Solar-Water-Heater Apartment-Building Retrofit

摘要

The purpose of this project was to demonstrate that an older inner-city 19-unit apartment building could be successfully retrofitted with a solar-heating system which would save energy, reduce operating costs, and offer a reasonable payback period on the capital investment. The project involved the design (glycol) solar-water-heating system. The glycol (antifreeze) is circulated through a series of ten solar-collector panels on the roof, where it picks up heat, and then back to the basement through a heat exchanger, where it transmits the heat to water, which is then stored for eventual use in the building. A variety of gauges and meters was installed to measure system performance. As much as 50% of the building's water-heating needs were contributed by solar heat during several weekly periods, with an average solar contribution over a one-year period of 18%. A savings of $950 in natural gas was realized during that year, resulting in a payback period of about 14 years. This fell short of the project goal and is probably too long of a payback period to be attractive to most investors. It was concluded that relatively large and complex solar-heating systems such as this require the help of a professional solar-energy contractor to achieve proper design and installation. Several system failures led to the conclusion that more emphasis must be placed on system reliability if this technology is going to be accepted on a wide scale. (ERA citation 08:025882)