Research On Air Conditioning Chilled Water Piping Network

Air conditioning energy consumption occupy a large proportion of energy consumption inbuildings, water systems and energy consumption accounts for about60%to80%of the total energyconsumption of air conditioning systems, it is how to effectively reduce air conditioning energyconsumption for energy conservation has become a research focus.Currently, the evaluation of air conditioning system stability traditionally is the hydraulic stability,while the system changed due to changes in other branches traffic flow regulation.when the system inactual operation, users tend to emphasize the heat energy demand direction, so this combination ofheat on the stability of the pipe network disturbing aspect,to assess the extent of the active branchflow regulating effect on passive cooling capability of air-conditioning equipment branch.Taking a project as a prototype for constant pressure variable flow air conditioning water system,considering network hydraulic properties and thermal properties, the establishment of a chilled waternetwork system model. Simulation of the initiative under the most unfavorable branch in a givenmanifold pressure control strategy, disturbances passive branch hydraulic and thermal characteristicswhen in different conditions, as well as the pipe network characteristic curve and pump operatingpoint change state corresponding to the state.The first chapter introduces the research status and application of variable flow air conditioningprogress history, air conditioning system’s status, variable flow air conditioning system andintroduced variable flow air conditioning control method and air conditioning pipe network stability.The second chapter to establish a system of air conditioning and refrigeration pipe networkmodel, including network model of pipe valve model, surface cooler model, pipe model, pump model,and the model is reasonable instructions were demonstrated.The model considers the chilled water network system in the actual operation of the pipe networkcharacteristics, operational parameters studied by theoretical analysis and numerical simulation methods such as valve position, chilled water inlet temperature, surface cooler heat transfer coefficient,the surface cooler factors affecting wind speed of contact factor and so on, are established theoreticalpipe network system model accuracy.The third chapter by chapter air conditioning chilled water network system model using constantpressure control strategy, the six most unfavorable conditions of the air conditioning pipe networkcharacteristic variable flow pump, valve position and temperature characteristics, the scope of thesurface cooler cooling capacity characteristics were analyzed to obtain a more precise parameterchanges, and the simulation results analysis integration.Air-conditioning chilled water network system model chapter use chapter two, the introduction ofgraph theory model and hydraulic stability and thermal stability index, thermal stability of the systemfor analysis. Air conditioning and refrigeration fluctuation range obtained water distribution networksystem stability, so as to require a temperature-controlled precision air-conditioning system provides atheoretical basis.The fifth chapter summarizes the main content and conclusions of the full text and summary ofthe thesis of innovation.