Conference article

This paper presents constructive aspects and preliminary experimental results of an adsorptive chiller as part of a 20 kW central air conditioning unit for providing thermal comfort in a set of rooms that comprises an area of 110 m². Some simulation results of the air conditioner regeneration system are also presented. The cooling system is basically made up of a cold-water storage tank – supplied by an activated carbon-methanol chiller; and a hot-water storage tank – fed by a field of high efficient solar collectors with complementary heat by natural gas. The adsorber – a compact heat exchanger containing the activated carbon – was conceived and constructed in four modules; in order to allow heat and mass recovery. Other components are the same existing on conventional central air conditioners; as a condenser; an evaporator and a cooling tower. Constructive details of the collector’s field; the adsorbers and the regenerating storage component are shown. The solar system is a 120 m² collection area field composed by 76 units of a flat plate collector covered with a high efficient transparent insulation. Results obtained from a multi-objective optimization based on a statistic modeling shown that – for a specific cooling power of 120 W/kg of adsorbent – the chiller’s COP can reach 0.6. With this COP value; and considering the mean value of the total daily irradiation in João Pessoa (7°8’S; 34°50’WG); we can expected a solar energy cover fraction of 70%; for a typical summer day. This scenario is expected for the following operation temperatures: 30°C for the condenser; 7°C for the evaporator and 105°C at the start of the regeneration process. For an acclimatization period of 8 hours (9 to 17 h); the main dimensioning parameters were: 504 kg of activated carbon; 180 liters of methanol; 7;000 liters of hot water; 10;300 liters of chilled water with its temperature varying in the fan-coil from 1°C to 14°C.

Solar-gas adsorptive chiller; Thermal storage; Numerical simulation