Solar energy system performance evaluation. Aratex Services, Inc. , industrial laundry, Fresno, California, June--September 1978

The system utilizes 140 collectors manufactured by Ying. The collectors are flat plate and lexan glazed. They provide an effective aperture area of 6500 square feet. The collectors are mounted in 24 rows on the flat roof of the building. The 12,500 gallon insulated fiberglass storage tank is mounted on an above ground slab in a partially enclosed area. All solar energy system piping is copper. All exterior piping is insulated with fiberglass covered by an aluminum jacket. The solar energy system is used in conjunction with a heat recovery system. Softened cold water is first pumped through a heat exchanger which recovers heat from the laundry wastewater. The water then flows into the solar storage tank and circulates through the collectors. It is then pumped through another heat exchanger which boosts the water to the required temperature of 170/sup 0/F. Steam from a low pressure gas-fired boiler located in the building is used as the auxiliary energy source. The hot water is stored in a 4,000 gallon holding tank which contains an immersed heat exchanger that adds heat to the water from the steam condensate. The ARATEX solar system has an average hot water demand of over 30,000 gallonsmore » per day at a temperature of 180/sup 0/F. The heat recovery system reduced the hot water load at the laundry by 30 percent. Of the remaining load, 25 percent was provided by solar energy.« less