Solar panels, worth the money ????

enquiringminds

evensteve wrote: »

Our family of four shower on average 1.5 times per day for an average of 3 minutes. This costs around 50 cents per day or (max) 200 euros per annum using electricity (the most expensive of the readily available domestice sources). The other hot water appliances in my house (kettle, washing machine etc.) heat the water directly themselves, and so are not suited to using solar heated water. As far as I am aware, even if my house was suitable oriented, there would be at least two months of the year when a solar installation would have to be supplemented by additional power sources. On an installation costing an net 2000 this would give a payback time of about 12 years. This is too long, in my opinion, as the longevity of the system itself is likely to be not a great deal longer. I would very much like if someone could point out any flaws in the above, as I would really like to stop paying the utilities their exorbitant charges.

Hi evensteve,

We have a similar number of showers per day. I've estimated that the annual cost is 257 euro. We have a pressurised system, so maybe use more water than you. We heat our hot water using a condensing gas boiler. It seems to me that your annual spend on hot water is quite low. The SEI estimate that solar panels provide 50-60% of hot water requirements. There is a running cost of a small pump and the system requires maintenance every 3-5 years. I would estimate that your payback will be over 20 years on that basis.

The first thing that you can do to minimise your utilities charges is to change your supplier if you haven't done so already. This could save you maybe 10-15% and will facilitate competition in the utilities companies.

How do you heat your house? Approximately 60% of the energy consumed in your home is used for space heating.

As far as electricity consumption goes, there are a number of measures that you can take to reduce consumption. The easiest thing to do is to do an audit, which you can do with a cheap plug in power monitor. That will identify areas where you can save money. There are simple things that you can do to consume less such as only boiling as much water as you need, and turning off items when not in use. Energy efficient appliances consume less than older less efficient units, but replacing units could have a long payback.

My general advice is to identify the changes you can make for little or no cost and make those. After that, I suggest to make the changes that give the biggest bang for your buck. These are often heating, heating controls and insulation.

saibhne

gizmo555 wrote: »

You could get much clearer, but it seems you're unable to. For all your exhorting of myself and other posters to read this paper, it's apparent you haven't read it thoroughly yourself. Two types of solar system are referred to in it - a parabolic trough system, and a space heating system with long term heat storage, neither of which are directly comparable to the systems being discussed in this thread for providing domestic hot water only.

The clarity I'm seeking and which, I repeat, neither you nor the other supplier of solar h/w systems on this thread has so far been able to answer, is what is the embodied CO2 and energy in these specific types of system, which produce far less energy than either of the above two types?

Gizmo,
I'm really not sure how you can be misreading this, this paper directly deals with the environmental impacts of solar thermal heating systems, Let me quote from the paper directly about what the author actually intended to research:

"From the LCA results it follows that for all renewable energy chains the inputs of finite energy resources and emissions of greenhouse gases are extremely low compared with the conventional system."

and

"The LCA (life cycle analysis) results are analyzed with regard to critical life cycle segments and materials and compared to conventional systems. To this end, data from manufacturers and system operators is compiled and the extensive IFEU database used, complemented with data from various literature LCAs (wind power [2], solar thermal power plants [3], geothermal energy [4], PV [5], solar thermal collectors [6], biogas [7]).
The materials, energy supply chains, transport services, etc. are modeled with the Umberto database (www.umberto.de)."

The local solar heating system with long term storage is the relevant system to assess here and is technically and materially the same as the systems commonly installed in Ireland. There is no reference to space heating with regards this system in the paper (although it is possible that the system have a space heating aspect as this is a common application in Germany.) This however would not significantly alter the make-up of the system in terms of material and life cycle.

saibhne

enquiringminds wrote: »

Saibhne,


I didn't make any prediction of fossil fuel prices in the future. I simply gave an indication that if any good or service increased in price by 2.5% it would increase by about 28% in 10 years. I then pointed out that inflation has averaged 2.5% over the past ten years to give an indication that 2.5% is a feasible annual price increase of any good or service.

As I see it this is the issue in a nutshell.. If you assume that energy prices or the price of "any good or service" is going to behave as they have in the past then as I have said, solar thermal (or any renewable energy) is not for you. So if you feel that energy prices will increase at a steady 2.5% for the next 10 years then we'll leave it at that.

On the other hand if you feel energy prices will increase as the SEAI and myself do and that there are hidden costs in environmental and security terms, then there are other costs to apply to the calculations about the benefits of solar thermal energy which are difficult to quantify accurately.

enquiringminds

saibhne wrote: »

As I see it this is the issue in a nutshell.. If you assume that energy prices or the price of "any good or service" is going to behave as they have in the past then as I have said, solar thermal (or any renewable energy) is not for you. So if you feel that energy prices will increase at a steady 2.5% for the next 10 years then we'll leave it at that.

On the other hand if you feel energy prices will increase as the SEAI and myself do and that there are hidden costs in environmental and security terms, then there are other costs to apply to the calculations about the benefits of solar thermal energy which are difficult to quantify accurately.

This is your post in the other thread Saibhne,

"SEAI have released a publication forecasting energy activity in Ireland to 2020, some people might find this interesting and a useful reference particularly the forecast on fossil fuel prices/MWh in 2020.

According to this the following increases will occur (table from report attached):

Oil in 2020: 94.71% increase on 2010 price
Gas in 2020: 48% increase on 2010 price
Coal in 2020: 41.66% increase on 2010 price

Also interesting is that a 40% share of electricty generation is projected from Renewables in 2020, mostly from wind, wave and biomass.. more than a fourfold increase in 10 years.."

If the price of gas went up by 4% per annum for the next 10 years then it would be equal to a 48% rise in the next 10 years.

Consider these scenarios using our annual spend of 257 euro, and that gas prices rise by 4% per annum, as above.
1. Solar panel provides 50% of hot water requirements. That gives a gross saving of 1543 euro over 10 years. Let's say that the system costs 20 euro per year to run and is serviced 3 times at a cost of 100 euro per time. That adds up to 500 euro. That means the system will save 1000 euro in 10 years.
2. Solar panels provide 70% of hot water requirements. That gives a gross saving of 2160 over 10 years. Again, subtract 500 euro and that gives a saving of 1660.

galwaytt

...a 'solar update', if you will.........

My heating system has caused me a few problems, nearly all associated with poor installation - apart from one component, the parts themselves seem fine.

So, I've got to the stage where some remedial work is needed, and that started yesterday. Basically, it involves the complete re-plumbing of hte primary work, and solar connections :eek: and yes, it's a big job.

But - look out the window today, and see the sun.

As part of shutting down the system, we have to drain the 1000L buffer, and to protect the solar system, shut that down. 2 days ago, that meant little - as it was drizzling and grey. Today however, at 11:50hrs, the water into the coil on the buffer tank, was 71.5 deg Celsius.

Now, frankly, I don't care whether people 'say' it does/doesn't work, or it is 'expensive' (it cost 5.5k to install), and I frankly don't subscribe to the 'it won't make a meaningful contribution/we're too far north/weather in Ireland is ****e, etc) - Hundreds and hundreds of litres of water, heated to those kinds of temperature's- yes, by a benign source, with no help from me, well, I'm not prepared to ignore it.

It's not science. It's not 'Green' awareness, or 'Green manifesto' - it is, quite simply, to me, common sense to avail of it. If you go home today, and need hot water, and have to provide ANY fuel/energy to do so, then frankly, the solar system I have, outperforms it.

I have seen, in the depth's of December, temp in excess of 55 deg C from the panels.

Oh, I nearly forgot: the bright day has brought one complication: I've had to climb onto the roof and COVER the panels while they work on the tank, to stop it overheating............!! :rolleyes: :rolleyes: Didn't think I'd ever see that, tbh.......

gizmo555

saibhne wrote: »

Gizmo,
I'm really not sure how you can be misreading this, this paper directly deals with the environmental impacts of solar thermal heating systems, Let me quote from the paper directly about what the author actually intended to research:

"From the LCA results it follows that for all renewable energy chains the inputs of finite energy resources and emissions of greenhouse gases are extremely low compared with the conventional system."

and

"The LCA (life cycle analysis) results are analyzed with regard to critical life cycle segments and materials and compared to conventional systems. To this end, data from manufacturers and system operators is compiled and the extensive IFEU database used, complemented with data from various literature LCAs (wind power [2], solar thermal power plants [3], geothermal energy [4], PV [5], solar thermal collectors [6], biogas [7]).
The materials, energy supply chains, transport services, etc. are modeled with the Umberto database (www.umberto.de)."

The local solar heating system with long term storage is the relevant system to assess here and is technically and materially the same as the systems commonly installed in Ireland. There is no reference to space heating with regards this system in the paper (although it is possible that the system have a space heating aspect as this is a common application in Germany.) This however would not significantly alter the make-up of the system in terms of material and life cycle.

I am emphatically not misreading the paper and it does not support the conclusions you are drawing from it. In particular, your claim that "The local solar heating system with long term storage is the relevant system to assess here and is technically and materially the same as the systems commonly installed in Ireland." is self-evidently wrong. Domestic solar h/w systems such as installed here never include long term storage, which involves large scale buffer tanks to store thermal energy on a seasonal basis. On the contrary, as Quentin points out, best practice is to include a heat dump to dissipate excess heat which cannot be used in the summer months. The methods are diametrically opposite.

I will also just note again that you are not answering the question as to what are the embodied CO2 and energy in typical domestic solar h/w systems such as you supply. I can only assume at this point that the reason you're not answering is because you don't know. Pehnt's paper does not provide the answer, because his figures are expressed in terms of resources used and pollution created per unit energy generated. Since the systems you supply do not include long term storage, they cannot generate as much energy and therefore Pehnt's figures are inapplicable to them.

muffler

enquiringminds, gizmo555 and saibhne would you all mind having a look at this thread and then get in touch with me by PM please.

Thanks

saibhne

gizmo555 wrote: »

I am emphatically not misreading the paper and it does not support the conclusions you are drawing from it. In particular, your claim that "The local solar heating system with long term storage is the relevant system to assess here and is technically and materially the same as the systems commonly installed in Ireland." is self-evidently wrong. Domestic solar h/w systems such as installed here never include long term storage, which involves large scale buffer tanks to store thermal energy on a seasonal basis. On the contrary, as Quentin points out, best practice is to include a heat dump to dissipate excess heat which cannot be used in the summer months. The methods are diametrically opposite.

I will also just note again that you are not answering the question as to what are the embodied CO2 and energy in typical domestic solar h/w systems such as you supply. I can only assume at this point that the reason you're not answering is because you don't know. Pehnt's paper does not provide the answer, because his figures are expressed in terms of resources used and pollution created per unit energy generated. Since the systems you supply do not include long term storage, they cannot generate as much energy and therefore Pehnt's figures are inapplicable to them.

gizmo555 wrote: »

Domestic solar h/w systems such as installed here never include long term storage, which involves large scale buffer tanks to store thermal energy on a seasonal basis. On the contrary, as Quentin points out, best practice is to include a heat dump to dissipate excess heat which cannot be used in the summer months. The methods are diametrically opposite.

I will also just note again that you are not answering the question as to what are the embodied CO2 and energy in typical domestic solar h/w systems such as you supply. I can only assume at this point that the reason you're not answering is because you don't know. Pehnt's paper does not provide the answer, because his figures are expressed in terms of resources used and pollution created per unit energy generated. Since the systems you supply do not include long term storage, they cannot generate as much energy and therefore Pehnt's figures are inapplicable to them.

Gizmo, whilst you are entitled to your opinion you do not back it up with anything meaningful. I disagree whole heartedly with you and with respect I feel you are not making the correct technical analysis. If you could show me some evidence about what you say that would be helpful.

Anyhow, I like Pehnt's paper because it makes a correlation between how solar thermal systems compare to conventional energy (oil and gas) in environmental terms. You have to remember that solar thermal water heating systems are technically very simple and materially contain very similar materials (cylinders, collectors, pipework and pumps) no matter what configuration. The point in Pehnt's work is that the more metal/iron ore contained in the system the worse the carbon footprint but the fact that the panels contained in the system produce carbon free energy over their lifetime they easily negate this.

There are other papers out there that support this conclusion but tend to be copyrighted and require purchase. However I found this one available dealing with solar thermal systems in the UK:
http://eprints.ucl.ac.uk/2642/1/2642.pdf it states the carbon payback on a solar thermal system (definitely similar to those installed in Ireland) is 2.2 years (excluding transport).

This paper here is also available relates to Pakistan and states carbon payback time of 0.5 years on a solar thermal water heating system. The panels would perform better there obviously but it also indicates a very small carbon footprint.

http://www.itee.uq.edu.au/~aupec/aupec06/htdocs/content/pdf/83.pdf

gizmo555

saibhne wrote: »

Gizmo, whilst you are entitled to your opinion you do not back it up with anything meaningful. I disagree whole heartedly with you and with respect I feel you are not making the correct technical analysis. If you could show me some evidence about what you say that would be helpful.

It is not an opinion, rather a fact, that is unheard of for domestic solar hot water systems in Ireland to incorporate long term storage of the type mentioned in Pehnt's paper.

saibhne wrote: »

Anyhow, I like Pehnt's paper . . .

No doubt you do, that doesn't necessarily mean you are applying his calculations sensibly though.

I don't think we're likely to get any further with this, so I'll leave it at that. For readers of the thread who are interested in delving further into the topic generally, there is a relevant symposium on during the "Rolling Sun" book festival in Westport next month.

On Sunday Nov 14th, at 10:30am in the Carlton Atlantic Coast Hotel, the topic "Are our sustainable resources sustainable? Who can you believe?" will be discussed by a panel including journalist Lorna Siggins, Dr Ken Whelan and James Ryan. Admission is €10. (I don't have anything to do with the festival myself - I just live locally and hope to attend this event.)

[EDIT - I see in today's Mayo News that the correct time for this is 10:30am not 12:30pm as I first wrote.]

ei.sdraob

I finally had solar tubes installed over weekend with several sensors thru the system, so far last few days have ranged from 70 (!) on sunday with clear blue skies to 40-50 last 2 days with some fairly ****ty weather with plenty of heavy rains we had

not bad for end of October i have to say

nophd08

ei.sdraob wrote: »

I finally had solar tubes installed over weekend with several sensors thru the system, so far last few days have ranged from 70 (!) on sunday with clear blue skies to 40-50 last 2 days with some fairly ****ty weather with plenty of heavy rains we had

not bad for end of October i have to say

Can you PM me details of system you got fitted as i'm in process of getting same done.
Thanks, N

Joey the lips

ei.sdraob wrote: »

I finally had solar tubes installed over weekend with several sensors thru the system, so far last few days have ranged from 70 (!) on sunday with clear blue skies to 40-50 last 2 days with some fairly ****ty weather with plenty of heavy rains we had

not bad for end of October i have to say

How much did it cost...The system that is...

Whats the payback like.

ei.sdraob

Joey the lips wrote: »

How much did it cost...The system that is...

new build, south facing side:
4K fitting+installation, 40 tubes, piping, 300 liter 3 coil cylinder, sensors panel and other bits

Unfortunately not qualified for any grants so came out of the overall built budget

Joey the lips wrote: »

Whats the payback like.

As for payback i dont know yet, the regulations required a renewable source so i followed them and solar water seemed like the cheapest and most practical option when compared to geothermal or woodchiping or whatever

time will tell and have to live there for while, i was just surprised it was working at all this time of year to be honest. The alternative is using oil and/or electricity to heat water (no gas available out sticks).

More importantly its part of larger budget i had spent on triple glazing, insulation, airtightness and heat recovery. The house is warm and has hot water without using oil and being located in a very wind chilled hilltop location.

Ill make a review in few months see how it works especially with the winter getting darker and colder.

Joey the lips

ei.sdraob wrote: »

new build, south facing side:
4K fitting+installation, 40 tubes, piping, 300 liter 3 coil cylinder, sensors panel and other bits

Unfortunately not qualified for any grants so came out of the overall built budget



As for payback i dont know yet, the regulations required a renewable source so i followed them and solar water seemed like the cheapest and most practical option when compared to geothermal or woodchiping or whatever

time will tell and have to live there for while, i was just surprised it was working at all this time of year to be honest. The alternative is using oil and/or electricity to heat water (no gas available out sticks).

More importantly its part of larger budget i had spent on triple glazing, insulation, airtightness and heat recovery. The house is warm and has hot water without using oil and being located in a very wind chilled hilltop location.

Ill make a review in few months see how it works especially with the winter getting darker and colder.

Price is good. Tube one is best. I would consider tucking a couple of spare tubes in a loft if you have space but having said that you should not need them

Your right...on the system if i had to pick one I would go with solar....

These should actually still give you heat in the sun of january feb

enquiringminds

Joey the lips wrote: »

How much did it cost...The system that is...

Whats the payback like.

Hi Joey the lips,

Please look at earlier posts for payback. The system can be expected to provide 50-60% of hot water costs for the year. Normal hot water costs run about 200 to 300 euro for a house, I guess. That works out at about 150 euro per annum. For a 4k outlay that would mean payback would take about 27 years. That doesn't take into account routine maintenance and running costs.

enquiringminds

Solar panels are powered by solar radiation. In the Summer time there is a max of about 17 hours of daylight, and an average of 6 hours of sunshine per day. In the Winter time there is a minimum of 8 hours of daylight and an average of 2 hours of sunshine per day.

Correct sizing of solar panels takes this into account. That leads to a situation where the solar panels provide almost all of the hot water requirement in the Summer, but will provide a much lower proportion in the winter time. According to the SEI website, a person can expect a solar panel system to provide 50-60% of the hot water requirements for a household.

Joey the lips

enquiringminds wrote: »

Hi Joey the lips,

Please look at earlier posts for payback. The system can be expected to provide 50-60% of hot water costs for the year. Normal hot water costs run about 200 to 300 euro for a house, I guess. That works out at about 150 euro per annum. For a 4k outlay that would mean payback would take about 27 years. That doesn't take into account routine maintenance and running costs.

I did....

Also i agree with the chap that although the payback is long its the cheapest way to meet your requirements. The tubeler on is also the best option imo...

I sell solar. I dont advertise that fact as i dont care to but i think the industry needs regulating. It reminds me of the wild west at the moment. They lay down the tracks and steam right ahead and have no one to police it and make sure its being done right....

Dont mention the SEI there function is to control the grants imo...

gizmo555

Interesting article in the Guardian environmental section today (2 Nov) which goes to the heart of the rationale for solar h/w. Basically it examines the earth-shattering concept that maybe one doesn't need to shower or bath every day of the week and that by cutting down to four or five times a week one can significantly reduce both energy and water use.

Personally I average about three or four showers a week, and a bath once a fortnight or so for relaxation more than cleanliness. So far as I'm aware (and I'm sure my wife would not be shy about letting me know) I'm not noticeably grubby or smelly.

The less hot water one uses, the less sense it makes to install a solar h/w system. Much greater environmental and cost savings can be made by simple changes of habit. Having three showers a week instead of seven would reduce one's personal hot water use by 57%! Even cutting the time spent in the shower, from, say 5 to 4 minutes, could easily give 20% savings. Certainly, I marvel at the post quoted below. How would anyone find the time for a daily 20 minute shower, especially in a household where others were waiting their turn for the bathroom, never mind the amount of hot water needed?

mink_man wrote: »

you only get hot water for shower and sinks and baths....now how much would you spend on a shower a year, about 120 per person if you spend 20 mins in a shower. you still use electricity to heat water for the ashing machine, dish washer etc etc.

championc

I got a system installed last Feb and am very happy with it. On thing I made sure to do was to get a two coil cylinder installed. I have a combi boiler which will instantenously heat water if the buffer water is not hot enough. I have a solar mixing valve which incorporates an anti-scald valve meaning water delivered from either the solar or the Combi is 46 deg C.

My plan (not done it yet) is to link the upper coil onto my heating system with a diverter valve attached and also a pump. My plan is to then extract heat from the buffer tank into the rads circuit when the rads water is cooler than the buffer tank and have rads running "warm" and times of the year when you don't really need much heat but want a bit in the evenings during the early and late summer.

I know many people would run this the other way around and use rads to heat their hot water but I've no need for this with the Combi and, the way I see it, there's no point using energy to heat water which you might not need.

I'd be interested in any views which anyone might have on this - whether you think it's worth doing or completely barmy.


C

quentingargan

championc wrote: »

I got a system installed last Feb and am very happy with it. On thing I made sure to do was to get a two coil cylinder installed. I have a combi boiler which will instantenously heat water if the buffer water is not hot enough. I have a solar mixing valve which incorporates an anti-scald valve meaning water delivered from either the solar or the Combi is 46 deg C.

My plan (not done it yet) is to link the upper coil onto my heating system with a diverter valve attached and also a pump. My plan is to then extract heat from the buffer tank into the rads circuit when the rads water is cooler than the buffer tank and have rads running "warm" and times of the year when you don't really need much heat but want a bit in the evenings during the early and late summer.

I know many people would run this the other way around and use rads to heat their hot water but I've no need for this with the Combi and, the way I see it, there's no point using energy to heat water which you might not need.

I'd be interested in any views which anyone might have on this - whether you think it's worth doing or completely barmy.


C

Hi ChampionC. You need to bring water to above 60 degrees regularly to sterilise it and prevent Legionnaires disease, so while you only want to circulate it at above 46 degrees, your store should generally be brought above 60 at least once per week.

I would use the top coil as a heat dump on occasions when there is too much hot water. Normally in this situation, the solar pump knocks off and stops the panel from heating the water further. It would be better to use the coil to cool the cylinder whenever it gets above 60, and ensure that your solar pump never just knocks off.

Knocking off the solar pump causes the panel to boil. This degrades the anti-freeze and can severely shorten the life of the system.

championc

Thankfully it regularly goes over 60 deg. This is helped by the fact that I went for a 180L store with a 30 tube system rather than a recommended 300L store. The smaller the quantity, the easier it is to heat.

You've got the idea - I want to see about dumping heat into the rads system. It's a closed system and so my plan was to tap off the existing ring and pass it through the upper coil. I'd obviously have to fit a separate pump onto the heating system unless I was able to run the heatings pump without the current boiler heating the water.

My system can go up to 85 deg C and auto vents once this limit is reached so at present, no requirement for a heat dump. However, since water only needs to be 60 or so, I can afford to extract any spare heat above this level.

I have a rebadged Steca 603 controller so plenty of options for controlling a pump and diverter valve based on temperatures.


C

quentingargan

championc wrote: »

My system can go up to 85 deg C and auto vents once this limit is reached so at present, no requirement for a heat dump.
C

Auto vents? Not sure what you mean by that. I suspect your system is one in which the tubes stagnate internally at 90 degrees because the heat pipe shuts down. If that is the case, it probably would be better not to bring the cylinder up to 85 degrees, as the system will already be shutting down by then.

On the other hand, in the summer time you may not want the heat, and 180L brought to 85 is the same as about 245L brought to 60 degrees, so that extra storage may keep the combi asleep for longer. Q

championc

The brand which has the lion as it symbol is the system I have. It has a "dry connection between manifold and tube" and then has a "Unique temperature limitation safety device - memory spring to limit temperature to 95°C" which basically allows the heat to escape into the air rather than continuing to transfer it into the system.

And having 180L at 60 deg is much better than 245L at maybe 45L and this was my reason for going with 180L and I had a very quiet combi during the summer. I reckon I'm looking at a saving of up to 100 units of gas year on year. However, I feel I can just do a bit more by supplementing some heat during April / May and Sep / Oct

So I'm back to my original question wondering if it's lunacy to try and extract heat from the solar store and pump it around the rads circuit. I have my rads in two circuits - down and up and would propose to run just the downstairs through it.


C

quentingargan

championc wrote: »

The brand which has the lion as it symbol is the system I have. It has a "dry connection between manifold and tube" and then has a "Unique temperature limitation safety device - memory spring to limit temperature to 95°C" which basically allows the heat to escape into the air rather than continuing to transfer it into the system.

And having 180L at 60 deg is much better than 245L at maybe 45L and this was my reason for going with 180L and I had a very quiet combi during the summer. I reckon I'm looking at a saving of up to 100 units of gas year on year. However, I feel I can just do a bit more by supplementing some heat during April / May and Sep / Oct

So I'm back to my original question wondering if it's lunacy to try and extract heat from the solar store and pump it around the rads circuit. I have my rads in two circuits - down and up and would propose to run just the downstairs through it.


C

You are quite right to do this. The system is the brand and type I had thought. The heat doesn't really escape that easily into the air, but accumulates inside the vacuum tube which gets to extremely high temperatures. For that reason, I would still consider it best practice to use a heat dump anyhow to ensure that this doesn't happen, particularly during summer vacation. So there are two reasons to use your second cylinder coil.

You will get some heat gain alright on the fringes of the season. Vacuum tubes don't lose that much efficiency by being brought to high temperatures, so I would opt for perhaps an upper limit of 70 to 75 in the summer, and perhaps a bit less in the winter to optimise heat gain at a time when it is useful.

I'm normally cynical about the benefits of space heating using solar - the gains are pretty miniscule, particularly if your house is well heated (as your space heating season is shorter), but I am a fan of heat dumps.

championc

I certainly want to power something more than just a towel rail.

Many thanks for the added inspiration to possibly have a go and do this. I suppose that once it doesn't cost too much then it's worth putting in.

A final question, will heat travel effectively from the store through the coil into the circulating water ?


C

quentingargan

championc wrote: »

A final question, will heat travel effectively from the store through the coil into the circulating water ?
C

Yes - the coil will have a lower surface area than the solar coil, so the temperature difference between this and the rads will be higher, but that shouldn't matter much. Just check by the way that all the TRVs aren't closed so that the heat can escape too! Q