Study On The Optimization Combined System Of Evaporative Cooling With Solar Heating In Northwest Region

The dry air has a high ability to contain water vapor in northwest region of ourcountry.This kind of natural resources can be used to develop evaporative coolingrefrigeration technology according to the principle of well-known “water evaporation”.Besides in the same area, there are quite rich solar energy resources. In winter, solarenergy heating technology can used to satisfy the demand of indoor heating. Accordingto the two technologies’ limitations of cooling and heating respectively, in this articlewe put forward a combined system of evaporation cooling air conditioning and solarheating (SHEC) in northwest region.We can switch the value to change the access of cold and heat source equipmentin SHEC system. The suitable regions to use SHEC system can be divided into nineparts based on the characters of evaporation cooling applicable regions and the solarenergy heating suitable regions. So introducing the concept of cooling load andthermal load ratio to analysis the matching of common terminal facilities、pipediameter and pump and to put forward to the adjusting methods in SHEC system.Through the analysis and calculation of cooling load and thermal load ratio ofthe applicative cities for using the combined system of evaporation cooling airconditioning and solar heating (SHEC) in northwest region,it ranges from0.27to0.44.Under the cooling load and thermal load ratio ranges，the terminal of SHECsystem studied in the area of matching optimization then the suitable choosingmethods were got.The evaporative cooling system can provide cold water’stemperature ranging from17~20℃, under the condition of17~20℃,when the fan coil units were used as terminal facilities, the matching hot water’s temperature wasadjusted ranging from32~52℃and the selective basis of fan coil units were obtainedby adjustable air volume; when the low-temperature radiant floor were used as theterminal equipments, the matching hot water’s temperature was adjusted rangingfrom30~47℃.The selection method of the common case of pipe during summer and winterseasons is proposed. And the selecting principles of economic specific frictionalresistance in two different conditions of pipeline system are proposed by comparingwith economic specific frictional resistance in single condition of pipeline system.The corresponding value is Which meet the pipeline system including bothinitial investment and running costs during summer and winter seasons when the totalenergy costs to a minimum.Using the same pumps require the water’s running point lying in the efficientregion. During summer and winter seasons, so the cooling load and thermal load ratiolies in the extent of [GG，GG,ab is the most left and right endpoints of pump’srunning efficient region. It can be controlled by using variable frequency and speedpump and impeller cutting method to change the pump running efficient region inorder to satisfy the operating demand of the system in case of dissatisfying the region.The conclusion provided a design basis for generalizing the applicability of SHECsystem in northwest region.