| The study of this thesis is household air conditioners using R22 refrigerant. From the basic conservation equations of fluid mechanics and on the basis of a reasonable simplification in various parts of the room air conditioner, this thesis establishs the steady-state mathematical model of the compressor, heat exchanger and capillary the steady-state distribution parameter model, and specifics the related calculation and algorithms of parameters to establish a steady-state parameter model of the whole system, and writes MATLAB simulation program to simulate the run performance of the room air conditioners after R290 substitution. In different filling amounts of refrigerant charge, do experimental tests for directly filling of R290 to replace the original system which the air conditioner is filled with R22 refrigerants to carried out the refrigerant performance, by comparing the experimental data and simulation results, and verify the feasibility of the simulation. Paper use the results of the simulation program, made the following findings:1 An experimental value represents:as the device structure and environmental parameters unchanged, replace R22 with R290 after filling amount of 0.61kg maximum cooling capacity,power down about 14.4% and energy efficiency increase by 2.2%.COP reaches a maximum when the amount of charge R290 for about 43% of the original cooling system.2 simulation performance analysis:a direct replacement for the best suggestions R290 charge fluence range R22 between 39%～45%; R290 adaptability to conditions from the perspective of the COP, with R22 same, but the cooling capacity point of view, R290 slightly less than the R22, R290 need to optimize the system in order to improve heat transfer.3 Capillary length optimization:a 50% increase compared with the original capillary capillary length, that is when the tube length 900mm, COP highest value, replacing the maximum value of R290 COP 5.5 percent increase after direct than the original R22 refrigeration systems, cooling capacity increased by 7%, but the charge Note also increased 25.7 percent, the amount does not meet the maximum charge limit.4 Condenser Optimization:COP value diameter is 6.16/6.52mm maximum time than when the original system structure unchanged charge of R290 COP increase of 6.9%; 6.9% increase in cooling capacity. Its filling amount of 356.7g, than the maximum allowable amount of 417.9g charge low of 14.6%. Can be found to reduce the impact of the condenser to reduce the diameter of the relatively large amount of charge.5 In the evaporator cooling capacity of the air volume:wind speed and meet the requirements under the premise outlet temperature, air volume increased by 20% to 30%, the cooling capacity can be increased by about 5%, COP can be increased by about 4%.6 Machine optimization:the capillary length to 900mm, diameter condenser to 6.16/ 6.52mm, the optimal amount of filling 398.5g (less than 417.9g), COP and cooling capacity of 3.66 3373, compared with the original system COP 8.6% increase cooling capacity increased by 8%. And the ratio of the diameter is reduced only to the condenser cooling capacity improved 4.2%, COP increased by 1.7%. |
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