Thermodynamic Test results - Not good

[Gavin A]

See entry here. http://www.wras.co.uk/Directory/Company_list_new.asp
This appears to be for one model being stainless steel cylinder. The regulations require a legionnella prevention system but on this unit I understand this is only achieved by manually turning on the immersion element as there is no automatic function. So does this comply?

1 - There are regulations relating to preheat systems, but this isn't a preheat system. http://www.wras.co.uk/Preheated-Water.htm

There are HSE regulations known as L8, which apply to non domestic settings, as well as recommendations for domestic solar water heating systems etc that could introduce Legionella risks, but they're not wras regulations, and are very much technology dependent in how they need to be applied.

2 - As this unit is supposed to be capable of heating the entire tank to the base to 53 deg in all weathers, and all legionella bacteria are killed off in water temperatures above 50 deg, there is no need for it to have a timed control on the immersion or any other Legionella control mechanism. This would be different if the unit were to be installed in a non-domestic setting where stricter L8 regs would apply, but for a domestic setting this unit should be absolutely fine without any need for additional legionella protection programme.

If the pre-heated water is stored at temperatures between 20[SUP]o[/SUP]C and 45[SUP]o[/SUP]C, which favours the growth of the Legionella bacteria, and large numbers of the bacteria develop, measures may be required to prevent these bacteria causing harm to health.

This isn't the case with these systems, which are capable of heating the entire tank to above 50deg, therefore no additional legionella control procedure is needed.

 

[zeljuga]

Legionella killed in minutes at 50 deg. And instantly at 60 deg C. All major cylinder manufacturers have option of heating cylinder once a day to 60 C to make sure no Legionella problem , as it likes temps. of 45`C and feeds on copper and plastic .

 

[Gavin A]

Legionella killed in minutes at 50 deg. And instantly at 60 deg C. All major cylinder manufacturers have option of heating cylinder once a day to 60 C to make sure no Legionella problem , as it likes temps. of 45`C and feeds on copper and plastic .

it's still not a problem as long as the tank temperature is above 50 degrees to the base though, as is the case here, so there's no requirements for any additional legionella control measures as standard, as is clear in the WRAS guidance I just quoted.

This whole heating the tank to the base once a day for an hour for domestic settings is a load of rubbish spread by the ex head of solartwin to discredit the rest of the solar thermal industry, it has no basis either in the legislation or in the science of legionella prevention - if it's already killed at 50 deg, then there's no point killing it again with a daily blast at 60deg.

 

[solarfred]

Thanks for the explanation. I was also just pointing out that the WRAS approval was for one model. I cannot see any reference to the manufacturer or other models but maybe it is just not obvious on the WRAS site.
These things are very popular in Ireland where WRAS does not exist.

 

[Gavin A]

I can't actually get that WRAS listing page to load up, but it could well be that the listing covers all the Energie tanks, as they're all the same design, it's just that they offer different size options on the same basic tank design.

alternatively you could be right and it's just listed for one of the size options, in which case there could be some slapped wrists or worse going on.

hard to know though as I can't load the page up.

 

[Gavin A]

I've found the listing now, and it does seem to only apply to the ECO280 model, whereas I'm sure it was the ECO250 model I was being sent prices for....

 

[stanwaterman]

I entirely agree with Gavin A, bandying about silly and totally wrong calculations is troublesome. These panels work just like any other heat-pump with a COP figure that depends on environmental factors but would rarely be less than 2 in a UK winter and often over 4 in the summer. These things are exactly he same as an air to air heat-pump with the external heat exchanger expanded, painted black and flattened out and the fan replaced by natural convection. They gain from being able to get heat from sun and rain but lose a bit from less efficient convective transfer from the air.
Nothing magic abut them- a good description would be "an environment to water heat-pump"

 

[Worcester]

They also benefit in having a direct to DHW condensor stage as opposed to going through an additional heat exchanger. so can make up some of the CoP in that way. They work, the problem is no-one will give real performance figures for the UK.

 

[stanwaterman]

If I could get one installed at a reasonable price, say about a £1,000, I'd be very happy to log it's every daily performance for a year!

 

[Gavin A]

we're just trying to sort out metering arrangements, then will have a couple of test units up and running over the rest of this winter - have the units in the warehouse, but the metering arrangements I'd been wanting to use turn out to cost nearly as much as the thermodynamic kit itself.

 

[wersolaruk]

we have about 4 systems installed and all are generating hot enough water all year for all our customers, so i can only speak of what these systems actually do and not some calculation. They do work, and hell of a lot better then solar thermal which is absolutely rubbish in my humble opinion

 

[MCS Renewables]

Despite asking at least three times we have yet to be sent reliable test evidence, reports etc by credible test labs such as TUV.

Thermodynamic manufacturers seem reluctant to publish any results at all and seem to just keep repeating the same old sales blurb.

As this technology costs considerably more than solar thermal, which is a proven technology and qualifies for the RHI and RHPP payments, I cannot see any benefit of promoting this technology until the MCS backs it.

Down our way the only companies promoting thermodynamics are the ones who do not fit PV or thermal, are not MCS registered and have fleets of shiny suited salesmen. These unregulated conmen are selling these systems for over £10K which would very nearly buy you two solar thermal systems.

 

[MCS Renewables]

Tom Callaghan director of the famous Simplee Solar, Staywarm, Energy Conservation Group and the Reds Technologies companies

They tell you solar panels are eco-friendly and save you money. The truth? They don't work much of the time and take 100 YEARS to pay for themselves... | Mail Online

Now runs ...

Green Home Energy

That sort of tells you all you need to know

 

[Gavin A]

As this technology costs considerably more than solar thermal, which is a proven technology and qualifies for the RHI and RHPP payments, I cannot see any benefit of promoting this technology until the MCS backs it.

1 - it doesn't
2 - new builds for developers don't qualify for RHI, and on a level playing field without subsidies I reckon thermodynamic panels win, particularly when used in conjunction with solar PV.

 

[MCS Renewables]

If solar thermodynamic is such a great product why are the manufacturers not getting proper testing done ?

Why did the manufacturers of thermodynamic panels originally need to con the MCS into getting approval ?

Why are thermodynamic modules still not MCS approved ?

Why are customers of this product complaining about the running cost on various forums ?