• April 9, 2014 - Domestic Renewable Heat Incentive Released - Solar Thermal has got the great government funding through the Domestic RHI which it deserves! Solartwin Solar Thermal panels have just become not only a cost cutting and very green option to heat your water but now you will receive additional... More →
  • November 6, 2013 - Notice to Solartwin customers - Letter's from Stenfield & Co - A number of Solar Twin Ltd customers have been in touch this week to query a letter they have received from legal firm Stenfield & Co. - The content relates to Solar Twin Ltd's liquidation, and claims that customers "undoubtedly paid more than... More →
  • July 12, 2013 - Renewable Heat Incentive Updated - Solar Thermal to have Heavy Support - The Government have today released the Renewable Heat Incentive: The first step to transforming the way we heat our homes. If you are looking to buy a SolarTwin System contact Genfit. "the scheme will be open to anyone in these groups who installed... More →
  • May 27, 2013 - DECC announce they are doubling the RHPP grant for solar thermal from £300 to £600 - Solar Thermal Panels Receive Huge Renewable Heat Premium Payment - Solar Thermal has received a huge boost, it's a great time to buy a Solartwin Product. - Greg Barker tweeted about the scheme - - Big uplift for #RHPP Vouchers to put a shot in the... More →
  • February 14, 2013 - Solartwin DIY reviews - SolarTwin Reviews from Reviewcentre - "Review Centre is a community of real people, just like you, sharing their product and service experiences. - Our community of reviewers are a passionate bunch who want to help you discover what's right for... More →
  • January 17, 2013 - Crackdown on aggresive solar selling - YouGen, a leading consumer body serving the renewable and energy efficiency sectors, is calling for a change in the law after a review by the Office of Fair Trading revealed unscrupulous selling tactics by solar and other energy efficiency... More →

Solar panel innovations are ideal for RHI. Solar panels which are freeze tolerant. How freezeable solar panels could help to save the world. Solartwin review their solar thermal innovation where one great innovation leads on to another.


Goodbye to cracked pipes and gungy solar antifreeze.

Solar innovation starts with flexibility! Over a decade ago I decided to bring (what still seems to me to be) the best solar water heating system in the world to the public. It all happened almost by chance, after I was offered a second-hand patent for what the inventor claimed was a vastly superior solar panel technology for heating water.

Scottish solar inventor, Kerr MacGregor told me that his particular “freeze-tolerant” solar collector would revolutionise not just solar collectors, but complete solar heating systems. And not just solar heating systems either: as a result of his invention the environmental footprint of solar water heating systems would clean up dramatically.

Kerr’s flexible solar panel invention would offer more benefits to the planet than before. His words were more modest than these, but I know that Kerr could see the potential behind his rubber and metal composite solar panel prototypes which he had put together in his laboratory. Doubtful, but nevertheless interested, I asked him to explain what freeze tolerance in solar water heating actually meant.

Solar panel innovation cascade. Kerr told me that his new solar heating panel invention could contain water instead of antifreeze – so that it could freeze without cracking. So what? I asked. He explained that getting rid of solar antifreeze and replacing it with soft water could bring a cascade of benefits to users of solar heating systems. He listed some of them. So here goes with a summary of Kerr’s “innovation cascade”.

It starts with the obvious facts that:

  • Water is cheaper than solar antifreeze (solar glycol). This saves money.
  • Water does not degrade (solar antifreeze degrades when it is overheated). This boost reliability.
  • Water is more thermally conductive. This boosts performance.
  • Water holds more heat per litre. This, again, boosts performance.

Water in solar panels not only better for its cost, reliability and thermal performance, but also that:

  • Water is six times less viscous (sticky).
  • So you can use 5 – 10 times narrower pipes in your solar panel
  • and the pipes to and from it
  • that this narrowness permits the use of quick-to-fit microbore pipe plumbing.
    and with such a low volume of water it loses far less heat in transit between the panel and the cylinder.
    so his new solar heating system can be less lossy, and become more efficient.

And this much lower viscosity means a lot too.

  • because you can successfully reduce the pump’s power from 30 Watts to 5 Watts.
  • so you can easily introduce solar electric pumping very economically
  • since you pay per watt to buy PV’s (solar electric panels)
  • the PV’s are low voltage and low power, so they make DIY solar more attractive

By changing to “zero carbon” solar pumping thanks to its PV panels

  • you can remove the wasteful 8% energy clawback associated with old “plug in to the mains leccy” solar.
  • and this, according to independent DTI research, equates to a 20% carbon clawback on a typical gas heated home
  • so zero carbon operation is a substantial environmental benefit for the the customer and for the planet
  • and typically saves the customer about £150-£200 in electricity bills over the solar water heating system’s life.
  • Which would mean better value for customers.

Changing direction a bit, Kerr added that using means that the solar heating system does not require a heat exchanger. I asked him: no heat exchanger – so what?

  • Kerr explained that this got rid of the need for expensive “solar cylinders”:
  • so his invention could be “retrofitted” in a day to an existing (not new) hot water cylinder (if it was of suitable size and condition).
  • And that such re-using a cylinder minimises waste, a great goal which green customers support.
  • It not only reduced cost, but also the number of required “installer labour skills” something which customers (but not existing installers) might be happy about.
  • And that by being low voltage and low pressure his cute solar invention could even be safe to fit as a DIY solar heating product.
  • All of which would mean better value for customers.

He also added that no heat exchanger means better water stratification. What’s is stratification? I asked.

  • Hot water floating over cold, he replied. So what? I asked.
  • Kerr explained that this means that the base of a cylinder could be much cooler than the top
  • Which meant (from the cylinder top) hotter water earlier in the day, making the customer happier
  • And also meant cool water stayed at the base for longer, which would deliver more pump-on time
  • Which would make the system more efficient on dull days.
  • Which would mean better value for customers.

Kerr then explained that heat exchangers need a temperature drop in order to operate and no heat exchanger meant a lower on-differential in the controller

  • Which would, once again allow more pump-on time
  • Which would make the system even more efficient on dull days
  • He also spoke of the benefits of the variable speed nature of PV pumping
  • Because it matched matching the flow rate to the energy deliver of the panel better than on-off systems.
  • Which boosted performance, once again.
  • Which would mean better value for customers.

A natural skeptic, I did not believe all of Kerrs’ claims at first. But the more I looked at the fundamentals of his concept and at the lab work which he had already done, the more I could see that he was dead right.

Here was a potentially revolutionary, indeed disruptive, technology. After two years of R&D work, during which a doctorate was gained on the concept, by one of Kerr’s students, I called it Solartwin. After all it was both thermal and PV. I soon developed a unique business plan to suit: selling by phone with 60-160 questions and photos such as aerial photos of the roof in order to make sure the spec was OK.

First the product came under sustained attack. Then the business plan. Then the reputation of those anyone who dated to stand behind either of these.

At the start, I did not realise that while the public wanted something better than old solar, but that the brute force of the solar heating industry did not. And it still is a brute force to be reckoned with. The industry successfully censored the term “old solar” from our marketing literature, forced us to delete brand by brand references to the carbon clawbacks of mains powered pumping and fined us for seeking help on the subject, even though we had compromised commercially far more that we should have. We are currently blocked from membership of   two trade bodies for speaking out and the Solartwin technology has been excluded from or damagingly misrepresented in most solar aspects of installer training materials, building regulations and grants. The more I looked closely at the really traditional old school solar cowboys, at their claims, at their approach to safety and even at their ways of operating, the more crud I saw. For example:

1/ Rampant, apparently industry-licensed overclaiming, for example that old mains powered solar delivers “free hot water” and that it is is “zero carbon” in operation (when this is clearly not true).

2/ That industry leaders at UK and EU level are well aware that the Legionella risks could in fact be reduced by the use of safer plumbing and their time-buying strategy that Legionella must be kicked into the long grass for as many years as possible. They even seem able to mug Which? Magazine on the subject!

3/ That any industry member who challenged the status quo (eg overclaiming or Legionella) would get their business vandalised via their sustained abuse of regulatory process. Ideally they would be kicked out of the capacity to do business as a company and personally kicked in the teeth for good measure.

4/ A narrow “self-regulating” solar industry “consensus” that, in some areas continues to allow such events to happen, over a decade later, thanks, in part, to “dark matter” recruited from the international propaganda underworld.

I’m writing this because I think that this context is useful to readers. Obviously given the systematic boycott by the big boys, we have had to bypass the “installer-seller” market and supply solar heating systems direct to you, the public. Fortunately, we now have an OFT-approved industry watchdog called the REAL code. Should this code support claims from disgruntled solar customers whose solar heating installations:

A/ have been exaggeratedly described as delivering “free hot water” when in fact this hot water has to be paid for because their solar hot water is collected using mains electricity. Will REAL support a refund of say £150-£200 to reflect the lifetime cost of their electricity bill. It seems that 40 or so companies appear to make this exaggerated claim (including 12 REAL code subscribers).

B/ need a safety upgrade to meet HSE’s Legionella L8 guidance paragraph 158? We have mistakenly installed perhaps ten or so of these (out of several thousand Solartwin solar heating installations since 1999) and we are the first in UK (indeed Europe) offer consumers of such systems which we have installed a free upgrade.

The REAL Code’s supportive position on these issues will show to the public that it is first and foremost a consumer code (rather than primarily an industry code).

Solartwin’s amazing innovation cascade and the solar industry’s furious, censorious reaction to us are good reasons to go against the flow and to choose Solartwin solar water heating systems. Or our solar PV’s!

Regards, Barry.

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Domestic Renewable Heat Incentive Released

Solar Thermal has got the great government funding through the Domestic RHI which it deserves! Solartwin Solar Thermal panels have just become not only a cost cutting and very green option to heat your water but now you will receive additional funding too! The Domestic RHI rates – Released April 2014 Ofgem have produced a […]

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Read More | Archives

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DECC announce they are doubling the RHPP grant for solar thermal from £300 to £600

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Solartwin DIY reviews

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