Study On Water-cooled Variable Refrigerant Flow Air-conditioning System Based On Indirect Evaporative Chiller

With rapid development of the construction industry,building energy consumption continues to increase.However,one of the reasons for the increase in energy consumption in the building sector is the increase in energy consumption of air conditioner.Therefore,research and develop new air conditioning system,and reduce the energy consumption of HVAC systems has great significance in improving building energy efficiency.As a new energy saving air conditioning system,water-cooled VRF system can provide some appealing benefits,such as outstanding part-load efficiency,installation flexibility,comfortable and energy saving,flexible control and so on.What?s more,as an efficiency,energy-saving and green refrigeration technology,evaporative cooling has been widely applied in building air conditioning refrigeration system in recent years.In dry climate region,utilize evaporative cooling technology can produce cold water,which can be used as the cooling source for the air conditioning system.Nevertheless,in semiarid climate region,the higher temperature cold water by using of the evaporative cooling technology cannot satisfy the demand of indoor cooling.How to promote the promotion and application of evaporative cooling and reduce building energy consumptionin semiarid climate areas is a valuable research issue.To solve the problem,a new air-conditioning system,named as water-cooled VRF system based on indirect evaporative chiller(or indirect evaporative water-cooled VRF system),which combine the water-cooled VRF system with indirect evaporative chiller is proposed in this paper.The objective of this paper is to investigate the feasibility of combining two energy-saving technologies and determine if this integrated system configuration can realize desirable levels of energy savings in the hot and semiarid climate of western China.Based on the structure and working principle of the indirect evaporative water-cooled VRF system are presented in this paper.And the article establishes the mathematical model of all parts.Next,write the system simulation program for the established mathematical model by using the MATLAB simulation software and the system performance simulation analysis of of an office building in Turpan area is carried out.In addition,comparisons on the energy consumption between the indirect evaporative water-cooled VRF system and air-cooled VRF system during the whole cooling season is analyzed,and makes a quantitative analysis of the system energy saving potential.At last,this paper will also compares and analyzes the energy consumption of the novel hybrid air conditioning system and traditional air-cooled VRF system in different regions to obtain the system energy saving potential and application evaluation in different regions.And the conclusions of this study are as follows.(1)In Turpan,the monthly energy efficiency ratio of the indirect evaporative water-cooled VRF system in June,July and August is 7.73,7.15 and 7.56 respectively.And the summer cooling season energy efficiency ratio is 7.48,its energy consumption is only 63% of the traditional air-cooled VRF air conditioning system,which achieves the desired energy saving effect.(2)The energy consumption of the novel hybrid air conditioning system in Yinchuan and Tieguanrik regions is 91% and 75% of the traditional air-cooled VRF air conditioning system,respectively.And the system has a certain energy-saving advantages in semiarid areas.(3)In Xi?an,a typical city in middle humidity areas,the energy consumption of the new hybrid air conditioning system is close to or even slightly higher than that of the traditional air-cooled VRF system.In terms of comprehensive initial investment and maintenance costs,the system is not suitable for popularization and application in middle humidity regions.