Implementation of energy-efficient windows in Swedish single-family houses

A questionnaire survey of 1010 homeowners in Jämtland and Västernorrland, which are two counties in central Sweden, was conducted to understand the factors influencing their decision to install energy-efficient windows. We complemented this survey with an interview of 12 window sellers/installers in the county Jämtland. The annual energy cost reduction, age, and condition of the windows were the most important reasons for the window replacement decision. Approximately 80% of the respondents replaced their windows with energy-efficient windows with U-value of 1.2 W/m² K. Condensation problems, perceived higher prices, and lack of awareness about windows with lower U-values were important reasons for non-adoption of more energy-efficient windows. Window sellers/installers have a strong influence on homeowners’ window selection that was indicated by the 97% of homeowners who bought the windows that were recommended to them. Sellers/installers revealed that they did not recommend windows with U-value of less than 1.2 W/m² K because they thought that investing in such windows was not economical and because windows with U-value less than 1.2 W/m² K could cause water condensation on the external surface of window pane.     

Social habits and energy consumption in single-family homes

Personal interviews (response rate = 96.1%) were made with both men and women in an area of 76 similar, all-electric single-family houses (November 15 to December 1, 1981). The total variation in energy consumption in the area is explained by differences in social habits (water consumption, about 50%; ventilation habits, about 35%; indoor temperature, about 15%) among the households. The consumer sociological variables chosen for this study statistically explain more than 60% of total variation in household energy consumption. A relation has been found between attitude to energy consumption and household energy consumption with r = 0.48. The households display no knowledge that they themselves consume about one third of total energy used. When major energy saving activities are undertaken by the households, the motive is often energy consciousness. When minor energy-saving activities are taken, the motive is an economic one. The male energy-related role is of greater importance for the variation in household energy consumption than the female role.In a discussion, the importance of distinguishing between household energy consumption and household energy use in order not to affect the welfare of the households when energy saving actions are undertaken, is maintained.     

北方新农村低能耗住宅

介绍了适于北方农村地区应用的低能耗住宅的设计方案,阐述了其工作原理及其使用效果.设计方案充分利用了生物质能和太阳能等可再生能源,设置了利用秸秆进行冬季采暖的地下燃池和太阳能空气集热器.该方案在农村应用,既解决了多余的农作物秸秆利用问题,也节省了采暖费用,在一个采暖期平均每户节约采暖费用1000元.     

Perspectives on implementing energy efficiency in existing Swedish detached houses

In this study, we first analyse energy-efficiency measures in existing electrically heated houses in Sweden from a societal economic perspective. Measures to a house envelopes and to energy supply chains are evaluated through a system analysis approach and we include the external costs of climate change and the effect of different Swedish climatic zones. We find that in a typical house from the 1970s, conversion from electric heating is highly motivated since the mitigation cost of conversion is lower than the estimated external costs of emitted CO₂. Both conversions and house envelope measures are more motivated in the northern part of the country, where there is a higher heat demand. A successful implementation of changes requires them to be attractive for consumers to adopt. We therefore secondly analyse the economic conditions for Swedish house owners to implement societal economic cost-efficient measures. We include the economic influence of an investment subsidy for heating system conversion, an income tax deduction for changing windows, customer electricity tax, real estate tax and of the cost of purchased energy from different energy suppliers. Apart from the economics, several other factors affect a house owner's decision to change heating systems. We therefore thirdly analyse house owners’ perceptions of different heating supply alternatives based on the results of two comprehensive questionnaires. These different perspectives are combined in a discussion whether the studied policy instruments encourage house owners to implement changes in accordance with the energy-efficiency goals of decision makers. We find that the investment subsidy could be useful to break the lock-in effect of resistance heaters, which house owners seemed to experience. The electricity tax makes heating systems in line with national goals more competitive and efficiency measures to the house envelope more profitable. The reduction of the electricity tax in the northern part of the country has the opposite effect. Also, the increase in real estate tax when implementing energy-efficiency measures gives a contradictory message. The price differences between energy suppliers has a larger impact on the house owners’ economic conditions than both subsidies and tax rate changes, and possibly also affect the house owner's attitudes towards various systems.     

Mass effects in residential energy consumption

The objective of this study was to determine the effect of mass on both the annual energy consumption and the maximum rate of energy consumption. There have been recent references in the literature to such effects as ‘mass resistance’, ‘capacity insulation’, and ‘thermal inertia’, suggesting that mass can actually resist the flow of energy through a wall. In this study it is shown that the annual energy comsumption is dependent on the R-factor and the heat capacity per unit area. An example compares two buildings, one with walls that are 400 times as massive as those of the other, and yet the annual energy consumption is identical; hence, the idea of ‘mass resistance’ is to be avoided. The real effect of increased mass is typically to increase the heat capacity. The effect of increased heat capacity in a building is shown to lead to a slight decrease in the annual energy consumption and a significant decrease in the maximum rate of energy consumption.     

芬兰低能耗建筑物

1993～1998年间,芬兰国家技术研究中心VTT建筑技术研究所在若干企业的协助下进行了一项名为RAKET的低能耗建筑物研发项目。他们按计划修建了系列独户住宅、3套公寓建筑、一座太阳房和一栋办公楼。据VTT建筑技术研究所计划主任MarkkuVirtanen教授说,上述建筑基于如下特点具有低能耗与优良的居住舒适性:1.墙壁、地板与房顶等外围护结构具有优异的隔热性,2.现代高能效窗,3.具备热回收功能的机械通风系统,4.精心建造以保证建筑的气密效果。通风与气密的重要性。Virtanen指出,外围护与低U值窗的有效隔热再加上具备热回收能力的通风设备对建…     

Energy renovation of single-family houses in Denmark utilising long-term financing based on equity

This paper aims to present an economic overview of the opportunities for energy renovation of single-family houses in Denmark financed over the long term. The paper focuses on the economic difference between energy savings and the repayment of investment.     

Owners perception on the adoption of building envelope energy efficiency measures in Swedish detached houses

The paper focuses on Swedish homeowners’ need for and perceptions about adopting building envelop energy efficiency measures. The paper is based on a questionnaire survey of 3059 homeowners (response rate of 36%) selected by stratified random sampling during the summer of 2008. The results showed that 70–90% of the respondents had no intention of adopting such a measure over the next 10 years. The main reasons for non-adoption were that homeowners were satisfied with the physical condition, thermal performance, and aesthetics of their existing building envelope components. A greater proportion of respondents perceived that improved attic insulation has more advantages than energy efficient windows and improved wall insulation, but windows were more likely to be installed than improved attic insulation. Respondents gave high priority to economic factors in deciding on an energy efficiency measure. Interpersonal sources, construction companies, installers, and energy advisers were important sources of information for homeowners as they planned to adopt building envelope energy efficiency measures. Policy measures to facilitate the rate of adoption of energy efficient building envelope measures are discussed.     

Experimental investigation of wraparound loop heat pipe heat exchanger used in energy efficient air handling units

Building legislation along with environmental and comfort concerns are increasingly driving designers of building services and air conditioning equipment towards more energy efficient solutions. Heat pipe technology is emerging as a viable, efficient and environmentally-sound technology for applications in efficient air handling unit designs. In this paper, an experimental investigation on the thermal performance of an air-to-air heat exchanger, which utilises heat pipe technology, will be presented. The heat exchanger consisted of 7 loop heat pipes with finned evaporator and condenser sections. The heat exchanger was fully instrumented to test for the effect of the variation of heat load and the air velocity, through the heat exchanger, on the overall thermal resistance of the loops. The values of the effectiveness of the heat pipe heat exchanger are shown to vary with the air velocity as expected but the results also allow the prediction of effectiveness variation with the heat load and operating temperature (previously assumed to be constant). The results allow an interpretation of the overall thermal performance of each loop heat pipe as a function of the load and air velocity. The paper concludes with a theoretical analysis of the energy savings that would be expected when utilising the technology in a representative application.     

The energy consumption performance of roof lawn gardens in Thailand

Statistics have confirmed that a lawn placed on a roof top can reduce the cooling load. In this study, the VISUAL DOE 4.0 energy simulation program was used to determine the effects of roof lawn gardens (RLG) on the annual energy required for cooling, and annual electrical usage in an experimental model. The overall heat transfer coefficient (U-Value) of the RLG was estimated by using data from site measurements and the effect of the RLG on the building’s energy consumption was calculated by the simulation program. The effect of different thicknesses of soil was also investigated. From the field measurements, it was confirmed that the RLG could reduce building heat gain. Thus, an experiment was set up to find the energy benefits of the RLG. With evaporative cooling by the RLG, it was found that the consumption of energy in a building with a RLG with 0.20 m of soil was 37.11% less than in a building with a bare roof surface (without evaporative cooling). Moreover, a building with 0.10 m of soil in the RLG consumed 31.07% less energy than a building with a bare roof surface. The results show that an increase in the thickness of the soil layer reduces the building energy consumption.     

水下工作柴油机排气降温系统设计及试验

排气背压对柴油机的动力性能和油耗有着重要的影响,排气背压过大会造成动力性能的损失和油耗的增加,因此,在为柴油机设计排气后处理装置时,要充分考虑排气背压的大小。本文针对水下工作的柴油机,设计了一套排气降温系统,可以使得该柴油机在水下工作时,其排气可以被冷却后直接排向大气,并且其动力性能不受影响,这就要求在设计过程中要使整个排气降温系统的流动阻力尽可能最小。通过试验结果表明:加装该排气降温系统后柴油机输出动力性能良好,无功率和转矩损失;特殊管壳式换热器换热效果良好,能使最高温度为503.4℃的高温烟气降低到39.4℃。本文研究的结果对小型水下动力装置排气降温系统的选择和设计有一定的参考价值。     

Assessment of Thailand indoor set-point impact on energy consumption and environment

The paper presents an investigation of indoor set-point standard of air-conditioned spaces as a tool to control electrical energy consumption of air-conditioners in Thailand office buildings and to reduce air pollutants. One hundred and forty-seven air-conditioned rooms in 13 buildings nationwide were used as models to analyze the electricity consumption of air-conditioning systems according to their set indoor temperatures, which were below the standard set-point and were accounted into a large scale. Then, the electrical energy and environmental saving potentials in the country were assessed by the assumption that adaptation of indoor set-point temperature is increased up to the standard set-point of 26 °C. It was concluded that the impacts of indoor set-point of air-conditioned rooms, set at 26 °C, on energy saving and on environment are as follows: The overall electricity consumption saving would be 804.60 GWh/year, which would reduce the corresponding GHGs emissions (mainly CO₂) from power plant by 579.31×10³ tons/year.     

郑州某超高层酒店生活热水系统改造案例分析

以郑州某超高层酒店生活热水系统改造为例,对酒店锅炉系统进行能源流向分析。考虑到系统冷热同源问题,不同热水分区设定不同的改造方案,同时确定各个分区详细的设备参数配置及节能量分析计算。对超高层酒店生活热水系统改造后,蒸汽锅炉系统综合节能率达28.4%,可为同类建筑热水系统改造提供借鉴。     

Behavioural,physical and socio-economic factors in household cooling energy consumption

As global warming continues, the current trend implies that the uptake of air conditioning in the residential sector will go up, thus potentially increasing domestic cooling energy consumption. In this context, this paper investigates the significance of behavioural, physical and socio-economic parameters on cooling energy in order to improve energy efficiency in residential buildings. It demonstrates that such factors exert a significant indirect as well as direct influence on energy use, showing that it is particularly important to understand indirect relationships. An initial study of direct factors affecting cooling energy reveals that occupant behaviour is the most significant issue (related to choices about how often and where air conditioning is used). This is broadly confirmed by path analysis, although climate is seen to be the single most significant parameter, followed by behavioural issues, key physical parameters (e.g. air conditioning type), and finally socio-economic aspects (e.g. household income).     

Impact of climate change on commercial sector air conditioning energy consumption in subtropical Hong Kong

Past and future trend of electricity use for air conditioning in the entire commercial sector in subtropical climates using 1979–2008 measured meteorological data as well as predictions for 2009–2100 from a general circulation model (MIROC3.2-H) was investigated. Air conditioning consumption showed an increasing trend over the past 30 years from 1979 to 2008. Principal component analysis (PCA) of measured and predicted monthly mean dry-bulb temperature, wet-bulb temperature and global solar radiation was conducted to determine a new climatic index Z for 1979–2008 and future 92 years (2009–2100) based on two emissions scenarios B1 and A1B (low and medium forcing). Through regression analysis, electricity use in air conditioning for the 92-year period was estimated. For low forcing, average consumption in 2009–2038, 2039–2068 and 2069–2100 would be, respectively, 5.7%, 12.8% and 18.4% more than the 1979–2008 average, with a mean 12.5% increase for the entire 92-year period. Medium forcing showed a similar increasing trend, but 1–4% more. Standard deviations of the monthly air conditioning consumption were found to be smaller suggesting possible reduction in seasonal variations in future years.     

Comparison of energy consumption and specific energy requirements of different methods for drying mushroom slices

Energy consumption for drying of mushroom slices was evaluated using various drying methods including hot air, microwave, vacuum, infrared, microwave-vacuum and hot air-infrared. Results of data analysis showed that the lowest and highest energy consumption levels in drying mushroom slices were associated with microwave and vacuum dryers, respectively. The use of vacuum in conjunction with microwave drying increased energy consumption relative to microwave drying alone. Energy consumption in the hot air dryer showed a downward trend with increasing temperature and an upward trend with increasing air velocity. In drying mushroom using infrared radiation, it was observed that increased air velocity increases drying time and consequently the amount of consumed energy. Using a combination of hot air and infrared drying decreased energy consumption relative to infrared drying alone and increased it relative to hot air drying. In the combined microwave-vacuum dryer, drying time and consequently energy consumption decreased in comparison to the vacuum dryer. Hot air-infrared drying of mushroom slices proved to have the lowest energy consumption.     

Application of the Structural Decomposition Analysis to assess the indirect energy consumption and air emission changes related to Italian households consumption

The design of sustainable production and consumption strategies and the assessment of implemented actions require to identify the driving forces that influence the trend of energy consumption and environmental impacts.For this purpose, the Structural Decomposition Analysis (SDA) was developed as a suitable methodology to analyse the driving forces of the changes in economic, energy and environmental indicators.The paper presents one of the first Italian studies that apply an energy and environmental extended input-output model, opportunely shaped to the examined context, combined with SDA. In detail, it aims at: (1) investigating the energy use and the air emissions arisen from the productive sectors to meet the household final demand in the period 1999-2006; (2) identifying the sources of variations in energy and environmental indicators; and (3) identifying which economic sectors are the most relevant sources of variation and must to be taken into account in the definition of sustainable production and consumption strategies.As sources of changes, the authors investigate: energy and emission intensity effects, Leontief effect and final demand effect.Outcomes point out that the increase of the final consumptions often nullifies the energy and environmental benefits due to the improvement of the eco-efficiency and to the introduction of innovative technologies of production.The sector level analysis shows that “tertiary” and “electricity, gas and vapour” result the highest Italian consuming sectors of energy. Thus they should be focused for energy saving strategies. “Agriculture, hunting and sylviculture” and “road transports”, that are primarily sectors affecting air emissions, should be taken into account for the reduction of environmental impacts.Results highlight that the current dichotomy of final demand growth and improvement of eco-efficiency represents a key problem that needs to be addressed. Therefore the presented study can aid to define suitable oriented strategies for the energy and environmental impact reduction.     

Estimating emissions on vehicular traffic based on projected energy and transport demand on rural roads: Policies for reducing air pollutant emissions and energy consumption

This study deals with the estimation of emissions caused by vehicular traffic based on transport demand and energy consumption. Projected transport demand is calculated with Genetic Algorithm (GA) using population, gross domestic product per capita (GDPPC) and the number of vehicles. The energy consumption is modelled with the GA using the veh-km. The model age of the vehicles and their corresponding share for each year using the reference years is obtained. The pollutant emissions are calculated with estimated transport and energy demand. All the calculations are made in line to meet the European standards. For this purpose, two cases are composed. Case 1: Emissions based on energy consumption, and Case 2: Emissions based on transport demand. The both cases are compared. Three policies are proposed to control demand and the emissions. The policies provided the best results in terms of minimum emissions and the reasonable share of highway and railway mode as 70% and 30% usage for policy I, respectively. The emission calculation procedure presented in this study would provide an alternative way to make policies when there is no adequate data on emission measurement in developing countries.     

Application of heat pump in rectification decreases energy consumption in the chemical industry

In the rectification, in essence, most heat energy brought in at the boiler of the column at the higher temperature is transformed into the condensation heat of the vapor, which is taken away at the lower temperature. The application of the heat pump makes it possible to transform the condensation het of the vapor to the higher temperature, by which the utilization is realizable. But, it is necessary to bring into the system the noble electric energy. The realization is judged not only by the energy efficiency, but also by the exergy efficiency. An example is given of the separation of ethylbenzene from the mixture C₈H₁₀/C₈H₈. The problem of the calculation is that the ethylbenzene vapors are not an ideal gas.     

Environmental cost of energy consumption and biodiesel as a solution (case study: Iran)

ABSTRACT

More than 8.5 million people live in Tehran, the capital of Iran, with 111 pollutant days during 2016. Based on Iranian 2016 energy balance sheet, more than 76% of SPM was emitted by gas oil combustion. To determine the main pollutant fuel-consuming sector, the amount of gas oil consumption and SPM production are investigated. Therefore, the transportation and power plant sectors are determined as the main gas oil users with 51.1% and 30.5% of its total consumption. Next, the reduced external cost of implementing biodiesel instead of gas oil for mobile and fixed sources is deliberated. Finally, by comparing the external cost of gas oil consumption and Iran's gross domestic production in 2016, it is revealed that by replacing gas oil with biofuels, 3.935 billion dollars (0.95% of gross domestic production of Iran in 2016) can be reduced.