Construction and Startup Performance of the Miamisburg Salt-Gradient Solar Pond

An account is given of the construction and 1.5 years of operation of the Miamisburg, Ohio salt-gradient solar pond which, with 2020 sq m, is the largest solar collector in the U.S. The 18% sodium chloride solution pond has reached storage temperatures of 64 C in July and 28 C in February. Under steady-state conditions, conservative heat-yield estimates on the order of 962 million Btu have been made. The heat is used to warm-up a summer outdoor swimming pool and in winter a recreational building. Installation costs were only $35/sq m, and heat costs based on a 15-year depreciation of installation costs is below that of fuel oil heating, at $9.45 per million Btu. Further study is recommended for maintenance of water clarity, metallic component corrosion and assurance of pond water containment.