Washing laundry, cleaning dishes and taking showers are among the many daily tasks that require hot water. Every home has some type of water heater to provide this much needed utility. The most common system includes a storage tank where water is heated and stored. Water heaters powered by electricity are popular, but there are alternative systems available.
Oil
Home heating oil can also be used to fuel water heaters. A pilot light remains lit, ready to ignite fuel when a temperature sensor detects the need to heat water in the tank.
Gas
Natural gas and bottled propane gas are also commonly used energy sources for water heaters. Bottled propane is very convenient for rural areas where there are no natural gas lines. Since bottled propane is easily stored, it is often used in campers for cooking and water heating.
Solar
Harnessing the power of the sun to provide free energy for domestic water heating is a well-developed technology that many homeowners are now installing. A small array of solar collector panels are mounted outside, usually on a home's roof, to collect heat. There are a variety of systems, some pump cold water up through the collector and down to a storage tank, while others pump a fluid through the collector, and heat from the fluid is transferred to water in the domestic water heater tank by a heat exchanger. The fluid type is a closed system; the fluid does not come in contact with potable water.
Geothermal
In North America, heating water using a geothermal system is uncommon, but in countries where it's warm underground, such as New Zealand and Iceland (due to volcanic activity), domestic water is heated taking advantage of natural underground heat, rather than using a combustible fuel.
Firewood-Fueled
One unconventional way to heat water for a home is to run heat collecting pipes around a wood burning fireplace to capture heat. In some countries, such as New Zealand and Australia, wood is directly used as fuel for water heating.
Solar & Gas Combination Units
At least one company, Phoenix Solar, is manufacturing a water storage tank that combines a heat exchanger and roof-mounted solar panels with a gas-fired system to ensure a constant supply of hot water.
Space & Water Heater Integration
Not very common in home installations is an efficient alternative system that integrates space heating with water heating. This indirect heating system circulates water from a boiler or furnace through a heat exchanger in a water storage tank. Thus, a building's heating system is also used for water heating.
Tankless Water Heaters
The theory that in some situations it can be more energy efficient to only heat water when you need it as opposed to keeping it hot all the time in a storage tank, has lead to heating units called "tankless water heaters." These can be powered by electric, natural gas or propane. There are pros and cons to tankless systems versus traditional storage tanks, but the best choice depends on how the system is used and the particular situation where it will be installed.
Tags: storage tank, water heating, domestic water, heat exchanger, heat water, also used
