Study On The Mechanical Ventilation Technic In Guangzhou

Ventilation is an effective method to improve the indoor thermal environment and airquality. Rational ventilation design is important for people’s health and building energyconservation. Firstly the adaptability to the climate of mechanical ventilation in Guangzhou isanalysed based on the experimental research on mechanical ventilation in this paper. Then aresidential mechanical ventilation control system is designed so as to realize the integratedoperation of fan and air-conditioning. In order to analyse the actual operation of the system anactual residence is choosed. The main research works are as follows:(1) The indoor thermal environment of mechanical ventilating room and naturallyventilating room is tested. The analysis results show that the difference between indoor andoutdoor temperature after10:00pm were greater than1.0℃, the maximum is5.9℃. Thecooling effect of mechanical ventilation is better than natural ventilation because thetemperature of mechanical ventilating room is lower than naturally ventilating room and themaximum temperature difference is about1.2℃. It can be conclude that in Guangzhoumechanical ventilation is more suitable for cooling. Further more, the experimental resultsshow that the indoor thermal environment of mechanical ventilation room is relatively stablecompared with natural ventilation room.(2) The mechanical ventilation system for a residence in Guangzhou is designed. Usingthe DeST-h software to determine the optimal ventilation rate.Based on market research,combined with the ventilation quantity and residential ventilation requirements, anappropriate fan is selected and installed in the choosing house.(3) A residential ventilation control system is designed and producted, includingdetermination of control parameters, control modes and control strategy. After installation ofthe controller in the choosing house in Guangzhou the system performance is tested, theresults show that: the ventilation control system is running well, and it can reduce the openingtime of air conditioning by56%from the evening of May10thto11th. The setSize of Tmaxand temperature of air conditioner directly affect the opening of the fan and air conditioning.Recommend users to set Tmax to29℃. The temperature of air-conditioning should not belower than26℃. And also the set temperature of air conditioning is higher, the opening timeof the fan is longger, which mean it is more energy saving.(4) Using CFD software to analysis the effect of outlet on indoor wind speed, the resultsshow that, when the ventilation quantity is certain, a bigger outlet doesn’t mean higher indoor wind speed. The ratio between the height and width of outlet has a certain influence on theindoor wind speed, when the ratio equals to1.0, indoor wind speed is lower, and ratio equalsto other values, indoor air velocity is higher.In this paper a research on the design of a mechanical ventilation control system in aresidence in Guangzhou is investigated in order to realize the coupling operation between thefan and air conditioning. The test of the system in a house shows that the system is runningwell, the room temperature can maintain in a certain scope after the fan opens, and it canefficiently save the opening time and electricity consumption of air conditioning. Theresearch in this paper could be a reference for in-depth study on residential ventilation controlsystem design in different climate area.