Thermo dynamics for hot water that runs off atmosphere

[Gavin A]

oh, can heat pumps not get RHI if they're just for water heating then?


or more accurately, is that the proposal in the consultation?

hmm, well that will be a serious problem then as a disincentive from using them for water heating and an incentive to companies to go around fitting them as space heating solutions in totally inappropriate situations. That certainly sounds like the sort of thing that DECC / Gemserve would manage to come up with.

 

[steve k]

I have installed a few of these systems and these are the facts:

Ambient air temp - 6 deg C
Water entering temp - 8 deg C
200l of water 8 deg to 55 deg = 2 hours
amp draw = 9amps

Now i'm no mathematician, but what does this calculate into?

Steve

 

[whinmoor]

I have installed a few of these systems and these are the facts:

Ambient air temp - 6 deg C
Water entering temp - 8 deg C
200l of water 8 deg to 55 deg = 2 hours
amp draw = 9amps

Now i'm no mathematician, but what does this calculate into?

Steve

A miracle?

If this is true, it's very impressive technology.

 

[Vegelen]

Will this amazing new technology cut my gas bill in half, allowing a fantastically quick payback time on a 5K installation cost?

Or will I be left scratching my gonads when reality hits, the debt has to be repaid and the snakeoil salesman has hit the highway?

 

[Worcester]

That works out at about 4.14 kWh...
That's the same as the immersion on for just under and hour and a half..

 

[steve k]

A miracle?

If this is true, it's very impressive technology.

Hmmm, yes it is true...... Ps....it's not that impressive, just basic refrigeration.

Will this amazing new technology cut my gas bill in half, allowing a fantastically quick payback time on a 5K installation cost?
Or will I be left scratching my gonads when reality hits, the debt has to be repaid and the snakeoil salesman has hit the highway?

This is where it all falls down.....the people selling it are charging too much....the ones we briefly installed were £7k.

Appx £950+vat for us, £1.5k+ vat for the kit and the rest for slimey HP salespeople, call centre battery chickens and entrepreneurs profit

 

[steve k]

That works out at about 4.14 kWh...
That's the same as the immersion on for just under and hour and a half..

Like any good primary school teacher would ask. " can you show your working out?"

Just curious, not doubting you.

 

[Eco Deal]

but if you want a free no obligation survey PM dablow84 or click the link to his website !
saved you some finger movement mate...

 

[Worcester]

230V x 9 Amps x 2 hours = 4.14kWh (230*9*2/1000 = 4.14)

3 kW Immersion for 1.5 hours = 3*1.5 = 4.5 kWh

 

[steve k]

230V x 9 Amps x 2 hours = 4.14kWh (230*9*2/1000 = 4.14)

3 kW Immersion for 1.5 hours = 3*1.5 = 4.5 kWh

is 230v x 9a not 2.07kW/h ??.. what I mean to ask is what is the energy required to raise the temp of water from 8 to 55 in 2 hours?

 

[Worcester]

You said it ran for two hours 2.07kW is the power 4.14kWh is the energy

1 calorie will raise the temperature of 1 gram of water 1 degree Celsius. (That's the definition of a calorie)
1 Calorie will raise the temperature of 1 Kg of water 1 degree C
I ltr of water weighs 1 Kg

So to raise 210 Litres from 8 degrees to 55 degrees requires 47 x 210 = 9870 Calories

1 calorie = 4.18 Joules
So
1 Calorie = 4180 Joules
1 Watt = 1 Joule/Second
In Simple Terms, 1 Calorie = 1.162 Wh

so 9870 Calories = 11469 Wh or 11.5kWh

(You asked ...)

 

[Gavin A]

I have installed a few of these systems and these are the facts:

Ambient air temp - 6 deg C
Water entering temp - 8 deg C
200l of water 8 deg to 55 deg = 2 hours
amp draw = 9amps

Now i'm no mathematician, but what does this calculate into?

Steve

200l at a little under 50deg temp rise needs around 11kWh of energy input.

9amps x 230 v = 2kW x 2 hours = 4kW

COP = 11 / 4 = 2.75

a COP of 2.75 at 6 deg c ambient air temperature is reasonable, but not particularly impressive for a heat pump tbh, though it at least demonstrates that it's considerably better than an immersion heater, and maybe just about on a par with a condensing gas boiler.

So possibly worth it for those on full electric heating.

 

[Gavin A]

dammit, where did that post from Worcester come from...

 

[The Solar King]

Only one problem with all of this calculation. We do not know that the whole tank was at 8degC at the start. To do this you would need to run cold water through it until the outlet temperature was at this level. We do not know that the whole tank had reached 55degC. We only know that at the location of the stat the temperature is 55degC. As a tank should stratify, it is possible that the temperature is not uniform throughout. You would need to run a de-stratification pump until the temperature was uniform throughout the cylinder to know that the entire contents were at 55degC. When you have done this, come back and tell us what the energy input to the cylinder was and what methodology was used to verify the data in a manner suitable for peer review.

 

[The Solar King]

If you have mains gas, any COP less than 3 is simply not worthwhile. Again do the maths regarding the cost of fuel. (not to mention carbon intensity).

 

[steve k]

Only one problem with all of this calculation. We do not know that the whole tank was at 8degC at the start.( a guess would say it was colder, the cylinder had been stored over night in an un-heated garage. The morning of installation was at an ambient of 0 deg C and 6 deg C at the time of commissioning) To do this you would need to run cold water through it until the outlet temperature was at this level. We do not know that the whole tank had reached 55degC. We only know that at the location of the stat the temperature is 55degC. (I measured the water temp at each tap outlet throughout the house) As a tank should stratify, it is possible that the temperature is not uniform throughout. You would need to run a de-stratification pump until the temperature was uniform throughout the cylinder to know that the entire contents were at 55degC. When you have done this, come back and tell us what the energy input to the cylinder was and what methodology was used to verify the data in a manner suitable for peer review.

Sorry to reply quoting your text..

Steve

 

[The Solar King]

Sorry to reply quoting your text..

Steve

Steve

You still do not empirically answer my question. A guess is of no use. Measuring tap outlet temperature does not confirm that the tank was uniformly heated throughout.
As such your reply is only anecdotal. This is no basis on which to make a purchase decision of this nature.

 

[Gavin A]

tbf though you';re asking installation companies for information that only the manufacturer could be expected to supply. AFAIK this data doesn't exist, which is why no supplier or installer can supply you with it.

the data supplied by steve k though is bit more detailed than most anecdotal evidence, it's just not been carried out under test conditions in a lab or verified externally, and a few bits of data are missing. As I read it he's stated that this warm up time is from cold on first filling the tank, therefore it's pretty much certain that the entire tank was at the temperature of the incoming supply when heating started. It's obviously not 100% accurate, but is likely to be in the right ballpark as long as the tank stat is placed in a sensible location such as the middle of the heating coil at the base of the tank.

I understand the desire for figures, but IMO some of those shouting down this technology are as bad the other way as the snake oil salesmen types in terms of giving the impression that the tech doesn't work at all, which is obviously false. This is a heat pump, as such it is proven technology that has been in operation in other forms for 50 years+, and there is zero reason to think that it won't work, or that a COP of 2.7ish isn't about right for the temperatures given. The technology works, that's not really in doubt (by anyone who understands heat pumps), the valid issue is the lack of accurate data to verify exactly how well it will work in different situations and for different uses, along with a decision from MCS over which category it should fall into for RHI etc (if RHI ever starts anyway) along with miss-selling by rogue marketing companies etc.

I do actually understand the difficulty for the manufacturers in supplying standard heat pump data though, as this is based solely on the air temperature, whereas these devices also collect radiated solar energy, and there currently are no standardised tests designed to measure devices that extract heat from both sources. I suspect that the cop of 2.7 would be the COP without significant radiant heat input from the sun, and that the COP would rise to more like 3.5-4 or higher with the addition of full sunlight giving an extra 1000W/m2 of energy input to the panel.

I really think that MCS are as much to blame here as the manufacturers, as these products have been available in the UK for at least 3-4 years to my knowledge, yet MCS seem to have just ignored them until they suddenly became the next big thing. Simply put, they're guilty of having been asleep at the wheel when they should have been proactively working with the manufacturers to device appropriate test methods and data requirements for these types of products since day 1 of MCS starting up.

That said, I have previously linked on this site to independent test data for one of these products, though the above caveats about it not incorporating solar input in it's figures would apply.

 

[The Solar King]

2.7COP is 0.2 above the accepted level published by the EU for the definition of renewable heat.

Heat pumps do work, but recent studies by the Energy Savings Trust shows that in a very large number of installations house holders were gaining no benefit for a large variety of reasons including design, specification, installation, heat emitter type and user interaction. There is real danger that without the kind of data I constantly ask for there will simply be an action replay of this kind of experience.

With heat pumps, it is horses for courses. Currently they are not an appropriate technology for all properties in all locations. The level of expertise to correctly assess and specify systems is in my opinion far higher than that needed for PV, ST, or installing a normal central heating system. The margin for error in all of them in far greater.

Sadly, to say you suspect something in terms of performance is not substantive. Would you be comfortable and more importantly legal going out and selling on such a basis?

There are other manufacturers of hybrid equipment who are in dialogue with MCS over their equipment to clarify it's position in terms of registration. Why was this so difficult for the manufacturer's of thermo dynamics? Why was something registered as a solar panel tested with ethylene glycol then sold for use with refrigerant in something that is clearly a heat pump?


If you go back and check in early threads on this kit, my interest was originally in performance data because I liked the look of it, and it appeared to promise something new. My interest was in the claims for space heating, principally for off-grid areas. My increasing disenchantment is because no one has been able or willing to provide the information.

If the manufacturers had gone to MCS with chapter and verse on the equipment four years ago, all the issues now raised could have been dealt with then, but it appears they did not. Issues surrounding compliance with the Building Regs and required competencies could also have been sorted. The equipment was registered under solar keymark, in a way which was not appropriate. If the equipment works as described, why would you do that? Registration only existed because this scheme is recognised in the UK as an equivalent to the MCS product scheme. It would be interesting to know what is happening to it's registration under Solar Keymark in light of the intervention by MCS.

DECC will decide whether this equipment is eligible for RHI and in what category, not MCS.

The issue of whether this equipment works in a cost effective manner in cooler climates is still unanswered. Why is it so difficult for the manufacturers to provide substantive performance data of this nature and verify the claims made? Facts speak louder than words. All we have had are words.

 

[jason121]

Introducing
the NEW Magic Thermodynamic Box, its a lean green hot water machine!


Delivering
hot water @ 55 degrees, 24/7 with a cop rating from 1 in 3 to 1 in 7!

 

[Berneray]

I just don't get it.

Without going into technical details and empirical data ect ect....all these panels can do in a normal house is heat tap water to 55 degrees.

Now the EST in conjunction with DEFRA published a report entitled "Measurement of Domestic Hot Water Consumption in Dwellings". The samples 124 houses over a set period.

The report is incredibly detailed with loads of cool graphs and stuff and runs to 62 pages (email me if you'd like a copy)....but long story short they found the average spend per year on domestic tap was was at that time £105.

So say these panels save me £105 off my oil or gas...I still then have to pay for the electricity to run the compressor which appears to be about £8 a month....So the net saving cannot be more than £50 a year.

So why would I spend £5000 on something that is going to save me £50 a year.....

Or am I missing something...

 

[Berneray]

Anyone come across this new "MAGIC BOX"

The Magic Thermodynamic Box

Got it in an email earlier today....

 

[Earthstore]

I asked a question but as many others have been ignored.
So, the cost of heating my hot water per year is around £140 (it may be a little either way) So to install a system that costs £5000 + running costs does not make economical sense, even if it meant my hot water would be totally free, which of course these systems do have running costs, but let's just say it halved my hot water running cost, that would be 35 years to recoup my initial outlay, plus another 17 1/2 years before I am in profit so a total of 52 1/2 years...

Of course there may be the RHI, which IF it ever happens and IF this system is included in the scheme may help.
I am not disputing whether it works, I am sure it does to some degree but the sums just do not add up at all, or am I missing something here?

I must learn to type quicker, someone beat me to it, strange though the figures are similar....

 

[Berneray]

Completely agree with Earthstore........I just don't get it......

If you sat down with a customer and told him the system would take 35 years to recover its costs and and 17 to be in profit......how many do you think would go ahead.....

Can this product be sold ethically......I wonder

 

[jason121]

Anyone come across this new "MAGIC BOX"

The Magic Thermodynamic Box

Got it in an email earlier today....

I got it, ASHP giving COP 1/7 at 25 degrees and 1/3 at -15

 

[Earthstore]

Great news chaps, just realised if I buy one of these systems I could celebrate my 100th birthday with the fact that I had broken even. :cake:

 

[CES Heating]

Anything with "Magic" in the product title deserves a wide berth... Is it magical because they don't understand how it works?

 

[Gavin A]

I asked a question but as many others have been ignored.
So, the cost of heating my hot water per year is around £140 (it may be a little either way) So to install a system that costs £5000 + running costs does not make economical sense, even if it meant my hot water would be totally free, which of course these systems do have running costs, but let's just say it halved my hot water running cost, that would be 35 years to recoup my initial outlay, plus another 17 1/2 years before I am in profit so a total of 52 1/2 years...

Of course there may be the RHI, which IF it ever happens and IF this system is included in the scheme may help.
I am not disputing whether it works, I am sure it does to some degree but the sums just do not add up at all, or am I missing something here?

I must learn to type quicker, someone beat me to it, strange though the figures are similar....

the same applies to solar water heating systems though, and folk do still get them installed as well for a multitude of reasons.

I think the price point really should be about £3.5k for an installed water heating only system, which makes things a bit different, and I reckon the main market for this ought to be in new builds, or situations where they need a mains pressure tank anyway , which is circa £1k inc fitting, so the thermodynamic element is only £2.5k, and with oil / electric heating and no need to pipe the boiler / heat pump output to the

 

[Marvo]

I'm probably missing something obvious here but what is the advantage of using a solar panel instead of having a standard finned evaporator with a fan? When it all boils down to it all heat pumps are solar powered, with an old fashioned evaporator the sun heats the ground, the ground heats the air and the air evaporates the refrigerant giving it latent heat.

I have a refrigeration question as well, how does the solar panel heat pump prevent the superheat figures of the refrigeration system going off the chart on a hot day?

 

[Gavin A]

I'm probably missing something obvious here but what is the advantage of using a solar panel instead of having a standard finned evaporator with a fan? When it all boils down to it all heat pumps are solar powered, with an old fashioned evaporator the sun heats the ground, the ground heats the air and the air evaporates the refrigerant giving it latent heat.

it can draw heat both from the air and from solar radiation falling on the panel, an ASHP can only draw heat from the air, so in theory it should have a higher COP when it's sunny, and a similar COP when it's not.

no fan and less moving parts ought to also mean a longer life, and certainly less outdoor noise.

I'd expect they'd be a better option than ASHP in some situations and not in others, but they should be a valid option IMO.

I have a refrigeration question as well, how does the solar panel heat pump prevent the superheat figures of the refrigeration system going off the chart on a hot day?

there's no insulation on the panel, so it will presumably max at out around the 60-70 deg that PV panels max out at in the UK even when stagnating. I assume the refrigerant is ok to cope with this, but haven't looked that far into it / found those figures.

 

[Vegelen]

it can draw heat both from the air and from solar radiation falling on the panel, an ASHP can only draw heat from the air, so in theory it should have a higher COP when it's sunny, and a similar COP when it's not.

no fan and less moving parts ought to also mean a longer life, and certainly less outdoor noise.

Gavin, Are you going to replace your current water heating system with Thermodynamic solar?

 

[Gavin A]

Gavin, Are you going to replace your current water heating system with Thermodynamic solar?

no.

I installed a solar water heating system 4 years ago which should be good for 30 years or so, I'd be pretty silly to replace it now.

If I were off the gas grid though, particularly if I was using electric for water heating, and didn't have a solar water heating system already, I'd probably install one of these panels plus solar PV. That's the sort if situation I see these possibly working in if the price was right, though I'd expect it'd need RHI payments to make it really financially viable.

- - - Updated - - -

that and new build eco homes off the gas grid.

 

[Gavin A]

btw, when I say this is likely to be better than an ASHP, I should probably point out that I don't advocate using ASHP's to replace condensing gas boilers either, as an ASHP is currently higher carbon than a condensing gas boiler for water heating.

 

[Marvo]

there's no insulation on the panel, so it will presumably max at out around the 60-70 deg that PV panels max out at in the UK even when stagnating. I assume the refrigerant is ok to cope with this, but haven't looked that far into it / found those figures.

60-70 deg on the evaporator is very very high compared to standard refrigeration systems. The negative effect this will have is on the compressor, not the refrigerant itself. I would have grave concerns about the the long term reliability of this system.

 

[The Solar King]

Its is good to see some more technical discussion of this technology, even without firm performance data. At the other end of the scale, how is this equipment going to avoid icing and what defrost cycle is available?

The running costs element is critical to its viability. Normal Solar Thermal has zero costs for energy production and pretty low running costs - a fluid change every five years and a pump if you are unlucky during it's lifetime. Properly designed and installed it will provide 50-55% of an annual hot water requirement. In some parts of the UK, this figure can be higher. This is the cost comparator. The cost of the fuel for auxiliary water heating enters the equation. As alluded to in this thread true running costs for thermo dynamics in UK conditions is currently unavailable.

There is a lot of hard work going on with DECC to make normal ST viable under the proposals for the RHI. If this is successful and IF the questions raised about thermo dynamic equipment can be answered by the manufacturers, then at some stage it may be included. However, the complexities currently involved in the RHI consultation over issues such as bi-valency, and issues surrounding what this technology is finally defined as may still exclude it.

I think the one thing the opinions expressed in this thread shows is the true market for appropriate use of this equipment IF it's performance can be validated is very very small. Use in conjunction with other technologies means it would need to to be compatible with a multi-coil thermal store or hot water storage vessel, not just a dedicated tank. If it is not compatible, you are possibly in to a two tank design, with all the space implications that entails.

 

[steve k]

I have a refrigeration question as well, how does the solar panel heat pump prevent the superheat figures of the refrigeration system going off the chart on a hot day?

The gas isn't in the evaporator long enough for it to be affected by the outside temperature.
When I commissioned the system I first posted about the systems had a saturated suction temperature of -12 deg C and a pipe temp at compressor inlet of 4 deg C, giving a compressor superheat of 16k. I didn't measure the evaporater superheat as the pipe run was so short.
I would not expect this to change whatever the weather / ambient conditions.

**Edit**

Colder outside temps could cause more problems for the refrigeration system than the hot. This is due the possibility of un-evaporated liquid refrigerant finding it's way back to the compressor.
To get around this possible problem, the systems I have installed have the suction line coiled around the compressor to boil off any remaining liquid refrigerant.

Steve

Steve

 

[steve k]

a pic to illustrate

Steve

 

[steve k]

how is this equipment going to avoid icing and what defrost cycle is available?

It can't....if you were to incorporate a hot gas defrost system into this, as in a commercial freezer, the refrigerant would shoot through the evaporator at about 70 deg C, the same as the hot surface temperature discussed in another post at a pressure of appx 300psi.

I have pressure tested the evaporators at 250psi with no ill effects.

Steve

 

[The Solar King]

So running at sub zero ambient temperatures, the panel will ice up?

 

[steve k]

60-70 deg on the evaporator is very very high compared to standard refrigeration systems. The negative effect this will have is on the compressor, not the refrigerant itself. I would have grave concerns about the the long term reliability of this system.

The compressor regularly deals with temperatures like these, it's what they do. Compress low (temp)pressure gas into high (temp)pressure gas.
It is this hot gas that heats up the water.

Steve