Numerical study on the heat transfer limits of a novel dual-condenser heat pipe integrated with photovoltaic/thermal (PV/T) system

The heat pipe PV/T system has the advantages of high solar energy utilization rate and heat transfer capacity, nonfreezing. Most existing heat pipe PV/T system has a single condenser structure and cooling method. Based on the novel dual-condenser heat pipe PV/T system proposed in this paper. The heat transfer limit mathematical model of the proposed system is established and the effects of the operating temperature, evaporator inclination, evaporator size and height difference on it is analyzed. As the temperature increases from 10 degrees C to 70 degrees C, the system's heat transfer limits in heating and hot water modes increased from 12.6 kW to 48.2 kW-51.8 kW and 197.6 kW, representing a growth of 311% and 309% respectively. The boiling limit and capillary limit gradually increase with the evaporator inclination increasing and decrease with the evaporator length increasing. The capillary limit gradually increases with the height difference increasing. However, the sonic limit is only related to temperature and system structure. Under the default condition, the sonic limit of the system in space heating mode and hot water mode is 22 kW and 84 kW respectively.