Experimental Study on Capillary Floor Radiation Heating System with Air-Source Heat Pump

The air-source heat pump capillary radiant floor heating system directly heats the floor using a refrigerant as the heat transfer fluid, which employs a simple system and promotes good heat transfer. This study developed an experimental device for capillary floor radiant heating with an air-source heat pump, and a heating experiment with parallel capillary floor radiant terminal was conducted at different outdoor ambient temperatures. The experimental results demonstrate that a longer time is required for the temperature of the capillary floor radiation terminal to reach steady as the outdoor temperature decreases. When the outdoor temperature was -5 ℃, the required time was 120 min. The temperature difference between the discharge inlet end and the condenser outlet end on the same capillary wall was large. The temperature difference on the capillary wall reached 6.40 ℃, while that on the surface of the 20 mm-thick cement floor reached 4.20 ℃. Conversely, the vertical temperature difference from the capillary wall to the cement floor surface was small, not exceeding 0.40 ℃, and the vertical heat transfer effect of the floor was good. The temperature difference at the same position of different capillaries was within 0.80 ℃, and the temperature uniformity was good. When the outdoor temperature was -5 ℃, the heating coefficient of performance of the unit reached 4.61 with good heating performance.