| According to statistics, the energy consumption of air conditioning in non-dry regions is much greater than the dry regions in China, At the same time, the disadvantages of traditional air conditioning system is that it uses very large amount of electrical energy and damages the ozone layer, while evaporative cooling is proved to be a green, environmentally friendly, energy-efficient cooling technology, but it only has been successfully applied in dry region of China.In non-dry regions, the energy consumption of air conditioning is very large, while it embraces abundant solar energy resources, and the evaporative cooling can save energy. Comprehensively considering the conditions of non-dry regions, a desiccant and evaporative cooling system driven by solar energy was established, and based on theoretical analysis, the experimental investigation and numerical simulation of the system was carried out.The indoor design parameters of desiccant and evaporative cooling system was discussed and analyzed in the thesis. Ensuring the same comfort condtion, a concept of "effective temperature" was introduced and the indoor design parameters applying to desiccant and evaporative cooling System driven by solar energy was obtained. ie dry bulb temperature was 27℃, relative humidity was 70%, wind speed was 1.0m/s.The design scheme and basis of desiccant and evaporative cooling system driven by solar energy applying in hot and humid region was confirmed. Based on analysis of the outdoor suitable weather conditions,the advantages and disadvantages of DC-style, closed-end, hybrid wheel desiccant cooling system, a improved Pennington air recirculation patterns applying in hot and humid region was proposed, and the working principle and composition of the system was introduced. Meanwhile, the design scheme and exergy analysis was carried out.Based on the above theoretical analysis, through constructing experiment system the desiccant wheel performance and system performance was tested under various operating condition (regeneration temperature, regeneration air volume, handling air volume, and regeneration angle). The results showed that:(ⅰ) the solar regeneration temperature ranged from 50℃to 80℃, comprehensive performance of desiccant wheel was the best when the temperature was 70℃—80℃; (ⅱ) In the regeneration and dehumidification area under the premise of the same face velocity, the angle of 90°regeneration of desiccant wheel performance was superior to the angle of 180°regeneration. Therefore, solar energy should be chosed within 90°angle regeneration. At the same time, the system on September 26th in Round-the-clock operation was tested.The results showed that solar energy is a reliable regeneration energy in the non-dry region.Based on the experiment of dehumidification, the cooling capacity and COP value of the system under different conditions was analyzed. The results showed that increasing the regeneration temperature or air volume could increase the cooling capacity, But for handling air volume, the cooling capacity first increased and then decreased, that there existed an optimal parameter value; For different regeneration temperature, Electric COP and thermal COP showed a reverse trend with the increase of regeneration temperature. While for the regeneration air volume and handling air volume, There existed an optimal value that makes the system with the highest electric COP and thermal COP.The mathematical model of dehumidification and mathematical model of direct evaporative cooling were established and the two mathematical models were couped. Practical calculation was carried out by using the coupled model. Compared with the experimental data, the mathematical model was correct. The calculation results showed that the influence of inlet temperature and rotor speed on the overall system performance was small.Through experimental and theoretical analysis, desiccant and evaporative cooling system driven by solar energy was proved to be a promising and worth further studying in the hot and humid region of China. |
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