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Thermal Solar - Water Heating

What is Solar Thermal Energy?

Solar thermal energy is based on harnessing from sunlight to heat a fluid, such as water. The hot water used in a home can be heated very efficiently and economically by a solar heating system manner.

Thermal Solar - Water Heating

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Thermosiphon Solarbasic 300 liters

€1,580.87 -35% €2,432.10

Thermosiphon Solarbasic 300 liters

Solar thermal equipment thermosiphon type for water Solarbasic of 300 liters. Spanish equipment adapted to the conditions of operation in Spain. A robust kit with all the guarantees and the best value for money.

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Kit Composition Solahart 302J


Thermosiphon Solahart 302J

300 liters Solahart thermosiphon, the market leader for quality and durability.

Size recommended in dwellings for 2 to 5 people.


Kit with everything needed for assembly.


Select your racking system ↓

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Kit Composition Solahart 151J


Thermosiphon Solahart 151J

150 liters Solahart thermosiphon, the market leader for quality and durability.

Size recommended in dwellings for 1 to 3 people.

Kit with everything needed for assembly.

Select your racking system ↓

¿ But how does a solar water heater work?

A solar heater has a normally metallic flat surface, called a collector in charge of collecting the incident radiation from the sun to later transfer it to the water as heat. The colector is a usually dark and matt element to capture as much radiation as possible, avoiding the reflection of sunlight. That is why some of the collectors / collectors are superficially treated with anti-reflective coatings or varnishes.

colector solar térmico

Once the collector is able to concentrate a certain amount of heat, it must be transmitted to the liquid that we want to heat (normally domestic sanitary water) through a coil installed just below the collector. In this way, a heat exchange is carried out between both parts, producing a heating of the fluid circulating through the coil.

This heat exchange can be done in two ways resulting in two types of heaters:

Natural circulation solar water heater or thermosiphon: The fluid circulating through the coil just below the collector moves due to heating. This type is widely used for its constructive simplicity, low maintenance cost and final cost of the solar heater.

Forced circulation solar water heater : The fluid that circulates through the coil below the collector moves thanks to the intervention of a pump that recirculates it. This type of heater achieves more thermal efficiency than the previous ones but requires more maintenance and the electrical consumption of the pump.

In either case, the fluid that passes through the coil, and which is heated by the action of the sun, is not the water that we are going to heat, but an intermediate fluid (usually a propylene glycol) that prevents the accumulation of lime and prevents a frost from resulting in equipment breakdown.

The next step is to transfer the heat obtained to the water we want to heat. For this purpose a deposit is used. Usually the tank is crossed by a coil of primary fluid that gives up its heat as it passes through it. The tank will be in charge of providing hot water to the sanitary circuit of our home when we need it. Solar water heaters with a capacity of between 150 and 400 liters are usually common, although there are different capacities depending on the needs.

esquemático circuito calentador solar

Finally, the solar water heater or solar sanitary water heater will have several additional elements to be able to function correctly:

-Shut-off valves: Like all hydraulic circuits, the corresponding shut-off valves and pressure compensators will be required to ensure that the system maintains the necessary conditions for its operation (flow / pressure / etc…)

-Circulation pump: Los calentadores solares con circulación forzada disponen de una bomba para que el fluido primario pueda moverse por el circuito hidráulico con una presión y caudal efectivos para que alcance la temperatura deseada.

The main advantages of a solar heater are:

-Very efficient system to heat the sanitary water of a home without the use of electricity. At their optimum, solar collectors have an efficiency of over 70%.

-Once the purchase of the solar heater is made, the operating costs are low, providing considerable savings compared to the use of a thermos or electric heater..

- Reduced system maintenance.

- Very suitable solution for homes without connection to the electricity or gas network. - Very respectful with the environment since it does not use any type of polluting substance.

- Compact system which requires a small space for its installation.

The main disadvantages of a solar heater are:

- The water temperature range can change depending on weather conditions (solar radiation and ambient temperature) and the time and intensity of use.

- Maintenance of the traditional heating system is always necessary, since the heater will cover only a part (in general most of it) of the consumption necessary to dispose of the necessary hot water.

Solar water heaters are a very good option to enjoy hot water economically and ecologically. Free advice and shipping. Find out! At Tienda Solar we distribute the best brands, mainly SolarHart. If you want to know what is the price of a solar heater? Visit our online store or if you need advice and answer other questions, find out at