Thermodynamic Test results - Not good

[MCS Renewables]

WPZ in Switzerland have tested a thermodynamic system
test number B-024-12-12

Tested for Energie EST Lda of Lote in Portugal. between 08.08.2012 and 13.08.2012.

It was tested as a domestic hot water heat pump (ie NOT solar thermal)

The test report 250 litre cylinder heated fropm 10.3 to 52.3, a rise of 42C , therefore the COP @ 15degrees C ambient temperature is 1.76.

Being as a decent heat pump can achieve a COP of over 3 at +5 degrees these thermodynamics kits are rubbish and should be used as skip liners.

The cylinders are also not WRAS approved.

Also
1kwhr of gas produces 190 grammes of CO2
1kwhr of elec produces 470 grammes of CO2
1kwhr of LPG produces 230 grammes of CO2
1kwhr of Oil produces 250 grammes of CO2

So unless you are installing in an all electric property these will never qualify for any incentive, ever, and at over £6000 for a COP of 1.74 the customers would have been better just burning the immersion heater as they will never get their money back.

The model shown here :- Energie Energia Solar Termodinmica - Products - ECO 200I
claims 390 watts for 150 litres of water so 9.36KW
it takes 1.16 watts per cubic metre x .15 x 50 litres so 8.7KW
So this model has a COP of 0.93 !!!!
And that is using the information from their web site ......

This kit needs leaving in Portugal where it may perform better, up to a COP of 2.73 , which is still poor at 15 degrees compared to most normal heat pumps.

 

[solarsavings]

MCS
Do you have a link?

 

[Gavin A]

I've found some test results listed, and they give it a COP of 2.7 or 3.3 depending on which method is used, with 4.1kWh used to heat a 250l tank to 53 deg.

It unfortunately doesn't say what that starting water temperature was, but a 250l tank is going to take in the region of 12kWh to heat to 53deg from somewhere around 10deg starting temperature.

12:4.1 = a COP of 2.9.

So not the best ever cop, but still not bad for heating water to 53deg.

http://institute.ntb.ch/fileadmin/Institute/IES/pdf/WPZ_Bulletin_01-2012.pdf page 18, Energie Est, lda, Eco 250esm

assuming this is the right kit under test.

 

[Eco Deal]

Are these panels covered by RHI ? or FITS ? or NONE ?

 

[wazzer]

I wonder how many of these units are fitted legally with full F Gas and unvented Part G also registered with building control as is a required

 

[Gavin A]

All the companies who've approached us about this have mentioned the F Gas requirements, and all MCS certified SWH companies would already have to have their unvented tickets and be registered with a CPS for building regs compliance.

I suspect there will be a few who're doing it without F Gas, but probably not that many - though it does sound like it's being scam marketed in some parts of the country, so maybe where this is happening.

 

[wazzer]

Surely they must be WRAS approved to get in the country and for companies to register them

 

[solarsavings]

What has wras got to do with it?

 

[Gavin A]

The model shown here :- Energie Energia Solar Termodinmica - Products - ECO 200I
claims 390 watts for 150 litres of water so 9.36KW
it takes 1.16 watts per cubic metre x .15 x 50 litres so 8.7KW
So this model has a COP of 0.93 !!!!
And that is using the information from their web site ......

I've no idea what you're doing with your calculation there, but you've got it wrong - you need to be working in kWh not kW when calculating heat input needed to raise the temperature of a volume of water.

8.7kWh is the energy required to heat 150l of water by 50 degrees, which I assume is what you were saying.

You can't actually get from that figure to the COP figure without knowing both the electrical input wattage, and the time taken to heat the 150l at that wattage of electrical input, and as far as I can see they don't give the time figures.

Assuming their figures are correct though, they give an electrical input range of 390-550 w, and a heat output range of 1690-2900 w.

The COP can be worked out from these figures as being a minimum of (1690/550) = 3.07


Working that backwards from the 8.7kWh heating requirement for 150l heated by 50 degrees, at the worst case of 1690W of heat being supplied, it would take 5.14 hours to heat the tank fully. 550W maximum electrical input x 5.14 hours = 2.83kWh of electrical input for 8.7kWh of heat output, or again a COP of 3.07 using the manufacturers worst case figures.

It's one thing stating that Energie should be supplying proper performance figures for their units at different external air temps, as is required for heat pumps - I'd agree with that, but it's just making the situation worse to start bandying around figures that seem to have been plucked from thin air, and bare no relation to the actual figures that are published, or any sort of understanding of how heat pumps actually work.

- - - Updated - - -

Surely they must be WRAS approved to get in the country and for companies to register them

they have the WRAS logo on their website, so I assume they must be WRAS compliant.

 

[sedgy34]

There seems to be more problems than benefits with these,

 

[wazzer]

Anything that is used with water has to be WRAS reg

 

[solarfred]

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?

 

[solarsavings]

Anything that is used with water has to be WRAS reg

You really should go and check that and you won't make the same mistake again.

 

[wazzer]

You really should go and check that and you won't make the same mistake again.

WRAS is an approval body which is able to verify compliance testing carried out by independent test laboratories. Upon successful verification WRAS are able to grant an approval which demonstrates that a product complies with the water supply (water fittings) Regulations 1999. Compliance with the water supply (water fittings) Regulations 1999 is a mandatory requirement for all products being installed in domestic water systems that may come into contact with potable water, ensuring the products can not affect the quality or taste of the water supply. No products should be installed within the UK that do not comply with these regulations.

 

[solarsavings]

Seriously, go away and check.

 

[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.