Study of floating condensing for energy saving on refrigeration plants in tropical areas

Abstract
The research concerns energy saving issues at refrigeration plants in warm tropical areas. The object is to optimize operating cost of the cold stores for food industries by calculating the energy consumption of refrigeration systems for different outside temperatures. The compressor energy consumption decreases as compression ratio becomes low for colder outside temperatures. The determined energy consumption of the fans shows a very small increase when outdoor temperature increases, thus it can be considered to be constant. The floating HP operating mode shows a better COP than the fixed HP one. The calculation for several refrigerants i.e. R717, R404A and R22 having been made, the results show that the COP is better for ammonia than for R22 and R404A. The annual energy gain is at least 600kWh/kW of cooling capacity compared to the fixed HP operating mode. In terms of energy consumption the refrigerant R404A gives the best gain (17%), and ammonia does 13%. Although temperature does not change a lot over the year in the humid tropical areas concerned, 15% energy saving can be predicted with floating condensation pressure control. For industrial refrigerating plant, the method appears to be very promising and competitive in terms of energy saving, with investment being very small. It can also permit the design and the management of more environmentally sustainable industrial refrigeration plants.