Solar Hot Water
Solar water heating for washing and bathing is an excellent solar application, perhaps more than central heating because the primary need for central heating is at night and in winter when solar gain is lower. Supply and demand are simply better matched when heating water. In many climates, a solar hot water system can provide up to 65% of domestic hot water energy. This can include domestic non-electric concentrating solar thermal systems.
Economics, Energy, & the Environment
The typical 50 gallon electric water heater uses 11.1 barrels of oil a year, which translates into the same amount oil used by a typical 4 door sedan driven by the average consumer. Electric utility companies often provide electricity by burning and releasing energy from fuels such as oil, coal, and nuclear energy. An electrical home hot water heater sits on an electrical grid and may be driving the use of unclean fuels on the other end of the grid. Solar water heating systems can significantly reduce such electricity consumption.
When calculating the total cost to own and operate, a proper analysis will consider that solar energy is free, thus greatly reducing the operating costs, whereas other energy sources, such as gas and electricity, can be quite expensive over time. Thus, when the initial costs of a solar system are properly financed and compared with energy costs, then in many cases the total monthly cost of solar heat can be less than other more conventional types of hot water heaters.
How Solar Hot Water Works 1.Thermal Collectors: Heat Pipes & Evacuated Tube Technology.
Solar Absorption: Solar thermal energy is absorbed within the evacuated tubes and is converted into usable concentrated heat.
Solar Thermal Transfer: Copper heat pipes transfer the thermal energy from within the solar tube into the copper header.
Solar Thermal Storage: A thermal transfer solution (water or glycol mixture) is pumped through the copper header. As the solution circulates through the copper header the temperature is raised by 5-10 °C / 9-18 °F.
Evacuated Tubes: The evacuated tubes are glass tubes manufactured from strengthened borosilicate glass. The tubes have a double outer layer; the outer layer is fully transparent to allow solar energy to pass through unimpeded. The inner layer is treated with a selective optical coating which causes energy absorption without reflection. The inner ?and outer layer are fused at high temperatures at the end leaving an empty space between the inner and outer layers. All air is pumped out of the space between the two layers (evacuation process) creating the thermos effect which stops conductive and convective transfer of heat which might otherwise escape into the atmosphere. Heat loss is further reduced by the low-emissivity nature of the type of glass that is used.
Heat Pipe: Inside the glass tube is the copper heat pipe. It is a sealed hollow copper tube that contains a small amount of proprietary liquid, which under low pressure boils at a very low temperature. In fact, the liquid contained in the heat pipe boils at only 86 °F (30 °C).
2. Solar Heat Exchanger Tanks
The solar heat exchanger tank stores 80 or 120 gallons of solar heated water depending on model selected. Typically the heat exchanger tank sits between the city/well water supply and the customers existing tank. When hot water is drawn from the existing tank, it is replaced by water from the solar tank that is already hot, meaning that the heating elements or gas burner of the existing tank do not have to operate.
3. Solar Pumping Station, Pumps & Controllers
Tying the collectors and the tank together is a system that consists of valves, a controller, and a pump.Options are available to configure the system using a pre-configure pump-station (left), or design it with best-of-breed components (right). Our installers use both methods, depending on the application.
Solar Tax Incentives
Solar hot water systems are a great way to a Green lifestyle. With a reduction of the cost of hot water by 85% plus progressive tax incentives, your solar water system will pay for itself in two to four years. Federal Tax Credits are available for up to 65% of the total installed cost of your solar hot water and space heating system.
Here are three examples of the cost savings of our hot water and heat systems.
1. Hot Water Only - 2 solar collectors
$11,000 - Complete Installation
-$3,300 - Federal Tax Credit
-$1,400 - North Carolina Tax Credit $6,300 - NET COST
2. Hot Water with Solar Space Heat - 2 solar collectors
$12,500 - Complete Installation
-$3,750 - Federal Tax Credit
-$3,500 - North Carolina Tax Credit $5,250 - NET COST
3. Hot Water with Solar Space Heat - 3 solar collectors
$15,700 - Complete Installation
-$4,710 - Federal Tax Credit
-$3,500 - North Carolina Tax Credit $7,490 - NET COST
Avery Tax Incentives for Solar Hot Water