Charge optimisation of a solar milk chiller with direct current compressors

Abstract

In view of promoting the utilization of solar photo-voltaic energy for milk chilling application a custom designed milk chiller with DC compressors was fabricated. Two different DC compressors were used operating with HFC-134a and HC-600a refrigerants to ascertain the performance of HFC and HC refrigerants when used in solar powered application. In view of optimizing the performance of both refrigerants, charge optimization was experimentally carried out for both refrigerant circuits. The optimum charge was obtained based on the maximum coefficient of performance and exergy efficiency. When comparing ice formation and coefficient of performance, the HC-600a refrigerant circuit was lower than that of HFC-134a circuit. It was also observed that the total exergy destruction experienced was maximum in the HFC-134a circuit than that of the HC-600a circuit. The magnitude of exergy destruction was found to be maximum in the compressor and then followed by the condenser, evaporator and finally the capillary for both refrigeration circuits. This study showed an efficient way for using the solar power for operating a milk chiller with DC compressors and with ice bank tank to avoid the dependency on batteries.

Performance, environment, and cost‐benefit analysis of a split air conditioning unit usingHC‐290 andHCFC‐22

“…This can be referred to as the minimum effective charge for this system. 36 Though, this need not be the optimum refrigerant charge, the AC unit was charged further to experience a plateau in COP. Therefore, the charge quantity of HCFC-22 was varied from 820 to 980 g in order to find the optimum refrigerant charge for the AC unit.…”

A comparative study of solar photovoltaic operated milk cooler for realizing the need for load management and starting circuits

“…8 These kinds of TES can be used for many applications in remote areas, 9,10 of which solar-operated milk cooler (SMCs) is one of the best examples. 11,12 When the number of bacteria in milk decreased from 100,000 to 50,000/ml of milk, the price of milk increased by 197%. 13 It can be achieved that fresh hot milk is best cooled to 10°C within two hours after milking and to 4°C within three to four hours.…”