Are you all pleased with your solar panels for hot water heating

solarstudent · 04-04-2012 10:36pm

Can you explain the difference between the super efficient tubes that will allow you to use that many fewer tubes for the same output? Is it a different technology or a better put together heat transfer tube that transfer higher heat output into the transfer fluid from the same insolation. Is there a difference in flow rate?
Thanks[/Quote]

No problem pm me your email address and I will attach you some college work and Info on the systems I have

championc · 04-04-2012 11:18pm

solarstudent wrote: »

Have been on work experience for 6 months at a solar company fitted over 20 different solar thermal installations and been to around 50 different installations.
And we don't just sit in a class looking at data sheets either in college btw.

How many of these installations fitted a data logger ?

Many customers may turn around and say how delighted they are with the results and we all know that you cannot believe data sheets. Data sheets are based on the "perfect" conditions.

Let me share the following with you. A neighbour of mine had a panel. He confirmed that he was delighted with his system because his water temp never fell below 56 or so deg. First alarm bell began to ring. He then confirmed that he didn't feel that he's saved a huge amount on his gas bill so far.

Basically, he had the central heating connected to a second coil and so it was likely that the CH was doing a fair amount of heating the stored water !!

rosepaddy · 10-04-2012 9:22am

tred wrote: »

Just thinking of starting a poll on this. Is everyone here happy or not with their solar panels, performing as expected?

good question, poll is a very good idea, we use solar to support our central heating using a diffused radiation collector from switzerland only one in ireland, i think there is alot of misinformation alot of people think if they buy more tube they get more heat not true , if people dont understand what the capabilities of solar are and they have nothing to compare there system to then it is possible they ae happy with their system, even though it may be providing little support campared to a better system,

the answer to your question on the poll very happy with solar here in Ireland, even happier that i use it well towards my central heating

steviebg · 10-04-2012 10:21am

Hey all,
I am really thinking about getting in solar but don't have a clue about what to get. From reading on here there seems to be some systems better suited for use in ireland is this true? If so is there a list of the best systems to use. Also i'm in the cork area if anybody could recommend an installer they've used that would be great! Thanks all.

championc · 10-04-2012 10:26pm

rosepaddy wrote: »

good question, poll is a very good idea, we use solar to support our central heating using a diffused radiation collector from switzerland only one in ireland, i think there is alot of misinformation alot of people think if they buy more tube they get more heat not true , if people dont understand what the capabilities of solar are and they have nothing to compare there system to then it is possible they ae happy with their system, even though it may be providing little support campared to a better system,

the answer to your question on the poll very happy with solar here in Ireland, even happier that i use it well towards my central heating

I'm happy with my system but it is good, is it working efficiently, is it working as it should - I haven't a clue.

Not sure how you support central heating though, given that I assume you have plentiful hot water stored during the summer - a time when I would assume you would have little use of CH. So are you "topping up" your store in some way other than via solar ? And what minimum temperature water do you use towards your CH ?

IMO polls are a waste of time unless you have some way of actually quantifying results and everyones system would need to be based on the same factor. In other words, I have 30 tubes with Aperature Area of 3.24m2 for 180 Litres store. So this would equate to 55.5l / per m2. My system raises the water temp by 4 deg C every 50 minutes.

So to start you all off, based on the current weather

1m2 Tubes takes 12mins to raise 55.5litres by 1degC

quentingargan · 10-04-2012 10:41pm

championc wrote: »

IMO polls are a waste of time unless you have some way of actually quantifying results and everyones system would need to be based on the same factor.

I also think polls are likely to be misleading if those of us who work in the industry also take part. I'm hardly going to say that I'm unhappy with my system now, am I?:rolleyes:

solarstudent · 13-04-2012 2:25pm

championc wrote: »

So to start you all off, based on the current weather

1m2 Tubes takes 12mins to raise 55.5litres by 1degC

There are so many variables to that calculation that you cannot use it as a comparison really. It all depends on the irradiation available to the collector and how much of that it can transfer to your cylinder, and therefore the less work your boiler has to do if it has to do any at all.

hop2it · 14-04-2012 11:04pm

I must say i,m very happy with my solar tubes
I have 40 tubes 58mm by 1800 mm and a 300 litre tank
adverage bottom tank temp of 55c d'ont know if thats good or bad but i'm happy

championc · 15-04-2012 12:14am

solarstudent wrote: »

There are so many variables to that calculation that you cannot use it as a comparison really. It all depends on the irradiation available to the collector and how much of that it can transfer to your cylinder, and therefore the less work your boiler has to do if it has to do any at all.

Agreed, but the point here is, can anyone do better ? We can all "say" we are happy but you have to know what it potentially possible to have any idea if your system is working at optimum or is crap.

hop2it wrote: »

I must say i,m very happy with my solar tubes
I have 40 tubes 58mm by 1800 mm and a 300 litre tank
adverage bottom tank temp of 55c d'ont know if thats good or bad but i'm happy

Is this purely heated from the tubes or is it supported by CH ? It demonstrate better to the solarstudent, if supported by the CH, then it could be argued / questioned as to how effective the tubes indeed are.

ADVICE TO EVERYONE THINKING ABOUT AN INSTALLATION
Ensure you get a data logger option with your controller. For the sake of another hundred or two, you'll have a full insight as to what your system is doing and how well it's performing. You can never beat hard data

hop2it · 15-04-2012 12:25am

Is this purely heated from the tubes or is it supported by CH ? It demonstrate better to the solarstudent, if supported by the CH, then it could be argued / questioned as to how effective the tubes indeed are.

sun light only

championc · 17-04-2012 9:54am

hop2it wrote: »

sun light only

That's pretty impressive for the bottom of the tank since I would have expected new water to be entering the bottom from the rising main and therefore, it would be in the low to mid teens

Even for the top of the tank, it could be said that AVERAGING at this level at this time of year is pretty impressive for 40 tubes on 300 l. How many deg of an increase would you get on an average sunny day - maybe a day like today.

C

freddyuk · 17-04-2012 6:03pm

I would suggest the bottom sensor is actually in the area of the incoming solar coil so 55c would be about right. The really useful water is at the top and needs to be getting to 70c+ with a TMV installed to make best use of the solar energy. Is there a top sensor?

hop2it · 17-04-2012 7:16pm

@ championc

as i type this the bottom tank is 53c
we usually bath and shower at bed time so morning temp is usually in the teen,s
so a 40 degree rise even on a day like today

championc · 17-04-2012 7:45pm

As Freddyuk asked, do you have a top sensor ?

However, you've really proved my point on here. I was happy with my system performance but now I'm not so sure. Here's my data for today.

hop2it · 17-04-2012 10:31pm

no top sensor fitted yet
what's a tmv ?

freddyuk · 17-04-2012 11:04pm

May be worth getting a top sensor (about €15) as this is where you draw your hot water from. Surprised you did not get 3 sensors installed. Unless you have issues with stratification the tank should be several degrees hotter at the top of the tank. Your measurement is taken from 2/3 down where the solar coil is heating the water but this is not the water you are using. 300 litres with 40 tubes is a tall order at this time of year so it is important to know the temperature at the top. If you have the best part of 200 litres at 55c+ using 40 tubes alone then you are doing very well but if you have a boiler system feeding in at the top then this would explain it! But you say you use the water at night (not ideal) and it is cold in the morning which suggests the boiler is not heating the cylinder. Is the boiler programmed to come on? What is the panel temperature during the day when the sun is out?
A TMV is a thermostatic mixer valve to cool down the hot water to prevent scalding risk from a solar system which is allowed to get as hot as possible. Essential kit!

freddyuk · 17-04-2012 11:16pm

championc wrote: »

As Freddyuk asked, do you have a top sensor ?

However, you've really proved my point on here. I was happy with my system performance but now I'm not so sure. Here's my data for today.

Looks OK ? You are getting 70c on the panel and up to 55c in the cylinder. Depending on where your lower sensor is installed will dictate the differential top/bottom temperature.You should have sufficient hot water - maybe 120 litres for the morning showers ?

championc · 18-04-2012 12:45am

freddyuk wrote: »

Looks OK ? You are getting 70c on the panel and up to 55c in the cylinder. Depending on where your lower sensor is installed will dictate the differential top/bottom temperature.You should have sufficient hot water - maybe 120 litres for the morning showers ?

Bottom sensor right at the bottom of the 180l tank and top sensor right at the top.

I'm getting part of my system changed tomorrow. The tank has twin coils. I am getting the tubes linked to the upper coil and with a diverter valve fitted. In this way, I can heat 90l up to maybe 55 deg C and then, once reached, the diverter valve will switch the heat to begin heating from the bottom. My hope is to maximize my heat gain in Spring and Autumn.

I have a combi solar mixing valve which will send water when 45 deg or over (the Valve incorporates an anti-scald mixer), straight to the taps or else, it cools it to 28 (if between 45 and 28) and sends it to my combi for heating up to 45 deg. The combi can only take input of 28 deg or less. So I want as much hot water to go straight to the taps as often as possible.

New setup - using the upper coil to heat the top half first

freddyuk · 18-04-2012 9:15am

Ah the joys of a good old Firebird! Just needs to top up any temperature of stored water.
I can't see why your system will not work if the combi valve works effectively. Do you have a heat dump system also?

championc · 18-04-2012 3:29pm

During Feb and March, I struggled to reach 40 deg. However, if I was only heating half the water on these occasions then I'd have a greater chance of water exceeding 45 deg after even half a days sunshine.

No heat dump necessary, my system is a Kingspan which autovents. I have the max temp set to 90 deg so it's only one or maybe two days per year that it will ever get up to this. You would need about 3 days of perfect sunshine in a row to hit this

freddyuk · 18-04-2012 11:27pm

It is important to get the correct sized collector for the size of the cylinder lots of tepid water will result.
You say your system auto vents? Please explain.
If there is an auto vent on the system you will lose all your fluid if it gets hot enough! A bypass cools the system without any drama, damage or refilling.

championc · 19-04-2012 8:36am

freddyuk wrote: »

It is important to get the correct sized collector for the size of the cylinder lots of tepid water will result.

Indeed, I'm glad I never got 30 tubes with 300l store or you'd need nearly a week of sunshine I reckon to get over 60 deg - so long as to water is not heated by other means like an immersion or CH

freddyuk wrote: »

You say your system auto vents? Please explain.

I understand that there is something special about the manifold / tube nozzles of the Kingspan tubes. There's no loss of fluid

freddyuk · 19-04-2012 8:37pm

Rule of thumb is quoted as 7.5 litres per tube (1.8m x 58mm tubes) although some reckon 5 per tube is better as over sizing gives you a longer "season" so yours is not over sized.
The essential thing is to have a way to cool the system down in the event of over heating which will happen in Summer and a basic bypass achieves this very effectively although it relies on an electronic valve to operate. Thermomax rely on an integrated spring valve device to retain steam in the system which is great providing it lasts 20 -30 years. In the event it fails the system will evacuate into the safety container and need recharging. I am not sure there is way of servicing this device so if it is required after some years of inactivity you just hope it works and is not corroded up. I can check my valve manually to ensure it works but for most customers this would not be an option unless they are keen DIY'rs. Keep it simple!!
Let us know how the new system performs.

Mothman · 22-04-2012 12:17am

freddyuk wrote: »

It is important to get the correct sized collector for the size of the cylinder lots of tepid water will result.

I don't subscribe to this thinking. Its important that supply meets the outgoings, usage plus loses. Once this happens, then generally the size of tank is not a major concern once the tank temperature is up. Though if it is poorly insulated then the losses are an issue and its harder to get through cloudy periods without backup and to keep tank temp up.

I used to have 300l tank with my 6 sq m flat plates. My tank failed and I replaced it with a 500l store. Once I dealt with the tank loses (it was badly insulated) I am really thrilled with how its performing and it seems to be performing much better than my previous arrangement. The solar coil in this store is much larger than the previous tank and I guess I'm harvesting more energy. For past 4 weeks, I haven't needed any backup. Have had panels for 14 years and have always used backup in early April. I think my new store is part of the reason, the other is the sunny weather, well above average though not as sunny as last year or 2007.

quentingargan · 22-04-2012 12:32am

Yes - OK if the tank is stone cold and you get a half-decent day, you will end up with 500L of lukewarm water that day, but sooner or later the heat will accumulate, provided you aren't losing it through poor insulation.

By the way, there is a myriad of "solar" cylinders that have two coils, but the bottom one for solar is not a high surface area coil. I have seen 300L ones with coils that had a surface area less than 0.7M2. Ideally the coil should have a surface area of at least 0.25 sqM per sqM of solar panel.

championc · 23-04-2012 1:51pm

freddyuk wrote: »

Let us know how the new system performs.

There was a setting missing on the controller which I have had clarified this morning with Steca. The threshold for the upper section was set to 60 deg C but over the weekend, it kept dumping the heat into the bottom section even though the top was at 51 deg C. It needs a "Quick Charge" function to be turned ON.

So hopefully, by the weekend, I can look forward to +50 deg C hot water in the top section for a large portion of the year and the same in the bottom section full during the summer months.

championc · 24-04-2012 9:06pm

I had a call with the Steca guy in Germany today who basically said that the system balances between top loading and boosting the whole system in the cleverest way, getting the best use from the energy being harvested (at least I think that's what he was getting at)

I have reviewed my data from today and the bottom seems to be getting topped up as it goes along, staying within about 8 deg of the top temperature which is not quite what I had hoped for.

I'll reserve judgement until I have lots more data but it certainly does not seem possible, using the controller, to load the top up to a certain level and then go to the bottom.

johnfoyvision · 04-05-2012 8:29am

could you pm the company me too please.....

championc · 24-08-2012 10:01pm

My Data is now online 24 x 7 x 365

See https://cosm.com/feeds/71436

RTT · 25-08-2012 7:56pm

championc wrote: »

My Data is now online 24 x 7 x 365

See https://cosm.com/feeds/71436

Impressive! Are they the temperatures you are achieving at the moment without any other source of heat other than solar?

championc · 25-08-2012 11:25pm

RTT wrote: »

Impressive! Are they the temperatures you are achieving at the moment without any other source of heat other than solar?

Absolutely, no other source

I have a Combi boiler if the solar comes up short during the year.

01-09-2012 2:21pm

It costs me 30 Euro's or so to heat the water with the immersion over the 5 months a year we don't need the heat.

In winter the heating heats the water costing hardly anything extra.

That's a very very very long time to pay back a 3k + solar thermal system ?

I would have thought Solar P.V would have been a better option for people because when your solar is generating it can continually export to the grid when you don't need it making you money. Or you buy it back at half the price during the night.

freddyuk · 01-09-2012 3:31pm

Quick calculation says that is only using immersion for half an hour once a day for 150 days? (excluding standing charge and VAT)
If you use hot water for baths/showers, washing up/dishwasher, washing machine it is not a huge amount of hot water. If you have a cold fill washing machine then you not using that but if you have hot fill machines the solar goes straight in so can be a benefit.
My temp in West Cork now are 50c on the roof and 45c in the buffer. It is a nasty day for solar! 39 tubes into 200 litre buffer. It may have dumped some heat into the DHW cylinder already - but unlikely today.

01-09-2012 5:19pm

freddyuk wrote: »

Quick calculation says that is only using immersion for half an hour once a day for 150 days? (excluding standing charge and VAT)
If you use hot water for baths/showers, washing up/dishwasher, washing machine it is not a huge amount of hot water. If you have a cold fill washing machine then you not using that but if you have hot fill machines the solar goes straight in so can be a benefit.
My temp in West Cork now are 50c on the roof and 45c in the buffer. It is a nasty day for solar! 39 tubes into 200 litre buffer. It may have dumped some heat into the DHW cylinder already - but unlikely today.

Including vat excluding standing charge which I and solar Thermal users have to pay anyway.

If you use loads of hot water maybe I can see a few year payback, but not for us as we conserve and we waste as little as possible.

Our yearly electric bill is around 550 per year in total. including a cold fill washing machine and to be honest you would want your washing machine close to the hot water cylinder to benefit as it would be nearly full by the time it fills up, unless you run the tap first.

We don't have a dish washer and a kettle of water does the job nicely.

I'd be more willing to install a night saver meter if I used a lot of leccy over a solar thermal.

If I could have solar thermal for my heating it might be more worth my while, but I would think that would have to be pretty large and expensive and then in winter daylight hours are short.

steifanc · 02-09-2012 9:49am

sinnerboy wrote: »

I'll sticky this awhile and add

Please indicate

cost self installed 3k
year of installation last week
m2 area 80,tubes
orientation south
flat plate or tubes tubes
cylinder size 300lt
summer heat dump strategy , ability to transfer from the 300l tank to a 500lt buffer and after that into the floor , when the 300l tank hits 70 degrees it dumps ontill it reaches 60 degrees
So far happy , plenty of hot water this week , tanks sits around 55/60 all this week , hopefully it performs in the winter

Reminder - no trade / company names please

.

.

freddyuk · 02-09-2012 7:33pm

championc wrote: »

My Data is now online 24 x 7 x 365

See https://cosm.com/feeds/71436

Well today I had /have 72c on the roof and buffer is 67 top and 66 bottom in 200 litres which seems pretty good compared to your expensive thermomax against my cheapo Chinese kit.

02-09-2012 8:54pm

freddyuk wrote: »

Well today I had /have 72c on the roof and buffer is 67 top and 66 bottom in 200 litres which seems pretty good compared to your expensive thermomax against my cheapo Chinese kit.

Can you provide a link to the kit you got ?

championc · 02-09-2012 10:19pm

freddyuk wrote: »

Well today I had /have 72c on the roof and buffer is 67 top and 66 bottom in 200 litres which seems pretty good compared to your expensive thermomax against my cheapo Chinese kit.

There are potentially so many variables here but as a matter of interest,

a. how many tubes do you have ?
b. how many deg of an increase did you get today ?

The great thing about data is that you can visibly see if something is not working correctly.

freddyuk · 02-09-2012 10:54pm

Of course there are and I am just tweaking you a bit! But anyway I did post my reading yesterday above. There is no log burner going so no additional heat into the buffer it is all Thermal at the moment.
42 tubes are 58mm

championc · 02-09-2012 11:28pm

So 40 up to 66 - not bad at all. Decent return on your investment there.

freddyuk · 05-09-2012 6:05pm

I am at 70c today top and bottom.

dathi · 07-09-2012 9:29am

30 Chinese tubes into 200 litre tank was at 65* yesterday having started the day at 31* it also heat dumped twice into central heating circuit yesterday as i dont let the water go above 65*(hard water)

freddyuk · 07-09-2012 2:23pm

Nice one! Up the Chinese!!:D

Qualitymark · 07-09-2012 5:50pm

Would anyone know what the *wholesale* price of solar panels is? I mean, if the Government bought half a million of them wholesale, and employed all the workless builders and plumbers and electricians to put them in on people's rooves (thus slashing Ireland's carbon footprint), with people paying the wholesale price plus the installers' wages, how much would the panels cost?

quentingargan · 08-09-2012 12:03am

Qualitymark wrote: »

Would anyone know what the *wholesale* price of solar panels is? I mean, if the Government bought half a million of them wholesale, and employed all the workless builders and plumbers and electricians to put them in on people's rooves (thus slashing Ireland's carbon footprint), with people paying the wholesale price plus the installers' wages, how much would the panels cost?

Not an awful lot less I'm afraid. There are also cylinders, pipes, pump stations etc. Most suppliers are working on lower margins than most hardware these days.

goat2 · 08-09-2012 12:33am

i do not use the immersion, in fact i have disconnected it from the mains, as it is not needed, could one get a spiral going from the solar panel to the tank taking out the immersion element and using the intrance of the element to put in a spiral from the panels, and in doing so save the price of tank and labour time

quentingargan · 08-09-2012 5:28am

goat2 wrote: »

i do not use the immersion, in fact i have disconnected it from the mains, as it is not needed, could one get a spiral going from the solar panel to the tank taking out the immersion element and using the intrance of the element to put in a spiral from the panels, and in doing so save the price of tank and labour time

There is a unit that can replace the immersion (and which has a replacement, smaller immersion) for about €250. PM Sent. Or you could get a unit made up by someone with oxy-actetylene.

However, there are other issues to watch out for. You can only use this with quite a small panel, and usually the existing cylinder is quite poorly insulated. But if that suits your needs for a modest hot water supply it is a convenient solution. You will need to insulate other pipes coming from the cylinder to ensure there is no heat loss into the heating system for example.

Roundtd181 · 19-10-2012 11:32am

Just a rant here. see people have been putting in the Chinese tubes that Kingspan are buying and selling as part of their kit, i hear they are of very poor quality and there is a lot less output in heat compared to other panels like the Solarfocus.

Anybody know anything about Worcestor Bosch?
What about swedish/norwegian/icelandic panels, i would be interested ins talking to a supplier for them.

At the minute i am going with 2 flat plate solar panels with a new 350litre Maxipod tank unless can be convinced otherwise!!

championc · 19-10-2012 3:14pm

I've never heard Chinese and Kingspan and Poor Quality ever being mentioned in the same sentence.

As for Tubes vs Flat Plate - do some research but my understanding is that Flat Plate deliver more heat under a cloudless sky but significantly less under broken sunshine. I think they also rely on the Sun to be alot more overhead so would not be too good with winter sunshine. With tubes, if you have a cloudless sky, you'll have no shortage anyway of hot water so you really want to maximize gains in Spring and Autumn

Hope this helps

Roundtd181 · 19-10-2012 4:06pm

championc wrote: »

I've never heard Chinese and Kingspan and Poor Quality ever being mentioned in the same sentence.

As for Tubes vs Flat Plate - do some research but my understanding is that Flat Plate deliver more heat under a cloudless sky but significantly less under broken sunshine. I think they also rely on the Sun to be alot more overhead so would not be too good with winter sunshine. With tubes, if you have a cloudless sky, you'll have no shortage anyway of hot water so you really want to maximize gains in Spring and Autumn

Hope this helps

Sorry shouldn't be slating Kingspan like that. One particular renewable guy near to where i live is selling and fitting solarfocus panels and he insists these are a far superior panel to the Kingspan panels. I would be interested to find out some thoughts from someone who knew both systems as he could be saying this as a selling tool.

Taking into account the pro's and con's of flat plate and tubes i will go going with the flat plate as the house is new build and i am doing this purely for aesthetics.

Are you all pleased with your solar panels for hot water heating

Comments