This paper presents a phototype for a direct expansion solar heat pump system for domestic water heating and its performance date. The prototype system consists of refrigerant-filled solar collectors as an evaporator, a variable-capacity compressor, a double-wall copper tube heat exchanger as a condenser, an electric expansion valve, and a thermal storage tank.
The collectors, which are made of anodized extruded aluminum, are bare (without cover glass and insulation) and can be integrated into a house structure (roof, wall) or (fence). The aperture area of the roof-integrated collector is 6.0 m2 ( 65 ft2 ). The compressor is a rotary type, and its capacity modulation is done by a frequency controller. The electric expansion valve can handle a wide range of refrigerant (R-22) flow rate in order to obtain an appropriate superheat in the collector. A thermal storage tank of 470 liters is used for the system.
Results of indoor experiments with a solar simulator in an environmental room show that the system can heat water up to 55°C with a high coefficient of performance, 3.7-4.2 throughout the year. Outdoor field tests resulted in coefficients of performance of 3.1-3.7 for the four systems tested throughout the year.
Units: Dual
Citation: ASHRAE Transactions, 1987, vol. 93, pt. 1, New York, NY
Product Details
- Published:
- 1987
- Number of Pages:
- 11
- File Size:
- 1 file , 900 KB
- Product Code(s):
- D-NY-87-3052
