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Differences between the thermosyphon system and forced circulation solar thermal equipment

We have already discussed the compact thermosiphonic system in previous articles, but this is not the only equipment capable of producing Sanitary Hot Water (DHW) using solar energy, another of the equipment that allows us get ACS It is the forced circulation solar thermal equipment.

Both are widely used and are good options to fulfill their mission, however, there are differences that make some users opt for one or the other depending on their needs.

To make it easy to understand, first we will talk about what makes them similar and then about their differences in a clear and concise way.

Similarities between both teams

The most basic thing is that the functioning Both systems are the same: they both use solar energy to heat sanitary water for domestic use.

Another clear similarity is the thermal panels they use, since they can use exactly the same. In fact, the materials with which they are made as well as their structure are also very similar because the two teams work with the same temperature range.

Secondly, as he thermosiphon as the forced circulation they have two independent circuits, one is the primary circuit (which mixes glycol and water, which is responsible for receiving the heat that accumulates and transporting it to the secondary circuit) and the secondary one, which basically accumulates the cold sanitary water in a tank where it is heated through the primary circuit for consumption.

Differences between thermosyphon and forced circulation

Now we will see the most obvious differences in its components. The first of these lies in the accumulation tank. As can be seen in the image, the thermosiphon has a tank attached to the top of the panels, or collectors, which is responsible for storing the DHW and the forced circulation one does not.

The second tank is located inside the house, while the thermosiphon is compact and is located all together outside. This is one of the reasons why a user can opt for one option or another: the space they occupy and the visual impact on the outside.

For smaller homes, it is advisable to install the compact thermosiphonic equipment as it makes better use of the space and it avoids having to install any equipment inside the house.

Another difference is the volume of the tank, in the case of forced circulation it could be higher, being able to find us with some of capacity for 500, 1000 liters or even more and in the thermosiphonics the normal thing is to reach a maximum of 200 or 300 liters. Likewise, for large DHW consumptions, several thermosiphonic equipment can also be installed, which allows reaching much higher accumulation volumes.

Forced circulation systems can also be used to support the generation of hot water for all kinds of uses, such as heating, pool heating or any other type of domestic or industrial use. Thermosyphonic equipment cannot be used for this purpose.

Finally, two differentiating elements are the circulation pump and the glass of expansion that only appear in forced circulation systems. In forced circulation equipment, the electric pump is necessary to move the heat carrier fluid to the tank in order to transfer the heat captured in the panels to the water accumulated in the tank. In thermosiphonic equipment this movement is carried out by thermodynamics thanks to the fact that the tank is always above the collectors and therefore no electrical energy is needed for its normal operation.

As for the expansion vessel in forced circulation systems, it is necessary to add it.

Once the differences between the two alternatives have been clarified, if you are thinking of investing in an equipment that allows you to obtain ACS in a clean and economical way but you have doubts regarding the equipment to choose, do not hesitate to contact us through our contact form or by writing to info ”@” SPSolar.com (without quotes).

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