Optimization And Development Of Single Cooling Split R290 Room Air-conditioner

In recent years,with the increasingly prominent environmental problems such as the ozone hole and global warming,the introduction and use of energy-saving and environmentally-friendly products have received more and more attention.In the room airconditioner industry,R290 has become an increasingly important refrigerant due to its excellent environmental friendliness and thermodynamic properties.In the context of refrigerant replacement in China’s room air-conditioner industry,this paper proposes a R290 room air-conditioner with high safety and good system performance through theoretical analysis and experimental research.This article first compares the thermophysical properties of R290,R22,and R410 A,and compares the theoretical cycle performance of these three refrigerants under standard refrigeration conditions,demonstrating the advantages and feasibility of R290 as an alternative refrigerant.Secondly,for each component of the R290 air-conditioner system that needs to be selected and designed,this article also analyzes the optimization that R290 may need when replacing R22 and R410A through the commonly used flow or heat transfer correlation and performance evaluation indicators in engineering.The results show that the small-diameter heat exchanger used in the R290 room air-conditioner may be helpful to improve system performance and safety.The emphasis of this article is on the design and debugging experiments of the R290 air-conditioner.Through six rounds of debugging,the components of the air conditioner are fully matched and optimized to determine the best R290 air-conditioner design scheme.In the best solution,the COP of the air conditioner reaches 3.61,the cooling capacity is 2741 W,and the refrigerant charge is only 250 g,which is 17.36% lower than the maximum allowable charge of flammable refrigerants which is specified by national standards,calculated based on the room area commonly used by this type of air conditioner.At the same time,during the experiment,it was also found that the evaporator of the R290 system is not suitable for the use of small-diameter copper tubes with a diameter of 5mm.On the contrary,after the condenser uses 5mm copper tubes and the splitting method is optimized,the system performance will improve.Finally,through the summary and analysis of the experimental data,the effects of refrigerant charge,capillary size,and air-conditioning indoor air flow on the system COP during the experiment were discussed.It was found that for the determined R290 air conditioner,there is an optimal combination of capillary size and refrigerant charge amounts,which makes the system COP maximum,and the choice of indoor air flow requires comprehensive consideration of comfort and performance requirements.