Heating Ventilation and Air Conditioning Design Air Conditioning Circulating Water Pumps Economic Tips and Tricks: 1 Choose the appropriate number of circulating pumps to avoid unnecessary waste of resources. Article 6.1.11 of the Code for Design of Heating, Ventilation and Air Conditioning (GBJ19-87, 2001 edition) stipulates that the number and flow of chilled water pumps (primary pumps) should correspond to the number of chillers and the flow rate under design conditions . Secondary pump settings should be based on the size of the cold water system, the pressure difference between the parallel loop of the degree of difference, conditions of use and regulatory requirements through technical and economic comparison. However, in practical work, designers often fail to conduct a comprehensive technical and economic analysis on the comprehensive disposition of various equipments of the air-conditioning system. As a result, the initial investment of the project and the waste of resources such as the "Malaysian car" are caused. To avoid this phenomenon, the majority of designers in the program design stage should be based on the use of features, peak load time, system characteristics and other conditions, for air-conditioning systems, chillers, circulating pumps, cooling towers and other equipment comprehensive configuration full Technical and economic analysis, with a view to meet the use of functional under the premise of reducing project cost and operating costs. 2, a clear project life and cycle of investment costs. I believe that in the process of circulating water pumps, chillers and other equipment, technical and economic analysis should introduce a concept - engineering life cycle costs. The life cycle cost of a project is the expenses incurred in the process of engineering design, development, construction, use, maintenance and scrapping, that is, the design fee, construction fee, construction fee, maintenance fee and other expenses incurred by the project during its definite life cycle or within the scheduled validity period. Operation and maintenance costs, the sum of scrap recovery fees. Life-cycle costs are also quite different for different projects and different project phases. Often, operating and maintenance costs are often greater than the one-time investment in project construction. Therefore, during the technical and economic analysis, it should be made clear that the cost of life cycle includes the cost items, the content and scope of each fee, and their interrelationship in the cost constitutional system, which is very important for our technical and economic comparison. 3, the use of value engineering concepts, and strive to minimum project investment to achieve the necessary use of functions. Value engineering aims to improve the value of a product or a job by seeking creative management of a user with the minimum life-cycle cost through organized and creative work, as expressed in Eq. 3.3.1. V = F / C (3.3.1) where V - the value of the research object F - the function of the research object C - the cost value of the research object Engineering technology has been widely used in research and development, design, construction and other industries, The core idea is that the product has the necessary functions it has at the lowest life-cycle cost. In the air conditioning equipment selection and technical and economic analysis, designers should make full use of value engineering concepts, and strive to achieve the minimum necessary investment in the use of functions. Of course, the current situation, to achieve such a design level will take time, but the majority of designers should work in this direction, with a view to achieve good social and economic benefits. 4, other matters needing attention: â‘ in the air conditioning design should objectively and accurately calculate the cooling load and system resistance, thus avoiding the resulting equipment selection is too large; â‘¡ select the circulating pump, pay attention to the pump operating point shift to the right to Ensure the pump lift change within the allowable range of normal operation of the system; â‘¢ project life cycle cost and value engineering are good tools for economic evaluation of engineering, technical and economic analysis should make full use of them.