Research On Floor Radiant Heating System Using Transcritical CO₂Heat Pump

Accompanied by the acceleration of the urbanization, the proportion of the building energy consumption in the total community consumption is increasing. The floor radiant heating system is more and more popularized with its operation energy saving, good thermal comfort. As a high efficiency and energy saving technology, heat pump is suitable as the heat source for the floor radiant heating system. However, the commonly CFCs with their destruction of the ozone layer and the greenhouse effect, already have faced been eliminated. The research object of this paper is the floor radiant heating system using transcritical CO2heat pump. This paper uses theoretical analysis and simulation method to respectively study the guest room and the heat pump components, provides theory foundation for its application.According to the energy balance equation and the human physiological regulatory characteristics, the thermal comfort factor is analyzed such as the vertical air temperature and the level air temperature, and the indoor thermal comfort evaluation equation of the floor radiant heating system is given.According to the outdoor climatic parameters and the building conditions, the load is calculated and the piping installation scheme is designed, the components of the transcritical CO2heat pump is designed. This paper numerically simulates the floor radiant heating system with software FLUENT. The average PPD in the people basically activity space is less than10%, when the water temperature of the floor radiant heating system inlet tube is between36-42℃, providing a comfortable thermal environment.This paper sets up the steady-state mathematical models of the transcritical CO2air-water heat pump system components. If the gas cooler water flow continues to increase when it meets the design flow, the gas cooler heating capacity Qh, fails to have obviously improved. So, this adjustment has little influence on the performance. Higher temperature of the gas cooler water inlet would lead to the heat transfer performance fell sharply. If the evaporator air flow continues to increase when it meets its design flow, the gas cooler heating capacity Qh and the system COPh, fails to have obviously improved. When the environmental temperature decreases, the gas cooler heating capacity Qh, and the system COPh decrease obviously.