Numerical Simulation On Silica Gel Watet Adsorption Chiller System

The whole world is suffering the energy crises and environmental issues, whichleads air conditioning and heat pump industry to look for new refrigerants and newrefrigeration technology. Compared with conventional vapor compression refrigerationtechnology, adsorption refrigeration systems have advantages of energy saving andenvironment friendly. Therefore adsorption refrigeration has become a new focus inrefrigeration technology.Based on a two-bed silica gel-water adsorption chiller, in this thesis mathematicalmodels on finned heat pipe adsorption bed, condenser and evaporator are respectivelyestablished to modeling the adsorption system. In order to analyze both the hea t andmass transfer characteristics of adsorption bed and the dynamic characteristics ofadsorption system, computer code is written by Fortran language. The main results inthis thesis include as follows:(1) Based on the mathematical model of adsorption bed, the process of heat andmass transfer is analyzed. The results show that the effectiveness of fin temperaturedifference on both temperature field of adsorption bed and the uptake of adsorbentincreases with the increase of fin length.(2) According to the mathematical model of adsorption bed, the adsorptionprocesses of different porosities in silica gel particles are analyzed. The results showthat the average uptake and the total uptake of adsorber both reach proper values whilethe porosity of particles among0.4~0.45.(3) The dynamic processes during the operation of the two-bed silica gel-wateradsorption system are researched, including the temperature field of adsorption bed,average temperature, average uptake, average pressure and the temperatures of fluid incondenser and evaporator. The influences of hot source temperature, inlet temperatureof cooling-water, evaporating temperature and cycle time on the performance of systemare also predicted. The results show that among those parameters studied above thecycle is the most important factor to COP, while the hot source temperature and inlettemperature of cooling-water have significant impact on SCP and cooling capacity.