Solar Thermal Install

[Onoff]

other option is to add a valve and dump hot water down the drain

This option is to be avoided - if you are on a metered water supply. That is another cost that simply increases, if water is dumped.

Thanks, not considered potential waste water cost!

 

[Onoff]

The usual order is to fit the frame before adding the tubes at the end of the installation.

I can do that. Means putting the access towers back up later but hey ho.

Just looking into the pipe "entry" method / flashing through the tiles...

 

[voipio]

Whatever pipework management (flashing, pipe clips, insulation) is used, it will need to withstand up to 150 degC, as these temperatures can easily be reached in the summer, if the water in the panels stops flowing e.g. if tank reaches set temperature. Ordinary pipe lagging will melt when the pump comes back on.

 

[Onoff]

Just being a cheapskate here but I wonder if there's a way of drilling and then waterproofing an existing concrete tile for the pipe entry without buying a lead esque flashing type tile?

Thinking drill the tile then clamp a stainless plate either side with a TIG'd pipe on the outer one. Plenty of high temperature silicone at the joint...

 

[JMS1972]

Just being a cheapskate here but I wonder if there's a way of drilling and then waterproofing an existing concrete tile for the pipe entry without buying a lead esque flashing type tile?

Surely you only need one tile?

I thought I was tight but ....

 

[Onoff]

Like this:

 

[Seadog]

What about expansion? Unless the plates can slide isn't there the risk of cracking the tile?

 

[knighty]

you could easily make something for the flashing

it doesen't need to be welded around the pipe going through, you just need a flat piece which slides up under the tile above and then has a raised arear around where the pipe goes through

so water running down the rood runs off the tile above onto your flat piece and then diverts around the sides of the pipe

 

[Gareth J]

Not at all. Tbh I've heard/read most of that before but nice to see it all down so concisely like that.

So oil, big old Warmflow oil boiler. Traditional, copper hot water cylinder up in the loft in the hip behind where the panels would go.

The house orientation is SW to NW and long. The lounge I've measured at near 30degC through solar gain through the patio door glass whilst the big, unheated, tiled bathroom on the shaded NW corner has been at 11degC. Tbf there is as yet no heating in the bathroom though there's wet UFH pipes in the slab and and towel rail all piped up ready to connect.

It's where to start and in reality the hip roof integrity first if I'm going to do this

You could consider upgrading the boiler if yours isn't a condensing one. S/h units are around and pretty cheap. Have picked up a couple of grant vortexs at the £100-200 mark recently. This, with a thermal store or a well sized c/h system will give you the opportunity to get the very most you can out of the oil you use. If it's then your aim to do some c/h as well as h/w with the panels, you'll need a BIG thermal store. Otherwise, as mentioned, you'll only be able to heat when it's hot anyway. Even with a ~500l store it'll probably be limited to running a couple towel rails morning/evening, rather than keeping the while house toasty...unless you can do an inter seasonal thermal store!

Otherwise, more cost effective oil reductions probably come through; insulation > draught proofing> (controlled) ventilation.

 

[Onoff]

You could consider upgrading the boiler if yours isn't a condensing one. S/h units are around and pretty cheap. Have picked up a couple of grant vortexs at the £100-200 mark recently. This, with a thermal store or a well sized c/h system will give you the opportunity to get the very most you can out of the oil you use. If it's then your aim to do some c/h as well as h/w with the panels, you'll need a BIG thermal store. Otherwise, as mentioned, you'll only be able to heat when it's hot anyway. Even with a ~500l store it'll probably be limited to running a couple towel rails morning/evening, rather than keeping the while house toasty...unless you can do an inter seasonal thermal store!

Otherwise, more cost effective oil reductions probably come through; insulation > draught proofing> (controlled) ventilation.

I think this existing boiler is something like 90% efficient. Why upgrade?

 

[Gareth J]

I think this existing boiler is something like 90% efficient. Why upgrade?

Fair enough - chasing tiny percentages in efficiency increases have long paybacks.

A note; it won't be anything near 90% efficiency short cycling to just heat small amounts of hot water so, you planning to do some h/w heating via solar has added benefit there

 

[jenki]

Biggest difference to my oil boiler (Warmflow) install was to wrap it in 4 inch of Rockwool reduced the short cycling I agree with Onoff the efficency difference between a condensing boiler and a non condensing is small compared to improving insulation and better boiler controls.

 

[gaz1]

for extra heat gained its better to use 4 hot water storage tanks

buy 2 expensive ones and 2 lower price ones on first start up

one of each if a brand new start up

for those on meters you can use an ibc tank filled by rainfall and used as an expansion tank that flows into a hot water cylinder as its the same as a high expansion tank in a loft area but use filters to make sure water is clean going into the ibc tank there cheap enough to buy

the filters are used in a cheaper higher tank before fed into the ibc tank that feeds into the cheaper hot water cylinder

better than using a radiator for excess heat to get rid of and better still than pouring it down a drain

you also need to plumb in 8 gate valves (for flow and return pipes ) for maintenance or replacement of the cylinders or expansion of the system

you can do it with 4 or 6 valves after the 2 series tanks are plumbed in but better with 8

 

[Onoff]

Biggest difference to my oil boiler (Warmflow) install was to wrap it in 4 inch of Rockwool reduced the short cycling I agree with Onoff the efficency difference between a condensing boiler and a non condensing is small compared to improving insulation and better boiler controls.

My insulation situation is dire. Boiler is in an otherwise unheated lean to. One replacement DG window (pictured) and DG back door. Rest of the windows, wooden, single glazed. The wall behind the boiler is 9" solid block. There's a long external wall (first post above the panels are leaning against) that's just 4" block.

I had to move the pipework by the window closer to the boiler to get the frame in:

I've started to box the boiler in. Plan is a 2x2 frame then with 50mm Rockwool batts inside & against the wall. Frame to be covered in fire resistant (pink) plasterboard. Door on the front. Maybe hinge the whole thing for access.

(It will be pink not green used).

 

[gaz1]

id stop what your doing

those panels need to be removeable

and its also way too close to that boiler

 

[Onoff]

id stop what your doing

those panels need to be removeable

and its also way too close to that boiler

Underneath the blue metal cladding is 2" of Rockwool esque insulation already then the boiler itself. I wouldn't be covering the top.

The whole wooden frame will be on hinges and swing away from the boiler.

 

[DanZac]

May be I'm being a bit thick but what's the advantage in insulating the boiler?

I can see that reducing heat losses is a positive anywhere in the system, but surely any heat that's escaping the boiler is heating the room it's in, its not like your boilers in an outside plant room. And doesn't the boiler need free air circulation around it?

 

[Onoff]

May be I'm being a bit thick but what's the advantage in insulating the boiler?

I can see that reducing heat losses is a positive anywhere in the system, but surely any heat that's escaping the boiler is heating the room it's in, its not like your boilers in an outside plant room. And doesn't the boiler need free air circulation around it?

The "boiler room" as we call it isn't lived in. Waste heat afaiac.

 

[gaz1]

a boiler room is better for

stopping your pipes freezing
also helps within the room with air taken from rooms to run the boilers not many do that any more but some still do
it highers the temp in the room helping the system get up to temp faster

residual heat from cylinders can higher that room temp rather well

dosnt really matter as long as the room or outside building is well insulated

@brewdexta he has a system like this installed in an outside unit with new storage tanks and other stuff as well

 

[Gareth J]

May be I'm being a bit thick but what's the advantage in insulating the boiler?

I can see that reducing heat losses is a positive anywhere in the system, but surely any heat that's escaping the boiler is heating the room it's in, its not like your boilers in an outside plant room. And doesn't the boiler need free air circulation around it?

Another reason is that during summer, you still want hot showers but don't need or potentially even want the house warmed a bit by heat leaked out of the boiler and pipes.