Potential energy savings and environmental impacts of energy efficiency standards for vapor compression central air conditioning units in China

Owing to the rapid development of economy and the stable improvement of people's living standard, central air conditioning units are broadly used in China. This not only consumes large energy, but also results in adverse energy-related environmental issues. Energy efficiency standards are accepted effective policy tools to reduce energy consumption and pollutant emissions. Recently, China issued two national energy efficiency standards, GB19577-2004 and GB19576-2004, for vapor compression central air conditioning units for the first time. This paper first reviews the two standards, and then establishes a mathematic model to evaluate the potential energy savings and environmental impacts of the standards. The estimated results indicate implementing these standards will save massive energy, as well as benefit greatly to the environment. Obviously, it is significant to implement energy efficiency standards for central air conditioning units in China.     

Household water conservation: The role of indirect energy savings

Recent regulations specify a cost-effectiveness analysis of implementing household water conservation measures to reduce the flow of wastewater as a prerequisite to federal funding of wastewater treatment plant construction. There is a wide variety of devices available to conserve water: hot water as well as water at ambient temperature. In this analysis we use a sample of 23 metropolitan areas to evaluate the indirect household energy savings which results from conservation devices to save hot water.

Devices to conserve hot water are cost-effective in all 23 metropolitan areas up to an equivalent annual cost of $1.50/1000 gal saved under an assumption of no inflation in energy prices, and about $7.00/1000 gal saved under an assumption of 20%/yr inflation in energy prices. The impact of the indirect energy savings can be further illustrated by noting that devices to conserve ambient temperature water are cost-ineffective in all 23 metropolitan areas at equivalent annual costs above $1.00/1000 gal saved. Besides increasing the level of cost-effective household water conservation from 114 gal/day to 146 gal/day for a family of four, while providing significant economic savings, the indirect energy savings from hot-water conservation devices can provide a 46–62% reduction in energy use for residential water heating.     

Utility energy efficiency schemes: savings obligations and trading

Utility financed and/or operated energy efficiency schemes have a long history going back to the first energy crisis in 1973. It is therefore appropriate to ask what is new about the recent raft of white certificate schemes and whether there is anything that makes them more effective than the older approaches. This paper attempts to answer these questions by reviewing the experience with earlier utility schemes and comparing them with the more recent schemes implemented on both sides of the Atlantic as well as Australia. Up-to-date results are reported on utility programme impact in all the regions, including a new indicator analysis of the collective, long-term impact of such schemes in the USA. From this it is clear that both the new and old schemes are highly effective in delivering substantial, sustained and cost effective energy savings and associated reductions in CO₂ emissions. A key component of programme impact, including cost-effectiveness, is the effective alignment of utility commercial incentives with the delivery of energy savings. There are essentially two new elements of the recent utility energy efficiency schemes: i) mandated energy savings obligations and ii) the flexibility to trade the obligations. The mandated savings obligation, when linked to a suitable non-compliance penalty structure, seems to be an especially effective means of ensuring that public policy objectives for energy efficiency are met. The importance of allowing obligations to be traded for programme success is not yet clear and will require more time before proper longitudinal evaluations can be attempted.

Building energy information systems: synthesis of costs,savings, and best-practice uses

Building energy information systems (EIS) are a powerful customer-facing monitoring and analytical technology that can enable up to 20 % site energy savings for buildings. Few technologies are as heavily marketed, but in spite of their potential, EIS remain an underadopted emerging technology. One reason is the lack of information on purchase costs and associated energy savings. While insightful, the growing body of individual case studies has not provided industry the information needed to establish the business case for investment. Vastly different energy and economic metrics prevent generalizable conclusions. This paper addresses three common questions concerning EIS use: what are the costs, what have users saved, and which best practices drive deeper savings? We present a large-scale assessment of the value proposition for EIS use based on data from over two-dozen organizations. Participants achieved year-over-year median site and portfolio savings of 17 and 8 %, respectively; they reported that this performance would not have been possible without the EIS. The median 5-year cost of EIS software ownership (up-front and ongoing costs) was calculated to be $1800 per monitoring point (kilowatt meter points were most common), with a median portfolio-wide implementation size of approximately 200 points. In this paper, we present an analysis of the relationship between key implementation factors and achieved energy reductions. Extent of efficiency projects, building energy performance prior to EIS installation, depth of metering, and duration of EIS were strongly correlated with greater savings. We also identify the best practices use of EIS associated with greater energy savings.     

Chillers energy consumption, energy savings and emission analysis in an institutional buildings

Chillers consume more than 40% of the total energy used in the commercial and industrial buildings for space conditioning. In this paper, energy consumption by chillers and chilled water pumps, condenser pumps and fan motors has been estimated using data collected by a walkthrough energy audit for the 16 faculties of the University of Malaya. It has been estimated that chillers and motors and pumps used in chillers consume 10,737 MWh (i.e. 51% of total energy consumption) of electric energy for different percentage of loadings. As chillers are major energy users, variable speed drives are applied in chillers to reduce their energy consumption. It has been estimated that about 8368 MWh annual energy can be saved by using efficient chillers at different loadings. It has also been found that about 23,532 MWh annual energy can be saved for chilled water supply pumps, condenser pumps and cooling tower fan motors by matching required speeds using variable speed drives for 60% of speed reduction. About 1,274,692 kg of CO₂ emission could be avoided for using energy efficient chillers at 50% load. It has been also found that about 2,426,769 kg CO₂ emission can be reduced by using variable speed drives for 60% speed reductions. Payback periods found to be only few months for using variable speed drives in chilled water pumps, condensers and fan motors.     

Advanced vehicles: Costs, energy use, and macroeconomic impacts

Advanced vehicles and alternative fuels could play an important role in reducing oil use and changing the economy structure. We developed the Costs for Advanced Vehicles and Energy (CAVE) model to investigate a vehicle portfolio scenario in California during 2010-2030. Then we employed a computable general equilibrium model to estimate macroeconomic impacts of the advanced vehicle scenario on the economy of California. Results indicate that, due to slow fleet turnover, conventional vehicles are expected to continue to dominate the on-road fleet and gasoline is the major transportation fuel over the next two decades. However, alternative fuels could play an increasingly important role in gasoline displacement. Advanced vehicle costs are expected to decrease dramatically with production volume and technological progress; e.g., incremental costs for fuel cell vehicles and hydrogen could break even with gasoline savings in 2028. Overall, the vehicle portfolio scenario is estimated to have a slightly negative influence on California's economy, because advanced vehicles are very costly and, therefore, the resulting gasoline savings generally cannot offset the high incremental expenditure on vehicles and alternative fuels. Sensitivity analysis shows that an increase in gasoline price or a drop in alternative fuel prices could offset a portion of the negative impact.     

The impacts of energy prices on energy intensity: Evidence from China

In this paper, we present a review of the deregulation of energy prices in China between 1985 and 2004 and assess the impacts of changes in energy prices on aggregate energy intensity and coal/oil/electricity intensity. We used time series data to provide estimates of energy price elasticities. Empirical results showed that: (1) The own-price elasticities of coal, oil, and aggregate energy were negative in periods both before and after 1995, implying that higher relative prices of different energy types lead to the decrease in coal, oil, and aggregate energy intensities. However, the positive own-price elasticity of electricity after 1995 probably indicates that the price effect was weaker than other factors such as income effect and population effect. (2) The impacts of energy prices were asymmetric over time. (3) Sectoral adjustment also drove the decrease in aggregate energy intensity. Although raising energy prices to boost efficiency of energy use seems to be an effective policy tool, other policy implications concerned with energy prices, such as energy supply security and fuel poverty, must also be considered.     

The analysis of the impacts of energy consumption on environment and public health in China

The emission parameters and expose–response functions of some pollutants, such as sulphur dioxide (SO₂) and Inhalable Particulate Matter (PM10), were introduced to calculate the emission caused by energy consumption in various sectors and regions in China under different scenarios. The impacts of economic growth, population, and technology progress on energy consumption and on the environment were also analyzed. Finally, the economic value of public health damage caused by the changes of pollutants' concentration related to energy consumption under various scenarios, different regions and sectors in China was analyzed. The results show that the PM-10 and SO₂ emissions and consequent health damage will increase significantly in the next 12 years. Thus, energy efficiency, population, economy, and urbanization are the main factors to be considered in this system.     

Developing low-carbon economy: Actions,challenges and solutions for energy savings in China

Global warming and financial crisis have brought severe threats to human existence and economic growth. Utilization of potential for energy savings is necessary for alleviating energy shortage, protecting environment and achieving sustainable economic and social development. This paper has not only comprehensively evaluated the China’s energy savings opportunities, but also systematically analyzed the primary challenges and deficiencies in China’s energy savings policies, and proposed targeted countermeasures and suggestions. This is of important guiding significance for China to establish a long-term effective mechanism to boost energy-saving technologies and products, and to promote the economic development toward a low-carbon mode.     

Energy consumption,energy savings,and emission analysis in Malaysian office buildings

This paper is concerned with the estimation of energy use in office buildings in Malaysia and with the energy use of major equipment. Energy intensity (EI) – a measure of a building's energy performance – is estimated for Malaysia and compared with a number of selected countries. Air conditioners are shown to be the major energy users (57%) in office buildings, followed by lighting (19%), lifts and pumps (18%) and other equipment (6%). It is estimated that 77,569 MWh of energy can be saved and a huge reduction of emissions achieved through the application of advance glazing, compact fluorescent lamps (CFL), insulation, housekeeping, and by raising thermostat set point temperature of air conditioners, and reducing EI.     

Residential past and future energy consumption: Potential savings and environmental impact

In order to identify main drivers behind changes in electricity and fuel consumptions in the household sector in Jordan, two empirical models are developed based on multivariate linear regression analysis. In addition, this paper analyzes and evaluates impacts of introducing some efficient measures, such as high efficiency lightings and solar water heating systems, in the housing stock, on the future fuel and electricity demands and associated reduction in GHG emissions. It was found that fuel unit price, income level, and population are the most important variables that affect demand on electrical power, while population is the most important variable in the case of fuel consumption. Obtained results proved that the multivariate linear regression models can be used adequately to simulate residential electricity and fuel consumptions with very high coefficient of determination. Without employing most effective energy conservation measures, electricity and fuel demands are expected to rise by approximately 100% and 23%, respectively within 10 years time. Consequently, associated GHG emissions resulting from activities within the residential sector are predicted to rise by 59% for the same period. However, if recommended energy management measures are implemented on a gradual basis, electricity and fuel consumptions as well as GHG emissions are forecasted to increase at a lower rate.     

折标系数的选取及其对节能量核算的影响

针对企业节能量核算过程中折标系数的选取问题,以实际案例为基础,通过对可采取的各种方法进行比较分析,提出较为快捷准确的折标系数计算方法,并进一步探讨了折标系数选取对节能量核算的影响,以供节能量核查机构和企业能源部门参考。     

Estimating energy savings due to conservation programmes: The BPA residential weatherization pilot programme

The Bonneville Power Administration operated a residential weatherization pilot programme from 1980 to 1982. The programme provided free home energy audits to more than 7000 electrically heated homes in the Pacific Northwest and gave zero-interest loans to weatherize over 4000 of these homes. The total cost of the programme was $11 million. This paper describes several mehtods used to estimate the net energy-saving effect of the BPA programme (ie the electricity saving that could be directly attributed to the programme). The simplest method ivolves estimation of weather adjusted annual electricity consumption for each household. The second approach uses this weather adjusted consumption as the dependent variable in a pooled time-series cross-section regression model of electricity use. The third approach involves estimation of qualitative choice models of the decisions to retrofit and to participate in the BPA programme. Results from these models are used to define Mills ratio terms that are then used as explanatory variables in the regression model of the second approach. The range in estimated programme saving, given the diversity of analytical methods used, is surprisingly small — 3100–3300 kWh/year per average programme participant.     

Household electricity demand forecast and energy savings potential for Vientiane,Lao PDR

This paper uses the survey data on household electricity demand from five districts of Vientiane, Lao PDR, for the demand projection up to 2030 using the end-use model. The scenario analysis is used to verify the potential of an energy-saving program by alternating selected appliances with more energy-efficient ones following the labelling standard of Thailand. The demographic structure of electrified households and the energy efficiency of electric appliances are considered as the dominant factors affecting electricity demand. Under the base-case scenario, the total electricity demand of Vientiane increased from 593?GWh in 2013 to 965?GWh in 2030. In the energy efficiency scenario, it is revealed that the appliance standard enhancement program can save total electricity demand in 2030 by 147?GWh (?15.2%), where 117?GWh (?12.1%) of which is contributed by the air conditioner and 30?GWh (?3.1%) by the lighting equipment.     

踏板发电装置的节能量计算及效益分析

利用电磁感应切割发电原理,设计出了简易的踏板发电装置,所产生的电力可用来照明和驱动小型电风扇,并且对节能量进行了计算和效益分析。对缓解日益匮乏的能源供求矛盾,改良人类社会能源利用结构,进一步推行绿色能源,保护环境,减少不可再生资源的使用量,具有重大意义。     

Micro-algae cultivation for biofuels: Cost,energy balance,environmental impacts and future prospects

Micro-algae have received considerable interest as a potential feedstock for producing sustainable transport fuels (biofuels). The perceived benefits provide the underpinning rationale for much of the public support directed towards micro-algae research. Here we examine three aspects of micro-algae production that will ultimately determine the future economic viability and environmental sustainability: the energy and carbon balance, environmental impacts and production cost. This analysis combines systematic review and meta-analysis with insights gained from expert workshops.We find that achieving a positive energy balance will require technological advances and highly optimised production systems. Aspects that will need to be addressed in a viable commercial system include: energy required for pumping, the embodied energy required for construction, the embodied energy in fertilizer, and the energy required for drying and de-watering. The conceptual and often incomplete nature of algae production systems investigated within the existing literature, together with limited sources of primary data for process and scale-up assumptions, highlights future uncertainties around micro-algae biofuel production. Environmental impacts from water management, carbon dioxide handling, and nutrient supply could constrain system design and implementation options. Cost estimates need to be improved and this will require empirical data on the performance of systems designed specifically to produce biofuels. Significant (>50%) cost reductions may be achieved if CO₂, nutrients and water can be obtained at low cost. This is a very demanding requirement, however, and it could dramatically restrict the number of production locations available.     

Energy, economics and environmental impacts of renewable energy systems

The renewable based electricity generation technologies were assessed against a range of sustainability indicators using data obtained from the literature. These indicators are cost of electricity generation, greenhouse gas emissions and energy pay-back time. All the three parameters were found to have a very wide range for each technology. For grading different renewable energy sources a new figure of merit has been proposed, linking greenhouse gas emissions, energy pay-back time and cost of electricity generated by these renewable energy sources. It has been found out that wind and small hydro are the most sustainable source for the electricity generation.     

Social,economical and environmental impacts of renewable energy systems

Conventional energy sources based on oil, coal, and natural gas have proven to be highly effective drivers of economic progress, but at the same time damaging to the environment and to human health. Keeping in mind, the social, economical and environmental effects of renewable energy system have been discussed in this paper. The uses of renewable energy system, instead of, conventional energy system, to control the social, economical and environmental problems have been discussed. The results show that the trends of total emission reduction in different years, which is exponentially increasing after the installation of renewable energy system in remote areas.     

Chilled ceiling and displacement ventilation system for energy savings: A case study

This paper studies the design and performance of cooled ceiling and displacement ventilation (CC/DV) systems application for buildings in Beirut for the purpose of saving energy. The transient thermal response of spaces cooled by the combined CC/DV system is needed for performance assessment. For that reason, the plume‐multi‐layer model of CC/DV cooled spaces is extended to transient applications. A design procedure for the combined CC/DV system in Beirut humid climate and buildings is developed to insure that both indoor air quality and comfort are satisfied within the conditioned zone. The contribution of the proposed procedure is that it guarantees that the stratification height (occupied zone) is at 1.1 m taking into consideration the plumes from internal sources and non‐isothermal walls. The design procedure is applied to a case study in Beirut to design a system for a typical office space at 85 W m^?2 sensible cooling load. The CC/DV system size is compared with the size of a conventional mixed convection system. It is found that the size of the CC/DV system is 10.2 kW compared to conventional system size of 7.9 and 13.4 kW at the 30 and 100% fresh air supply, respectively. For the same indoor air quality and thermal comfort level, the CC/DV system consumed 21% less cooling energy than the conventional 100% fresh air system over the cooling season. The initial cost of the CC/DV system is higher, but the pay back period based on transient operation is less than 5 yr. Copyright © 2006 John Wiley & Sons, Ltd.