solar panels with thermal store

[BigBurner]

So you are talking 3,500 litres. Is this the type of storage you think necesssary

Here are may two 1,000 litre stores arriving http://i194.photobucket.com/albums/z10/v1505guy/dsc00004.jpg

Food grade containers £145 the pair delivered.
Can withstand 110 degrees Celcius continuous, as they are not to be sealed they cannot get higher. A small amount of antifreese to kill legionella a silver spoon in each. All heat transfer indirect in and out using thethe old coils from copper domestic hot water cylinders which at todays scrap prices are costing £13 each on average.

I assume you are encasing these in a frame with heavy insulation inside. Or are they going underground wrapped in heavy foam insulation?

So these hold the heat from the panels, which in time will serve UFH.

The DHW? They are a pre-heat for a cylinder in the house using a solar coil?
Do you have a control setup where hot water from the panels goes directly to the DHW cylinder if hot enough?

The heat from the panels can go to a solar coil in the bottom of DHW thermal store in the house and the return to the large plastic thermal stores. DHW always get the heat first. Once up to temp the surplus then is piped to the plastic thermals stores. UFH taken directly from the plastic thermal store.

Old cylinder coils will probably not be big enough. A coil of 10mm or 12mm pipe will be better, and easier to spread out.

See:
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm

http://www.builditsolar.com/Projects/SpaceHeating/Space_Heating.htm#Storage

 

[Paul Barker]

Hi

I bought a length of 25m 10mm to use as the coile for £34 plus vat

but then thought to use old cylinder coils in series. At their price they are worth a go.

The plan was originally to use the thermal store with a pair of collector coils at the top one for dhw one for ufh.

However an emergency at home has occured ahead of the whole project so the leaking (which wives of plumbers balme plumbers vehemently for) open vented ancient dhw cylinder is now disposessed by a £134 off ebay almost new 145 litre Megaflow. A delv through my bits and pieces turned up a lever type iso valve double check valve filter and pressure regulator. I decided to add a 24 litre expansion vessel so that when the bubble is gone it is forgotten about. For the moment I have turned the pressure right down as I could only find a 3 bar prv will have to order a more suitable one. At the monent the D2 pipework is not outside but the family got their bath last night.

So now the plan is two panels on the roof to heat this cylinder for the summer.

I had to condemn my own boiler so a Buderus regular boiler (in need of a wiring harness and perhaps pcb need to replace harness to find out) I have in stock shall be the new alternative heating. (hydrocarbons have relegated themselves to alternative energy in my house on grounds of cost.)

For alternative DHW I shall probably pass the output of the dhw cylinder through a plate heat exchanger and heat the primary with the regular boiler. The water should always be preheated by the cylinder and the family will simply have to adjust the flow rate at the tap to attain satisfactory temp.

If I had a combi in stock I would have used it but I didn't. If things cost too much there is no point in any of it. Being green is about recycling.

To which end for insulation I have told the local copper scrap merchant that I will have all his bs1566 cylinder jacket material of which he chucks away bags full each week. I don't know it's R value whether it is as good as kingspan but it is free.

The bowsers will be dug into the ground and surrounded by broken up recycled insulation material.

Of late it is now likely that I shall erect a solar shed in the garden with the angle of elevation to suit the UK winter conditions (60 degrees?) The remaining 3 20 tube collectors will go up there. THis is primarily a learning excercise but the principles are to only use hydrocarbon as a final resort and never to use it to partially heat any thermal store with the intention that whenever UV is available it can be stored.

I did buy a twin line pumping station and controller. Armaflex duo SS solar pipe etc.

But now discover that an established firm uses copper pipe soldering is fine and just the lagging from armaflex. They use standard Grundfos 15/50 on speed one for up to 11 panels.

As project unfolds I shall link pictures and results.

The trombe wall is my most ambitious plan, probably contensious with neighbours have you any idea how planners see this? AFAIK I am not in a conservation area and house not listed.

 

[BigBurner]

Sounds like you are winging it as you go along. You need an overall well thought out plan and aim to achieve the plan. Having to integrate distress purchases can't help at all.

I didn't quite get what the plate heat X was doing.

I find that temperature differential controllers are "usually" the best way. If heat is in the plastic thermal stores then it can be used. Using UFH, an injection pump taking heat from boiler or t/store may be the way.

Planners are favourable of anything "eco".

 

[Agile]

Hi

The bowsers will be dug into the ground and surrounded by broken up recycled insulation material.

How are you going to keep the insulation dry?

If it becomes waterlogged the "U" value falls greatly!

Tony

 

[BigBurner]

Hi

The bowsers will be dug into the ground and surrounded by broken up recycled insulation material.

How are you going to keep the insulation dry?

If it becomes waterlogged the "U" value falls greatly!

Tony

Foam insulation does not absorb water. It is best to have rigid sheets surrounding the tanks. The tank should be resting on one too. Around the the tank should be hardcore to acts as drainage to take the water away from the tanks. Also, poly sheet over the tanks, like an umbrella will divert water soaking into the ground from above (rain) - it must run away from the tanks with an apex (umbrella shape). Under the poly can be insulation to prevent frost from working its way down to the tank. This can be way larger than the tank

It may be best to dig around the tanks a linear soakaway. In short, do everything to keep water away from the tanks, and if it does get near, it soaks into the soakaway. Insulation is important.

 

[Paul Barker]

I was told you need one of these

one of these

some of this

 

[Paul Barker]

These are very cheap and nasty

But these are meant to be the same as fitted to European panels

 

[Paul Barker]

You have to know someone with one of these

But if you are a struggling heating engineer sick of boiler bashing you would probably buy one like I did.

 

[Paul Barker]

If you have a son in need of pocket money he can reclaim one of these

while you are knocking up one of these to shut the wife up

 

[Paul Barker]

Notice water damage on the controls from the old one.

I would have been happy to "manage" the situation for a lot longer but got wrong footed by wife the other day.
"I don't like what you have done to my tree" ( I had to cut it back ready for bowsers. As eveyone knows the only gardening tool a plumber posesses is a panel saw. So I cut it back the most efficient way.

Anyway being totally unprepared fro that telling off I walked right into her next salvo.

Couldn't thi9nk quick enough and being a basically honest person admited I knew the water cylinder was oosing a tiny bit of water.

Had to leave the house at that point. Sometimes the best thing to do as to remain visible during a broadside with the kind of mind that can't quickly think of the best way out of such a powerful barage would end up like Nelson very fast.

Returned home with new cylinder fitted it next day wife gone back to her angelic self.

 

[Paul Barker]

will eventually fit a tmv to the cylinder.

solar will go to the one primary.

dhw draw off will be diverted to a plate heat exchanger when not hot enough which will have a flow switch etc to fire up regular boiler. Only a top up.

Thanks very much for the advise about the bowsers.

What I@ may do is just build a solar shed. I had originally planned 4" kingspan so it is at the lockup ready for use. But when scrapping the old cylinder I realised the reuse potential of the lagging. Could make a 12" surround beyond the kingspan with it. Kingspan lid.

 

[Paul Barker]

That really nasty 15mm pipe in the corner is the original central heating combined feed and vent. I might upgrade it to 22mm or just convert to sealed system. I stress it is not my work. The pipes I have fitted will be lagged of course.

The prelagged flexible solar pipework has to come down in that corner and go up through the corner of two further rooms until it reaches the loft.

Pump station and expansion vessel for solar and a new boiler have somehow to get into that airing cupboard yet. PRobably take it down beneath the cylinder where the old Ideal mexico lies battleworn.

 

[Paul Barker]

The south pitched roof is the one with a gable pointing to the road the pitch is nearest us exactly south. Hoping my roofer friend will come this Saturday and we'll have the makings of solar hot water for starters next week. Possibly after a number of expletives.

 

[Paul Barker]

I know the front bay needs painting. The only paint brush a plumber owns is for cleaning burner trays and applying flux when his finger gets red raw if he's installing all the time. So unless I need to sell the gaff it will do. Or until the next unexpected broadside.

 

[BigBurner]

Interesting. How about using a combi for DHW and throttle it open as Alpha do with their theral store assist, the FlowSmart I think.

So the thermal store acts as a pre-heat to increase combi DHW flow - could be set to give 20 litres/min or more. Mains water runs through the large thermals store tanks through the copper coils - a lot of preheat if the coils are big enough.

Have a TMV on the combi outlet. If the solar heated water is above setpoint of the combi all DHW is free, if below the combi "assists". The TMV regulates the tap temperatures, say set to 45-50C. The combi could be set to say 1C above the TMV setting. Water from the store could be entering the combi at 90C, but the TMV will keep the temp at the taps right.

Even during winter, the odd bit of sunshine will raise the store temp and give adequate pre-heating for the combi to give high flowrates - especially using a lot of panels on the roof.


It appears you are to use the unvented megaflow as a thermal store in the completed system using plate heat X for DHW take-off. A good ploy. Hot water from the panels can heat the inside store (a megaflow) and when over 95C, it diverts the panels to heating the plastic tank thermal store.

Mains water runs through a coil in the outside tanks thermal store and is preheated as well, so this prolongs the heat in the inside store (megflow). The boiler only comes in when the inside store is below, say 70-75C.

A control mechanism can be fitted to hold off the boiler if the panels are giving heat to the inside store. They should be fast enough as you have a number of large panels.