| If there is a solar power house application that | | | | tanks inside a glazed insulated box where cold water |
| stands out as the place to begin, it is the production | | | | is preheated in the solar collector tanks before |
| of solar hot water for domestic consumption. The | | | | moving into a conventional water heater. |
| reason for this is that this application is usually the | | | | If a "zero-carbon" active system is desired, there are |
| most cost-effective and simplest home solar | | | | also some good, inexpensive DIY solar power |
| application that can be undertaken. On average, the | | | | electricity packages which make it practical to |
| cost of producing domestic hot water by | | | | generate sustainable onsite electricity with which to |
| conventional means constitutes between twenty-five | | | | pump the fluid and to operate its control electronics. |
| and thirty-three percent of total home energy costs, | | | | Regardless of whether an active or passive system |
| and a solar hot water system can save between | | | | is employed, both usually have a backup heat source |
| two-thirds and eighty-five percent of this energy | | | | included to heat the water as necessary to maintain |
| cost. | | | | appropriate temperatures. |
| Another important reason to start with this project in | | | | Flat-plate panels are normally used to collect heat in |
| converting a fossil energy home to solar is the | | | | residential solar applications for two reasons: they |
| increasing possibilities of good do-it-yourself (DIY) | | | | achieve adequately high temperatures (less than 200 |
| solar water projects, either from scratch or buying | | | | degrees Fahrenheit), and they are significantly less |
| easy to install kits available on the internet that are | | | | expensive than next collector alternative. A flat-plate |
| easy to implement and much cheaper than a | | | | collector usually consists of (1) a black metal or plastic |
| "turn-key" contractor installation. Additionally, if full or | | | | plate to absorb the solar heat, (2) a transparent glass |
| partial solar water home heating is a feasible | | | | or plastic cover which allows the solar heat to pass |
| prospect, such a system can be very economically | | | | through to the absorber but reduces heat loss, and |
| and efficiently integrated. | | | | (3) a plastic or metal insulated box with which to |
| Most solar water systems consist of solar thermal | | | | enclose the heat absorber. The heat transfer fluid |
| panels (heat collectors), a fluid system to move the | | | | usually flows through tubes integrated with the heat |
| collected heat from the panel to storage or its point | | | | absorber. The usual practice is to use flat-plate solar |
| of usage, a heat storage unit (usually); and a method | | | | collectors with a fixed orientation to the sun. And, |
| for moving the fluid between the collector and | | | | the highest solar capture efficiency is obtained if the |
| storage of the point of usage. An active system | | | | collector faces toward the sun and slopes at an angle |
| uses electric pumps and controllers to move the fluid, | | | | to the horizon equal to the latitude plus about 10 |
| and a passive system uses only thermosyphon and | | | | degrees. |
| gravity to naturally circulate the fluid as it is heated. | | | | In this as in all alternative energy applications, there is |
| However, in some passive systems an integral | | | | the dual benefit of reducing fossil power expenses |
| collector storage system (ICS or "batch system") | | | | while reducing the associated fossil fuel environmental |
| may be employed if usage patterns are appropriate. | | | | impacts of conventional energy generation. |
| These systems have one or more black storage | | | | |