Experimental investigation of air conditioning system using evaporative cooling condenser

• DEC could drive the system into sub-cooled operation condition.
• DEC could reduced the compressor work and increase of COP.
• Under partial load, the DEC performed better than conventional condenser systems.
• DEC could achieve up to 14.3% power savings with negligible cost of operation.

This paper presents an experimental investigation of the Coefficient of Performance (COP)’s augmentation of an air conditioning system utilizing an evaporative cooling condenser. The experimental facility consisted of four major components, which are, the compressor, the evaporator, the thermal expansion valve, and the condenser. An evaporative cooling unit was located upstream from the condenser. Thermal parameters, such as relative humidity, dry bulb temperature, and wet bulb temperature were measured to evaluate the effect of in-direct evaporative cooling on the system's COP. The results indicated an inverse relation between the condenser inlet dry bulb temperature and the COP. The changes in specific enthalpy of the air across the evaporative cooled condenser were due to latent heat transfer and sensible heat exchanges, whereas the specific enthalpy changes for the conventional condenser were primarily caused by sensible heat exchanges. By using the evaporative cooling condenser to pre-cool the air, the saturation temperature drop through the condenser increased from 2.4 °C to 6.6 °C. It also resulted in an increase of the mass flow rate of refrigerant that went into the evaporator. This mass increase of liquid entering the evaporator consequently resulted in the increase of COP from 6.1% to 18%. A power reduction up to 14.3% on the compressor was also achieved. The result reveals the relation between water consumption and compressor energy saving regarding to their costs. Although greater power reductions were fulfilled at higher dry bulb temperatures, in this circumstance, the cost-optimal applicable temperature is around 33.1 °C.