Energy-efficient air conditioning system with combination of radiant cooling and periodic total heat exchanger

The main thrust of this paper is directed toward a novel air conditioning system that can maintain a healthy indoor environment and be energy-efficient. This system consists of a low-temperature regenerative periodic total heat exchanger, radiant ceiling-cooling coil, and conventional air conditioner. The natural cold energy of the tap water in the cooling coil provides comfortable and uniform cooling, and the desiccant-packed bed in the total heat exchanger recovers the indoor energy to handle the fresh air. The performance of each component is discussed, and the actual performance of the whole system is investigated in an office at the Taipei Water Department. The results indicate that using a radiant ceiling-cooling coil to precool the indoor environment enables the traditional window-type air conditioner to reduce two-thirds of the original operating time. In addition, the test of the whole system was conducted in the same office, and it was observed that using this system to handle the incoming air could save 13%–19% of the energy consumption per month during a year-round operation compared to directly introducing untreated fresh air.