The Indoor Environment Numerical Simulation Research Of Radiant Refrigeration Of Capillary Network And Personalized Ventilation

Nowadays,refrigeration modes in most buildings remain traditional,resulting not only in energy waste but also in low air quality.As a kind of refrigeration method with outstanding performance,radiant refrigeration is becoming more and more popular.However,the quality of indoor air cannot be guaranteed when the radiant refrigeration system is used separately.Thus,it must be used in combination with fresh air system.The personalized ventilation can meet the requirements of thermal comfort of people indoor.In this paper,a new type of composite system is formed by combining the radiant refrigeration system of capillary network and the personalized ventilation system.The mechanism and simulation theory of the composite system were described.The proposed system was numerically simulated by Airpak 3.0 and the feasibility of this software is checked and the grid irrelevant is verified.In view of the actual condition in Xi'an,the geometric model of a simple double office in an office building was established and its indoor load was calculated.Numerical simulation of three refrigeration systems,floor radiation combined with replacement ventilation,all-air conditioning,radiant refrigeration of capillary network and personalized ventilation,were studied respectively.The thermal comfort of three systems was analyzed comparatively.Meanwhile the relationship between the air supply temperature,the placement position of the capillary pipe network,the proportion of personalized air supply,the location of air supply inlet,the air supply speed,and the proposed system were also studied.The results show that the addition of a personalized ventilation system can reduce the ambient temperature and increase the speed of the air flow around the human body,which is why the thermal comfort of the composite system is better than those of the other two systems.Under the condition of meeting the requirements of interior design,increasing the ratio of cooling load of the capillary pipe network or reducing the air supply temperature will improve the thermal comfort of human body.When the capillary pipe network bears a certain cooling load,applying it to the top of the room is more in line with the body's thermal comfort requirements than applying it to the bottom of the room.Increasing the air supply speed of the background air vent or the personalized air vent will enhance the body's thermal comfort.If the air supply speed of both vents increases at the same time,the improvement of thermal comfort will be more noticeable.However,personalized air vents have limits on air supply speed,and excessive wind speed can cause a sense of blowing.The position of the air vents can affect the indoor air distribution.When the capillary pipe network is placed on the top of the room,the influence on human thermal comfort is more obvious by adopting the air supply method of down-supply down-return.Increasing the proportion of air supply of the personalized air vent can also effectively enhance thermal comfort,but the effect will be relatively weak when this proportion exceeds 50%.This paper provides a reference for the setting of the design parameters of the radiant refrigeration system of capillary network and personalized ventilation.It also establishes theory foundation for the actual application of such composite system in public buildings in Xi'an.