• Title/Summary/Keyword: Energy Efficiency Measure

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On the Energy Conversion Efficiency of Piezoelectric Vibration Energy Harvesting Devices (압전 진동 에너지 수확 장치의 에너지 변환 효율에 대한 고찰)

  • Kim, Jae Eun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.5
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    • pp.499-505
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    • 2015
  • To properly design and assess a piezoelectric vibration energy harvester, it is necessary to consider the application of an efficiency measure of energy conversion. The energy conversion efficiency is defined in this work as the ratio of the electrical output power to the mechanical input power for a piezoelectric vibration energy harvester with an impedance-matched load resistor. While previous research works employed the electrical output power for approximate impedance-matched load resistance, this work derives an efficiency measure considering optimally matched resistance. The modified efficiency measure is validated by comparing it with finite element analysis results for piezoelectric vibration energy harvesters with three different values of the electro-mechanical coupling coefficient. New findings on the characteristics of energy conversion and conversion efficiency are also provided for the two different impedance matching methods.

An Application of Divisia Decomposition Analysis to the Measurement of Thermal Efficiency Improvement of Power Generation (화력발전소 효율개선 측정에 대한 디비지아분해기법의 적용)

  • Choi, Ki-Hong
    • Environmental and Resource Economics Review
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    • v.9 no.5
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    • pp.811-827
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    • 2000
  • Since improved thermal efficiency reduces capacity requirements and energy costs, electricity producers often treat thermal efficiency as a measure of management or economic performance. The conventional measure of the thermal efficiency of a fossil-fuel generation system is the ratio of total electricity generation to the simple sum of energy inputs. As a refined approach, we present a novel thermal efficiency measure using the concept of the Divisia index number. Application of this approach to the Korean power sector shows improvement of thermal efficiency of 1.1% per year during 1970-1998. This is higher than the 0.9% improvement per year given by the conventional method. The difference is attributable to the effect of fuel substitution. In the Divisia decomposition context, we also show the limitations of the popular $T{\ddot{o}}rnqvist$ index formula and the superiority of the Sato-Vartia formula.

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Measurement of Energy Efficiency For the Reduction of Greenhouse Gases (온실가스 감축에 대비한 에너지 효율의 계측)

  • Kang, Sang-Mok
    • Journal of Environmental Policy
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    • v.11 no.1
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    • pp.75-97
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    • 2012
  • The purpose of the paper is to estimate the functions of the energy input efficiency and the energy intensity efficiency, and measure their energy efficiencies for the reduction of greenhouse gases focusing on OECD countries. The efficiency of the traditional energy intensity was rarely connected with the energy efficiencies of the stochastic frontier function. It seems that the energy efficiency by the function of energy input efficiency sensitively responds to the order of GDP, capital stock, labor, and energy input quantity as explanatory variables. In the future, we need to reduce energy quantities by the optimal mix of inputs, and pursuit low-carbon economic growth through the production of the goods consuming small energy.

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The Study of Financing for Energy Efficiency Homes (주택 에너지효율향상을 위한 재정지원 방안에 관한 연구)

  • Park, Kihyun
    • KIEAE Journal
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    • v.12 no.6
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    • pp.63-68
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    • 2012
  • The aim of this study is to evaluate current policies and suggest the way of overcome financial impediments to the energy efficiency function of residential buildings. Based on this analysis the paper enumerates policy recommendations for enhancing how energy efficiency is addressed in building codes and other policies for residential buildings. For achieving this goal, this study conducts the cost-benefit analysis to measure total energy savings and associated total cost. The results of study shows that the cost is greater than the benefit from 1st to 4th year but the benefit will be greater than the cost for the rest of the year. In addition, this study designs a financial support method and an implementation mechanism. Investment from the capital market will take place with the government's interest subsidy. Home retrofit will be undertaken with low interest rate with 2.5% and the return will be paid by a monthly energy bill. The results of this study provides some useful insights for the policy design, including the importance of developing information tools for providing appropriate information to households.

Customer Baseline Load Calculation using Time Series Prediction Technique in Energy Efficiency Programs (시계열 모델을 이용한 행동기반 에너지 효율화 프로그램의 고객기준부하 산정 방안)

  • Koh, Sae-Hyun;Joo, Sung-Kwan;Lee, Jae-Hee;Moon, Guk-Hyun;Wi, Young-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.1
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    • pp.19-26
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    • 2019
  • As global demand for energy, energy prices, and power generation has increased worldwide, the government is turning to supply-oriented electricity supply and demand policies, such as behavior-based energy efficiency programs. In order to measure the implementation effect of the behavior-based energy efficiency program, the energy reduction must be accurately calculated by calculating the customer baseline load.

Analysis of the Building Energy Efficiency Rating Certified for Public Office Buildings (공공기관 업무용 건물의 건축물에너지효율등급 인증 현황 분석)

  • Lee, Han-Sol;Kim, Seo-Hun;Kim, Jonghun;Kim, Jun-Tae;Jang, Cheol-Yong
    • KIEAE Journal
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    • v.15 no.5
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    • pp.75-82
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    • 2015
  • Purpose: The first grade of Korea's Building Energy Efficiency Rating System(BEERS) is required for new government office buildings as a mandatory measure to reduce greenhouse gas emission. However, there is no specific criteria about performance that which level should apply to energy-saving design element for obtaining Building Energy Efficiency Rating 1st grade. Therefore, Certification status should be analyzed firstly, about the office building which is certificated. Certification analysis for office buildings acquired certification therefore should be done first. Method: In this study, Certification status(Office buildings acquired Building Energy Efficiency Rating Certification)was analyzed by classified year, region, specific scale etc. And we analyzed statistically by eliciting an average value of each element influencing to the amount of energy. Result: Energy demands were gradually decreased due to revision of thermal insulation standards for enhanced u-value. Energy consumptions were different from the kind of equipment and yearly trends applied depending on the size of the building. Total primary energy consumptions were influenced by heat source types and the primary energy scale factors.

Experimental Study on the Cooling seasonal Performance Factor of Room Air-conditioner (에어컨의 냉방기간 에너지 효율 산출을 위한 실험적 연구)

  • Lee, H.W.;Moon, J.H.;Bae, Y.D.;Park, J.C.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.4 no.3
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    • pp.204-216
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    • 1992
  • In most cases, EER(Energy Efficiency Ratio) is available to present energy efficiency of air-conditioners. But, EER is not adapt to measure energy efficiency at actual life environment because it is based on fixed temperature and humidity contditions. To overcome this disadvantage, there is need to introduce SEER(Seasonal Energy Efficiency Ratio) established at time varient temperature and humidity conditions. In this paper, SEER measurement method and conditions based on actual life environment of the country is introduced, and discussed SEER value about two air-conditioner type, that is, non inverter air-conditioner and inverter air-conditioner. As a result of, inverter air-conditioner was superior to non inverter air-conditioner at cooling seasonal energy efficiency.

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Comparison of Energy Efficiency by Production Frontier Approach: Based on OECD Countries (생산 프론티어 접근을 통한 에너지효율 비교: OECD 국가를 중심으로)

  • Kang, Sangmok;Kim, Haechang
    • Environmental and Resource Economics Review
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    • v.20 no.1
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    • pp.33-60
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    • 2011
  • The purpose of the article is to compare the impacts of energy efficiency and economic growth for energy demand through production frontier approach in OECD countries. We compared the traditional energy intensity with energy efficiencies of production frontier approach, slack efficiency on the frontier, and estimated elasticity of energy demand for GDP growth. First, the energy intensity has a low relationship with energy efficiency by radial approach, but has constant correlations with slack energy efficiency, slack-adjusted efficiency by non-radial approach, and energy efficiency by horizon approach. If we measure energy efficiency only with energy elasticity, it may make a mistake. Especially the energy efficiency by radial approach has a tendency to overestimate most OECD countries. Second, as many countries have excess energy consumption of 17.3% even on the points of the frontier, reduction of energy consumption is necessary in addition. Third, the average energy elasticity of OECD countries is 1.1 close to elasticity 1. There exists the difference of elasticity among countries and the energy demands are also high in countries with high elasticity.

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Estimating Potential Energy Consumption and Carbon Emission Reduction in South Korea Using Non-radial Data Envelopment Analysis Approach (Non-radial Data Envelopment Analysis를 적용한 지역별 에너지 및 이산화탄소 저감가능성 추정)

  • Kim, Kwang-Uk;Kang, Sang-Mok
    • Environmental and Resource Economics Review
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    • v.25 no.2
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    • pp.299-320
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    • 2016
  • This study estimates an energy efficiency of 16 metropolitans and provinces in Korea, and measures potential energy-saving and carbon emission reduction using a non-radial data envelopment analysis method. Based on energy mix scenarios, this study also evaluates the impact of changes in energy structural adjustment on a regional environmental performance. The empirical results show that, on average, 12.70% of energy consumption and 13.73% of carbon emission can be reduced by improvement in energy efficiency, and low efficiency of oil usage in metropolitan cities is a major source of the inefficiency. Furthermore, it is found that energy mix policy should be considered to achieve an extra energy-saving and carbon reduction.

Estimation of Rebate Level for Energy Efficiency Programs Using Optimization Technique (최적화 기법을 이용한 에너지 효율 프로그램의 지원금 수준 산정)

  • Park, Jong-Jin;So, Chol-Ho;Kim, Jin-O
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.3
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    • pp.369-374
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    • 2008
  • This paper presents the evaluation procedures and the estimation method for the estimation of optimal rebate level for EE(Energy Efficiency) programs. The penetration amount of each appliance is estimated by applying price function to preferred diffusion model resulted from model compatibility test. To estimate the optimal rebate level, two objective functions which express the maximum energy saving and operation benefit are introduced and by multi-objective function which can simultaneously consider two objective functions the optimal rebate level of each appliance is estimated. And then, using the decided rebate level and each penetration amount, the priority order for reasonable investment of each high-efficiency appliance is estimated compared to the results of conventional method. Finally, using a benefit/cost analysis based on California standard practice manual, the economic analysis is implemented for the four perspectives such as participant, ratepayer impact measure, program administrator cost and total resource cost.