| In recent years, air source heat pump (ASHP) has been widely applied in ourcountry, but frost formation on the outdoor heat exchanger is the main problem withASHP, when it is operating in winter under certain weather conditions. Experts havecarried out many studies on defrost performance, which, however, are mostly basedon traditional methods such as hot-gas bypass defrosting. Is there a new methodwhich has all advantages of common defrost methods? How does the energy changein all parts of system during defrosting? This paper is an attempt to answer thequestions above.With ASHP split type air conditioner as the experiment object, this paper addedheat storage defrosting device to the original experimental platform. Pressure,temperature and humidity were measured before and after heat storage defrosting andcompressor power was calculated according to the collected real-time current.Pressure and temperature of two compressors and throttle bodies were investigatedand analyzed by comparative study of the data acquired and regular defrostingexperimental data. Experimental results indicate that heat accumulator can act aslow-grade heat source to ensure steady indoor heat supply. Compared with commondefrosting, pressure of compressors during suction and discharge are higher but theduration of heat storage defrosting period is shorter. Appropriate changes in theposition of heat accumulator and indoor unit make different heat accumulation andrelease modes. Based on comparative analysis of heat storage result and defrostingperformance and calculation of compressor power of each mode, the most efficientdefrosting method can be figured out. Based on different access of heat accumulator to the system, different heatstorage and release capacity in different working conditions were analyzed by theexperiment of inorganic material CaCl2ยท6H2O. Heat quantity supplied in the processof heat accumulator defrosting and its proportion in total heat quantity werecalculated, in order to figure out the most favorable defrost mode and better thedesign.Error analysis of all data and devision of measuring devices carried out in thispaper show that experimental error is within the error range and data is reliable. |
PDF Full Text Request