| Two of the bigger energy uses are cooling and | | | | power systems have a very high initial cost, but a |
| heating. Green heating systems are designed to | | | | very low operating cost. This low operating cost is |
| minimize such energy use during cooler periods. | | | | often overlooked in the planning stages when more |
| There are several heating systems used in green | | | | attention is being paid to the initial costs. In order to |
| homes. One type uses geothermal energy for heat. | | | | maximize the advantages of the low operating cost, |
| Geothermal refers to using the natural heat of the | | | | it is important to make sure that the home is well |
| earth. Most systems work by running water from | | | | insulated. In the case of water heating systems, all |
| under the earth through a series of pipes called a | | | | pipes must be heavily insulated. |
| loop. The loop takes the water to a heat exchanger | | | | Solar water heating systems can be either passive or |
| where the heat is removed from the water and used | | | | active. Passive systems use natural convection to |
| for heating purposes. The most simple is the open | | | | move water from the heat source to the heat |
| loop. Since ground water generally maintains a | | | | exchange point. An active system uses pumps and |
| constant temperature, water is pumped from one | | | | controllers. The water is collected in a tank fitted |
| well through a heat exchange device, and deposited | | | | with solar panels or heat absorbing materials where it |
| into a second well, usually at a distance from the | | | | is warmed by sunlight. The pumps move it to a heat |
| first. | | | | exchanger where the heat is removed and circulated |
| A closed loop geothermal system circulates the | | | | through the home. In the case of a water heater, |
| water through a series of pipes. The pipes are buried | | | | the water can be used directly, and it is replaced by |
| in the ground and the water picks up heat and the | | | | cold water from the existing water supply. |
| heat exchanger removes it. There are several | | | | Geothermal and Solar heating systems are two |
| arrangements of piping, but the general idea is the | | | | examples of green construction types of alternative |
| same. Although geothermal heat is very inexpensive, | | | | sources for heat and energy. The advantage is the |
| a system has to be fairly extensive to provide all of | | | | reducing of the reliance on fossil fuel generated heat |
| a homes heating requirements, and most systems | | | | or energy. The technology for utilizing these sources |
| are intended to supplement other heating sources. | | | | of heat is still in its infancy. It is expected that the |
| A much better source of heat is sunlight. Solar power | | | | rise in green construction philosophy will encourage |
| systems convert sunlight to heat for use in space | | | | further experimentation in this area. |
| heating and domestic water heating. Most solar | | | | |