Improvement of refrigeration/air-conditioning performance with mechanical sub-cooling

Significant amounts of energy are consumed by refrigeration/air-conditioning systems. An energy-saving approach that can be applied to new or existing refrigeration/air-conditioning installations is discussed to increase system performance and reduce energy consumption. It consists of adding a mechanical subcooling loop to a conventional vapor-compression cycle. The performance of a modified system is demonstrated for three different applications. It was found that the system performance peaks at a sub-cooler saturation temperature midway between the condensing and evaporating temperatures. Simulations show that performance improvement for air-conditioning systems can be as high as 20% during peak periods of high condensing temperatures whereas high-temperature and low-temperature refrigeration systems under these same conditions will provide energy-savings of 20 and 40%, respectively.