Abstract
A nocturnal greenhouse cooling system by a silica gel (adsorbent) -water (adsorbate) pair adsorption cooling method was proposed for an alternative cooling system by applying solar heat and waste heat from industry. According to the calculated results of the negative heat acquisition for the system, the adsorbent bed having 100 m2 surface area would be able to cool a greenhouse of 340 m2 floor area. The values of COP and exergy efficiency ζfor the proposed system were estimated to be 0.216 and 0.0056, respectively. Both of these are smaller than those for the absorption cooling system reported previously, because the rate of heat exchange between the adsorbent bed and medium water is limited by heat conduction and a large amount of exergy is dissipated in absorbing the solar heat. The amount of solar heat input was 3.6 times larger than that of the waste heat input in this simulation. This suggests that it is important for system stability to develop a method for concentrating the solar heat, considering the solar heat variation due to meteorological conditions.
