Management of Condenser Fan Speed and its Influence on the Split Air Conditioner Performance

Abstract

Energy saving is the challenge of decreasing the quantity of energy consumption needed. This can be done by employing reliable and smart control system. In this article, an experimental study has been carried out to investigate the performance of a split air conditioning unit having a variable speed condenser fan. The rate of heat rejection airflow has been controlled according to the outdoor air temperature via a Proportional Integral Differential (PID) controller. The control algorithm allows increasing the condenser fan speed with the increase of outdoor air temperature and vice verse. The maximum rate of air flow of the fan is 0.43 m3/s at 42ºC outdoor air temperature and the minimum flow is 0.28m3/s. To facilitate variation of refrigerant flow rate according to the evaporator load, the traditional capillary tube was replaced with a suitable thermostatic expansion valve and liquid refrigerant reserve. The influence of condenser airflow modulation and its temperature on the air conditioner performance and also on the compressor power consumption has been investigated and presented at different evaporator loads. It has been found that a 10 % reduction in compressor power is achieved by increasing the condenser air flow by about 50%.