Solar Heating and Thermal Storage tank

[Adrian80]

Hi Guys,

Im new hear, and have read as much stuff on the old tinternet as possible, but nothing really answers my question.

With the old gas and leccy price going through the roof, and that im renovating my house. I was thinking about doing DIY solar evacuated tube thingy!

The thing is i realize they arent the best in the winter, but apparently the still work a little. So i was wondering how to hook up my existing sealed combi so i can get the best of both worlds, i.e. as much free hot water and heating as possible.

My idea is to get a thermal storage hot water tank, with two flow and returns. One set for the solar panel and one set to connect to the combi central heating flow and return, and not sure if you can get it but an immersion heater in the tank as well, ( a real belt and braces effort).

However i have read that combis should not have hot water pre feeding them. But with a central heating loop there must be a fair bit of heat in the return loop, so i dont understand this argument.

I am hoping in the summer the solar should heat the cylinder plenty to do all the hot water, and then in the winter for it to do some work to take the chill of it, and because its winter ( and the mrs) the heating will be on full tilt, so the combi will doing most of the work heating up the old thermal storage tank, consequently with enough hot water for all her baths.

I was then thinking of just not using the hot water part of the combi.

Does this sound like a completely stupid idea or vaguely sensible.

All comment greatly received, even if it is your a plonker.

Cheers
Adrian

 

[htgeng]

Not all combi boilers accept pre heated water due to fact they have a rubber diaphragm at the cold water inlet. Some combis do - Atag for one, because they don't use the diaphragm approach.

Your idea is ok, but think a bit over complicated. Just have a twin coil unvented cylinder with a system boiler. ok, you can't diy the cylinder.. depends how much of the rest of the system you want to install

 

[BigBurner]

Best have a cheaper heat only boiler heating a solar heat bank. Then, a CH buffer as well with no TRVs on all rads when using a Smart pump.

This will be no more expensive and alot more on offer.

 

[Adrian80]

The thing is i already have a room sealed condensing boiler, so dont really want to buy another boiler if this one will do the job.

I was hoping not to have an unvented system, as you say you need to get someone in to fit it.

But fingers crossed i had hoped that a thermal store could be easily linked to a couple of heating sources.

Cheers Adrian

 

[oilman]

You need a place to store the solar heat anyway, so you will need a tank. This does not mean a new boiler, you just have to move the hot supply from the boiler to the tank, and do away with the combi part of the boiler.

Look here for a more useful way to use the heat. They have a lengthy report which is worth reading too. You won't need a fancy tank either. However, with any solar heating, unless you do a lot of the work yourself, you are unlikely to see a return on the investment in your lifetime.

 

[Agile]

If you already have a combi then its best to continue to use it for the kithen hot water.

Solar gives a 2-3% return on capital when professionally installed. Its better value to put the money in the building society!

Tony

 

[Adrian80]

Cheers for all the replys

You would think the govt would start to knock out 1000's of solar panels in the hope we wouldnt use so much gas and oil.

Im not an eco nut just very tight and dont want to pay for extortionate gas and leccy.

Oh well,

Cheers
Adrian

 

[oilman]

You would think the govt would start to knock out 1000's of solar panels in the hope we wouldnt use so much gas and oil.

Not when the reality is the amount saved would be naff all. They only pay lip service to gain votes. You don't see THEM cutting down on their consumption.

 

[BigBurner]

If you already have a combi then its best to continue to use it for the kithen hot water.

Solar gives a 2-3% return on capital when professionally installed. Its better value to put the money in the building society!

Tony

When DIYed, with current energy price hypes, solar will pay for itself a lot sooner than you think. A solar heat bank gives heat to DHW and CH.

Best use a pressurised solar heat bank and connect up the combis flow and return to it. Just forget the DHW side and use the boiler as a system boiler. It is just something else to go wrong. Not used it will not go wrong on the DHW side.

Best have the CH run off the heat bank too. Use TRVs all around and a Smart pump, then no room stat is needed.

See:
http://www.advanceappliances.co.uk

 

[BigBurner]

You would think the govt would start to knock out 1000's of solar panels in the hope we wouldnt use so much gas and oil.

Not when the reality is the amount saved would be naff all. They only pay lip service to gain votes. You don't see THEM cutting down on their consumption.

That is childish. Bullet proof Jags will never be cheap to run.