Impact of the ambient temperature rise on the energy consumption for heating and cooling in residential buildings of Greece

Annual values of heating and cooling degree-days for two typical base temperatures, namely 15 °C for heating and 24 °C for cooling, and for the two main cities of Greece (Athens and Thessaloniki) from 1983 to 2002 are presented in the study, calculated using hourly dry bulb temperature records from the meteorological stations of the National Observatory of Athens and of the Aristotle University of Thessaloniki. The decade average (1983–1992 and 1993–2002) values of the heating and cooling degree-days of the two cities are compared, for various base temperatures. The results show that the average value of heating degree-days of Athens for the decade 1993–2002, depending on the base temperature, is reduced from 8% to 22% as compared to the corresponding value of the decade 1983–1992. Similarly, the reduction in the Thessaloniki case is found in the range 4.5%–9.5%. The difference in the average value of cooling degree-days of the decades is more pronounced, the increase ranging from 25% to 69% for Athens and from 10% to 21% for Thessaloniki. In order to evaluate the effect of these changes on the energy requirements for heating and cooling of a typical residential building, the latter were calculated using the variable base degree-day method and the data sets of the two decades. The results show a reduction of the heating energy demand by 11.5% and 5% and an increase of the cooling energy demand by 26% and 10%, for Athens and Thessaloniki respectively.     

兰州地区住宅建筑供暖能耗影响因素分析

为研究影响兰州地区住宅建筑供暖能耗的因素,在围护结构参数完全符合国家现行寒冷地区住宅建筑节能要求的前提下,以兰州市2栋住宅建筑为基准模型,运用De ST-h软件对供暖季的热负荷进行逐时模拟计算,分析窗墙比、体型系数、朝向三大因素对总供暖热负荷的影响,得到了兰州地区住宅建筑南偏西30°朝向与南偏东30°朝向、正南方向相比,总热负荷最小,但最大热负荷最大的结论,为南偏西建筑进行供热调节实现节能提供依据。南向墙面内凹的住宅建筑不宜通过面积热指标法来估算热负荷。     

Vary-therm wall for cooling/heating of buildings in composite climate

A modified form of Trombe Wall in which the glazing has been replaced by weather resistance material has been proposed and examined for winter heating and summer cooling in mixed climate conditions characterized by a mild winter and a relatively harsh dry summer. The experimental results indicate the potential applications of such a wall, known as Vary-Therm Wall, in solar passive building architecture for mixed climatic conditions.     

Impact of passive cooling techniques on energy demand for residential buildings in a Mediterranean climate

This study presents the thermal analysis of a building prototype, which was designed and built in accordance with energy efficiency measures to improve indoor thermal comfort, particularly in summer. The building prototype is located in Souidania (20 km southwest of Algiers, latitude 36°7N, Longitude 03°2E). The location is characterized by a temperate Mediterranean climate. In order to perform this analysis, various activities are carried out: a series of monitoring campaigns; dynamic simulations with TRNSYS software, calibration of the model with experimental data and comparative study with buildings that use different wall constructions. Based on a validated building thermal model, dynamic analysis is carried out in order to evaluate the impact of thermal mass and of eaves and night ventilation. The results demonstrate that cooling energy demand is more affected by thermal transmittance values than by the envelope thermal mass. A recommended guideline for the optimum overhang length for south-facing windows is proposed. Ultimately, it is found that the combination of both natural ventilation and horizontal shading devices improves thermal comfort for occupants and significantly reduces cooling energy demand.     

Efficiency of solar energy use for residential heating and cooling

The possibility of using solar energy collected on flat plate collectors situated on roofs for residential space heating/cooling and domestic water heating is considered. The study is carried out on a typical house situated in various locations in Libya. Two types of constructions involving heavy and light insulation, three roof tilts, and three values of system efficiency are considered. The study shows that the demand in a great part of the country can be provided from solar energy by a medium efficiency system, even with light insulation and a horizontal roof. Only in a few locations should the roof be tilted at an angle of 10 °. For a low-efficiency system, insulation is necessary; for a high-efficiency-system, it was found that there is no need for either heavy insulation or tilting of the roof.     

农村住宅清洁能源供暖方式经济性分析

以莒县农村地区冬季供暖方式为依据,研究分析太阳能辅助空气源热泵、燃气壁挂炉、地埋管地源热泵3种清洁能源供暖方式。通过对3种供暖方式的设备造价、运行费用的经济性分析,得出最优的清洁供暖方案,对实际农村住户冬季采暖提供建议。     

Effect of building regulation on energy consumption in residential buildings in Korea

According to the International Energy Agency (IEA), the energy demand for the building sector constituted about 25.3% of the final energy use in South Korea. The energy demand for residential buildings counts for 50.3% of the building sector and has also increased by 2.9 percent every year. The Korean government has shifted focus and is now promoting energy efficiency within the building sector and has set long-term energy conservation goals.Despite these efforts to minimize building energy, the Korean government has changed the building regulation to allow remodeling of the balcony space as a living space. Remodeling the balcony space to become an indoor space means that a buffer space for the outdoor environment is lost, causing thermal discomfort and discomfort glare and moreover, increasing the heating and cooling energy demand in residential buildings. Also, it results in an increase in building energy demand in South Korea.In this study, the effect of the alteration of balcony space on the indoor thermal environment and the heating and cooling energy demand of residential buildings in Korea were investigated by field measurement and simulation. From the measurement results, the indoor temperature of the condition without a balcony was 0.8 °C lower than that with a balcony. The heating and cooling load of the unit without the balcony space was 39% and 22% higher, respectively, than that of the unit with the balcony space. This increase results in considerable energy loss in the national scale and the ratio will be 0.3% of the final energy use in Korea. Also, it represents about 1.3% of the final energy use within the building sector of Korea.     

Impact of energy efficiency upgrade retrofits on the residential energy consumption in Canada

The impact of various energy efficiency upgrade scenarios on the annual energy consumption of the Canadian housing stock is assessed using the Canadian Residential Energy End‐use Model (CREEM). The energy efficiency upgrade scenarios that are considered include major retrofits, such as the improvement of the house envelope by adding insulation, and the replacement of the existing heating system and appliances by higher efficiency units, as well as minor retrofits, such as lighting fixture, thermostat, showerhead and aerator upgrades that reduce energy consumption. The economic feasibility of each upgrade was assessed using the indicator ‘energy savings per dollar investment’. The results indicate that the energy savings potential of the retrofits is rather small, resulting in savings of 0–8 per cent of the total energy consumption of the Canadian housing stock. Copyright © 2001 John Wiley & Sons, Ltd.     

窗墙比对某大型商场冷热负荷的影响分析

通过DeST软件模拟某大型商场的冷热负荷,重点分析建筑窗墙比对其冷热负荷的影响,得出建筑负荷值随窗墙比变化的曲线,并应用曲线分析了负荷值的变化趋势,拟合出负荷值随着窗墙比变化的关系式,分析结果对建筑设计具有一定的参考价值。     

Target-oriented obstacle analysis by PESTEL modeling of energy efficiency retrofit for existing residential buildings in China's northern heating region

According to the “Comprehensive Work Program of Energy Efficiency and Emission Reduction” of the Chinese government, during the period of the “11th Five-Year Plan”, 1.5×10⁸ m² of existing residential buildings in China's northern heating region are to be retrofitted for energy efficiency. However, at present, this “Energy Efficiency Retrofit for Existing Residential Buildings” (EERFERB) faces many obstacles. Under the current working and market system, both the central and local governments and the energy supply companies can not push on this work smoothly. Using both the results of the annual national special inspection of building energy efficiency and some case analyses, this paper examines the necessity for energy efficiency retrofit, along with the relationships among the various Political, Economic, Social, Technological, Environmental and Legal (PESTEL) factors affecting it. Furthermore, organizational, financial and technical support systems are explored to promote the development of retrofit. Finally, some primary principles to be followed toward the implementation of EERFERB are suggested.     

Impact of climate change on building heating energy consumption in Tianjin

This paper investigated the variation of building heating energy consumption caused by global warming in Tianjin, China. Based on the hourly historical and monthly projected future (B1/A1B emissions scenarios) meteorological data, the variation of those relevant meteorological parameters was first analyzed. A TRNSYS simulation model for a reference building was introduced to investigate historical variation of office building energy consumption. The results showed that the 10-year-average heating energy consumption of 2001–2010 had reduced by 16.1% compared to that of 1961–1970. By conducting principal component analysis and regression analysis, future variation of building heating load was studied. For B1/A1B emissions scenarios, the multi-year-average heating load was found to decrease by 9.7% (18.1%)/10.2% (22.7%) compared to that of 1971–2010 by 2011–2050 (2051–2100).     

集中供暖热计量模式多样化的必要性分析

通过工程实例对我国节能建筑集中供暖热计量系统设计所存在的问题进行讨论。目前我国居住建筑集中供暖系统热计量设计模式单一,没有充分考虑我国国情和不同类型居住建筑的特点,加之我国的供热体制改革滞后,使得新建居住建筑的节能效果无法保证,还增加了工程建设费用。相关的技术规程予以补充和完善。     

Analysis of cooling,heating, and power systems based on site energy consumption

Feasibility of cooling, heating, and power systems frequently is based on economic considerations such as energy prices. However, a most adequate feasibility of CHP systems must be based on energy consumption followed by economic considerations. CHP systems designs must yield economical savings, but more importantly must yield real energy savings based on the best energy performance. For CHP systems, energy savings is related to primary energy and not to site energy. This paper presents a mathematical analysis demonstrating that CHP systems increase the site energy consumption (SEC). Increasing the SEC could yield misleading results in the economic feasibility of CHP systems. Three different operation modes are evaluated: (a) cooling, heating, and power; (b) heating and power; and (c) cooling and power, to represent the operation of the system throughout the year. Results show that CHP systems increase site energy consumption; therefore primary energy consumption (PEC) should be used instead of SEC when designing CHP systems.     

中国住宅中能源消耗的CO2排放量及减排对策

利用生命周期评价方法,根据中国煤电链和水电链的温室气体排放系数,计算了各种燃料的温室气体排放系数,并在此基础上,计算出了1999年我国住宅中由于家用电器的使用、冬季集中供暖及农村生活能源消费所造成的温室气体排放量.通过数据分析得出住宅中主要能源消耗所产生的CO2排放量约占全国总排放量的34.34%.分析计算了一栋被动式太阳能建筑的减排潜力,提出了住宅中CO2减排的对策.     

Integrated evaluation of radiative heating systems for residential buildings

Based on the need to reduce CO₂ emissions and minimize energy dependency, the EU Member States have set ambitious energy policies goals and have developed respective, specific regulations, in order to improve the energy performance of the building sector. Thus, specific measures regarding the buildings’ envelope, the use of efficient HVAC technologies and the integration of renewable energy systems are being constantly studied and promoted. The effective combination of these three main aspects will consequently result in maximum energy efficiency. Germany has played a key role in this development, with intensive work focusing in the improvement of the energy behaviour of the residential building stock. In this paper, the use of radiative heating systems placing special emphasis on infrared is being studied as part of the energy renovation of residential buildings from the 1970’s. This is done by applying an integrated assessment model to evaluate specific interventions regarding the improvement of the energy behaviour of the buildings’ envelope and the use of radiative heating systems, based on a thorough Life Cycle Analysis according to criteria of energy, economic and environmental performance, as well as thermal comfort.     

夏时制对北京地区住宅建筑的照明能耗影响研究

本文通过DeST软件模拟北京地区一栋典型住宅建筑的天然采光逐时照度,进而计算该建筑的照明能耗,比较在标准北京时间和实行夏时制时的照明能耗分布特点。通过分析可得出结论:对于北京地区的住宅建筑,夏时制可以节约照明能耗;夏时制的起止日期可以考虑从三月第四个星期开始到九月第三个星期结束;在此期间,采用夏时制可节约照明能耗7.95%。     

Life-cycle energy of residential buildings in China

In the context of rapid urbanization and new construction in rural China, residential building energy consumption has the potential to increase with the expected increase in demand. A process-based hybrid life-cycle assessment model is used to quantify the life-cycle energy use for both urban and rural residential buildings in China and determine the energy use characteristics of each life cycle phase. An input–output model for the pre-use phases is based on 2007 Chinese economic benchmark data. A process-based life-cycle assessment model for estimating the operation and demolition phases uses historical energy-intensity data. Results show that operation energy in both urban and rural residential buildings is dominant and varies from 75% to 86% of life cycle energy respectively. Gaps in living standards as well as differences in building structure and materials result in a life-cycle energy intensity of urban residential buildings that is 20% higher than that of rural residential buildings. The life-cycle energy of urban residential buildings is most sensitive to the reduction of operational energy intensity excluding heating energy which depends on both the occupants' energy-saving behavior as well as the performance of the building itself.     

Modeling of end-use energy consumption in the residential sector: A review of modeling techniques

There is a growing interest in reducing energy consumption and the associated greenhouse gas emissions in every sector of the economy. The residential sector is a substantial consumer of energy in every country, and therefore a focus for energy consumption efforts. Since the energy consumption characteristics of the residential sector are complex and inter-related, comprehensive models are needed to assess the technoeconomic impacts of adopting energy efficiency and renewable energy technologies suitable for residential applications.The aim of this paper is to provide an up-to-date review of the various modeling techniques used for modeling residential sector energy consumption. Two distinct approaches are identified: top-down and bottom-up. The top-down approach treats the residential sector as an energy sink and is not concerned with individual end-uses. It utilizes historic aggregate energy values and regresses the energy consumption of the housing stock as a function of top-level variables such as macroeconomic indicators (e.g. gross domestic product, unemployment, and inflation), energy price, and general climate. The bottom-up approach extrapolates the estimated energy consumption of a representative set of individual houses to regional and national levels, and consists of two distinct methodologies: the statistical method and the engineering method.Each technique relies on different levels of input information, different calculation or simulation techniques, and provides results with different applicability. A critical review of each technique, focusing on the strengths, shortcomings and purposes, is provided along with a review of models reported in the literature.     

Analysis of combined cooling,heating, and power systems based on source primary energy consumption

Combined cooling, heating, and power (CCHP) is a cogeneration technology that integrates an absorption chiller to produce cooling, which is sometimes referred to as trigeneration. For building applications, CCHP systems have the advantage to maintain high overall energy efficiency throughout the year. Design and operation of CCHP systems must consider the type and quality of the energy being consumed. Type and magnitude of the on-site energy consumed by a building having separated heating and cooling systems is different than a building having CCHP. Therefore, building energy consumption must be compared using the same reference which is usually the primary energy measured at the source. Site-to-source energy conversion factors can be used to estimate the equivalent source energy from site energy consumption. However, building energy consumption depends on multiple parameters. In this study, mathematical relations are derived to define conditions a CCHP system should operate in order to guarantee primary energy savings.