Experimental study of an evacuated tube solar adsorption cooling module and its optimal adsorbent bed design

A novel design is proposed that couples an evacuated tube solar collector and adsorption cooling system in one module, namely, an evacuated tube solar adsorption cooling module. The module is basically a simple adsorption cooling system placed inside an evacuated glass tube with a length of about 180 cm, and an internal diameter of 5.5 cm. One side (top section of the tube) represents the adsorbent bed (generator) and contains the adsorbent, while the other side (bottom section of the tube) represents the condenser/evaporator and contains the refrigerant. In this paper, the module was investigated experimentally to find its optimal adsorbent bed design and results show that the system is promising from energy and cost point of views. Zeolite 13X was examined and it shows an excellent adsorption rate which gives it an advantage over other adsorbents for cooling applications. Additionally, the solar COP of the evacuated tube adsorption cooling module was experimentally evaluated to be 0.15. Cost analysis displayed that our proposed system is comparable with vapor compression systems driven by solar PV.