Modeling the performance characteristics of water-cooled air-conditioners

Water-cooled air-conditioning systems (WACS) are widely used in the commercial sector for energy efficiency, but not in the domestic sector. It has been found that there are no mathematical models and energy simulation programs to enable detailed investigation and evaluation into the energy performance of water-cooled air-conditioners. To improve the applicability of water-cooled air-conditioners in the domestic sector, the development of a prediction model for energy performance analysis is needed. This paper addresses the development of an empirical model for predicting the operational performance and energy consumption for the use of water-cooled air-conditioners. The model consists of four sub-models which has taken into account the energy consumption of the condenser water system. A prototype WACS was set up and tested in an environmental chamber to validate the resultant model. The overall COP of the WACS was found to be greater than 3 at 90% rated capacity. The predictions from the model compared well with the experimental results, with RMS error within 11%.     

The uses of energy in the domestic sector

Energy consumption in the domestic sector is influenced by the level of the user’s living standards. Moreover, the general ignorance of the energy services that make up most of the energy bill does not permit concerted action to rationalize energy use.In order to contribute to a better understanding of energy consumption and use in the domestic sector, three households were monitored.This paper sets out the results of this study and discusses these results produced from the monitoring of energy use over a period of 1 year of household use.     

Overcoming barriers to implementation of carbon reduction strategies in large commercial buildings in China

With an economic growth in GDP of around 10% per annum in recent years, energy consumption in the building sector in China now accounts for 25% of the total energy use in the whole nation. In large buildings in Beijing and Shanghai the consumption rate, at approximately 190 kWh/m² per annum, is around five times the energy use in residential buildings in those cities. Addressing this ever increasing energy consumption and the consequential green house gas (GHG) emissions must be a priority to achieve low carbon sustainability in China.     

Energy-saving occupant behaviours in offices: change strategies

As regulated energy consumption in buildings is reduced, the proportional importance of unregulated energy consumption increases. Reducing unregulated energy use in the commercial office requires an understanding of the factors that influence workplace behaviour. To date these factors have been assumed to be similar to those that influence behaviour in the home. However, the social dynamics of the workplace are different to those in the home. This study examines the degree to which theories of behaviour change generated largely in a domestic building setting could be used as the basis for designing interventions to reduce unregulated energy consumption in the workplace. It studies the unregulated energy consumption of 39 workers engaged in office-type activities in two separate locations. Following a 100-day monitoring period, three behaviour change interventions were developed and their impact measured over a 100-day period. Results from the study found, on average, an 18.8% reduction in energy use was achieved. Furthermore, by comparing pre- and post-intervention responses to an environmental questionnaire, it was evident that savings were realized without significant changes to pro-environmental attitude or perceived social norms, which may have implications for energy-saving interventions in the commercial sector.     

Proposal of a modeling approach considering urban form for evaluation of city level energy management

The importance of developing a method to bridge the gap between the current increasing trend of CO₂ emission from the commercial sector and the reduced emission level for ensuring long-term sustainability has increased. Various concepts exist for managing the energy use and CO₂ emission. These concepts can be categorized into advancement in technologies, dissemination of energy saving measures in buildings, optimization of local energy generation and distribution systems, spatial building stock pattern management, and improvement in CO₂ emission factor of the grid electricity. In this paper, we propose a modeling approach for energy use in the commercial sector in order to evaluate the options involved in the abovementioned energy management concepts in an integrated manner. In this modeling approach, a district is dealt with as a basic unit. Districts are first classified into several categories according to the spatial building stock pattern, or urban form. The end-use energy consumption per unit floor area is then calculated for each district category using a simulation of energy use in buildings in a representative district; this is used for quantifying the total end-use energy consumption at the municipal level. We carried out a case study in order to demonstrate the simulation capabilities and features of the suggested modeling approach in contrast with the conventional modeling approaches. In this case study, certain scenarios of CO₂ abatement integrating the energy management concepts are applied in the commercial sector of Osaka city, Japan, in order to investigate alternative avenues toward which policy efforts must be directed.     

Renovation of existing office buildings in regard to energy economy: An example from Ankara,Turkey

Unit energy consumption of existing buildings in Turkey is excessive. While average energy consumption of residential buildings in Europe is 100 kWh/m² per year, it is about 200 kWh/m² per year in Turkey. The principle reason for this, is that there was not any regulation on thermal insulation issues until recent years. However, the fiscal value of total energy consumption in residential buildings is about $2.5 billion. Recent research has shown that 40% of this energy consumption could be saved, provided that using energy efficiently. Furthermore, every reduction in energy-usage has a significant influence on environmental protection and CO₂ emissions. This study has focused on energy efficiency in a building of public sector that had been inaugurated in 1988 in Ankara. During the pre-investigative step, it has been determined that 47% of total energy consumption of the building could be saved.     

The relationship between the characteristics of transportation energy consumption and urban form

In this paper, we analyze the relationship between the characteristics of transportation energy consumption and urban form elements that were actively argued along with Environmentally Sound and Sustainable Development (ESSD). This paper can be divided into two parts: an examination of the theories and a practical analysis of domestic, small-, and medium-sized cities. Firstly, in the examination of theories, we surveyed the arguments about the sustainable urban form. Secondly, we made some hypotheses about the relationships between transportation energy consumption, city size, density, and center distribution pattern. Thirdly, we tested those hypotheses and examined the suitability of policies for each alternative for small- and medium-sized cities in Korea. The main themes in this paper are as follows. Firstly, how does the city size, density, etc. affect the transportation energy consumption? Secondly, in an overcrowded Korean situation, which alternative is the more suitable sustainable urban form from the point of transportation energy consumption, i.e., concentration or decentralized concentration? Thirdly, we examined the argument that a densely centralized development can reduce the need for travel, increase the transit use, and decrease automobile use. From the results of the analysis, we found that as the population increases, transportation energy represented by yearly gasoline consumption per automobile and the average yearly energy consumption as a result of surface transportation per 1,000 persons tends to decrease. Further, if the degree of city’s concentration represented by Gini coefficient is high, energy efficiency tends to decrease. Besides, the influential factors on the transportation energy consumption among the indicators of urban form could be road ratio and density. Whereas the road ratio is not related to the transportation energy consumption, road density is. From the analyzed results, we can deduce planning implications concerned with Korean cities. Firstly, Korean cities are already highly centralized so a decentralization policy should be carried out to increase transportation energy efficiency. In any case, in the case of high-density cities, multinuclei cities are better than mononuclear ones. Further, to increase the transportation energy efficiency, policies for high road densities through the construction of new roads in spite of narrow road widths are more effective than those for high road ratio-widening existing roads.     

Industrial electricity consumption efficiency and energy policy in Japan

This study analyzes the potential for energy savings by identifying inefficiencies in electricity use and their determinants in the Japanese industrial sector. Specifically, we used stochastic frontier analysis to estimate inefficiencies in electricity consumption based on data obtained from electric power companies. We identified significant determinants of electricity consumption efficiency and that changes in national energy policy following the Great East Japan Earthquake changed electricity consumption behavior. The contribution of this study is that its findings can be used to improve the cost-effectiveness of policies aimed at improving energy efficiency.     

The taxation of housing consumption

The chief objective of this paper is to bring the subject of the taxation of housing consumption into future analysis of the housing system. It is shown that the domestic rates levied by local authorities in Britain are precisely such a tax and that net of various remissions total receipts in 1981–82 from the twenty million hereditaments in the domestic sector probably exceeded £4 billion. This is less than the flow of subsidies on housing consumption but of the same order of magnitude. It is also made clear that in recent years there has been widespread ignorance of housing consumption taxation amongst specialists from a variety of ‘schools’ and an explanation is advanced for how this came about.     

Analysis of energy consumption in Finland based on the selected economics indicators

Energy is one of the main inputs of productions. Therefore, national policies have emphasised on accessibility, availability, and affordability of energy supply. This is very important for energy importers, in particular countries with high dependency on industrial products. Finland is one of such countries that has high-energy consumption due to its cold climate, energy-intensive industries, and low population density. Therefore, security of energy supply to respond domestic consumption is one of the main concerns of the Finnish government. To have a resilience energy supply, it is necessary to understand the energy system in Finland. Energy modelling is a tool that helps policy-makers and researchers to understand the fluctuations and changes in the energy system. This research is to investigate the relationship between energy consumption and selected macro-economic factors in Finland. Therefore, energy consumption in each sector is analysed and the importance of renewable energies is also considered. Finally, a regression model is presented to predict energy consumption.     

Pollution from energy supply,conversion and use a review of the U.K. problem

Trends in U.K. consumption of coal, oil, natural gas, nuclear and hydroelectric energy are discussed, and forecasts of use to the year 2000 A.D. are given. More detailed forecasts of fuel use by different sectors to 1985 are presented. Wastes, the resulting pollution and their likely future trends from the following energy sources are reviewed: primary energy — oil treatment, natural gas transhipment, coal production and nuclear and hydroelectric power: secondary energy — electricity generation, coking and gas making: tertiary energy — use of fuels in transport and the domestic sector. Emission forecasts for several air pollutants from all energy sources to 1985 are presented, the pollution and damage arising being discussed. The need for further waste and pollutant monitoring is then debated, and the necessity of continuing to consider environmental protection in energy policy decisions, along with fuel conservation and relative price is stressed.     

Optimum, technical and energy efficiency design of residential building in Mediterranean region

Jordan heavily relies on imported oil and gas for meeting its energy need as the same time the construction sector consumed more than half of the total electricity consumption in Jordan in 2008. In order to provide the occupants with thermal comfort at least cost, applying energy saving measures into early design stage can be significant to achieve this goal.This paper discusses an assessment of best orientation of the building, windows size, thermal insulation thickness from energetic, economic and environmental point of view for typical residential building located in Mediterranean region. The results show that about 27.59% of annual energy consumption can be saved by choosing best orientation, optimum size of windows and shading device, and optimum insulation thickness. The Life Cycle Cost (LCC) is reduced by 11.94%. The specific energy consumption per square meter is 64 kWh/m² a.     

Heat consumption for preparing domestic hot water in hospitals

This study analyses heat consumption for heating domestic water in large hospital facilities with over 600 hospital beds. The tests were carried out in 2 hospitals: the 715-bed University Hospital in Bydgoszcz and the 690-bed Provincial Hospital. The tests were performed over a period of 4 years: 2005-2008 for the first hospital and 2003-2006 for the second.The aim of this study is to analyse the variations and seasonal changes in the heat consumed to produce domestic hot water during the specified time periods. The results of this study show the yearly, monthly, daily, and hourly consumption of heat for domestic hot water. Particular emphasis is placed on the daily and hourly heat-consumption irregularity coefficients for domestic hot water.The results of this study may be used, for example, to predict heat consumption when designing new hospital facilities with 500-800 beds, to determine the heating power of the heat source and individual centres. Data on the constant and low-temperature heat consumption for domestic hot water throughout the whole year are particularly useful, as these data may be used to analyse existing large hospitals that are seeking alternative solutions (such as renewable energy or energy recycling) to reduce fossil fuel consumption.     

集中供热系统的节能措施

分析了居住建筑供暖能耗不达标的原因,探讨了采用节能设备及锅炉房节能控制的供热系统节能措施.结合工程实例,对采取节能措施的3座住宅小区的供暖能耗进行了计算分析.采取节能措施后,居住建筑单位面积综合耗煤量达到了节能标准.     

集成太阳能热水器窗系统技术浅谈

建筑能耗在我国所有能耗中占的比重较大。其中生活热水是排在供暖、空调和照明之后的第四大建筑能耗[1]。充分利用太阳能与建筑结合的技术,将太阳能作为生活热水的能量来源,是降低建筑能耗行之有效的方式。新型太阳能热水器窗系统在传统门窗和太阳能热水器系统功能的基础上,将太阳能真空管与窗的中空玻璃相结合,使得窗具有热水器的功能,进一步拓展了门窗系统的功能,降低了建筑能耗,提升了资源利用率;新型太阳能热水器窗系统结构紧凑,单位面积上对太阳能利用率较高。     

Trends in home computing and energy demand

Household energy demand due to domestic computer usage has changed beyond recognition over the past thirty years. Computers are now used in most homes, almost every day and laptop ownership has overtaken traditional desktop computers. Mobile devices give access to services that in the past required desktops, and they are usually more energy efficient. Today's computers usually rely on wireless routers that are often run all day. The effect of these changes on electricity use in the home has been profound. At least 60% more electricity was used for UK home computing in 2012 than in 1990. The implications of recent changes in information technology use are assessed for domestic electricity use and carbon emissions, using data from the Household Electricity Survey (HES) – the most detailed survey of electricity consumption in UK homes. On average, routers use twice as much energy per day as the laptops they serve. Laptops also draw power at a different time of day compared with desktop computers – which has implications for generation. Policy and practical recommendations are made for reducing energy use for information technology, including the estimated energy savings that could be achieved if UK routers met the US Energy Star standard for energy efficiency.     

Energy efficiency and building construction in India

The energy conservation has become an important issue in building design, it is logical to apply the principle of energy costing to building projects, and to look for ways to minimize the total energy consumed during their lifetime. Even though the total quantity of energy consumed in a building during its lifetime may be many times than that consumed in its construction, there are number of reasons why the energy use in the construction process, and in particular in the building materials used, should be treated as a matter of importance in looking for ways to minimize energy use in the built environment as a whole. In this paper the energy costs of alternative construction techniques using an optimization framework are assessed and compared. The techniques of construction evaluated in this paper are commonly used pucca techniques as well as low-cost construction techniques. Energy consumption and resource requirements due to the use of alternative techniques of construction for a representative room of size 3.5 m×3.5 m×3.14 m are evaluated. An assessment of the magnitude of energy consumption, if housing shortages have to be met, shows that a huge amount of energy would be consumed in housing sector alone. The associated levels of carbon dioxide emissions associated with this construction would also be prohibitively high. Finally the paper concludes with recommendations for structural changes in the energy and construction policy in India to minimize energy consumption in building construction.     

Transportation energy in Swedish towns and regions

An investigation of 97 towns and 15 commuting regions in Sweden shows that the developmental pattern has a significant influence on the energy consumption for transportation. The main source for the energy data is the officiai Swedish statistics on fuel sales quantities in the municipalities in 1989, adjusted for fuel consumption in the agricultural sector. For the individual town, a dense pattern of development clearly gives the lowest per capita energy consumption for transportation. At the regional level, however, a decentralized pattern of residence seems to be favourable with respect to energy conservation, provided that each individual town and village has sufficiently high population density.     

Assessing the value of information in residential building simulation: Comparing simulated and actual building loads at the circuit leve

Building energy simulation tools are now being used in a number of new roles such as building operation optimization,performance verification for efficiency programs,and-recently-building energy code analysis,design, and compliance verification in the residential sector. But increasing numbers of studies show major differences between the results of these simulations and the actual measured performance of the buildings they are intended to model. The accuracy and calibration of building simulations have been studied extensively in the commercial sector,but these new applications have created a need to better understand the performance of home energy simulations.In this paper,we assess the ability of the DOE's EnergyPlus software to simulate the energy consumption of 106 homes using audit records,homeowner survey records,and occupancy estimates taken from monitored data.We compare the results of these simulations to device-level monitored data from the actual homes to provide a first measure of the accuracy of the EnergyPlus condensing unit, central air supply fan, and other energy consumption model estimates in a large number of homes.We then conduct sensitivity analysis to observe which physical and behavioral characteristics of the homes and homeowners most influence the accuracy of the modeling.Results show that EnergyPlus models do not accurately or consistently estimate occupied whole-home energy consumption.While some models accurately predict annual energy consumption to within1%of measured data, none of the modeled homes meet ASHRAE criteria for a calibrated model when looking at hourly interval data. The majority of this error is due to appliance and lighting energy overestimates,f ollowed by AC condensing unit use. These inaccuracies are due to factors such as occupant behaviors and differences in appliance and lighting stocks which are not well-captured in traditional energy audit reports.We identify a number of factors which must be specified for an accurate model, and others where using a default value will produce a similar result.The use of building simulation tools reflects a shift from a component-focused approach to a systems approach to residential code analysis and compliance verification that will serve to better identify and deploy efficiency measures in homes. By better understanding the limitations of home energy simulations and adopting strategies to mitigate the effects of model errors, simulation models can serve as valuable decision making tools in the residential sector.     

Sustainability policies to reduce pollution in energy supply and waste sectors in the V4 countries

Sustainability is directly connected with less natural resources consumption and consequently, with less pollution. However, carbon dioxide emissions could be controlled through policies that are designed starting from empirical results. The aim of this study is to assess the impact of electricity prices for non-household consumers, innovation and economic development on pollution in energy supply and waster sectors in V4 countries (2010–2021). The analysis is based on fixed-effect panel threshold and dynamic GMM models and revealed a U pattern for energy supply sector and an inverted U for waste sector. Higher electricity prices for non-households and more renewables consumption in waste sector are necessary, while more patents in environment-related technologies have expected impact on pollution only at higher levels of GDP. These empirical findings are subject to policy proposals.