Research On Several Problems Of Air-cooled Multi-line Application In Xi’an Area

Air-cooled multi-connection is one of the main development directions of current and future air source heat pumps,but the defrosting problem under low temperature and high humidity conditions in winter and the high temperature or ultra-high temperature conditions in summer severely restrict the multi-line operation efficiency,as well as in large steel.The design and installation technology in structural public buildings has its own unique characteristics.In order to solve these two problems,under the premise of mastering the working principle of the multi-line air source heat pump,taking the actual application project in Xi’an as an example,the following work was carried out:The market application status of air-cooled multi-connection in Xi’an area in recent years is studied.The market rules and future development prospects of air-cooled multi-line connection in Xi’an area are analyzed.The results show that in recent years,the air-cooling multi-line bidding project in Xi’an area,The winning bidding project and the winning rate have shown an increasing trend year by year,and the proportion of air-cooled multi-connection in all air-conditioning projects is increasing year by year.According to the actual project,the design of air-cooled multi-connection in large-scale steel structure public buildings is studied.And the characteristics of the installation and construction technology to provide theoretical support for practical engineering applications;According to the designed experimental procedure and the verification requirements of the experiment,the corresponding test plan was designed,and the defrosting test system diagram of the sprayed ground freezing point solution under the air-cooled multi-connected winter low temperature and high humidity condition was constructed.The machine was tested on the system of spray cooling,and the test equipment and instruments were selected.The mixture of ethylene glycol and water was selected as the representative of the winter spray ice point solution,and the summer spray was cooled to select the treated aqueous solution.Prepare the basis for subsequent testing work;Under the winter conditions,by tracking the frosting and defrosting of different brands of the unit,the defrosting characteristics of the frosting condition point and the non-stop group in Xi’an area were obtained,and the defrosting using the spray low freezing point solution was proposed.The defrosting method has the characteristics of precise defrosting control,good defrosting effect and fast defrosting,and can prolong the frosting cycle,which is beneficial to the development of the air-cooled heat pump;The weather in Xi’an area under the summer conditions in summer is over 36 °C,and the future climate characteristics and high temperature trends are analyzed.The spray cooling of small air-cooled units is studied.Cooling can effectively reduce the air temperature at the air inlet of the outdoor unit,improve the operating efficiency of the unit,and extend the service life of the compressor;The research work of this paper is based on actual test and test verification.It provides theoretical basis and technical reference for the application of air-cooled multi-line in Xi’an area,and provides ideas for more efficient use of air-cooled multiple connections.