Performance Investigations of Energy Storage Unit Applied to Subcooling of Air Conditioners
Date Issued
2009
Date
2009
Author(s)
Cheng, Chiao-Hung
Abstract
This dissertation experimentally investigates the performance of the air conditioner utilizing an energy storage unit as a subcooler. The energy storage unit is composed of the charge and discharge heat exchangers, energy storage material, and tank. The energy storage unit, applied to be a subcooler of air conditioner, can improve the system coefficient of performance (COP). To avoid the liquid compression is one of the advantages. In addition, the energy management of air conditioner is always performed at high efficiency running condition of the compressor. The characteristic of passive and automatic operation without moving parts can enhance the stability and reliability of system. Besides, the initial cost of energy storage unit less than the variable frequency device is also one of the merits. The energy storage unit charges when the cooling load is less than the nominal cooling capacity of compressor. While the cooling load is larger than the nominal cooling capacity, the energy storage unit discharges for subcooling and increasing the system COP. There are three types of air conditioners combined with the energy storage unit and examined the performance enhancement in this dissertation. The air conditioners include single split type air conditioner, air cooled packaged air conditioner, and heat pump. In each air conditioner test, the experiment procedures are divided into the subcooled experiment and non-subcooled one. The results of split type air conditioner test show that the energy storage unit can improve 15.3% system COP. In the exanimation of air cooled packaged air conditioner, the system COP can be increased about 9% by utilizing the energy storage unit as the subcooler. The results of heat pump experiment indicate that the energy storage unit can enhance more 11% heat pump COP, 15% refrigerator COP, and 9% total COP.
Subjects
energy storage unit
air conditioner
subcool
coefficient of performance(COP)
Type
thesis
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