Research On Life Cycle Climate Performance And Synthetical Evaluation Index Of Domestic Air Conditioners

As refrigerants being one of the most important parts of air conditioning systems,more attention has been paid to its environmental protection performance,and more and more stringent protocols are issued to limit emissions of CO₂ by international organization.However,the present evaluation index of GWP?Global Warming Potential?is not able to represent the environment protection performance of the whole air conditioning systems.Therefore a comprehensive evaluation index named LCCP?Life Cycle Climate Performance?is introduced by international organization.So far,a number of researches and LCCP evaluation software on domestic air conditioners?DACs?have been carried on abroad,while there is little comprensive research in China.Furthermore,LCCP is only an evaluation index in environmental protection level which cannot represent the overall performance including environment level,security level,cost level and performance level of air conditioning systems,therefore,a synthetical evaluation index to estimate air conditioning systems quantificationally is of great necessity.In this paper,Radiant Time Series Method?RTSM?is set up to calculate the transient thermal load of a DAC over its lifetime,and then an experiment of R290 and R410 A variable frequency air conditioners in actual operation condition was carried out to validate the necessity of transient thermal load calculation.Also,the switch on condition of air conditioners has been redefined through synthetically considering the outdoor environment,temperature zone and personnel status in air conditioning room.Afterwards,an organic combination of RTSM and LCCP is put forward to develop a comprehensive LCCP software of DACs through programming,and also influencing factors of LCCP are analysed in detail by this software.Furthermore,two synthetical evaluation indexes AP_ref and AP_DAC which named Alternative Potential?AP?on refrigerants and air conditioning systems are introduced separately by Fuzzy-Borda Method,throughout these two AP evaluation indexes,it can provide the quantitative evaluation basis for alternative refrigerants and DACs in air conditioning area.The detail content is as follows:Firstly,Period Response Factor Method is applied to calculate the heat gain of an air conditioning room,and then the cooling load is calculated by dividing the heat gain into radiation part and convection part through RTSM,so that the characteristics of lagging and attenuation during the process of energy conversion can be taken into consideration.Besides,through synthetically considering the influences of the outdoor environment,temperature zone and personnel status in air conditioning room,the switch on condition of air conditioners has been redefined,resulting in the annual energy consumption being closer to reality.Secondly,integrating RTSM to the calculation of air conditioning LCCP model,in which the equivalent CO₂ emissions during the process of air conditioning system's production,transport,operation,leakage and recycle have all been considered.Based on Visual Studio 2013,a monolithic LCCP calculation software has been developed.Throughout this software,the influences on air conditioning system LCCP by different refrigerants,different temperature zones,different energy structure,different life characteristics and different construction class have been analyzed in detail.The results show that LCCP of room air conditioning system can be effectively reduced by means of applying low GWP refrigerants,environmental energy structure,heavy wall construction and high refrigerant recovery rate.Thirdly,an experiment of R290 and R410 A variable frequency air conditioners in actual operation condition was carried out.This experiment can not only validate the necessity of transient thermal load calculation,but also the feasibility of R290 DAC's actual cooling capacity.However,before R290 DAC entering the market,the strategy of temperature control should be further improved,reducing the temperature difference of frequency switching,so as to enhance the energy conservation effect and comfort.Finally,two Alternative Potential evaluation indexes AP_ref and AP_DAC on refrigerants and air conditioning systems?in comparison to R22 refrigerant and R22 DACs?are introduced respectively through Fuzzy-Borda Method,which take environment level,security level,cost level and performance level into consideration.The evaluation results show that,in the aspect of refrigerant,natural inorganic refrigerant R717 and R744 own the best alternative potential,and through flammable refrigerants,the alternative poteitial of A3 refrigerants R290 and R600 a are inferior to A2 L refrigerants R32 and R152 a.In the aspect of air conditioning system,however,R290 air conditioning system owns the best alternative potential.The reason can be explained that during the actual operation,many optimization measurements will be taken to reduce the refrigerant charge of R290,including applying small-diameter tubes heat exchangers and micro-channel heat exchangers,so that the disadvantage of air conditioning system security level between R290 and other nonflammable refrigerants is significantly reduced.In conclusion,these two Alternative Potential evaluation indexes AP_ref and AP_DAC can provide the quantitive evaluation basis for choice of new refrigerants in air conditioning area.