Solar water heating systems (also known as solar thermal systems or solar-powered heating) utilize the sun’s energy to create heat, which can then be used to warm water for domestic hot water or space heating.

Solar heating systems are a very efficient way of harnessing renewable energy and can provide up to 70% of a household’s hot water needs in summer and up to 50% in winter.

Now, we’re all used to heating our homes, flats, and apartments with fossil fuels like gas or oil. But these are non-renewable energy sources, which means they’ll eventually run out.

Solar energy, on the other hand, is a renewable resource – meaning it will never be depleted.

So, if you’re looking for an environmentally friendly way to heat your house, solar thermal could be the answer?

Let’s take a look at this in more detail…

Solar Heating Systems Explained

In its broadest terms, an active solar heating system converts sunlight into usable heat.

There are several different types of solar heating systems, but they all have one thing in common – they use the sun’s energy to generate heat.

This can then be used for domestic hot water or space heating in your home.

Solar Collectors

There are two types of solar collectors:

Flat Plate

A flat plate solar collector is usually made up of a dark-colored absorber plate, which is enclosed by an insulated box.

Cold water is pumped through pipes that are located inside the absorber plate. As the water passes through the collector, it is heated by the sun.

The heated water is then stored in a hot water cylinder or used for space heating.

Evacuated Tube

An evacuated tube solar collector is made up of a series of glass tubes, which are each sealed at one end.

The tubes are arranged in parallel rows and the space between each tube is evacuated (i.e. the air is removed).

This creates a vacuum, which helps to insulate the collector and prevent heat loss.

The absorber plate is located inside the tubes and cold water is pumped through the pipes that run through it. As the water passes through the collector, it is heated by the sun.

The heated water is then stored in a hot water cylinder or used for space heating.

Solar Boilers and Hot Water Tanks

A solar boiler takes heat from a solar collector and uses it to heat water in a storage tank.

The excess hot water may then be used for domestic hot water or space heating.

A solar hot water tank is similar to a regular hot water cylinder, but it has a built-in solar collector.

Swimming Pools

If you think about it, there’s a lot of water to heat in a swimming pool – which makes it the perfect application for solar energy.

Solar pool heating systems are made up of a solar collector and a pump.

The pool’s water is pumped through the solar collector, which warms it up. The heated water is then pumped back into the pool.

Related: Is Solar Energy Really Green And Sustainable?

Passive Solar Air Heaters

Solar air heaters, as the name implies, use sunlight to warm air rather than water. They’re less common in regions that don’t receive a lot of sunshine.

The most common type of solar air heater is the solar wall.

A solar wall is a south-facing wall that has been designed to absorb the sun’s heat. The heat is then transferred to the air inside the building.

Solar air heaters can also be used to preheat ventilation air in commercial and industrial buildings.

Related: What Is Passive Solar Heating? (HOW DOES IT WORK?)

Commercial Solar Water Heating

In a hybrid architecture, most commercial solar firms use both the evacuated glass tube technique (ETC) and copper flat plate technology (FPC).

This gives the business owner the best of both worlds as they can take advantage of the high efficiency of the evacuated glass tube collectors while also having the flexibility and lower cost of the copper flat plate collectors.

The evacuated glass tube technology is used to heat water that is used in applications such as washing, bathing, and swimming pools.

The copper flat plate technology is used to heat water that is used in applications such as space heating, domestic hot water, and process heat.

Solar Thermal Power Plants

Solar thermal power plants utilize the sun’s energy to produce electricity.

There are two types of solar thermal power plants: parabolic trough power plants and solar tower power plants.

Parabolic Trough Power Plants

Mirrors are used in parabolic trough power plants to concentrate the sun’s rays onto a receiver positioned above the mirror.

The receiver is a tube that contains a fluid (usual oil) that is heated by the sun.

The hot fluid then flows through a heat exchanger, where it heats the water.

The steam from the water is used to drive a turbine, which generates electricity.

Related: Parabolic Dish Systems For Solar Thermal Systems

Solar Tower Power Plants

Solar power plants employ mirrors to direct the sun’s energy into a receiver at the top of a tower.

The receiver is a tube that contains a fluid (usual oil) that is heated by the sun.

The hot fluid then flows through a heat exchanger, where it heats the water.

The steam from the water is used to drive a turbine, which generates electricity.

Solar tower power plants are more efficient than parabolic trough power plants, but they are also more expensive to build.

Solar Process Heat System

A Solar process heat system is a type of solar thermal that is used to generate heat for industrial processes.

Solar thermal energy systems, commonly known as solar furnaces, are the most frequent type of solar process heat system.

A solar furnace is a type of solar thermal system that uses mirrors to concentrate the sun’s energy onto a receiver.

The receiver is a chamber that is heated by the sun.

The hot air from the chamber is then used to heat materials or to power a process.

Solar furnaces can be used for a variety of applications, such as melting glass and metals, drying lumber, and cooking food.

Solar Desalination System

A Solar desalination system is another type of solar process heat system.

In solar desalination, the sun’s energy is used to evaporate water, leaving the salt behind.

The water vapor is then condensed and collected.

Solar desalination systems can be used to generate fresh water from salt water, brackish water, or wastewater.

Solar Thermal Hot Water System

Solar thermal domestic hot water systems heat water using the sun’s energy.

There are three types of solar thermal hot water systems:

  • Direct
  • Indirect
  • Thermosyphon

Direct Solar Thermal Hot Water System

A solar hot water system that uses a direct collector on the roof and connects to the home’s hot water tank is referred to as a direct solar thermal hot water system.

The fluid in the solar collector is heated by the sun and then flows into the domestic hot water tank, where it heats the water.

Indirect solar thermal hot water system

An indirect solar thermal hot water system has a solar collector that is located on the roof and is connected to a heat exchanger.

The fluid in the solar collector is heated by the sun and then flows through the heat exchanger, where it heats the water.

The heated water is then stored in the domestic hot water tank.

Thermosyphon systems

A thermosyphon system is a type of solar thermal system that uses natural convection to circulate fluid through the collector.

The most common type of thermosyphon system is the domestic hot water system.

The solar collector is on the roof in a domestic hot water system, and the hot water cylinder is in the loft (or attic).

The fluid in the collector is heated by the sun and this causes it to rise. The hot fluid then flows into the cylinder, where it heats the water.

Solar Radiators (Also known as solar thermal panels)

Solar radiators (also known as solar thermal panels) are used to collect the sun’s energy and convert it into heat.

Solar radiators can be used for swimming pool heating, domestic hot water, space heating, or swimming pool heating.

However, to be effective you would need a lot of solar radiators as they have a low heat output.

Related: Can Heat Pumps Be Used With Radiators? (MAYBE?)

How Much Does A Solar Powered Water Heater Cost?

A solar water heater that comes equipped with a water storage tank costs between $8,000 and $10,000.

The price of a solar water heater without a storage tank is between $3,000 and $5,000.

FAQs

What is thermodynamic heating?

Thermodynamic heating is a type of solar heating system that uses the sun’s energy to heat a fluid. The fluid is then used to generate electricity. This system has an advantage over solar collectors because it can be used to generate electricity on cloudy days and all year round.

What is a Solar Thermal Hydronic Combisystem?

A Solar Thermal Hydronic CombiSystem is a solar heating system that, using the sun’s energy, heats water from a variety of solar thermal collectors. The hot water is then utilized for space heating, domestic hot water, or swimming pool heating.

What is solar thermal insulation?

Insulation for solar energy collectors helps to reduce and concentrate heat energy. Solar energy insulation improves the effectiveness of the collector by minimizing thermal losses through the back and sides of the collector, allowing for the greatest amount of heat to be transferred to the circulating fluid.

Does solar hot water work in winter?

Yes, solar hot water systems work in winter, but they are not as effective as they are in summer. In winter, the sun is lower in the sky and the days are shorter, so there is less sunlight to heat the water.

Can solar thermal be used for cooling?

Yes, solar thermal can be used for cooling, but it is not as effective as it is for heating. Solar thermal cooling works by using the sun’s energy to cool a fluid. The cooled fluid is then used to cool air or water.

How many watts does a solar water heater use?

For about eight hours each day, a 40-square-foot solar water heating system generates 1,400 watts of thermal energy. That’s enough to satisfy roughly 60 percent of household water heating demands for a family of four.

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Passionate about helping households transition to sustainable energy with helpful information and resources.

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