SOLAR TECHNOLOGY

HEATING WATER ACCOUNTS FOR OVER 30% OF ALL ENERGY USE IN DOMESTIC SITUATIONS

Solar power energy is a renewable energy solution that uses sun energy to create solar electricity and solar hot water.

Flat-plate collectors for capturing solar power energy and using it for solar water heating were popular in Florida and Southern California in the 1920's. Levi Yissar built the first prototype Israeli solar water heater and in 1953 he started the NerYah Company, Israel's first commercial manufacturer of solar water heaters. Despite the abundance of sunlight in Israel, solar water heaters were used by only 20% of the population by 1967. Following the energy crisis in the 1970's, the Israeli Knesset passed a law requiring the installation of solar water heaters in all new homes (except high towers with insufficient roof area). As a result, Israel is now the world leader in the use of solar energy and energy per capita, 3% of the primary national energy consumption.

During this time, there was some resurgence of interest in solar power generation and heating in North America. Technical innovation has improved performance, life expectancy and ease of use of these systems. Solar panel installation for solar hot water heating has become the norm in countries with an abundance of sun energy from solar radiation, like Cyprus, Israel and Greece, as well as in Japan and Austria.

Solar power generation and hot water systems have become popular in China. It is said that at least 30 million Chinese households now have one, and that the popularity is due to the efficient evacuated tube solar power which allow the heaters to function even under grey skies and provide solar power energy even at temperatures well below freezing.

In 1980, Israel became the first country in the world to require solar thermal systems and solar panel installation in new construction. 85% of the households today use solar thermal systems to create solar hot water from sun energy, and the use of it, saves 3% of the yearly electricity consumption in Israel.

In 2005, Spain became the first country in the world to require the installation of photovoltaic electricity generation in new buildings, and the second (after Israel) to require solar panel installation for solar hot water systems in 2006. Australia adopted the mandatory regulation for solar thermal systems for new construction in 2006 as well. 70,000 domestic solar water heaters were sold in Australia in 2008.

Solar hot water is water heated by the use of solar energy from the sun, which provides a renewable energy source. Sunlight systems are generally composed of solar thermal collectors to collect sun energy, a fluid system to move the heat from the collector to its point of usage. The system may use electricity for pumping the fluid, and have a reservoir or tank for heat storage and subsequent use. The systems may be used to heat water for a wide variety of uses, including home, business and industrial uses. Heating swimming pools, under floor heating or energy input for space heating or cooling are more specific examples.

In many climates, a solar hot water system can provide up to 85% of domestic hot water energy from a completely renewable energy source. This can include domestic non-electric concentrating solar thermal systems. In many Northern European countries, combined hot water and space heating systems (solar combisystems) are used to provide 15 to 25% of home heating energy.

Residential solar thermal installations typically include an auxiliary energy source (electric heating element or connection to a gas booster system or combustion heater) that is activated when the water in the tank falls below a minimum temperature setting such as 50°C. Hence, hot water is always available.

The combination of solar hot water heating and using the back-up heat from a wood stove chimney to heat water can enable a hot water system to work all year round in cooler climates without the supplemental heat requirement of a solar hot water system being met with fossil fuels or electricity.

In the Southern regions of Australia solar water heaters have been slow gaining popularity due to most systems not having the ability to operate in the colder winter months. However now the evacuated tube solar technology, which will work in low temperate zones, is the best product to use and when employed in arrays of 16 to 30 or more, the efficient but slightly more costly evacuated tube solar collectors have net benefit in winter and also give real advantage in the summer months. They are well suited to extremely cold ambient temperatures and work well in situations of consistently low-light so this mind-set is rapidly changing and with Government rebates that are promoting more environmentally friendly water heating solutions it is making it even more cost effective for the consumer.