Investigation On Internally Cooling Dehumidification-evaporative Refrigeration Air Conditioning System Using Solar Energy Regeneration

With the rapid growth of global building area and the corresponding increase of refrigeration demand.Traditional refrigeration technology has caused a large amount of freon emission and power load,leading to serious environmental pollution and other problems.Therefore,evaporative cooling technology is a good substitute for traditional refrigeration because of the many advantages of energy saving,environmental protection,high efficiency,and good air quality.In this paper,the solar regenerative internally cooling desiccant bed dehumidification and direct/indirect evaporative cooling in series constitute a dehumidification-evaporative refrigeration air conditioning system using solar regenerative.When the system is working,the air can carry out twice coolingly,greatly improving the cooling range and cooling efficiency of the direct/indirect evaporative cooling system operated separately.The main research contents and conclusions of this paper are as follows:（1）To improve the water vapor adsorption capacity of activated carbon fiber（ACF）,composite activated carbon fiber ACF-silica sol-Li Cl（ASL）was prepared by impregnating silica sol and Li Cl in ACF.After impregnating silica sol and Li Cl,Si O₂particles in silica sol provide support points for the soft ACF to cure ACF,and Li Cl can effectively improve the water vapor adsorption capacity of the ACF.Dynamic adsorption tests showed that the adsorption rate coefficient（k）of ASL was significantly improved compared with ACF.The k value of ASL is1.58×10^-4-2.05×10^-4,which is 0.27×10^-4-0.59×10^-4.The adsorption capacity of ASL can reach 2.2876 g/g,which is 2.67 times the maximum adsorption capacity of ACF.TG and DTG showed that the optimal desorption temperature of ASLH30 was89℃,only 1.35 times higher than that of ACF.（2）The cooling coil and ASL constitute the internally cooling desiccant bed.The dehumidification quantity of desiccant bed calculation value and experimental value of the maximum relative error between the|e|1.04-11.86%only.This indicates that ASL can still give full play to its adsorption capacity when placed in the desiccant bed.The desiccant bed test results showed that after 4-10 cycles,the average dehumidification volume of the desiccant bed decreased by less than 6%,and the temperature rose by 0.8-1.2℃,basically achieving stable recycling and isothermal dehumidification.（3）The influence of inlet air temperature,relative humidity,cooling water temperature and air velocity on the cooling efficiencyη,cooling capacity Q_c and COP were investigated experimentally.The results show that the above test parameters increase with the increase of inlet air temperature and the decrease of inlet relative humidity,cooling water temperature and air velocity.（4）The the supply air temperature in the dehumidification-evaporative cooling system increased by 3.1-4℃compared with that in the evaporative cooling system working alone;The cooling efficiency can be increased to 1.2-1.68,breaking the limit of cooling efficiency when the evaporative cooling system works alone;The system cooling capacity and COP are increased from 497-1274.8 W and 1.43-3.79 to770.5-2027.6 W and 2.22-5.83.