Design and development of a low GWP stand alone solar PV milk cooler with IBT

Abstract

This thesis envisages on the design and development of a low GWP newlinestand-alone solar PV milk cooler that uses an eco-friendly refrigerant and newlineoperates with solar PV energy. Milk has to be transported to the processing newlinecentres as soon as milking is done in the morning and evening to avoid newlinespoilage. In rural areas the local processing centre itself will be away from the newlinefarm. In such a situation it is better to have a milk cooler at the farm itself to newlineimmediately cool the milk below 4 newline o newline C and to transport it later conveniently. newlineThe commercially available bulk milk cooler is at a minimum capacity of 250 newlinelitres and has an inbuilt refrigeration system that is operated in grid power. newlineConsidering a small rural milk farm, where 10 litres of milk is produced each newlinein the morning and in the evening, the farmer owing to the low quantity of newlinemilk and inconsistent grid supply could not use the bulk milk cooler. In this newlinestudy, a standalone Solar Milk Cooler (SMC) to cool and store 20 litres of newlinemilk with an Ice Bank Tank (IBT) was designed, fabricated and tested for newlineperformance. This milk cooler would be a great solace for such small farmers. newlineFirst, the total heat load for cooling 20 litres of milk daily from newline37 ºC to 4 ºC and to maintain the temperature below 4 ºC for 24 hours was newlineestimated and then the required cooling capacity of compressor was newlinedetermined for this heat load requirement. A survey of Literature has shown newlinethat DC compressors based on R134a refrigerant are used in solar newlinephotovoltaic (SPV) refrigeration applications. Due to the high global warming newlinepotential of R134a, the low GWP R600a DC compressor was considered. newline