumption of their computers in a large extent; emails were considered better communication channels than posters and leaflets; a combination of feedback messages was more useful, with personal advice, self monitoring and education being the most powerful; finally and most importantly energy reduction and proper use of equipment continued for 13 weeks after the feedback was removed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The influencing factors on energy efficiency of data center are reviewed. • Energy efficiency metrics are classified according to different priorities. • Appropriate metrics should be selected according to data center function for optimization. • Metrics are analyzed by hierarchy according to the degree of sustainable development. • Challenges and gaps are highlighted and suggestions are given for future works. The rapid development of the Internet requires data center infrastructures to be extended to a large scale with a higher power capacity and a reduction in energy consumption and carbon emissions. It is of great significance for this application to reduce energy consumption, capital cost and carbon emissions while ensuring a safe and reliable data center operation. Evaluation metrics have been considered an effective method to assess the energy efficiency of data centers and have been widely used in various data centers for many years. This work reviews the latest progress of data center evaluation metrics development in recent 20 years. Energy efficiency metrics are summarized based on energy conservation, eco-design and data center security, with the advantages and disadvantages and their correlations discussed. The applicability of each metric is analyzed. The influencing factors of energy efficiency of data centers discussed include site selection, IT equipment, power supply and distribution systems, cooling systems, building structure, and temperature control. The results show that the current evaluation metrics are valuable for the assessment of energy saving of data centers. However, more comprehensive and multi-scale evaluation metrics combining energy consumption, eco-design and data center security are needed to accelerate the progress towards carbon neutrality. In this paper, the hierarchy analysis of metrics is carried out according to sustainability, and metrics in line with sustainable development should be used preferentially. [ABSTRACT FROM AUTHOR]

Using energy conservation measures (ECMs) for building retrofit can significantly reduce building operational carbon emissions (BOCEs) and contribute to Chinese carbon neutrality by 2060. This paper involves 11 feasible ECMs for commercial buildings in hot-summer and cold-winter zone, China, and proposes a quick assessment approach to BOCEs reduction. Prototypical models are simulated for ECMs using EnergyPlus and the emission intensity is corrected by the building shape factor and window-to-wall ratio. Based on pre-simulated results, effects on reducing emissions of individual measures and packages of them are studied to develop regression models in SPSS. The results show that decreasing the U-factor of external walls, lighting power density (LPD), or shading coefficient can reduce BOCEs linearly. BOCEs are most sensitive to LPD and using daylighting control can reduce emissions by 5–15%. In addition, increasing the boilers' efficiency reduces emissions linearly, while performance improvement of chillers or heat pumps reduces emissions logarithmically. Furthermore, utilizing variable speed pumps, heat recovery ventilation, and air-side economizers can reduce emissions by 3.8%, 6.6%, and 15.2%, respectively. Finally, significant interactions exist among measures of enhancing glazing U-factor, adding external shading, using energy-saving lamps, and improving cooling/heating system efficiencies. The developed regression models are validated in a retrofit case in Shanghai. Through assessment, the case can reduce BOCEs by 15.9 kgCO 2 /m2, with a reduction rate of 20.8%. Compared with recorded data, the relative error of assessing emission reduction is −13.0% and that of assessing reduction rate is 0.5%, which are acceptable in the decision-making stage of retrofit strategies. [ABSTRACT FROM AUTHOR]

More than one-third of energy expenditure is attributable to buildings. Urbanization is leading to tighter spatial interrelationships among buildings, which is escalating building energy consumption due to the impact of buildings on one another. This, in turn, is exacerbating Urban Heat Island (UHI) effects. We sought a bio-inspired solution to this significant engineering issue and discovered a similar heat island effect in flowers, namely the “micro-greenhouse effect.” However, a special cooling effect has been observed in a temperate flower— Galanthus nivalis —which generates cooler intrafloral temperatures. In this paper, we studied the special retro-reflecting property of the flower petals, which has been suggested as a possible contributor to this cooling effect, and modeled a bio-inspired retro-reflective building envelope. We conducted cross-regional energy simulation of building networks in order to examine its thermal-energy impact. We found that building surface temperatures dropped considerably when neighboring buildings were retrofitted with a bio-inspired retro-reflective façade. We concluded that a bio-inspired retro-reflective building envelope can; (1) lessen the reflected heat of solar radiation in spatially proximal buildings leading to reduced UHI, and (2) reduce the energy required for cooling. These findings have broad implications for building design, urban planning, development of retro-reflective technology, and environmental conservation. [ABSTRACT FROM AUTHOR]

Occupancy interventions, which are typically used to diffuse energy conservation practices among commercial building occupants, are showing promising but un-sustained energy savings. One possible explanation to the observed results is the presence of extreme energy users in the buildings who can have an important influence on their moderate peers and revoke the benefits of occupancy interventions. While this ‘extremism’ in human behavior phenomenon has been extensively studied in various social science fields, it has yet to be applied on the study of energy conservation from occupancy interventions in commercial buildings. Using agent-based modeling and data from actual commercial buildings, this paper evaluates the influence of extreme energy users (1) on their peers and on the energy performance of commercial buildings and (2) on the effectiveness of commonly implemented occupancy interventions. Parametric variations and statistical analyses indicate that extremism can highly affect the effectiveness of traditional occupancy interventions. In parallel, a combination of methods has shown to empower moderate energy users, helping diffuse and maintain energy conservation practices even in the presence of extreme energy users. The demonstrated capability to test and optimize occupancy interventions is expected to support and boost their adoption in large-scale energy conservation initiatives. [ABSTRACT FROM AUTHOR]

With an old mean construction age, Italian buildings are considered as long-lasting goods; 75% and 17% of Italian live respectively in buildings built before 1990 and before 1950. The potential energy savings that can be achieved from the refurbishment of existing dwellings are clearly high. To this regard, the European Directive EPBD recast defines a comparative framework to improve buildings energy performance aiming to the nearly zero energy target by 2020. It is thus important to point out energy retrofit actions to be widely applied to the whole existing buildings stock and to be cost optimal. This paper analyzes the application of space heating control devices such as thermostatic radiators valves (TRVs) on an old existing multi-family building in Turin by means of the EnergyPlus dynamic simulation code. Measured data of the energy supplied by the district heating network were used for calibrating the model. In order to evaluate the impact of the TRVs, simulations were performed with and without TRVs. The application of the dynamic energy simulation to different patterns of TRVs use was proved to bring back significant energy savings from a minimum of 2% up to a maximum of 10%. [ABSTRACT FROM AUTHOR]

Interior insulation is often the only possible post-insulation technique to improve the thermal performance of single leaf masonry walls. As a result of potential damage patterns such as frost damage, interstitial condensation and mould growth however, there is often some reluctance to adopt this technique. To fully exploit the capacity for energy savings offered by interior insulation while avoiding hygrothermal failure, a reliable risk assessment is extremely important. This requires a probabilistic approach, since the uncertainty of all influencing parameters might result in widely varying results. As, so far, no real methodology is available to select the interior insulation system and thickness resulting in the best balance between energy savings and hygrothermal risks, this paper presents a decision tool based on a Monte Carlo analysis. Additionally, the influence of the rain load and some masonry characteristics is discussed. In the study, both vapour tight interior insulation systems and a capillary active insulation system are considered. Overall, vapour tight systems tend to be preferable for structures that are resistant to frost damage. For buildings sensitive to frost damage or when wooden beam ends are present, however, capillary active systems are shifted forward. [ABSTRACT FROM AUTHOR]

Solar-ground source heat pump system (SGSHPS) is a new type of high efficiency, energy saving and environmental protection air-conditioning technology. In this paper, experimental studies and numerical simulation on the performance of a SGSHPS operated in different heating modes were carried out. The experimental system was installed in Nanjing of China and solar collectors were coupled with ground heat exchangers (GHE) through an insulated water tank. Four operation modes including ground source heat pump (GSHP), combined operation mode, day and night alternate operation mode and solar U-tube feeding heat alternate operation mode were investigated during winter season. The heat pump performance, solar collecting performance and borehole wall temperature variations were analyzed and compared for various modes. The experimental results indicate that for the combined operation mode, the system operation efficiency during day can be improved by the assistance of solar energy, and the excess solar energy collected during day can be stored in ground by the GHE to improve the operation performance of GSHP during night. The proportions of heat source burdened by solar and geothermal energy are 43.3% and 50.2% respectively. For the alternate operation modes, the temperature resumption of ground surrounding the GHE can be well achieved due to the intermittent heat extraction of GHE or feeding solar heat into ground and thus the overall utilization efficiency of solar and geothermal energy can be improved greatly. During the whole experimental period, the average COPs are 2.37 and 2.72 for GSHP and SAHP operation mode respectively, and the corresponding parameters are 2.69, 2.65 and 2.56 for the combined operation mode, day and night alternate operation mode and solar U-tube feeding heat alternate operation mode, respectively. The average solar collecting efficiency are 43.6%, 47.3% and 38.8% for the combined operation mode, SAHP operation mode and solar U-tube feeding heat operation mode, respectively. Based on the unit modeling, a dynamic simulation program was constructed to investigate the seasonal performance of the SGSHPS operated in different heating modes, the simulation results show that the seasonal average COP are 3.67, 3.64, 3.52 and 3.48 for the combined operation, day and night alternate operation, solar U-tube feeding heat and GSHP mode, respectively. From the view of improving the overall efficiency and increasing heat source fraction of solar energy, the combined operation mode is the best. [ABSTRACT FROM AUTHOR]

The residential sector represents about 30% of the total energy demand in Europe. Included in this percentage, lighting consumption is one of the basic end uses in all households and it may come to represents 15–20% of the total electricity bill. This figure can be reduced using advanced control techniques or more efficient lighting technologies, requiring previous detailed information about current consumption patterns. In this context, bottom-up stochastic models are established as the main tools to study new energy savings. In this paper, a high-resolution stochastic model for simulating lighting consumption profiles was developed, obtaining both daily active and reactive instantaneous power demand profiles, with a 1-min resolution. The model takes into account the number of household residents and differentiates between weekdays and weekends. Moreover, the monthly and annual amounts of electricity demanded by lighting in Spanish households were simulated. The proposed model was also used to quantify the impact of LED technology's penetration into domestic lighting systems on consumption patterns. Research has revealed the existence of two consumption peaks matching with morning and evening. Although these peaks are hard to shift since they are due to human behavior, they are easy to reduce through the improvement of lighting systems. [ABSTRACT FROM AUTHOR]

Thermal comfort is one of the many aspects that affect human well-being and productivity. There is an increasing interest in understanding occupants’ requirements for maintaining the indoor comfort range while minimizing energy wastage. In this paper, a thermal perception map was developed for residential buildings in the humid tropics of Malaysia using logistic regression. Sharma and Ali's [1] concept was used for the elaboration of the thermal comfort map. This map helps in exploring the effect of climate changes on subjects’ thermal perceptions at various indoor air temperatures. The thermal comfort map should be useful for researchers in order to accurately estimate the required energy for maintenance of comfortable temperature. [ABSTRACT FROM AUTHOR]

In order to optimize the global energy performance of a ground source heat pump system, special attention needs to be paid to the auxiliaries as they stand for a considerable part of the total energy consumption. A new in situ experimental methodology based on the frequency variation of the water circulation pumps in order to optimize the energy performance of the system was previously published by the authors for a ground source heat pump system using a single stage heat pump with ON/OFF regulation. The original single stage heat pump was recently replaced with a multistage unit consisting of two compressors of the same capacity working in tandem. A new experimental campaign was carried out and a new study was performed in order to adapt the in situ optimization methodology to the performance of the tandem compressors unit, and, by extension, to the multistage case. This paper presents the in situ optimization methodology for the water circulation pumps frequency adapted for multistage ground source heat pump systems. Results show that energy savings up to 32% can be obtained by applying this optimization methodology. [ABSTRACT FROM AUTHOR]

The paper aims at studying the effect of both high thermal insulation and high thermal mass techniques in buildings dynamic behaviour in Mediterranean climates. The two techniques can lead to conflicting requirements when considering winter and summer conditions, or even high daily temperature ranges. Therefore, the best solution for the summer can be the worst solution for the winter. It is necessary to identify insulation measures that conserve the mass dynamic behaviour. Experimental investigations were carried out on a single-family house to characterize the behaviour of two walls with different thermal inertia. Thermal simulations made it possible to explore different retrofit configurations also including dynamic strategies. The solutions were compared on comfort, energy savings and global cost. The study shows that the most suitable intervention is the maximization of the internal heat capacity and the introduction of an external insulation layer sealed in wintertime and ventilated in summer, thus maintaining the existing massive envelope seasonal dynamic behaviour by alternatively maximising thermal barrier effect and heat loss. Considering this, the authors introduced a recently patented dynamic system that reduces both summer discomfort levels and consumption, respectively, of about 20% and 43% respect to the worst retrofit solution. [ABSTRACT FROM AUTHOR]

China is currently experiencing rapid urbanization. The building sector plays an important role in China's energy conservation and emission reduction. An increasing amount of energy will be steadily consumed in the building sector as the urbanization process accelerates. China's government attaches great importance to building energy efficiency (BEE). How does the urbanization process affect building energy consumption (BEC)? How much energy can be saved in the building sector through implementation of energy polices? These questions are critical for government development strategies and planning. Thus, in this paper, an econometric model (co-integration technique) is developed to analyze how China's BEC is affected by macroeconomic variables in the context of urbanization, and also forecast the BEC and BEE potential until 2020 under different scenarios. The research result shows that occupants’ lifestyles, residents’ living standards, and energy price have significant influences on BEC. The building sector is likely to contribute approximately 20% to China's energy conservation through electricity pricing reform. [ABSTRACT FROM AUTHOR]

A selection of hygroscopic salts and desiccant matrices (salt in matrix, SIM) were chosen from the literature as candidate materials for open thermal energy storage (TES) systems. The aim of the paper was to narrow this selection through the application of selective criteria to those that had a high affinity of each working pair to each other, were environmentally stable, had low raw material costs with high availability, a low regeneration temperature for charging (<130 °C), a high temperature lift during reaction, high cyclic efficiency and high energy density. Candidate materials included silica gel, zeolite, activated carbon and vermiculite as matrices with CaCl 2 , MgSO 4 , Ca(NO 3 ) 2 , LiNO 3 and LiBr as salts. Scanning electron microscopy was used to verify salt presence. The pore geometry and structure was mapped through the use of nitrogen (N 2 ) physisorption with application of both Brunauer–Emmett–Teller and Barrett–Joyner–Halenda analysis, gas pycnometry and gravimetric testing. The hygrothermal properties were characterised using modified transient plane source, differential scanning calorimetry and modified dynamic vapour sorption (DVS) techniques. Vermiculite with either lithium bromide (SIM-3e) or calcium chloride (SIM-3a) appear to have significantly higher TES potential when compared to both the raw desiccants and the other SIM's. [ABSTRACT FROM AUTHOR]

This paper aims to integrate decentralized energy systems in a village in Switzerland, which has the goal to phase out fossil fuels and rely on local renewable energy sources. To reach this ambitious target, a revision of the current energy system is required together with retrofitting of the building stock. The method applied is based on the energy hub concept, which can be used to optimize the energy consumption during planning and operation. To apply the energy hub concept at neighbourhood level, a three step approach is required, including modelling the energy demand of the buildings, the evaluation of the local renewable potential, and the management and optimization of demand and supply. Centralized and decentralized local renewable sources are investigated, namely photovoltaics, biomass, or small hydro power. Scenarios are evaluated based on their environmental performance and savings of CO 2 emissions. Results show that an energy sustainability (ratio of energy demand covered by renewables) of 83% and a CO 2 emissions reduction of 86% can be achieved. The results further suggest that up to 50% of the available energy potential from renewables cannot be utilized in this community when insufficient storage is provided in the energy system. [ABSTRACT FROM AUTHOR]

The heat transfer performance on the wall has a great influence on the energy conservation and the indoor thermal comfort. Once it can be adjustable according to the requirement, the wall can effectively regulate the indoor temperature, thereby directly reducing the building energy consumption. In this paper, a new type of passive solar energy utilization technology, the wall implanted with heat pipes (WIHP), was proposed, and its heat transfer performance and energy-saving characteristic were investigated theoretically and experimentally with the typical meteorological data of Jinan. The results indicate that the theoretical results agree well with experimental ones. The heat transfer performance of the WIHP is adjustable and controllable, which can reduce the heating load and improve thermal environment. During the winter in a typical year, the heat loss of the south external wall is reduced by 14.47%. Therefore, such a type of wall can apparently improve the indoor thermal environment, which can be popularized in engineering applications. [ABSTRACT FROM AUTHOR]

Radiant cooling systems work fundamentally differently from air systems by taking advantage of both radiant and convective heat transfer to remove space heat. This paper presents an experiment investigating how the dynamic heat transfer in rooms conditioned by a radiant system is different from an air system, and how such differences affect the sensible cooling load and cooling load calculation methods for radiant systems. Four tests with two heat gain profiles were carried out in a standard climatic chamber. For each profile, two separate tests were carried out to maintain a constant operative temperature: one with radiant chilled ceiling panels; and a second with an overhead mixing air distribution system. The experiments show that, during the periods the heat gain was on, the radiant system has on average 18–21% higher instantaneous cooling rates compared to the air system, and 75–82% of total heat gains were removed, while for the air system only 61–63% were removed. Based on the study, we conclude that a new definition must be used for radiant system cooling load. Calibrated dynamic energy simulation based on a fundamental heat balance approach showed good accuracy. Simplified cooling load calculation methods may lead to incorrect results for radiant systems. [ABSTRACT FROM AUTHOR]

Several studies have proven the energy savings associated to the incorporation of phase change materials (PCM) into plastering mortars for application in buildings, in view of thermal comfort. However, the simultaneous incorporation of more than one type of PCM (hybrid PCM) into plastering mortars may even bring about added benefits for the thermal efficiency as they can be tailored for specific performance targets. One of the aims of this paper is to demonstrate the feasibility of hybrid PCM mortars at the material level. This study encompasses the evaluation of several mortars with and without microencapsulated PCM. Hardened mortar samples were assessed through scanning electron microscopy (SEM), and also through differential scanning calorimetry (DSC). The DSC tests that were performed have demonstrated a clear dependence of the measured thermograms in regard to the adopted heating/cooling rate. Therefore, this research work also focused on this issue, both for single and hybrid PCM mortars. The following effects of heating/cooling cycles on DSC results were evaluated: the shape of the thermograms, the peak phase change temperature, the calculated specific enthalpy and the hysteretic behavior between heating and cooling cycles. [ABSTRACT FROM AUTHOR]

The primary goal of the project is to design a lighting system that provides the highest visual comfort and conserves energy for different uses and furniture layouts, which considers that the design of the house will be used by many different users. Indoor system designs vary in layout, goals and optics with two levels of intervention: when initially furnished and during daily use. Lighting is managed by a building automation system, which is equipped with motion and daylight sensors and human interfaces with user scenarios. An outdoor design that requires only a standalone system and is powered by photovoltaic and eolic devices has been developed. All systems incorporate LED technology and have been custom-developed for Med in Italy, which resulted in new patents. Lighting system projects have been involved in several competitions, e.g., Med in Italy placed in the Solar Decathlon in Architecture, Electrical Energy Balance, House Functioning, and Sustainability and took third place in the final ranking. Further research developments are in progress and will be seen in next Solar Decathlon Europe in Paris in 2014. This paper describes the project, installation and analyses of the energy savings that the Medinitaly system can achieve compared with traditional solutions. Simulation data are compared with measured data from the period of the Solar Decathlon competition. [ABSTRACT FROM AUTHOR]

There is a need for energy conservation mechanisms, especially in university campuses, as students do not have any direct feedback on their energy consumptions, which leads to excess usages. There are few existing approaches aiming to reduce electricity usages in higher education institutions through real-time feedback applications. These approaches mainly apply student experimental studies with incentives (gift reward). Their feedback systems present data only in near real time using data loggers and Modbus data collector, which are characterised with a slow and unstable data transfer rate. Furthermore, they are not designed for long-term deployment in a wider campus energy management environment. Thus, the challenges for reducing energy consumption and carbon emissions in the higher education sector still remain. To address these challenges, we have designed, configured and implemented a robust persuasive feedback support system (PFSS) to facilitate energy conservation and carbon emission reduction. This paper presents the complete architecture of the proposed PFSS, its system interface and the real time measurement output strategies. To demonstrate the applicability of the proposed system and to assess its performance in comparison with the previous systems, we used the student halls of residence at the University of Kent as a use case scenario. [ABSTRACT FROM AUTHOR]

The paper introduces a new kind of thermal insulation material using coal fly ash as main raw material by the method of foaming and slip casting process. The foaming ability of the suspensions with solid loading of 30, 35 and 40 wt% at different foaming agent additive levels were measured. The green bodies were then sintered under different sintering temperatures from 850 °C to 1000 °C for 2 h following the steps of foaming and drying. Effects of solid loading of suspensions and sintering temperature on the porosity, compressive strength and thermal conductivity were investigated. The sintered bodies, with porosity from 86.3 vol.% to 94.5 vol.% and compressive strength from 0.43 MPa to 1.01 MPa, contained spherical pores with no preferred orientation. The thermal conductivity of the sintered thermal insulation material, measured by the transient plane source (TPS) at room temperature, could reach as low as 0.0511 W/(m K). As an environmental friendly material, it is suitable for wall application to save energy. [ABSTRACT FROM AUTHOR]

Demand for water is increasing with buildings accounting for the large majority of increased water consumption. As such, the development of methods to effectively promote water conservation in buildings has become an important focal area for research. Specifically, providing feedback of resource consumption to residential building occupants has been demonstrated to be effective in promoting conservation. Although water and energy are inextricably connected, there is a lack of research that investigates the bridge between water and energy in the representation of feedback to promote water conservation. In this paper, we investigate the impact of two different representations of water consumption eco-feedback on water conservation (i.e., gallons and associated estimated embodied energy). We collected consumption data in 18 residential dormitories, involving nearly 4700 occupants over a period of approximately six weeks. We found that representing water consumption simultaneously in terms of gallons and associated embodied energy led to a statistically significant reduction in water consumption, while representing water consumption only in terms of gallons did not. This has significant implications for the growing body of research at the nexus between water and energy consumption and can inform future eco-feedback system designs. [ABSTRACT FROM AUTHOR]

Highlights: [•] This paper analyses the energy performance of LEED certified buildings. [•] We have conducted energy simulations with actual data validations. [•] The results show that green vegetation on LEED certified buildings is not economically viable. [Copyright &y& Elsevier]

Highlights: [•] A CFD simulation shows that In-row cooling system can solve the problem in case of cool air cannot reach to the top of rack. [•] This paper shows the new combined cooling system for using in data center. [•] A correlation of dimensionless parameters is presented by SHI and product of Re, Pr and β. [•] Correlation obtained helps to control the rack temperature at any height more effective. [Copyright &y& Elsevier]

Highlights: [•] A new smart method NNPSO of optimal chiller load is proposed. [•] This paper used neural networks and particle swarm optimization algorithm. [•] This study can save 12.68–17.63% as the load varies from 0.55 to 0.95 PLR. [•] The NNPSO method had fast convergence and highly accurate results. [•] The results demonstrate the highly nonlinear process with sufficient accuracy. [Copyright &y& Elsevier]

Abstract: Liquid desiccant air-conditioning system is a novel air-conditioner with good energy saving potential. For the liquid desiccant air-conditioning system, the energy consumption mainly relies on the regeneration process of desiccant solution. As the regeneration process of the liquid desiccant air-conditioning system only needs low-grade energy, solar energy (a kind of renewable energy) can be used to regenerate the desiccant solution and the solar desiccant regeneration system has attracted many attentions. In this paper, recent theoretical and experimental works on solar thermal regeneration method and solar electrodialysis regeneration method of the liquid desiccant air-conditioning system are extensively reviewed. Moreover, the comparison of solar TH regeneration method and solar electrodialysis regeneration method is discussed. The results showed that compared to the solar thermal regeneration system, the solar electrodialysis regeneration system is more energy-efficient but expensive. [Copyright &y& Elsevier]

• Occupants on-demand heating control behavior in a rural residential building is investigated. • Independently controlled split-type heating equipment were used to elucidate actual demand patterns. • Data collection over three years under an interference avoidance scheme. • Five representative intermittent heating patterns were obtained from a real-world case study. A better understanding of actual heating demands is crucial for optimizing operational heating systems, because disparities between expected load and actual demand are key factors in inefficient heating system design, implementation, and corresponding energy loss. Additionally, the discrete, energy consumption-based billing systems applied to freestanding rural residential buildings encourages reductions in energy waste but produces spatially and temporally distinct heating patterns. Conventional heating systems have only basic controls and slow response times that cannot reflect actual user demand. Hence, this paper presents an experimental scheme for measuring room-wise heating demands, and thus, the actual heating demand patterns of rural residential buildings. A case study was conducted on a typical rural residential building in Beijing to validate the method's feasibility. Real-world usage patterns were obtained using indoor environment sensors and independently-controlled heating devices that collected the operational parameters of each room over three years, in a long-term non-intervention study design. Clustering analysis and various indicators were used to characterize heating demand for each room: heating patterns, usage intensity, and temporal variation. In most case, the occupants heated only a few rooms, rather than the whole building. These results have potential real-word implications for predicting occupant heating behavior and energy conservation. [ABSTRACT FROM AUTHOR]

Interest in urban building energy modeling as a tool to evaluate effective management of urban building energy and carbon reduction policies is increasing. Since it takes a lot of time to model all buildings in the city with the lack of information about buildings, archetypes have been used. However, the deterministic method using archetypes does not reflect uncertainty with the disadvantage of not presenting design alternatives. To overcome such problems, we proposed an urban building energy modeling method using a stochastic-deterministic-coupled approach. In this paper, the identifiability of unknown parameters in a building stock was verified by analyzing the effect of the meta-model accuracy on the estimation of unknown parameters in the proposed urban building energy model. In addition, the possibility of using energy conservation measure analysis of the proposed model was evaluated. As a result, the posterior distribution of unknown input parameters was distorted when using the meta-model instead of the original building energy model in Bayesian calibration for building stock. However, the distorted posterior distribution could evaluate the effect of energy conservation measures within 0.71% errors. [ABSTRACT FROM AUTHOR]

• End-use of electricity consumption in residential buildings in Gulf Cooperation Council countries was presented. • Discrepancies in certain indicators have been observed by the end-use of electricity consumption. • Improving the efficiency of air conditioners and thermal insulation of the walls are the best measures to conserve electricity in residential buildings. • The results can be used in areas with a similar climate, living standard, buildings types, and the inhabitants' behavior. Energy conservation and improvement in energy efficiency yield multiple technical, economic, environmental, and social benefits and realize comfort and sustainability of residential buildings (RBs). This review paper presents the end-use of electricity consumption in RBs and the results of economic analysis. In addition, a description and discussion of studies on energy conservation measures, Net Zero Energy Building, and renewable energy in RBs are discussed. The percentage of end-used energy consumption for different purposes obtained in many studies are often not consistent. Moreover, discrepancies in certain indicators have been observed, necessitating the need to clarify the factors in the consumption of electricity in RBs. Further, a few studies used the term energy consumption in buildings (total or electrical); however, specifying the type of buildings to identify and use the necessary indicators of energy consumption in each type of building are desirable. Furthermore, most studies emphasized improving the efficiency of air conditioners and thermal insulation of the walls as these are the best measures to conserve electricity. [ABSTRACT FROM AUTHOR]

Abstract: Thermostatic radiator valves (TRV) have proved their significant contribution in energy savings for several years. However, at low heat demand conditions, an unstable oscillatory behavior is usually observed and well known for these devices. This closed-loop instability is due to the nonlinear dynamics of the radiator which result in a large time constant and a large gain for the radiator at small flow rates. In order to improve stability of radiators under the low demand circumstance, one way is to replace the fixed-parameter controller of TRV with an adaptive controller. This paper presents a gain scheduling controller based on a proposed linear parameter varying model of radiator dynamics. The model is parameterized based on the operating flow rate, room temperature and radiator specifications. Parameters of the model are derived based on the proposed analytic solution that describes dissipated heat by a radiator to ambient air. It is shown via simulations that the designed controller based on the proposed linear parameter varying (LPV) model performs excellent and remains stable in the whole operating conditions. [Copyright &y& Elsevier]

Abstract: In order to study the influence of moisture transfer on the wall internal surface temperature, a coupled heat and moisture transfer transient model was proposed in this paper. Relative humidity and temperature were chosen as the driving potentials. The accuracy of the proposed model was verified by comparing the simulated results with the experimental data. By employing the developed model, the internal surface temperature of walls made of different materials was evaluated under the constant and variable boundary conditions. The results show that the effect of moisture transfer on the wall internal surface temperature is significant. When the moisture transfer is taken into account, the internal surface temperature has cooling effect on the indoor air and is beneficial to improve the indoor thermal environment during the working hours in summer, which lays a scientific basis for low energy building design. [Copyright &y& Elsevier]

Abstract: Earlier studies used field testing of swimming pool temperatures to validate a mathematical model for predicting the temperature of an unheated pool. Combining those results with manufacturers’ data on the performance of vapor-compression air conditioners as a function of heat rejection temperature, the analyses in the paper suggest that rejecting air conditioning heat to a swimming pool can save approximately 25–30% of single-family residential cooling electricity use and reduce cooling electricity demand during peak conditions by 30–35%, as compared to using the same compressor to reject the heat to ambient air. The savings is expected to vary depending on the severity of the climate, as well as the pool temperature experienced during the summer. The original model was refined so as to accommodate air-conditioner heat rejection to predict pool temperatures based on weather data, pool size, shading of the pool, and air-conditioner heat rejection to the pool. The results of an experimental validation of the augmented pool thermal model are presented here. In addition, the model of a pool-coupled air conditioning system was used to develop a design tool for determining the pool size needed to absorb realistic heat rejection from air conditioners in various California climate zones. [Copyright &y& Elsevier]

Abstract: Complex human or engineered network systems can be examined as a series of coexisting layers. A variety of dynamic perturbations, such as information flows across computer networks, traffic flows across transportation networks and the spread of energy saving practices across human networks, have been treated separately as single networks in previous research. However, because these phenomena often consist of human networks interacting with engineered networks, analyzing the properties of the multi-layer network systems may provide more accurate insights. In this paper, we examine a multi-layer network system to provide insight into the diffusion of energy consumption practices through peer networks within and across residential buildings. We introduce a new model-the Layered Network Model-that treats that treats a residential peer network and a geospatial building network as a single, layered network. We compare this model to a previously published Multi-Layer Interactive Network Model by simulating diffusion through a real multi-layer network system consisting of a residential peer network and a geospatial building network from three experimental data-sets. We found our model to be more accurate and efficient, hence contributing an efficient mathematical model and set of simulation algorithms that accurately capture the post-perturbation response of a layered, residential peer network and a geospatial building network. [Copyright &y& Elsevier]

Abstract: This paper aims to investigate the effects of retrofitting existing public buildings in the “Hot Summer Cold Winter” climate region of China, using simulation and a case study, to see how retrofitted public buildings perform in the face of climate change in the region. This area of China is one of the most challenging regions for providing occupant comfort in buildings, with high demands for heating as well as cooling, together with high humidity levels. The simulation results suggest that energy reduction of up to 40% with improvements to the building enclosure is possible by retrofitting current existing public buildings to the new Chinese National Standard for the Zhejiang Province. Requirements for combating possible increase in energy consumption from heating and cooling demands due to future climate change was also investigated, and it was found that by simply improving U-Values of the building envelope to the new national standards set for the Zhejiang Province, the effects of future climate change can be nullified up to the 2080s. Further improvements to having similar standards as developed countries such as England and Wales will have less significance and cannot nullify the effects of climate change from the newly retrofitted public buildings. However, this can be achieved by involving other energy-saving strategies and installing suitable energy-saving technologies for the region. [Copyright &y& Elsevier]

Abstract: The building sector consumes, even today, about one third of primary energy used in countries like Germany, which, in addition to tons of CO2 and depletion of energy sources, involves a cost of millions of Euros. This paper shows how, only through the optimization of the system technique regulations, energy savings by a margin of 30% can be achieved in offices and administrative buildings. This potential reduction or even elimination of expenses is possible with the use of the automation system that is proposed in this article. It is important to emphasize that simulation models of HVAC systems and rooms are very often used during the planning phase of a project for a proper system design. However, these simulation tools offer additional possibilities for control algorithm development and performance observation which are not used in practice so far. This article demonstrates that simulation based predictive control, using a system operation that is not depending on a main computer but on the components of an intelligent bus, offers the opportunity of a better utilization of the buildings and their thermal mass. [Copyright &y& Elsevier]

Abstract: In general, a proper balance of temperature and humidity control is essential for efficient datacenter operation and is integral to protecting the significant investment in computer and network technology in datacenter facilities. However, the rising costs of energy and the drive to be green are resulting in a greater demand to conserve energy. One method of reducing facility costs for a chilled water plant is by adding an economizer. The purpose of this study is to develop energy models of the most common economizer systems. A normal chiller plant with an air-side economizer and a water-side economizer are compared. Results show that outdoor conditions influence facility energy consumption. This paper provides terminology and definitions for the two different types of economizer modes and compares their energy performance against key datacenter attributes in temperate or subtropical regions. The electrical end use breakdown and the Power Usage Effectiveness (PUE) value for a typical year were estimated. The water-side economizer made it possible to achieve a maximum energy performance improvement of about 16.6% over the reference base cooling system, whereas the air-side economizer made it possible to achieve about 42.4% improvement. [Copyright &y& Elsevier]

Abstract: To bury absorber tubes in diaphragm wall as heat exchanger is a new energy saving technology. This paper is dedicated to study this new technology based on the field experiment at Shanghai Museum of Nature History. By the experiment, the heat transfer performance of heat exchanger in diaphragm wall and its impact factors including heat exchanger type, water velocity, inlet water temperature and operation mode were investigated. The test results show that (i) the heat exchange rate of W-shaped heat exchanger reached to 66.3 and 73.7W/m for tube type (a) and (b) at the inlet temperature of 35°C, which are approximately 1.2–1.4 times higher than that of single U-shaped type (c); (ii) under the experimental condition, the reasonable water velocity is 0.6–0.9m/s; (iii) the exchange rate reached to 40.3, 66.3 and 85.0W/m at the inlet temperature of 32, 35 and 38°C, respectively, for tube type (a), every 1°C rise of inlet water will promote 15% heat exchange rate; (iv) in intermittent operation mode, the average heat exchange rate is 82.8W/m while 72.7W/m for continuous mode under the experimental condition, i.e., 14.7% higher than that in continuous mode. [Copyright &y& Elsevier]

Abstract: A number of radiant heating/cooling systems have been applied in Mainland China in recent years for its improved thermal comfort and inherent energy saving potential. Because the systems require relatively higher temperatures for cooling and lower temperatures for heating, many natural low-grade energy sources can be directly or indirectly used. However, because of a lack of information about prior practical projects, a number of difficulties in design, construction and management of the systems have been encountered, and energy efficiency is not necessarily achieved in all situations. This paper reviews the practical applications in four major projects involving different building types located in different climatic cities and presents the associated considerations in system design. Other factors affecting the energy efficiency of the systems are identified, such as the spatial convection and radiation heat transfer processes in indoor environments and the envelope thermal properties. Further studies are needed to achieve system optimization and to realize the full energy saving potentials of radiant systems by developing analytical design methods and monitoring the actual energy use of such systems in completed projects. [Copyright &y& Elsevier]

Abstract: Recently, there has been an intensive research in the area of Model Predictive Control (MPC) for buildings. The key principle of MPC is a trade-off between energy savings and user welfare making use of predictions of disturbances acting on the system (ambient temperature, solar radiation, occupancy, etc.). Usually, according to international standards, the thermal comfort is represented by a static range for the operative temperature. By contrast, this paper is devoted to the optimization of the Predicted Mean Vote (PMV) index which, opposed to the static temperature range, describes user comfort directly. PMV index is, however, a nonlinear function of various quantities, which limits the applicability and scalability of the control problem formulation. At first, PMV-based formulation is stated, the main differences between typical MPC problem formulation and PMV based formulation are outlined, a computationally tractable approximation of the nonlinear optimal control problem is presented and its accuracy is validated. Finally, control performance is compared both to a conventional and predictive control strategies and it turns out that the proposed optimal control problem formulation shifts the savings potential of typical MPC by additional 10–15% while keeping the comfort within levels defined by standards. [Copyright &y& Elsevier]

Abstract: In hot arid desert environments, the solar radiation passing through windows increases the cooling loads and the energy consumption of buildings. Shading of windows can reduce these loads. Unlike the woven solar screens, wooden solar screens have a thickness that provides selective shading properties. Perforated wooden solar screens were traditionally used for windows shading. Developing modern types of these shading systems can lead to significant energy savings. The paper addresses the influence of changing the perforation percentage and depth of these screens on the annual energy loads, hence defining the optimum depth/perforation configurations for various window orientations. Series of experiments were performed using the EnergyPlus simulation software for a typical residential building in the Kharga Oasis, located in the Egyptian desert. A range of perforation percentages and depths were tested. Conclusions prove that external fixed deep perforated solar screens could effectively achieve energy savings up to 30% of the total energy consumption in the West and South orientations. Optimum range of depths and perforation percentages were recommended. These are: 80–90% perforation rate and 1:1 depth/opening width ratio. These lighter and deeper solar screen configurations were found to be more efficient in energy consumption in comparison with the traditional ones. [Copyright &y& Elsevier]

Abstract: The water-intake temperature is a key factor affecting the system energy efficiency of an open-loop surface water source heat pump system (SWHPS). In addition to the conventional single-pipe water-intake design, we proposed two new design options that can improve SWHP efficiency. The numerical model that pertains to a SWHPS is presented and parameters such as the fluid-intake temperature and energy-saving rate of the heat pump system are analyzed and compared with experimental measurements. Our results demonstrate that on the basis of energy-saving rate, reducing the velocity of the water delivery has no significant influence while intake via multiple ports delivers superior efficiency. In conclusion, the water-intake design impacts on the SWHPS energy-saving rate because of its efficiency in drawing lower temperature water from a water retention body during summer. The method presented in this paper can provide a reference for a more detailed improvement on the energy performance of an open-loop SWHPS. [Copyright &y& Elsevier]

Abstract: This paper presents a new hybrid steady-state modeling approach for air-conditioning systems. At the system level, it follows the first principles to keep the conservation of mass, energy, and momentum, respectively. At the component level, the physics-based component models are entirely or partially replaced with neural networks. Component neural networks can be trained using the data from laboratory or from the well-validated physics-based component models. Numerical comparisons between the system model consisting of component neural networks and that consisting of physics-based component models indicate that the two system modeling approaches give very close predictions in a wide range of operating conditions. With the proposed hybrid modeling approach, robustness and speed of system modeling can be significantly improved. [Copyright &y& Elsevier]

Abstract: In Hong Kong, conventional air-conditioning (AC) systems cause a high energy consumption and poor indoor thermal comfort. This paper investigated the AC load profiles of three typical local commercial buildings, i.e. office, hotel and retail, and examined the energy consumption of liquid desiccant cooling system (LDCS) for these buildings. Simulation results showed that the cooling load contributed to more than 98% of total annual load, with high latent load proportion from March to September. The high reheating ratio, i.e. from 60% to 90%, is found to be the main reason for the poor thermal comfort. Therefore, the LDCS which could handle sensible and latent loads separately was proposed. However, the electricity-driven LDCS was found not suitable for local commercial buildings. significant energy saving could be achieved by the solar-assisted LDCS system with thermal storage, when the installation area for solar collectors is larger than the minimum required one, i.e. 9.7m2/(kWm−2) for office and 12.7m2/(kWm−2) for hotel buildings. Energy saving of different system types with different installation areas was also studied. The solar-assisted LDCS shows more energy saving in winter but less in summer. Results and conclusions can be useful for researchers and local engineers. [Copyright &y& Elsevier]

Abstract: Retrofitting of fossil fuel powered hot water radiator heating systems of the existing buildings by groundwater heat pumps can provide significant energy savings followed by economic and environmental benefits. The paper describes the procedure for selection of optimal low-temperature groundwater heat pump vapor compression cycle based on thermodynamic analysis of applied high temperature heat pump heating system. In comparative energy and exergy analysis observed are six different heating cycles, five of which utilize two-stage refrigerant compression, and one operate as basic one-stage heat pump system with an auxiliary heater. The systems validation is performed accounting strongly for the boundary conditions of the selected location. [Copyright &y& Elsevier]

Abstract: The exposure and diffusion of energy consumption information in building occupant peer networks has been shown to influence an individual''s energy consumption decisions. In this paper, we develop an agent-based computational model for individual energy consumption behavior based on data collected during an experiment on residential energy use. We simulate the building occupants’ decision making and the information transmission process. By comparing the impact of several parameters in the network level computational model and validating the parameters in a second experimental setting, our research serves to clarify how network relations can be leveraged for modifying energy consumption behavior. Network degree and weight were identified as the major structural parameters that impact building occupants’ conservation decisions, while network size was found to have no significant impact. These findings have important implications for the design and effectiveness of residential energy feedback systems designed to promote energy conservation in residential buildings. [Copyright &y& Elsevier]

Abstract: Nowadays, vast amounts of data on building operation and management have been collected and stored. However, the data is rarely translated into useful knowledge about building energy performance improvement, due mainly to its extreme complexity and a lack of effective data analysis techniques. This paper reports the development of a new methodology for examining all associations and correlations between building operational data, thereby discovering useful knowledge about energy conservation. The method is based on a basic data mining technique (association rule mining). To take full advantage of building operational data, both daily and annual time periods should be mined. Moreover, data from two different years should be mined, and the obtained associations and correlations in the two years should be compared. In order to demonstrate the applicability of the proposed method, the method was applied to the operational data of the air-conditioning system in a building located in Montreal. The results show energy waste in the air-conditioning system as well as equipment faults. A low/no cost strategy for saving energy in the system operation was also proposed. The results obtained could help to better understand building operation and provide opportunities for energy conservation. [Copyright &y& Elsevier]

Abstract: Elevators and escalators have received little attention from an energy efficiency perspective in the past. To close this gap, this paper analyses energy efficiency potentials and suggests policy measures for the European elevator and escalator market. As a precondition, the electrical energy demand of elevators and escalators in the European market is analyzed, based on expert estimations and the results of a monitoring campaign. The estimated current demand is compared to scenarios where the implementation of best available technology for the relevant equipment is assumed and the savings potentials thereof are calculated. The results indicate that considerable technical efficiency potentials exist for elevators (more than 60%) and escalators (around 30%). However, various specific barriers impede the diffusion of these energy-efficient technologies. They include issues like a lack of awareness and relevant information as well as split-incentive problems. The technological analysis is therefore complemented by an investigation of how to overcome these barriers, leading to a set of recommendations on how to improve energy efficiency in the elevator and escalator market. Suitable measures could be implementing standardized methods for electricity measurement, introducing a labeling system and including elevators and escalators in the legislative framework. [Copyright &y& Elsevier]

Abstract: BREEAM, LEED, CASBEE, BEAM Plus and Chinese ESGB have been formally launched at different stages in the last twenty years. How well the certified and rated buildings compare with each other is always an interest of building designers and policy-makers. This paper presents a side-by-side comparison of energy use assessments of the five schemes. The comparisons are on the assessment method and criteria, default parameters, trade-offs allowed, performance scales, approved simulation tools, performance indicators and assessment results. Comparison results showed that all the five schemes are based on relative performance. It was also found that despite the variations in default parameters among the five schemes, market positions of certified buildings are comparable. LEED was found to be the most stringent and relatively less flexible in its assessment criteria. Nonetheless, the energy cost budget approach, adopted only by LEED, is able to fulfil emission reduction and cost saving objectives on the condition that a “fuel neutral” approach should be adopted. [Copyright &y& Elsevier]