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Abstract: This paper deals with the method of how to regenerate the potential energy for a hybrid hydraulic excavator (HHE). After studying the structure and working cycle of the HHE, two energy regeneration systems are considered. Then, the control strategy and parameter matching for the proposed energy regeneration system (ERS) are discussed. United simulations with AMEsim and MATLAB/simulink for the conventional control system and two ERSs are carried out in this paper. An estimated 41% of the total potential energy could be regenerated at the lowering of the boom in accumulator-motor-generator system while the recovery efficiency in the motor-generator system is only about 17%, and it is also shown that the accumulator-motor-generator energy regeneration system (AMGERS) features better speed control of the boom and response characteristics than the motor-generator energy regeneration system (MGERS), hence, the AMGERS is a good configuration for the HHE at present. [Copyright &y& Elsevier]

Abstract: Along with high-speed economic development and increasing energy consumption, the Chinese Government faces a growing pressure to maintain the balance between energy supply and demand. In 2009, China has become both the largest energy consumer and CO2 emitting country in the world. In this case, the inappropriate energy consumption structure should be changed. As an alternative, a suitable infrastructure for the implementation of renewable energy may serve as a long-term sustainable solution. The perspective of a 100% renewable energy system has been analyzed and discussed in some countries previously. In this process, assessment of domestic renewable energy sources is the first step. Then appropriate methodologies are needed to perform energy system analyses involving the integration of more sustainable strategies. Denmark may serve as an example of how sustainable strategies can be implemented. The Danish system has demonstrated the possibility of converting into a 100% renewable energy system. This paper discusses the perspective of renewable energy in China firstly, and then analyses whether it is suitable to adopt similar methodologies applied in other countries as China approaches a renewable energy system. The conclusion is that China’s domestic renewable energy sources are abundant and show the possibility to cover future energy demand; the methodologies used to analyse a 100% renewable energy system are applicable in China. Therefore, proposing an analysis of a 100% renewable energy system in China is not unreasonable. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports an experimental and simulation study of application of radiant cooling using natural air for ventilation under hot and humid climate of Thailand. To avoid condensation of moisture on the cooling panel, the temperature of water supplied to the panel was limited to 24°C. This led to the expectation that the low heat reception capacity of the panel would limit its use only to situations when loads were low. Experiments were conducted in an experimental room over the hot and dry period of March, the humid period of May, and the cool period of December. The results generally confirm the good potential for application of radiant cooling. However, the room was served by radiant panels with a total area of 7.5m2. Its capacity was grossly inadequate during the hot period, even for night time application only. A special configuration was devised to achieve thermal comfort for the area served by the panel. The well-known TRNSYS program was used to simulate the use of cooling panels and conventional air-conditioning in the experimental room. Simulation results match experimental results very well. Using comfort criterion adopted by ASHRAE and International Standards Organization, results from experiments and simulation show that thermal comfort could be obtained with application of radiant cooling. [Copyright &y& Elsevier]