The Study Of Heat Transfer Enhancement Of New Pin-Fin-Plate Adsorbent Bed In Solid Adsorption Refrigeration System

The solid adsorption refrigeration system is received much attention for it can use the solar energy and the waste heat. The solid refrigeration system is environmentally friendly, noiseless along with low cost and low maintenance requirements. It does not need a liquid pump, and does not present corrosion problems due to the working pairs normally used, and it is less sensitive to shocks and to the installation position. These last two features make it suitable for application in locomotives, buses, boats.The adsorbent bed is the core component in solid adsorption refrigeration systems, and it act in the solid adsorption refrigeration system as the compressor in the vapor compression system. It is made by packing the adsorbent in metal bed and has deep influence over the capacity of solid refrigeration systems. The system usually also has the drawbacks of low coefficient of performance (COP). It has low thermal conductivity and high contact thermal resistance between the bed and the adsorbent because the adsorbent is a porous media. However, these inconveniences can be overcome by improving the heat transfer rate by using new adsorbent bed.The paper presented the results obtained with the prototypes and some adsorption machines already on the market, and has given a new adsorbent bed called pin-fin-plate adsorbent bed by using the high pin-fin surface as the heat-transfer surface to improve the heat transfer rate. The main works in the paper are as follows:(1) The new pin-fin-plate adsorbent bed was firstly given, and the mathematical model of the heat transfer of the new bed was built in the paper.(2) The CFD software was used to simulate the heat transfer of the pin-fin-plate adsorbent bed and plate-fin adsorbent bed. Compared with the plate-fin adsorbent bed, we can find the pin-fin-plate adsorbent bed has higher heat transfer capacity.(3) The technological process of the direct preparation of the silica gel in the pin-fin-plate adsorbent bed was given firstly in order to reduce the dead volume in the bed and improve the strength of the pin.(4) The heat transfer theory of the porous media was used in order to set up the heat transfer model in the adsorbent. The coupling fractal dimension was given by using the fractal theory.