Comparison of correlations for modelling heat exchanger performance in a compact ammonia refrigeration unit

This paper compare the correlations for heat transfer coefficient that can be used for modelling performance of plate heat exchangers when used in compact ammonia chillers. A 27 kW ammonia chiller was used to collect data of four different operating conditions. After that, the most representative data from the system were used to validate a numerical model of the chiller.

The model simulated the performance using several correlations of heat transfer coefficient. The results showed that a suitable combination of heat transfer coefficient correlations for refrigerant and water to calculate the heat flow rate through the evaporator could yield a deviation between -16 % and -12 % when compared against experimental data.

In the case of the condenser, the correlations presented a deviation between -9.9 % and -6.1 % in heat flow rate.