Wasn't pleased with pipe layouts - so I did them myself - are they any good? Limecrete floor

[Pablo Blowfish]

I had some pipe layouts done and wasn't pleased with the density / layout so  I read a bunch of stuff on the internet and had a go.  - have I got this right?

Refurbing an 1850 stone build terrace - 

 

- 16mm at 100mm centers - 8 runs of 70 ish m  -

Total floor area 65m2 give or take

 

Looking to use an 8KW ASHP - for a room temp of 17-20 c flow temp 20-25 c?

 

The floor build up

 

old house 

geotextile /260mm Glass foam insulation / geo textile / Geo Grid with piping  cable tied  / 70mm limecrete base (1:1.5 lime NHL 5 / Nosterfield) / 70mm Lime adhesive  / upto 70mm thick slate slabs 

 

80's extension

 

100mm PIR / Geo Grid with piping  cable tied  / 70mm limecrete base (1:1.5 lime NHL 5 / Nosterfield) / tiles

 

and similar but toped with engineered oak in the lounge

Needless to say we're adding lots of Insulation it the roof.

Rough  heat loss calcs come out around 3kw +Ventilation loss + performance gap etc.

Looking forward to your feedback
 

[Pablo Blowfish]

Forgot to follow the topic!

[JohnMo]

You need to do a proper heat loss calculation, this plus this, plus this with no numbers is rubbish.

 

The flow rates quoted will not support the flow needed to keep an 8kW heat pump happy. Check your dT and run higher flow rates. You will upwards of 14l/min as a minimum.

 

Min flow temp from a heat pump is 25. But most run rubbish at temperature with a lot of cycling. Not helped by trying to set it to run 4 zones and one of those is way to small to allow heat pump to run.

 

100mm centres no issue, except do you need to have them that tight. Work out room by room heat loss, then look at W/m2 output and fine tune.

[Pablo Blowfish]

Thanks - I'll check the flow rates - BTW of the two examples the first one was the one that was amended the seconded was the one I wasn't happy with - cheers 

[JohnMo]

Don't really like either.

 

So looking at both layouts, you have loads of pipes transiting through hall all bunched up. Delete the dedicated loops and spread those pipes out. The transiting pipes will heat the hall for you. You could also do the same in the utility by using A7, 8 and 9 in the utility. That removed three dedicated loops, making everything a little more simple

 

[ringi]

Why not 2nd manifold in kitchen and main manifold in top right off boot room with removing a few bricks to get pipes directly to living room?

 

I would spread pipes out more in boot room so floor is not as uneven temperature.

 

Zones are interesting, as a small zone is only an issue if it can "call for heat".   For example my wife study gets a lot of thermal gain, so could have a thermostat to prevent overheating that can never trigger the heatpump to run, with running the rest of our home as a standard openloop.

[JohnMo]

53 minutes ago, ringi said:

so could have a thermostat to prevent overheating

Just wouldn't bother with a low temperature UFH system. As room temp rises the floor output stops as soon as floor and room temp match.

[ringi]

22 minutes ago, JohnMo said:

Just wouldn't bother with a low temperature UFH system. As room temp rises the floor output stops as soon as floor and room temp match.

 

Clearly that how it should work if the insulation of the buildings is good enough.   My plan is to design the loops to match possible zones, but not to install any thermostats or activators.   Partly as designing the zones will let me balance the loops to control relative temperature of rooms if required.

[Mike]

And, to return to a debate discussed in the past, I'd run the pipework under the units in the kitchen & utility room too.