Solar Energy Facts-Hot Water

Solar water heating is a good first step when considering going solar due to low cost and high efficiency. When we look at solar energy facts we find that hot water represents the second highest energy demand in U.S. households. On an average most water heaters use as much energy in a year as a medium-sized car. A typical solar water heating system reduces the need for gas or electric water heating by about two-thirds.

Our solar energy facts tell us systems that use direct heating of water using the sun's rays consist of two main parts: 1. a collector which heats the water, and 2. a storage tank. The main types of collectors are integral tank and flat-plate. The flat-plate collectors are the most widely used for domestic solar water heating. They have an operating range from well below 0 deg f to around 180 deg f, which is almost exactly what is required. Flat-plate collectors are rectangular shallow boxes typically four by eight feet with a strong frame and glazing fastened to the front. The frame has a solid back and an absorber plate just beneath the glazing. The absorber plate has riser tubes, usually half-inch copper pipes running vertically, spaced 3 to six inches apart, and welded into manifold pipes which are positioned horizontally top and bottom. Copper fins welded to the risers help with the efficiency of the absorber. Insulation provided beneath the absorber also contributes to the efficiency of the whole unit. Low iron tempered glass is preferred for the glazing.

There are a number of tank options available for the person desiring to invest in solar hot water. The type of tank needed depends on several factors-climate, size, and cost being among the most important. One of the simplest designs calls for a flat-plate collector using coolant or anti-freeze coupled with a regular hot water tank with an insertable heat exchanger installed. This is called a closed loop system. This arrangement also requires a pump for cycling the anti-freeze from the collector, through the heat exchanger, and back to the collector.

These systems can cost anywhere from around a thousand dollars for a small do-it-yourself project, to as much as six to fifteen thousand for a high end, northern climate deluxe product. Federal tax credits are available nationwide and state credits and grants are available in some states.

The solar energy facts assure us that a domestic solar water heater is a practical and cost effective way to generate hot water for a home. Today's solar thermal industry includes reliable, efficient products and trustworthy professionals who can install and maintain your equipment.

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