Heat Transfer Characteristics Of Tall Public Buildings’ Stratified Air Conditioning System

In recent years, with the improvement of living standards and economic power, our country has constructed many large public buildings, such as theaters, waiting hall, gymnasium, etc. Because of the high energy consumption of tall buildings, so how to reduce the energy consumption of building has become a problem that researchers pay attention to. The research shows that, stratified air conditioning units can reduce cooling capacity and reduce the energy consumption of buildings. Stratified air conditioning heat transfer characteristics is the focus and difficult research, this paper was based on lots of literatures, and through the experiment and simulation to study the heat transfer characteristics.The main research contents are as follows: In the winter condition, through building the model experiment platform, study eight kinds of different ways of indoor air temperature distribution and measured the temperature and speed of each outlet. Through analysis, under the experimental conditions, when the air outlet height is 1.6m, the indoor temperature distribution is uniform and the effect is best of upper row of wind lower air return airflow forms. According to the similarity principle, the experimental platform for model calculation model, through measuring the air temperature and wind speed, to provide boundary conditions for simulation.This paper is also to simulate the effect of heat transfer characteristics of air height and load ratio. Taking the summer working condition as the research background, the model of the air outlet is established, and the boundary conditions are calculated by the actual air inlet parameters and the heat transfer quantity of the envelope, use of CFD software for the calculation model simulations to evaluate the comfort criteria analysis calculated temperature field, velocity field and PMV distribution. Finally, for large public buildings, when the air inlet height is 3M, the human activity area environment can meet the design requirements can meet human comfort requirements. The air conditioning area outlet height of 3M as the benchmark, a set of air intake system is arranged in non air conditioning area, thereby establishing a calculation model, by changing the proportion coefficient of load, analysis of the calculated temperature field、velocity field and PMV distribution, and ultimately obtain when the load ratio coefficient is 0.75, the air conditioning area will get best comfort.