Energy-saving performance of commercial air-conditioner with spraying apparatus attached to the outdoor unit.

As one way to reduce the electric power consumption of air conditioners in summer, the water spraying apparatus attached to the outdoor unit of air conditioners for business use are commercially available. In this study, in order to evaluate quantitatively the energy-saving performance of the water spraying apparatus, we carried out the detailed partial load performance tests of a packaged type air conditioner (PAC) and multi-split type air conditioners for buildings (MAC) with the water spraying apparatus attached to their outdoor units. As a result, it was found that the effect of water spraying on COP improvement of PAC was the maximum under the rated load condition, while that of MAC depended on its control method of compressors and/or expansion valves. In case of MAC without an intermittent operation under the around half load, the effect of water spraying on COP improvement was maximum under the partial load operation with the cooling load ratios about 80%. On the other hand, in case of MAC with an intermittent operation under the around half load, that was the maximum under the rated load condition.