Enhanced energy conservation in houses through high performance design

Key design features of high performance houses are investigated for improving energy efficiency in cold climates. Reference dwellings with typical constructions and system designs are compared with high performance houses using the best technology available. The dwellings used for reference are a multi-family apartment building and a single-family detached house, designed according to a mix of Nordic building codes of 2001. The high performance houses designed fulfilled the target requirements of IEA Task 28, Sustainable Solar Housing. Simulations of the buildings are performed using the computer programme DEROB-LTH and results from simulations give the hourly space-heating demand and peak load of the buildings. A comparison of reference houses to high performance solutions shows that the space-heating demand can be reduced by up to 83% for single-family houses and by up to 85% for apartment buildings. The climate data used for all simulations is Stockholm, Sweden. The environmental effects in terms of CO₂ equivalent emissions and use of non-renewable primary energy are quantified for each building type and construction. The energy saving potential of high performance houses in cold climates is demonstrated.     

Options to reduce the environmental impacts of residential buildings in the European Union—Potential and costs

A typology of buildings representative of the building stock for the EU-25 was developed characterizing 72 building types in terms of their representativity, geographical distribution, size, material composition, and thermal insulation. The life cycle impacts of the building types were calculated for different environmental impact categories both at building and EU-25 level. The use phase of buildings, dominated by the energy demand for heating is by far the most important life cycle phase for existing and new buildings. The environmental impacts were allocated to single building elements. Ventilation, heat losses through roofs and external walls are important for a majority of single- and multi-family houses. Three improvement options were identified: additional roof insulation, additional façade insulation and new sealings to reduce ventilation. The measures yield a significant environmental improvement potential, which, for a majority of the buildings types analyse represent at least 20% compared to the base case. The major improvement potentials at EU-level lie with single-family houses, followed by multi-family houses. Smaller reductions are expected for high-rise buildings due to the smaller share in the overall building stock. For both roof insulation and reduced ventilation, the measures were shown to be economically profitable in a majority of buildings.     

Toolbox for development and validation of grey-box building models for forecasting and control

As automatic sensing and information and communication technology get cheaper, building monitoring data becomes easier to obtain. The availability of data leads to new opportunities in the context of energy efficiency in buildings. This paper describes the development and validation of a data-driven grey-box modelling toolbox for buildings. The Python toolbox is based on a Modelica library with thermal building and Heating, Ventilation and Air-Conditioning models and the optimization framework in JModelica.org. The toolchain facilitates and automates the different steps in the system identification procedure, like data handling, model selection, parameter estimation and validation. To validate the methodology, different grey-box models are identified for a single-family dwelling with detailed monitoring data from two experiments. Validated models for forecasting and control can be identified. However, in one experiment the model performance is reduced, likely due to a poor information content in the identification data set.     

Energy-efficient houses built according to the energy performance requirements introduced in Denmark in 2006

In order to meet new tighter building energy requirements introduced in Denmark in 2006 and prepare the way for future buildings with even lower energy consumption, single-family houses were built with the purpose to demonstrate that it is possible to build typical single-family houses with an energy consumption that meets the demands without problems concerning building technology or economy. The paper gives a brief presentation of the houses and the applied energy-saving measures. The paper also presents results from measurements of the overall energy use, indoor climate and air tightness. Furthermore, results from detailed calculations of the utilization of electricity-related heat gains are presented. Looking at the energy consumption in relation to the new energy requirements, the paper concludes that the single houses can relatively easily keep the future energy demands. The energy consumption of the houses is on a level corresponding to a classification as “low-energy house class 2” or an energy consumption of 75% of the required maximum energy consumption. With minor modifications, some houses could be classified as “low-energy building class 1” corresponding to an energy consumption of only 50% of the required and almost the level of typical passive houses.     

A study of the effectiveness of passive climate control in naturally ventilated residential buildings in Singapore

Singapore has the hot and humid climate throughout the year. Many passive climate control methods are adopted in the naturally ventilated residential buildings to help achieve thermal comfort and reduce the energy consumption of air-conditioning. A field measurement and computational energy simulations were conducted to examine the effectiveness of commonly used passive climate control methods for these buildings. The effect of building orientation, façade construction, special roof system and window shading device on indoor thermal environment and cooling load was studied. The surface temperature of external wall and indoor thermal environment was measured to analyze the façade thermal performance. The cooling load was simulated to evaluate the effectiveness of various passive climate methods. Using the special roof system as thermal buffer is the most efficient method to reduce the room cooling load.     

西藏地区太阳能采暖建筑热工性能优化研究

西藏地区太阳能资源非常丰富且冬季温度低,该地区非常适合大面积推广太阳能采暖系统,以达到节能减排的目的。但是由于实际大部分太阳能采暖工程,忽略了建筑围护对太阳能主动式采暖系统初投资与运行费用的影响,造成了太阳能主动式采暖系统初投资过高、太阳能保证率低。为了分析建筑热工性能对太阳能主动式采暖系统的影响,笔者利用数值模拟方法,将建筑热工性能与主动式太阳能采暖系统作为一个整体进行计算分析,利用初投资费用最低与全寿命周期总费用最低两个目标函数,对主动式太阳能采暖建筑热工性能的保温性能进行优化。结果表明,提高建筑围护结构热工性能,不仅可以降低太阳能采暖建筑的采暖运行费用,而且可降低整个系统的初投资。     

The impact of consumer behavior on residential energy demand for space heating

Besides technical parameters, consumer behavior is the most important issue with respect to energy consumption in households. In this paper, the results of a cross-section analysis of Austrian households are presented. The impact of the following parameters on residential energy demand for space heating have been investigated: (i) thermal quality of buildings; (ii) consumer behavior; (iii) heating degree days; (iv) building type (singleor multi-family dwellings). The result of this investigation provides evidence of a rebound-effect of about 15 to 30% due to building retrofit. This leads to the conclusion that energy savings achieved in practice (and straightforward the reduction in CO₂ emissions) due to energy conservation measures will be lower than those calculated in engineering conservation studies. Straightforward, the most important conclusions for energy policy makers are: (i) Standards, building codes, respectively, are important tools to increase the thermal quality of new buildings; and (ii) Due to prevailing low energy prices, a triggering tool has to be implemented which may be rebates or loans.     

A user-centric space heating energy management framework for multi-family residential facilities based on occupant pattern prediction modeling

Space heating is the highest energy consumer in the operation of residential facilities in cold regions. Energy saving measures for efficient space heating operation are thus of paramount importance in efforts to reduce energy consumption in buildings. For effective functioning of space heating systems, efficient facility management coupled with relevant occupant behaviour information is necessary. However, current practice in space heating control is event-driven rather than user-centric, and in most cases relevant occupant information is not incorporated into space heating energy management strategies. This causes system inefficiency during the occupancy phase. For multi-family residential facilities, integrating occupant information within space heating energy management strategies poses several challenges; unlike with commercial facilities, in multi-family facilities occupant behavior does not follow any fixed activity-schedule pattern. In this study, a framework is developed for extracting relevant information about the uncertainties pertaining to occupant patterns (i.e., demand load) in multi-family residential facilities by identifying the factors affecting space heating energy consumption. This is achieved using sensor-based data monitoring during the occupancy phase. Based on the analysis of the monitoring data, a structure is defined for developing an occupant pattern prediction model that can be integrated with energy management strategies to reduce energy usage in multi-family residential facilities. To demonstrate the developed framework, a multi-family residential building in Fort McMurray, Canada, is chosen as a case study. This paper shows that integrating the developed occupant pattern prediction model within space heating energy management strategies can assist facility managers to achieve space heating energy savings in multi-family residential facilities.     

Building leakage analysis and infiltration modelling for an Italian multi-family building

The presented paper aims at detailing the results of an investigation that was recently conducted in Italy to evaluate the contribution infiltration makes to meeting ventilation needs in a recently renovated apartment building and the corresponding energy costs. It is years that increasing importance has been placed on the energy efficiency in residential buildings as about 70% of the existing Italian residential building stock was built before 1976 (i.e. before any measure related to the energy efficiency in buildings). As existing dwellings have been traditionally considered ‘leaky’, the actions for improving their energy efficiency have often determined tighter buildings, raising concerns about whether the amount of infiltration is sufficient to provide occupants with acceptable indoor air quality (IAQ). The current state of knowledge on infiltration in multi-family buildings in terms of measuring procedures, corresponding air change rates and airflow patterns was reviewed. The air tightness of a three-storey, six-unit, multi-family building which can be considered representative of the existing recently renovated Italian building stock was characterized by means of a series of fan pressurization tests. The performed blower door tests are documented and results of the data analysis are reported and discussed. A simulation model was developed; simulations were performed to analyse in detail the winter magnitude of air infiltration. Winter is usually detrimental to IAQ, as severe outdoor weather prompts occupants to keep closed any opening that could allow cold drafts into their homes. Modelling results were validated on the basis of a 3-week monitoring campaign. The developed model enabled to estimate the variation with time of infiltration rates and therefore the influence of infiltrating air on the resulting heat loss and IAQ. Numerical predictions were derived using the EnergyPlus simulation tool which allowed to combine whole building thermal simulation and detailed multi-zone airflow modelling. Results show that, during the considered heating season (October–April), the average air change rate due to infiltration was approximately 0.1 h^?1. It was concluded that infiltration cannot be relied upon to provide adequate ventilation air and, if not assisted by other means of ventilation, IAQ deterioration is likely to occur.     

Passive control methods for a comfortable indoor environment: Comparative investigation of traditional and modern architecture of Kerala in summer

Scientific investigation on traditional architecture of Kerala, that is known for its use of natural and passive methods for a comfortable indoor environment, has been revealing remarkable results recently. Qualitative analysis of the passive methods adopted in traditional buildings and detailed quantitative investigation carried out during all seasons to evaluate thermal comfort have already been reported. As a step ahead, in order to understand the performance of traditional building in comparison with that of modern building, a field study was conducted simultaneously in a selected traditional and a modern residential building during the most unpleasant summer period. The study was conducted by continuously monitoring the indoor and outdoor conditions of both the buildings using a custom made instrument called “Architectural Evaluation System”. The results reveal that an efficient passive and natural control system exists in Kerala traditional architecture in providing a comfortable indoor environment irrespective of the outdoor climatic conditions.     

Energy performance and indoor environmental quality in Hellenic schools

School buildings constitute a major part of the non-residential building stock, though due to their operational characteristics, they represent a low percentage of the overall energy balance of the building sector. Although health and productivity of pupils and teachers is strongly affected by the indoor environmental quality of their school, poor indoor air quality has been reported in published literature, even so for recently constructed school buildings. The same applies for the energy consumption, with large amounts of energy being wasted because no energy saving measures are applied for the operation of schools. This paper presents the outcome of a study on the energy performance of Hellenic school buildings. The general features of the contemporary building stock are presented along with the results from an energy survey in 135 Hellenic schools. The derived energy consumption benchmarks are compared with published literature. Finally, the energy performance and indoor environmental quality of a representative sample of schools in metropolitan Athens are assessed in a holistic approach to the “energy efficiency – thermal comfort – indoor air quality” dilemma. The IEQ assessment was based on an objective evaluation by monitoring crucial indoor conditions and a subjective occupant evaluation using standardized questionnaires. The potential of several energy conservation measures is evaluated in terms of energy savings and reduction of greenhouse gas emissions along with the related payback periods.     

夏热冬暖地区绿色建筑性能后评估研究

为了解夏热冬暖地区绿色建筑运行后实际能耗和室内环境品质，文章详细介绍了该气候区内绿色建筑主要技术的应用情况及应用效果。选取位于该气候区内共11个获得绿色建筑认证的办公建筑，通过调研实际能耗，结合用户主观问卷调研，与常规办公建筑的能耗和室内环境品质主观满意度进行了对比研究。结果表明，对于A类办公建筑，绿色建筑与常规建筑无明显差异，均略低于引导值；对于B类而言，绿色办公建筑的总能耗显著低于常规办公建筑，但与能耗指标相比二者能耗均较高，是建筑节能工作的重点。在室内环境品质满意度方面，用户对绿色建筑的满意度明显高于常规建筑，在空气品质和室内环境控制上尤为明显，光环境的差异则更多是归因于天然采光的设计，而非人工照明的优化。最后通过一个案例从节地、节能和室内环境等3个方面全面地介绍了适宜于夏热冬暖地区的绿色建筑设计。     

Hybrid ventilation for low energy building design in south China

Buildings and their related activities are responsible for a large portion of the energy consumed in China. It is therefore worthwhile to investigate methods for improving the energy efficiency of buildings. This paper describes a low energy building design in Hangzhou, south China. A hybrid ventilation system which employs both natural and mechanical ventilation was used for the building due to the severity of the climate. The passive ventilation system was tested using computational fluid dynamics (CFD) and the results showed that, in the mid-seasons, natural ventilation for the building is viable. The likely thermal performance of the building design throughout the year was evaluated using dynamic thermal simulation (DTS) with local hourly standard weather data. It is evident from the modelling results that the hybrid ventilation system is a feasible, low energy approach for building design, even in sub-tropical climates such as south China.     

Research on the application of water-loop (tank) heat pump systems in catering buildings

The use of thermal energy in catering buildings is normally mishandled and causes significant waste of thermal energy. To increase the efficient use of energy and decrease the total amount of a catering building’s energy consumption, independent thermal systems should be integrated. If thermal systems are integrated, coupling utilization of thermal energy will be possible, and the primary energy input of a building will be utilized to a greater extent. To implement this concept, a water-loop (tank) heat pump system is necessary and its most important aspect is the design of the thermal storage tank (serving as the water-loop). In this paper, a typical catering building has been selected, and the building’s thermal service systems (processes) are studied in detail. The amount and state of the current thermal energy utilization within each service system is analyzed, and a specific integrated thermal system model is suggested. The research work conducted for this study is based on simulations, such as building thermal load simulations (DesignBuilder software), characteristic simulations of the water-loop heat pump system (TRNSYS software), optimal dimensions and thermal characteristic simulations of the thermal storage tank, etc. The energy consumption characteristic analysis and the technical and economic analysis of the entire building model are discussed, and the optimal scheme for process allocation and optimal operation mode are also presented in this paper. Based on the analytical results (including simulation of building thermal load, simulation of systematic energy consumption, performance analysis of the system, economical analysis, and exergy analysis), the advantages of the system model are demonstrated.     

中国被动房外围护系统研究——以寒冷、严寒气候区被动房项目为例

德国的被动房是目前世界公认的具有超低能耗、超低碳排放量、超高室内舒适度等特点的建筑技术体系。德国的气候特征与中国华北地区的气候特征具有相似性,因此,研究并建造被动房对于我国建筑节能工作的发展具有重大的意义。外围护系统作为被动房设计的重点要素,对建筑的节能效率有重大的影响。以寒冷、严寒气候区的被动房项目为例,对被动房外围护系统进行分析与阐述,并以秦皇岛"在水一方"被动式住宅示范项目为例,进行能耗模拟与对比分析。提出适合我国寒冷、严寒气候区气候特点的被动式超低能耗建筑外围护系统的设计策略。     

沈阳周边农村地区住宅建筑节能改造实测分析

为了解决沈阳周边农村地区住宅建筑能耗较大的问题,研究了传统非节能建筑的特征,以及新建节能建筑的节能措施。选取该地区节能住宅和非节能住宅各一例,对建筑围护结构的热工性能和建筑环境参数进行检测分析,确定出采暖供回水温度、室内环境温度、相对湿度的数值,通过现场调研和仪器检测确定出PMV-PPD室内环境评价指标。结果表明,节能建筑与非节能建筑相比,采用围护结构节能等措施的建筑的节能率提升了17.7%,同时,室内环境舒适度也有大幅度提高。     

建筑节能方案设计与经济性分析

为提高建筑室内热舒适环境,减少建筑能源消耗,建设部于2001年颁布实施了《夏热冬冷地区居住建筑节能设计标准》(JGJ 134-2001),并提出了两种节能评价方法。对一建筑模型采用两种节能评价方法进行了节能方案设计与经济性分析评价。结果表明,若设计合理,采用性能性指标进行节能评定可明显减少建筑节能的增量成本。因此,建议建筑节能方案的设计应尽可能采用性能性指标评价法。     

Enhancing the sustainability and energy conservation in heritage buildings: The case of Nottingham Playhouse

Today, there is a growing interest in developing energy efficient buildings since it is estimated that buildings account for about 40% of the total primary energy consumption in the world. In relation to existing buildings, energy efficiency retrofits have become an important opportunity to upgrade the energy performance of commercial, public and residential buildings that may reduce the energy consumption, demand and cost. In this paper we cover the energy efficiency deep retrofit process that has been carried out for Nottingham Playhouse theatre building for the aim of enhancing its environmental performance and analysing the energy efficiency gained after implementing certain proposed modifications. It is a nationally protected historic building, listed as Grade II1 on The National Heritage List for England (NHLE). The building has had insulation enhancement, doors modifications, solar energy installations, energy-saving lights, in addition to improved heating and air conditioning system. The paper presents a novel methodology; and its results indicate significant improvements in the building's energy performance which is demonstrated using infrared thermographic images and data logger sensors where significant energy savings to the building's thermal performance are obtained. The energy saving measures have been completed while maintaining the heritage building's general appearance and architectural features, which have received a Commendation Certificate from The Nottingham Civic Society for this achievement.     

建筑围护结构热工性能现场检测技术探讨

对建筑围护结构热工性能现场检测技术进行了总结,指出为了系统全面地评价围护结构节能效果,应对现场测试装置进行改进,并检测更多的热工参数,为建筑物的运行能耗分析提供依据。     

关于农村住宅冬季热环境与节能改造的分析研究

本文采用实地调查测量以及应用DeST与TRNSYS软件模拟分析相结合的方法,对陕西华县的农村建筑概况、供暖方式和建筑室内热环境进行了分析研究,并对建筑围护结构进行节能改造前后室内达到不同供暖设计温度时的热负荷进行了模拟分析,为今后通过改变建筑材料及添加保温材料来达到降低能耗及改善室内热环境、提高农村建筑热舒适性、合理设定冬季室内采暖计算温度提供了参考依据。在此基础上,简单对比分析了2种软件模拟结果存在差异的原因。