Insulate ufh supply pipes in screed?

[FarmerN]

 

Hi first real post on here, I have found the information gained from site invauable, Thanks.

New build bungalow, beam and block floor , 180 mm PIR insulation over screed to be around 70mm depending on tile or carpet finish. UFH by GSHP so hope to run at low temperature, supply pipes as low as possible, below 30Deg C ??

The feed to the manifolds from the buffer vessel/GSHP are well insulated.

 

Is there any need to insulate the supply pipes  to indervidual rooms in the screed, especially where they are grouped together, down one wall the plan shows 4 suppy,4 return pipes laid close together in the screed? This area will be tiled.

 

Few more details of build 200m2 bungalow, masonary constuction throughout, wet plaster , 125 cavity wall, 115mm Kingspan insulation in walls, Rational tripple glazed windows , MVHR , GSHP. PV in roof panels. 200mm PIR in ceilings or roof.

The ufh pipes and screen are due to go down in a couple of weeks. Plenty of mistakes made in construction already and it will be interesting to do the airtight test , that is the bit I have had most trouble comunicating with builder.

However overall I am absolutly thrilled with the build so far.

[JohnMo]

Your build is basically the same size as ours. My opinion is the pipes all grouped together will make a hot area, I just deleted any loops on the hall and used the pipes going to the different rooms spread across the hall floor. Our hall is internal, so no outside walls, so takes no heating really. But it keeps the hall the temp as the rest of the house. So don't insulate use the heat to your benefit. 

 

If you operate as a single zone, no need for a buffer.

 

 

[FarmerN]

Thanks for reply, makes good sense, I’ll look at the layout and see how it works out.

 The heat pump installer has suggested not having a buffer tank, I rather favoured one as I am guessing much of the year we will have ufh on in bathroom and shower room and nowhere else, but I don’t really grasp the pros and cons, of a buffer.

 

The builder had the ufh layout done by a design / supply company. A lot of the supply pipes go through block walls which I was surprised by. One group of 3 supply through in one point along with the 3 returns. The max loop length is 90M off 150M coils, pipe spacing 150mm, because of room sizes, means rooms have 2 or3 circuits each room.

The plant room is to double as a drying room, so has a MVHR extract, we have made no provision for a tumble dryer, as we have never had one where we live now.

[Conor]

No need to insulate, you just use fewer loops from the other zones where the pipes pass through. You can use flexible 20mm electrical conduit for the first metre or so, just so that the room where the manifold is doesn't get too hot.

 

How come GSHP over ASHP? Haven't heard of anybody here installing one recently at all.

Edited October 21, 2023 by Conor

[FarmerN]

Plans started 4 years ago when we were going to get a big payment for GSHP . We also have a field with wet sand a meter or so down so near perfect conditions for GSHP.

Also wanted all plant in the house, to make use of all 'waste' heat from machinery , and didn't want a big white box in the garden.

My main concern now of GSHP over ASHP is avaliability of service and spares in the future. I hope my set up is there for the long term ground pipes 50+ years, heat pump 30 years?

The digger to lay 600m of pipe( 3 x 200M runs) cost me £2,500.00 so not dear , laid pipe at 1.4m deep 1.2m apart in 6 trenches about 5 meters apart. When he had back filled the grass was still there where the spoil had been stacked !  Pipes and manifold cost on top of this so not cheap all together.

[JohnMo]

52 minutes ago, FarmerN said:

. The max loop length is 90M off 150M coils,

Sounds like a lot of waste, they should be providing 300m+ length rolls!

 

Not seeing why you would to go though walls? There should be no reason?

 

A buffer provide a reservoir of working fluid for the heat pump. But depending on the plumbing it can result in a drop in CoP. You can plumb them as a two port either in the supply OR return lines or across the supply AND return - these methods give no hydraulic sepereration between the heat pump and heating system. The more normal way is 4 port, basically the flow and return all go into a single cylinder, the heat pump and heating systems are hydraulically seperate, so both need their own pump - this config nearly always results in a fall in CoP.

 

If you are going buffer a 2 port would be best.

 

https://www.kensaheatpumps.com/installer/buff-up-your-knowledge-of-buffer-tanks/