Experimental evaluation of refrigeration performance of degassing and regassing of an inverter driven R410a system

Abstract

This paper details an experimental investigation of the operation of an R410a system under partially filled conditions, i.e. emulating a leaking unit. Experiments were performed lowering the refrigerant charge in steps of 10% degassing from the full refrigerant charge to 50 % of the full refrigerant charge. Regassing of the unit was performed in 10% steps back to the full charge quantity. Since R410a is a refrigerant mix, regassing was specifically performed without emptying the unit completely to experimentally test any effect of refrigerant composition change. This regassing without emptying is of great interest as it is easier for maintenance workers to top-up the refrigerant rather than recover the remaining refrigerant and refill with a full new charge. Topping up also reduces consumption of new refrigerant and also reduces the quantity of gas that is recovered and needs to be disposed of by the maintenance company. The experimental campaign showed that there is very little difference in performance between the originally filled condition and the regassed/refilled condition. The Coefficient of Performance, Cooling Capacity, Heat Rejection, electrical consumption and other pertinent data from the experimental campaign are shown and discussed. The evaporator and condenser heat exchangers used water as the other fluid for a robust application of calorimetric measurement of the air-conditioner heat flows. The water temperatures of the evaporator and condenser heat exchangers were maintained at 20°C and 35°C respectively. Experiments were performed on all frequencies at which the compressor can be used (90 to 150 Hz).