Numerical Study Of Indoor Thermal Comfort Under Stratum Ventilation

Nowadays, a lot of countries have been perplexed, so energy saving and emission reductions have been an urgent issue. Energy consumption by constructions has taken up 30% or so of the total. Of all the energy consumption, the HAVC system becomes the largest consumer, and its consumption of energy takes up over 50% of the total energy consumption by constructions. So it is meaningful to realize HAVC energy saving.So far, in order to realize that, the designed temperature of HAVC indoors in summer must be increased. The common way is to increase air supply temperature and decrease fresh air volume. But in this way, it may cause some other problems, for instance, short of flowing air, maldistribution of temperature, increase of pollutants in breath areas, weakening of air quality. And as a result, the staff would make complains, so that the efficiency would be lower. What is worse, it may causes the Sick Building Syndrome. However, in terms of traditional hybrid ventilation system, it is greatly limited by the fresh air volume and the way of air supply. Under the condition of increase air supply temperature and decrease of fresh air volume, hybrid ventilation has defectiveness in comforts and increase of air quality. So it becomes a key research project how it can both provide comforts and high quality of air. In this background,a lot of researchers came up with new type of air conditioner--Stratum ventilation system under high temperature. It not only solves energy consumption of air conditioner but also makes up the weakness which means the traditional air apply mode cannot both decrease air supply volume and make the staff comfortable. But, it is not widely studied. Different flow parameter in different working conditions should be studied further.In order to further study the influence of Stratum ventilation system and its practical advantage, this thesis studies a office using Stratum ventilation system and set up mathematical model and physical model. And also this thesis chooses and simplifies these models and settles reasonable border conditions. In general, RNG k-? and simplification of near wall function method are used here. And it also calculates indoor temperature field, velocity field, air age, the comforts of staff and efficiency of air supply mode. In order know air supply mode better, it studies the displacement ventilation and mixing ventilation under the same condition respectively. At the same time, it analyzes how air supply temperature and ventilation rate affect air quality in office.Through the studies of simulation results, it turned out although air supply temperature is high, Stratum ventilation can provide high quality air and make the staff comfortable. This make possible the decrease of energy consumption of air conditioner in buildings. This thesis can be a reference for other room air distribution designs.