A COMPARATIVE STUDY:DESIGN STRATEGIES FOR ENERGY-EFFICIENCY OF HIGH-RISE OFFICE BUILDINGS

Tall buildings are being designed and built across a wide range of cities.A poorly designed tall building can tremendously increase the building’s appetite for energy.Therefore,this paper aims to determine the design strategies that help a high-rise office building to be more energy efficient.For this purpose,a comparative study on twelve case buildings in three climate groups(temperate,sub-tropical&tropical)was performed.The exterior envelope,building form and orientation,service core placement,plan layout,and special design elements like atria and sky gardens were the subject of investigation.effectiveness of different design strategies for reducing the cooling,heating,ventilation and electric lighting energy usage.Finally,lessons from these buildings’were defined for the three climates.Furthermore,a compari-son of building energy performance data with international benchmarks confirmed that in temperate and sub-tropical climates sustainable design strategies for high-rise buildings were performing well,as a result leading to lower energy consump-tion.However,for the tropics the design of high-rise buildings needs additional consideration.

Energy-efficient methods for production methane from natural gas hydrates

Gas hydrates now are expected to be one of the most important future unconventional energy resources. In this paper, researches on gas hydrate exploitation in laboratory and field were reviewed and discussed from the aspects of energy efficiency. Different exploiting methods and different types of hydrate reservoir were selected to study their effects on energy efficiencies. Both laboratory studies and field tests have shown that the improved technologies can help to increase efficiency for gas hydrate exploitation. And it also showed the trend that gas hydrate exploitation started to change from permafrost to marine. Energy efficiency ratio （EER） and energy return on energy invested （EROI） were introduced as an indicator of efficiency for natural gas hydrate exploitation. An energy-efficient hydrate production process, called ＂Hydrate Chain Energy System （HCES）＂, including treatment of flue gas, replacement of CH4 with CO2, separation of CO2 from CH4, and storage and transportation of CH4 in hydrate form, was proposed for future natural gas hydrate exploitation. In the meanwhile, some problems, such as mechanism of C02 replacement, mechanism of CO2 separation, CH4 storage and transportation are also needed to be solved for increasing the energy efficiency of gas hydrate exploitation.

America's Journey to Energy Independence and Its Revelation on China's Energy Supply Security

Ever since 2005, the US' shale oil and gas production growth and effective adjustment of domestic energy consumption mix have made it possible for the country to be less dependent upon imported energy and gain energy independence. What should we learn from it to guarantee energy supply security? This paper tried to answer the question.

Energy Management Strategy for Hybrid Electric Vehicle Based on System Efficiency and Battery Life Optimization

A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle（HEV）equipped with continuously variable transmission（CVT）is proposed.Based on consideration of the efficiency of pivotal components,electric motor,system efficiency optimization models are developed.According to the target of instantaneous optimization of system efficiency,operating ranges of each mode of power-train are determined,and the corresponding energy management strategies are established.The simulation results demonstrate that the energy management strategy proposed can substantially improve the vehicle fuel economy,and keep battery state of charge（SOC）change in a reasonable variation range.

Study on operation strategy and load forecasting for distributed energy system based on Chinese supply-side power grid reform

This study focuses on the development and analysis of a real-time updated operations strategy of a distributed energy system(DES).Owing to the relevant Chinese policy of electrical transmission and distribution,combined cooling,heating,and power system(CCHP)and photovoltaic(PV)systems are not currently allowed.However,with the Chinese supply-side power grid reform,the permissions for connections between DESs and utilities are gradually evolving.By performing building simulation and using mixed integer linear programming(MILP),a real-time updated operation strategy of a DES is established.Then,considering the DES from Tianjin Eco-city as a case study,a comparative analysis between this updated strategy and the current operation strategy is performed by evaluating three factors:economic efficiency,energy consumption,and CO2 emission.The results show that the updated strategy can reduce 29.12%of electricity time-of-use cost,10.11%of total fuel consumption,and 18.40%of CO2 emission during the cooling season.Besides,a method of“rolling load forecasting”for DES by using Support vector regression machine(SVR)is proposed and discussed.The testing shows that the Mean Absolute Percentage Error(MAPE)is below 7.5%.And when the training sample is large,the particle swarm optimization algorithm can be used to shorten the modeling time of the air conditioning load forecasting model.