Optimization On Air Distribution Of Air Conditioning Systems And Strengthened Ventilation By Solar Chimney In The Commercial Restaurant

Commercial restaurants are an important part of urban commercial complexes,providing people with daily dining and social gathering places.In restaurant business,the large heat and moisture load of the restaurant is usually removed by turning on the air conditioning.In addition to providing the necessary refrigerating capacity,whether the air conditioning is reasonable or not will affect the thermal comfort of the people.Besides,in order to save energy consumption,air conditioning and ventilation facilities will be turned off during non-meal time,which will lead to poor indoor thermal environment.Therefore,it is of great significance to rationally design and optimize the air conditioning and ventilation airflow distribution and create a healthy and comfortable catering environment.It takes the indoor thermal environment of a commercial restaurant using a fan coil and a fresh air system in Chongqing as the research object.First,it measures the indoor airflow distribution of the restaurant when the air conditioner is running and the indoor ventilation airflow distribution when the air conditioning is off during the non-meal time.The reliability of the numerical simulation is verified by comparing the measured results and the simulated results(under the measured conditions)of the commercial restaurant indoor air distribution.On this basis,analyze the indoor air distribution of the original air conditioning system using different air supply angle under the summer design conditions,find the optimal air supply angle to guide the project commissioning,propose an improvement plan for the shortcomings of the original air conditioning system and carry out optimization calculation and analysis.According to the characteristics of the restaurant's thermal environment during non-meal time,a general model of a room with an internal heat source combined with a Trombe wall solar chimney is established to study the influence of the heat flux density,temperature of internal heat source and chimney gap width on the solar chimney ventilation performance and room the internal thermal environment.Provides a basis for commercial restaurants to enhance natural ventilation with solar energy.research shows:(1)The air supply angle of the single-layer louver has a great influence on the indoor air distribution and air quality in the restaurant.The decrease of the air supply angle leads to the increase of the horizontal velocity component of the air supply port and the temperature stratification along the horizontal direction.At the same time,the vertical velocity component of the air supply port will decrease,so that the air supply will spread rapidly,the temperature of the occupied zone will increase,and the mean age of air will increase.(2)Under the design conditions of commercial restaurants in summer,compared with 60°and 45°,the airflow distribution and thermal comfort distribution are better when the air supply angle of the air conditioner is 90°.But,there are still problems such as the overall low indoor temperature,the excessive wind speed under the fresh air outlet,the temperature in the occupied zone is too cold,and the temperature distribution in the horizontal direction is unbalanced.(3)By raising the temperature of the air outlet in zone I and zone II,the local undercooled phenomenon in the occupied zone is effectively improved,make indoor temperature distribution in the comfortable range from 24?to 26?.By increasing the size of the fresh air outlet,the wind speed of the fresh air outlet is reduced,and the diffusion range of the fresh air is increased,so that the wind speed of the fresh air is reduced to less than 0.3m/s before it is sent to the occupied zone.Compared with the optimal design condition when the air supply angle of the air conditioner is 90°,through the integrated optimization of increasing the air supply temperature and increasing the size of the fresh air outlet,the average temperature in the occupied zone is increased by1.7?,the average PMV value is increased by 0.52,the average PDD value is decreased by 8.14%,and the average air age is shortened by 104.6s,improving the uneven distribution of horizontal temperature effectively.(4)Increasing the heat flux density of the heat storage wall,the temperature of indoor heat source and the width of the chimney gap can all improve the ventilation performance of the Trombe wall solar chimney.And in addtion,the influences of the width of the chimney gap and the heat flux density of the storage wall,the width of the chimney cavity and the temperature of the internal heat source on the ventilation volume of the solar chimney are mutually gained.However,the internal heat source temperature and the heat flux density of the heat storage wall are mutually inhibited.(5)The use of solar chimney can improve the indoor thermal environment of the room with internal heat source.When the indoor heat source is 40?,to the Trombe wall solar chimney room that the heat flux density of heat storage wall is 100W/m~2,the average temperature of the personnal activity area is decreased by 0.14?,compared with the unorganized natural ventilation room with a heat storage wall that heat flux density is0W/m~2,PMV value lower 0.05,PDD values isdecreased by 1%,the indoor thermal comfortableness gets a improvement.And the mean age of air is reduced 396s,the air exchange efficiency is improved obviously.