Research On The Applied Technology Of Low-temperature Air Source Heat Pump

The promising air source heat pump technology has the flexibility andapplicability of using air as the low-temperature heat source by which it has beenstanding up rapidly and stably in southern areas in China. However, when it spreads tothe North and Northeast China, some deadly problems of experienced ordinary airsource heat pump technology appear. Most apparently, in low-temperature conditions,the overlarge compression ratio reduces the quantity of circulatory work medium,raises the exhaust temperature, then leads to declining the indicated efficiency a little,and even causes the low-temperature shutdown protection of the unit frequently, whichinfluences the heating performance and running stability.In order to overcome these obstacles and spread the air source heat pumptechnology to northern areas efficiently, on the basis of summarizing the technicalcharacteristics of ordinary air source heat pump and studying the low-temperatureinfluence mechanism, this thesis comes up with a new low-temperature air source heatpump heating technology which can be used widely and practically in northernareas——Enhanced Vapor Injection Air Source Heat Pump System Coupled withScroll Compressor and Undercooling Economizer，which is EVIU system in short.Then, do with the technology implementation and field test about the EVIU systemcooperating with the enterprise platform.Put forward an air-conditioning mode applying to southern areas meaning thedigital scroll air source heat pump matching the ice storage technology and a heatingmode applying to northern areas meaning the EVIU system matching the capillarynetwork technology. Mainly study the capacity calculation method of the former, andanalyze the cost performance of the latter via certain projects. Make sure that thesemodes can be more environmental protection, energy conservation and higherefficiency on the foundation of guaranteeing the functional quality.Through systems’ comparison tests, verify that the application of the EVIUsystem in the low-temperature environment is available. Compared with the Dc inverter heat pump, the conclusion is that the EVIU system lower powered has higherheating capacity as well as it is steadier in ultralow-temperature conditions. On behalfof evaluating the EVIU system projects themselves and their economic performance,analyze the economic performance of the triple generation unit operating in theheating period and in the domestic hot water and air-conditioning cases. At the systemdesign angle, discuss the heat calculation and design method of the EVIU systemswimming pool machine engineering.There is an alternative and competitive low-temperature air source heat pump inthe market, naming two-stage compression heat pump technology. Study its COP andrelevant technical parameters in addition that analyze its technical factors andeconomic performance using actual project data. Draw the conclusion that in theaffirmative performance meeting customers’ needs condition, not only in the annualoperating cost aspect, but also the initial and running cost, the EVIU system is better.The low-temperature air source heat pump scheme proposed in this thesis ispractically valuable.