Tuesday, October 23, 2012

Quick guide to solar hot water systems

Solar energy isn't only used to generate electricity like this is the case with photovoltaics, it can be also used for much simpler process, namely to directly heat water, without generating electricity in the process. Despite the fact that solar hot water systems do not generate electricity there are certain types of these systems that use electricity to pump the water.

Now that we know that solar hot water systems use solar energy to heat the water let us look of what exactly are they composed. The typical solar hot water system has these parts: a water storage tank, solar thermal collectors, interconnecting pipes and the fluid systems that moves the heat from the collector to the tank.

Using solar hot water systems is good from the environmental point of view because these systems do not emit greenhouse gases, and therefore do not contribute to climate change and air pollution. It is also good to use them from the economic point of view because they can help reduce our dependence on foreign fuels, meaning that our money stays within our borders where it can be used to create new jobs.

Solar hot water system.

The amount of heat delivered by a solar hot water system primarily depends on insolation values in given area. Tropical areas usually have the highest insolation values which makes them ideal areas to install these systems.

In order to determine economics of installing solar hot water systems in certain area we need to take a more closer look at these factors:
1)      The price of solar hot water system
2)      Its efficiency
3)      Availability of state or government subsidies
4)      Price of electricity in given area per kWh
5)      Number of kWh of electricity used per month by your household
6)      Annual maintenance costs

The most popular solar hot water systems are the ones with evacuated tube systems because they enable heaters to function even under gray skies and at temperatures below freezing point.

The cheapest solar hot water systems can be found in China, with the average prices in China being approximately 75% lower than the ones in Western world.  Because of these favorable prices and the growing economic power there are now more than 30 million households using these systems in China.

It would be certainly very good if all countries were to follow the positive example of Israel and Spain, two countries that introduced the mandatory installation of solar hot water systems into new buildings.