5 ton Indirect Hybrid Unit

This project tests the performance and efficiency of a 5-ton indirect evaporative hybrid roof top air-conditioning unit developed primarily for the small commercial market segment. Commercial buildings consume more electricity than any other end-use sector in California, and space cooling loads account for 15% of the total electricity consumption. The California Long Term Energy Efficiency Strategic Plan targets a 50% improvement in efficiency in the heating, ventilation, and air conditioning (HVAC) sector for small commercial and residential buildings by 2020, and a 75% improvement by 2030. The plan also identifies the need for more climate appropriate HVAC solutions that are suitable for California’s hot and dry climate. Southern California Edison’s (SCEs) Emerging Technologies Program identified the 5-ton indirect evaporative hybrid roof top unit (RTU) by Coolerado Corporation as one possible solution suitable for California’s arid climate. This technology works on the principle of Maisotsenko refrigeration cycle, or M-cycle, to perform heat exchange. It uses a two-stage cooling technique to lower the outside air temperature that is ultimately delivered to the conditioned space. In stage one; the outside air is passed through a water media called a heat mass exchanger for preliminary cooling. In stage two, this precooled air is passed through a high efficiency compressor, with R-410A refrigerant system, to cool down the air further. After this stage, the cold air is introduced to the conditioned space. This field evaluation tests the operation of the hybrid technology described above, and how it saves energy through a two-stage cooling system by using water as a refrigerant. In addition to demand; water consumption, temperature and humidity of conditioned space, supply, return, mixed and outside air of the unit was also monitored. Performance results of the hybrid unit were compared to the performance results of a baseline 5-ton direct expansion package unit . Results of demand reduction and energy savings and comparison of mechanical performance of the hybrid unit with the baseline unit are shown in Table 1 and Table 2, respectively.