Influence of Parallel Plate Stack Spacing on the Temperature Difference of Thermoacoustic Refrigerator by using Helium as a Working Medium

Abstract

The refrigerants are usually provided in the conventional refrigeration system despite the fact that, they produce CFCs and HCFCs, which are hazardous to the environment. However, these disadvantages can be overcome using air or inert gas in the thermoacoustic refrigeration system. The present research involves the effect of spacing of parallel plate stack on the performance of thermoacoustic refrigerator (TAR) in terms of temperature difference (ΔT). The entire resonator system as well as other structural parts of the refrigerator are fabricated by using PVC to reduce conduction heat loss. Three parallel plate stacks have been used to study the performance of TAR considering different porosity ratios by varying the gap between the parallel plates (0.28 mm, 0.33 mm and 0.38 mm). The parallel plate stacks are fabricated by using aluminium and mylar sheet material and the working fluid used for the experimental study is helium. The experiments have been carried out with different drive ratios ranging from 0.6% to 1.6% with operating frequencies of 200 – 600 Hz. Also the mean operating pressure used for the experiment is 2 to 10 bar and cooling load of 2 to 10W are considered. The ΔT between the hot heat exchanger and cold heat exchanger is recorded using RTDs and Bruel and Kjaer data acquisition system. Experimental results shows that the lowest temperature measured at cold heat exchanger is -2.1 oC by maintaining the hot heat exchanger temperature at about 32 oC. The maximum temperature difference of 32.90 oC is achieved.