Study of an integrated radiant heating/cooling system with fresh air supply for household utilization

Abstract

With the increasing demand for indoor thermal comfort in recent years, radiant heating & cooling systems have been very popular in China. However, for the household air-conditioning in hot-summer and cold-winter regions, an effective solution of heating and cooling source supply for radiant air-conditioning system remains to be developed. In this paper, an energy-efficient radiant heating/cooling system with fresh air supply is proposed and investigated for household utilization numerically. Under summer conditions, dehumidified fresh air supply is a tough problem in radiant cooling since the chilling water temperature for radiant cooling is much higher than traditional air-conditioning systems. In the proposed system, the fresh air handling unit is composed of both pre-cooling dehumidification coil and liquid desiccant dehumidifier, where high-temperature chilling water is used for cooling source and small part of condensing heat is used for liquid desiccant regeneration. The results indicated that the fresh air can be steadily supplied and sufficiently dehumidified for indoor air quality and humidity control. The chilling water flow rate in pre-cooling coil (mw,coil) and the solution flow rate from regenerator to dehumidifier (ms,SS) can be recognized as control parameters to reliably regulate the indoor air humidity. The load ratio of sensible heat to latent heat had no significant impact on COPsys, which means the system can operate with a steady energy efficiency despite of the indoor heat load. Satisfactory energy-saving potential was revealed in the proposed system with a COP improvement of 25.8%–30.1% compared to the conventional system under typical summer conditions in Nanjing.