Solar thermodynamic heating explained

Solar thermodynamic heating is a form of renewable heating that is supposed to produce heat come rain or shine – even in the snow, apparently!
Thermodynamic panel
Solar thermodynamic heating is not currently accredited under the MCS scheme, but we understand that this is because there are complications with regards to the ability to measure the technology’s performance (and therefore the amount due for the grant) rather than it not being an effective renewable energy solution. This means that they do not qualify for either the Feed in Tariff or the Renewable Heat Incentive currently. This is not to say that this will not change in the future. You can find more information in our news post on the MCS suspension for thermodynamic products.

How does a thermodynamic system work?

They are a form of heat collector that uses solar energy to heat coolant that in turn is used to heat water for heating or hot water inside your home. In very simplistic terms, they work like a cross between solar thermal panels and an air source heat pump. The theory is that this makes them more efficient than traditional solar thermal panels, particularly when there is no direct sunlight, which is estimated to produce only about a quarter of the heat they produce.

The coolant is passed through a compressor to concentrate the heat, just like in a heat pump, and then a heat exchanger which heats your water so you can use it for washing or heating. They do need an immersion heater to boost the temperature a little to a usable level.

Thermodynamic system

Thermodynamic system (source: Thermogroup)

How good are thermodynamic panels?

The reality is hard to know for sure. We have not had contact with anyone who has done any meaningful comparisons, and there are no independent tests available.

Solar thermodynamic panel manufacturers claim that they produce over 3 times the energy that they use to run, so they are apparently fairly efficient. They don’t currently qualify for the available grants (FITs or RHPP), however, which make the financial returns significantly less attractive.

If you spent in the region of £6,000 on a thermodynamic system (a single panel and a 250 litre tank) you should get sufficient hot water to meet the needs of a 3 bed house.

What next?

While you cannot register solar thermodynamic heating under the MCS, this is simply because they cannot register them, rather than any sign of poor performance. You are perfectly free to have them fitted – and if you do, please tell us all about your experience.

Have a look at our free energy assessment to see what other energy saving solutions might be suitable for your home.

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