Optimized Design Of Air Heat Metering For Fan-coil Performance Test System

As the economy develops and the quality of people's life increases,people's requirements for air quality have also increased.The demand for air conditioning equipment for regulating indoor air quality has also increased year by year.The resulting energy consumption and energy waste cannot be ignored.In response to the call for national energy conservation and emission reduction,we must pay attention to the problem of excessive energy consumption and energy waste.Since air-conditioning equipment has become an indispensable equipment in people's lives,we can optimize the design based on existing equipment to reduce energy consumption.This topic combines fluid dynamics simulation with experiments to optimize the thermal performance test system of the fan coil unit to improve the quality of the fan coil and ultimately reduce energy consumption.The main research contents and conclusions of this topic are as follows:?1?Design and construction of fan coil test system.It mainly includes the design of the wind system,the design of the water system,the design of the air pretreatment unit,the design of the air volume measuring device,and the design of the cold and heat source.The focus of this topic is on the optimization design of air heat metering.The design of the fan coil test system is briefly introduced in this paper.Most of the technical indicators and technical parameters of the test system designed in this subject are designed according to the parameters and indicators given by the national standard.?2?Optimized design of gas uniformity in the sampler tube,specifically,the design of the air mixer inside the tube.The air uniformity of the test chamber is directly related to the measurement accuracy of the wet bulb temperature.The venturi tube is divided into a constricted section,a throat,and a divergent section.The venturi tube can be used not only as a throttling device but also as a mixed fluid.Based on the Venturi principle,this project designed a new type of in-pipe air mixer.The auxiliary design methods are Solidworks,CFD and Fluent.The size of the in-line air mixing tube with the best mixing effect is 15mm of L₁/L₃ and 4.7mm of d₁/d₃.?3?Optimized design of wet bulb temperature measurement.Specifically,the design of the wet bulb thermometer automatic humidification device.The measurement of the wet bulb temperature is directly related to the value of the air enthalpy.Increasing the measurement accuracy of the wet bulb temperature is to improve the measurement accuracy of the enthalpy value.A small intelligent automatic humidification device designed by this subject is based on 51 single-chip microcomputer.When the humidity signal transmitted by the humidity sensor is lower than the set value?80%?,the pump starts to work,and the device automatically humidifies the wet bulb thermometer until When the humidity signal transmitted by the humidity sensor is greater than 99%,the water pump stops supplying water.The design of the automatic humidifying device improves the test precision on the one hand,and avoids the trouble of frequent water addition on the one hand.?4?Optimized design of test chamber air uniformity.In detail,the research and design of the air venting plate.Due to the large number of holes in the air supply orifice plate and too many calculation details,the numerical simulation analysis exceeded the capacity of the general computer,which made the fluid mechanics simulation work impossible.In this paper,the similarity theory is deeply studied and the research method of similar model law is proposed to overcome this problem.Since the fluid studied in this paper belongs to the regulated incompressible fluid,gravity plays a major role,so this paper selects the similar model of Furuo.Based on this research method,the fluid dynamics simulation of orifice plates with different pore sizes was carried out by CFD and Fluent methods.It can be found from the simulation results that when the pore diameter is 12 mm,the gas in the test chamber is relatively uniform.Based on the experimental test bench built by this subject,the thermal performance test was carried out.The experimental results show that the optimized design of air heat metering in this subject has greatly improved the test accuracy and has great practical value.