Estimate the heat loss from the surface of a swimming pool with a 3-m × 10-m surface area and an average depth of 1.5 m and then design a solar heating system for it. Previously, the pool had been heated by an electric heater that is used as a backup when there is insufficient solar radiation to maintain the pool’s temperature, but which is shut down when there is enough radiation for the collectors to heat the pool. The collector panels are oriented toward the south at a slope equal to the latitude minus ten degrees, as recommended by solar experts (see, e.g., J. F. Kreider, C. J. Hoogendoorn, and F. Kreith, Solar Design: Component, Systems, Economics, Hemisphere Publishing, 1989). The pool is located in San Diego, California, where wind speeds average 15 km/h, and is to be maintained at a temperature of 28°C yearround. The solar-heating system is a closed water loop with a piping arrangement that permits flow to the existing heater alone, flow through the electric heater and solar panels, and to the solar panels only as shown in the schematic diagram. The solar collector is to be made of a black plastic extrusion without a cover to minimize cost. The heat transfer coefficient for the water in the rectangular-flow passages of the collector is estimated from Table 1.3. Suggest ways to reduce the heat loss from the pool at night and estimate the cost-effectiveness of the system.

Data from in Table 1.3

Transcribed Image Text:

Retrofit Solar Swimming Pool Heating System Collector panels 111111 Pool Incident solar radiation Water Pump Filter Solar Panel Detail Heater Valve