PV, PVT or PV and T

PhotoVoltaic, Photovoltaic Thermal or PhotoVoltaic and Thermal. That is the question

A solar panel can reach 80 degrees centigrade in the noon day sun, if we cool it down to say 20 degrees centigrade it could be up to 30% more efficient.

I have been investigating an amazing solution from Smiths Environmental Products (http://www.smiths-env.com/), now this is a cool piece of kit

Simply put the system runs water around the rear of the panel, this cools the panel making it more efficient.

The by-product is hot water.  Run this through Smith’s Heat Pump and this will bring it up to a temperature that can be used to heat the water in your cylinder for domestic and heating hot water.  If it is not needed (the heat of the day) it can be stored for later use (at night)

So throw out the gas guzzling boiler and put in PVT (PhotoVoltaic Thermal panels).

It gets better though because we then recommend a Low Temperature Heating System.  Because the water travelling around the system is not as hot as a conventional system you need either to increase the size of your radiators (nahh) or to use fan convectors.

The fan convectors are great, they use a low power fan to blow the air around.

BSRIA figures suggest that this is 24% more efficient than conventional radiators, rising to 31% when used in conjunction with a low temperature system

So now we have no boiler, sun powered hot water assisted by electricity which might have been made by the panels (during the day at least) and a more efficient and responsive heating system

So, is it worth it?  Well, actually the PVT works out to be about 3 times more expensive than straight PV.  I have just quoted £16k for a 10 panel system but I have a feeling that I might lose money on that one.  Still, we all have to install our first one and Smith’s are being very very helpful

According to the Governments guidelines if the panels were south facing at 30 degrees they should generate about 1,631kWh of electricity a year, the Feed in Tariff income would be around £367.  If we assume that the efficacy from cooling will add 15% that is now £420

Using the electricity we generate ourselves might save a further £200 a year making the PV element worth around £620 a in the first year (increasing with inflation each year for 25 years)

On the saving we have a system which will cost around £600 a year compared to a conventional gas system of around £900, so a further £300 a year and rising with prices.

In the first year the client will be around £920 better off, not a bad return on £16k especially if you factor in the effects of inflation in future years.

This becomes even more valuable if you needed a new boiler anyway (as this client does), they had factored in £2k to install the boiler and that is money saved

On the downside you will have to add in the cost to change all your radiators to Fan Convection

So for £16k plus radiators minus new boiler you get

–          A tax free income of £420 a year index linked

–          An energy saving of £500 a year rising with the cost of energy

–          A more responsive heating system

–          A more efficient house

To me that is financially marginal, if you want to increase your self-sufficiency in a green way then this is the route for you

Leaving the best for last is the ever threatened Renewable Heat Incentive (RHI).  Not wishing to pre-guess when it will come in and how much it will be worth I would hazard a guess that the value of this incentive makes the whole deal financially sound as well.  This system should be entitled to the RHI when it is introduced.

It has been a long learning curve for me but I am now convinced it is a good idea and I hope that my client goes for it

If you would like to know more please contact me, Charles@usethesun.co.uk or 01268 415447

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