1、Thermal environment design and calculation method of large space buildings

Temperature stratification in the indoor thermal environment of large space buildings is significant, and mastering its characteristics is of great significance to thermal environment design and air-conditioning load calculation. For a long time, indoor air temperature and wall temperature of large space buildings have been solved separately and in isolation. After nearly 20 years of research, the research team has used and developed the BLOCK model for solving air temperature in Japan and the GEBHART model for solving wall temperature in the United States, and established the BLOCK-GEBHART (B-G) model to simultaneously solve vertical temperature distribution and vertical wall temperature in large spaces. This model has been verified in saltwater model experiments, gaseous scale model experiments, and large space thermal environment experimental bases with heat sources and exhaust air. The analytical solutions of air temperature and wall temperature of the B-G model provide a strong foundation for indoor thermal environment design and stratified air conditioning load calculation of large space buildings.

2、Calculation method of stratified air conditioning load in large space buildings

For large-space buildings that aim to meet the comfort of personnel activity areas, layered air conditioning is often used to meet the indoor thermal environment requirements of personnel activity areas. However, the traditional calculation method for stratified air conditioning load has many problems such as unscientific and insufficient empirical basis for value calculation. After several years of theoretical research and experimental research, based on the analytical solution of the indoor thermal environment B-G model, the research team established a load calculation method for the stratified air conditioning load of large spaces under the two situations of nozzle air supply and downward air supply, and proposed the relevant line calculations required for calculation. This method has been verified in actual large-space buildings.

3、Design method for nozzle supply air flow organization based on heat source plumes in large space buildings

The airflow organization design of large space buildings is one of the important factors that determine the quality of indoor thermal environment. Conventional methods do not consider the jet deviation problem when the indoor heat plume acts. Through theoretical research and experimental research, the research team obtained a series of trajectory equations for air flow organization design under the action of the heat source plume. Using this trajectory equation, the airflow organization can be designed more accurately to achieve a meeting indoor thermal environment. The research team proposed a design method for nozzle supply air flow organization under the action of heat source.

Taking the dimensionless trajectory equation of an air-conditioning horizontal jet under the action of two unequal heat sources as an example:

4、Design method for long-span jet relay in large space buildings

The lower the layered air conditioning level in a large space building, the less the air conditioning energy consumption. However, at this time, the supply air range is limited and the cold air reaches the smaller the area. The long-span jet relay design method for large space buildings is a new type of air flow organization that uses secondary relay equipment to relay a primary air supply jet to increase the area where the jet reaches. Theoretical research and experimental research results show that this jet relay method can improve the uniformity of the indoor environment and reduce the cold air sensation, which is suitable for the uniformity of the indoor thermal environment over a long span. Through theoretical and experimental research, the research team obtained a design method for indoor secondary relay equipment configuration based on indoor environmental needs.

5、Liquid scale model experimental platform that can simulate the thermal environment of large space buildings under multiple airflow organizations

The illustrated salt water experimental bench is a liquid scale model test platform for multiple airflow organization in a large space building. By installing various tuyere accessories, the test bench can simulate the indoor thermal environment of the building under various air flow forms such as common nozzle side feed and downward feed and central return. The environmental water tank in the figure can simulate the ground, wall, and roof. Indoor thermal environment of large space buildings under different loads. The experimental platform obtains the air flow temperature distribution by measuring the salt water concentration in different areas. The PIV particle image velocimetry technology can obtain the velocity field, that is, the velocity field and temperature field can be quantitatively measured. At the same time, the experimental platform can also realize the visualization of air flow motion. The salt water concentration of the entire experimental bench can be automatically equipped through setting, and all salt water pumps and clear water pumps in the system adopt frequency conversion control. This experimental platform can be used to explore the thermal environment status of large space buildings under different air flow organizations. The experimental platform has reached the international advanced level through expert appraisal.

6、Large-scale PIV airflow velocity field testing device

PIV particle image velocimetry technology is generally used for small-scale flow field measurement. The research team has developed a large-scale PIV airflow velocity measurement device, which uses electric guides to accurately position the PIV sheet light source and camera, realizing unmanned operation of indoor measurement, and controlling indoor space Flow field Fine measurement of key areas and full-field flow splicing technology have expanded the measurement range to 1.2m×2.2m. The following picture is the velocity field spliced by 20 and 18 pictures taken in a gas scale model experiment.

7、Design of energy-saving plan for the utilization of natural ventilation and mechanical ventilation throughout the year

Large space buildings have high heights and high indoor heat, which will lead to increased hot pressure. Natural ventilation or mechanical ventilation methods will be used to eliminate indoor load through orifices such as lower doors, windows and upper smoke exhaust windows of the building; for general buildings, air conditioning systems are used to carry out fresh air throughout the year. Natural cooling source is utilized to reduce air conditioning start-up time and reduce air conditioning energy consumption. Since the amount of heat discharged by natural ventilation or mechanical ventilation depends on the outdoor air temperature, the available natural ventilation or mechanical ventilation heat discharged varies due to the different temperatures of the building throughout the year. To this end, obtaining a maximum utilization plan for natural ventilation or mechanical ventilation based on different temperatures throughout the year, reducing the start-up time of air conditioners, and reducing air conditioning energy consumption are the key to the utilization of natural ventilation or mechanical ventilation. The scientific research team used a number of engineering natural ventilation or mechanical ventilation technology applications to summarize the design method of the year-round natural ventilation or mechanical ventilation utilization plan for large-space buildings, so as to maximize the use of natural ventilation or mechanical ventilation to remove indoor heat during building operation.