Critique this Loopcad design & report

[Post and beam]

Good evening wise ones.

I have tried an experiment and commissioned Someone via Fiverr to do me a UFH design & heat loss report.

If the collective opinion is that this appears to be a competent piece of work, first off i will be very pleased and secondly i would be happy to share his details on here for any one else that feels the need. It might be a useful resource.

 

230825.pdf 230825_Heatloss Report.pdf 230825_UFH Report.pdf 230825_U-Value Report.pdf

[BadgerBadger]

Possibly hard to judge accuracy without knowing your build details, but we're just getting towards UFH so I'd be very interested to know who used from Fiverr. (I did a bit of looking myself after your previous posts!)

[JohnMo]

Do you need dedicated hall loops, you have loads of pipe passing through the hall, spread those across the hall floor area.

 

Could you combine loops 4 and 5?

 

Are you operating as one zone or loads of zones?

[MikeSharp01]

Loops look very fine. More worried about the U values of the fabric which, given the size of the property, means it will be relatively costly to heat. 

[JohnMo]

4 minutes ago, MikeSharp01 said:

Loops look very fine. More worried about the U values of the fabric which, given the size of the property, means it will be relatively costly to heat. 

Didn't look at that, just looked, floor and roof are fine.

 

Double glazing is at the very poor end of acceptable, you should be aiming at 1.4 for double glazed (whole window not just the glass). Doors 1.0 to 1.4, walls should be aiming to half the current heat loss.

[Post and beam]

35 minutes ago, MikeSharp01 said:

Loops look very fine. More worried about the U values of the fabric which, given the size of the property, means it will be relatively costly to heat. 

150mm centres with a design flow of 35 degrees. Those 2 parameters came from me.

Which exactly becuase i expect the house to be very well insulated. So, either i have given the guy duff info or he has made some assumption that i have missed.

 

40 minutes ago, JohnMo said:

Are you operating as one zone or loads of zones

I am looking at either one zone only, or possibly 2 ( lounge and everything else)

Edited August 25, 2023 by Post and beam

[Post and beam]

28 minutes ago, JohnMo said:

Double glazing is at the very poor end of acceptable

I did provide a SAP report so the figures should not be that bad.

[JohnMo]

Looking at the water volumes if you operate in 2 zones you will need around a 25L buffer. One zone no buffer.

[Post and beam]

1 hour ago, BadgerBadger said:

so I'd be very interested to know who used from Fiverr. (I did a bit of looking myself after your previous posts!)

Hi dude, As i said before. When and if i get to the point where i think what has been provided is competent i will happily put his details up. Not sure at the moment whether i gave duff info or he has interpreted something wrongly.

[Post and beam]

What about the litres/min for the circuits?  Is the idea to get as much flow as possible at the desired temp, or the minimum at desired temp.  Can you have too high or too low a requirement?

[JohnMo]

Are you doing a heat pump?

 

If directly driven from the heat pump, it's a matter of initially setting the loop flow rates and then balancing the system to get the room temps as you want them. Something like a 6kW heat pump will want to flow 1m3/h at max output. Your dT will be circa 5 degs and that will be dictated by the heat source it will modulate flow rate to keep this constant.

 

 

 

 

[Gus Potter]

2 hours ago, Post and beam said:

I have tried an experiment and commissioned Someone via Fiverr to do me a UFH design & heat loss report.

That is a good start so well done.

 

My thoughts are:

 

1/ It looks great on paper.

 

2/ UF heating is not an exact science.. have designed and built my own UF systems several times over the last 30 years.. learnt what works and what I could have done better.

 

3/ Your pipe spacing of 150mm should work well and give you a good bit of redundancy. That will serve you well. Say you want to put a rug on the floor.. your calcs are then shot to pieces. Big sofas trap the heat under.. you see the calcs are quickly invalid.

 

4/ Your loop lengths are not going to work in the long term. They vary too much. Yes you may say that the "experts know how to design" I say.. but what happens when you controls and valves start to get sticky in a couple of years time.. I have been there and worn the tee shirt. I'm not kidding you the valves and controls will get sticky and you will end up with your head up your bottom.. then remember you may want to sell the house! how do you explain that to a buyer.. well when it works it's great but you need to ...  even if you don't you need consider the maintenance costs.

 

Your loop lengths are not practical as when you actually see what happens on site and how folk bend the pipes.. your calcs are again shot unless you want to install youself. You have folk pouring concrete, tramping on the pipes.. one little dent in a pipe..

 

Keep it simple and accept the elegance of the simplicity. If you can embrace that you will do well.

 

Advice.

 

As others have said try and rationailse the zones. Accept that UF has its limitations and that from time to time some rooms may be a bit too hot or too cool.. too cool that is what the redundancy is for.

 

You need to consider how a UF system is going to perform  - 5 years after installation and how you operate and maintain that. I seems on BH that folk from time to time are trying to make UF into some kind of technical magic.. which it is NOT! the beauty lies in it's simplicity. For me I have gone for a max loop length of 75m. In my big rooms I have two loops in case one fails and it makes it much easier to balance.

 

If I was you I would now go back to you Architectural design and review. Then make sure all this stuff on your UF can be practically intalled and how much that is going to cost you to maintain in 5 years time.

 

Try this. On the ground floor have one set of loops that does the main living spaces then another that say does any ground floor bedrooms /office. Upstairs have another set. See how that works for you and cost it and only then start getting technical. You should start from the basics.. if you don't you will loose control of the cost and risk big dissapointment in a few years time.

 

 

 

 

 

 

 

 

 

 

[Post and beam]

13 hours ago, JohnMo said:

Something like a 6kW heat pump will want to flow 1m3/h at max output.

Hi JohnMo. So this is 16.7 litres minute ?

I have read various pieces on here about modulating the flow rates either up or down to suit the requirements at the time.  Are you saying this is the maximum that a 6Kw heat pump would want to run at?

 

In the design that i was provided with i see a list of flow rates per zone. And the fact that some zones provide more than 200% of the apparent need.  In what way might this cause issues , is it even an issue and how do i learn what i need to know of this aspect.

 

Thanks in advance

[Post and beam]

13 hours ago, Gus Potter said:

Try this. On the ground floor have one set of loops that does the main living spaces then another that say does any ground floor bedrooms /office

I have 2 zones on the ground floor, probably.  The living room and then everything else.

There will be no UFH upstairs

13 hours ago, Gus Potter said:

Your loop lengths are not going to work in the long term. They vary too much.

I have not seen another example posted where the circuits are of equal length.

[JohnMo]

2 hours ago, Post and beam said:

Hi JohnMo. So this is 16.7 litres minute ?

I have read various pieces on here about modulating the flow rates either up or down to suit the requirements at the time.  Are you saying this is the maximum that a 6Kw heat pump would want to run at?

 

In the design that i was provided with i see a list of flow rates per zone. And the fact that some zones provide more than 200% of the apparent need.  In what way might this cause issues , is it even an issue and how do i learn what i need to know of this aspect.

 

Thanks in advance

16l min or there abouts, will be max flow rate, the bigger the heat pump the higher the flow rate. The ASHP will modulate flow rates from its circulation pump, not you. If you start zoning the ASHP has limited options of where to dump heat and flow to, it needs both. It will need approx 50l of engaged water to satisfy defrost and prevent short cycling.

 

When you balance the system those circuits with a high output will have the flow rate reduced to balance heat output with the other circuits. Or you can increase flow rates of the lower output circuit to increase output from circuit. All a bit of rob Peter to pay Paul type thing.

 

As said by @Gus Potter embrace simple. All the sicking valves will occur, if you have them. Once the flow meter is set it's set (after you balance), you don't need actuators if single zone, so the manifold isolation valves stay open 100% of the time. No manifold mixers or pumps. One thermostat controls heat pump starting and stopping. Other than that there is a cylinder and 3 way valve. Wiring centre above the manifold is no longer connected, wasted money having it the first place, as well as room thermostats in each room, and mixer and manifold pump.

[Post and beam]

On 25/08/2023 at 20:25, BadgerBadger said:

I'd be very interested to know who used from Fiverr.

@richard5800  Richard joseph

He has done me a revision with more realistic U values for windows. The thing is, i am not qualified to know whether his design and assumptions are optimal. A worthwhile exercise though.