CHINA ENERGY LABEL: A strategy to encourage energy conservation and the challenge ahead in power markets

ABSTRACT This paper aims to elucidate China energy label and《The minimum allowable values of the energy efficiency and energy efficiency grades for room air conditioners 》 implemented recently (2005). Energy efficiency ratio (EER) considered in this standard was compared with coefficient of performance (COP), based on it, two air-conditioners with different EER were calculated to be contrasted by their total cost during the operational life. At the same period, the content, significance and result of the energy standard was analyzed. The results show that air-conditioners with higher EER can be more economical, and they can obtain better qualities as well as utilization effects. Also, this standard determines the energy efficiency grade index of room air-conditioners below 14 kW and the market entrance admission index of energy efficiency. Starting this standard requires that each air-conditioner should have an energy label, thus market transformation goals can be achieved, consequently, it will accelerate the advancement of enterprises and reinforce the energy-saving management of the government. However, designers, manufacturers and high efficiency product sellers in the power market will be challenged

IMECE2008-67290 ANALYSIS OF THE IDLING START OF THE MOVING COIL LINEAR COMPRESSOR

ABSTRACT The linear compressor is driven by a linear motor. Because it has no crankcase, the piston motion and its control of the linear compressor are differing from that of the conventional reciprocating compressor

EXPERIMENTAL STUDY AND APPLICATION ANALYSIS ON GROUND-WATER SOURCE HEAT PUMP IN NORTH CHINA

ABSTRACT To describe the economical performance and operational characteristic of ground-water source heat pump system (GWSHPS) in North China, GWSHPS was compared with traditional central air-conditioning system (TCACS) for their total investments based upon a GWSHPS demonstration project in Beijing (88000 m 2 covered area, 4572 kW heat exchange amount). At the same period, an experimental system of GWSHPS in Hebei was investigated with its operational data such as coefficient of performance (COP). The results of the demonstration project showed that the total investment for GWSHPS was 15.2% lower than TCACS, while annual operating cost for GWSHPS was 42.2% lower than TCACS. The test data of the system in Hebei showed that heating coefficient of performance of the heat pump and primary energy ratio (PER) were raised while heating water temperature was decreased. The entering water temperature to the unit ranged from 13.1℃ to 17.4℃, with an average value of 15 ℃, the heating water temperature varied from 40℃ to 50℃, with the standard work condition of 45℃. The COP HP was about 4.12 at the minimum of heating water temperature, while it was about 3.47 at the maximum of heating water temperature and fluctuated between these values in other temperature. The results of the present work implies that GWSHPS is favorable for North China. However, buildings in North China have high heat load in winter, consequently, GWSHPS designed upon heat load will cause a waste in summer, thus, the solar-assisted ground-water source heat pump system (SAGWSHPS) which combines heat pump with solar water heater can be suggested as the best solution in North China

IMECE2010-40121 The Entropy Analysis on NH 3 /CO 2 Cascade Refrigeration Cycle

ABSTRACT This paper introduces a cascade refrigeration cycle that uses natural refrigerants of CO 2 and NH 3 at low temperature. It introduces the character of CO 2 and NH 3 , besides analyzes the cascade refrigeration cycle. The optimal intermediate temperature of NH 3 /CO 2 cascade refrigeration cycle is determined by the entropy production minimization method．We analyze the four processes entropy production in both CO 2 cycle（LT side）and NH 3 cycle（HT side） and research how the total entropy production changes in the conditions of different T 0 ，different T CL and different △T. We also find that in order to enhance the efficiency of NH 3 /CO 2 cascade refrigeration cycle，it is necessary to reduce △T. It can be concluded that NH 3 /CO 2 cascade refrigeration cycle has a good future

Thermodynamic Analysis of a Waste Heat Driven Vuilleumier Cycle Heat Pump

A Vuilleumier (VM) cycle heat pump is a closed gas cycle driven by heat energy. It has the highest performance among all known heat driven technologies. In this paper, two thermodynamic analyses, including energy and exergy analysis, are carried out to evaluate the application of a VM cycle heat pump for waste heat utilization. For a prototype VM cycle heat pump, equations for theoretical and actual cycles are established. Under the given conditions, the exergy efficiency for the theoretical cycle is 0.23 compared to 0.15 for the actual cycle. This is due to losses taking place in the actual cycle. Reheat losses and flow friction losses account for almost 83% of the total losses. Investigation of the effect of heat source temperature, cycle pressure and speed on the exergy efficiency indicate that the low temperature waste heat is a suitable heat source for a VM cycle heat pump. The selected cycle pressure should be higher than 100 MPa, and 200–300 rpm is the optimum speed

Thermodynamic Analysis on an Integrated Liquefied Air Energy Storage and Electricity Generation System

For an integrated liquefied air energy storage and electricity generation system, mathematical models of the liquefied air energy storage and electricity generation process are established using a thermodynamic theory. The effects of the outlet pressure of the compressor unit, the outlet pressure of the cryogenic pump, the heat exchanger effectiveness, the initial air temperature and pressure before throttling on the performances of the integrated liquefied air energy storage, and the electricity generation system are investigated, using the cycle efficiency and liquid air yield ratio as the evaluation indexes. The results show that if the compressor outlet pressure is raised, both the compression work and the expansion work increase, but because the expansion work increases more slowly, the cycle efficiency of the system gradually decreases. Increasing the cryogenic pump outlet pressure and heat exchanger effectiveness can significantly increase the cycle efficiency of the system; the higher the air pressure and the lower the air temperature before throttling, the greater the liquid air yield after expansion, and the higher the cycle efficiency. The theoretical analysis models and research results can provide a reference for the development of an integrated system of liquefied air energy storage and electricity production, as well as for the development of medium-capacity energy storage technology