Optimal Design Of Building Hot Water Supply System

With the continuous improvement of people’s living standard in China, people’s demandfor their living environment is becoming more and more high. The hot water supply of livingarea is an important reference index about comfort of living environment. However,compared to the research of domestic water system and domestic sewage systems, theresearch and development of hot water supply system are relatively backward. From a designperspective, code for design of building water supply and drainage in China are basicallyadapted from the former Soviet union’s Code for design of building water supply anddrainage, the portion of hot water supply and drainage has been revised for many times,because of the relative lag of our economical development in our country, the portion of hotwater supply exist more controversy than the portion of water supply and drain. Plagued bycontroversy, designers often set the foreshadowing about security and stability in designing，thus strengthen the research on hot water supply is very necessary.This paper systematically expounds the type of the building hot water supply system,points out that all kinds of advantages and disadvantages of supply system and the scope ofapplication. This papers summarize the hot issues on system design, hot water systemenergy saving, water saving, security control of hot water pipe network and so on. Meanwhilethis paper describe research model of hot water system and the methods that solve the modelin detail. This article from the perspective of building water supply and drainage design, wepropose new definitions about reversed return hot water system. If the hot water through thehot water pipe network in different paths has the same head loss，we consider this hot watersystem belongs to reversed return hot water system. The old definition is just a special case ofunder the new definition. In this paper, we study model that has different high, not reversedreturn hot water pipe network, calculation of hot water system took a computer calculationgreatly simplifies the calculation process, improves the accuracy of calculation. Bycalculating we can reach some conclusions, such as the each section of pipe diameter, flowvelocity, flow, temperature drop, heat loss and node temperature. Based on the beginning andend of the pipe network each path (return water main point), we establish Bernoulli equationto find out the hot water system control points (the lowest pressure point in water distributionpipe) calculating the head loss of each path, by adjusting the head loss of the path to make itsame with head loss that of the control point path through, so as to meet the newly definedand make sure the safe operation of the hot water pipe network system. At the end of the paper, we use project to prove the veracity and practicability of the newdefinition. We probes into controversy about code for design of building water supply anddrainage and come to the conclusion.