A Research Of A Bidirectional Ventilation Device To Improve Indoor Environment

With the economic developed rapidly and the people’s living standard improved,urban residents average spend more than80%of their time on living or working indoor.The quality of the indoor environment not only has an effect on the residents’ health andcomfortable but also has a significant impact on the work efficiency of workers workedin the room. So, buildings’ indoor environmental quality has been paid attention.Currently, the office extensive uses the split-type air-conditioning. Thus, the roomhasn’t organized fresh air and it relies mainly on the penetration of door and window orobtains fresh air by ventilation to opening window. But, the way will be restricted byusing air-conditioning to make room cooling or heating and haze or sand weathercondition. In order to study the effectiveness of the ventilation in the office, simulated theventilation and ventilation rate impact on indoor air environment in transition season andsummer or winter climate conditions in typical operating condition and explored theparameters of the small ventilation device how to select. The main contents of this thesisare as follow:1. Simulated of the external wall of the constant heat flux and adiabatic boundaryconditions, the air velocity and the air temperature distribution has large differences. Inthe summer condition, the wall transfer heat compared with the wall heat insulation, theformer office’s indoor temperature is higher than the latter1.5℃. In the winter condition,the wall transfer heat compared with the wall heat insulation, the former office’s indoortemperature is lower than the latter3.5℃, furthermore, the former residents’ draughtsensation is less than the former and the velocity distribution is more uniform.2. Simulated the indoor air velocity、air temperature、CO₂concentration and thethermal comfortable distribution of the ventilation mode of the ventilation device used intransition season. Results shown that when the outdoor temperature is20℃, indoor airtemperature is22.3℃, the average CO₂concentration is about890ppm in breathing zone.3. Simulated the ventilation device worked in heat recovery mode by change theamount of ventilation is impact the indoor air environment. Through simulation anlysis,in order to control the concentration of CO₂in the breathing zone is1000ppm, theminimum ventilation rate is49.8m3/h.4. Under premise on the meet indoor ventilation, by changing the ventilation rate ofthe ventilation device in heat recovery mode combined with the optimum supply airwhen the split-type air-conditioning heating or cooling, simulated the distribution ofoffice’s velocity field、temperature field、CO₂concentration field and thermalcomfortable, it will give reference for selection guide for the use of the device in theoffice. The results shown, with the velocity of air increased, the average indoor airflowvelocity is increased in summer, but the average indoor airflow velocity is decreased inwinter.