Renewable Heating Hub Heat Pump Forums

Search with Wattson
Forums
Renewable Heating
Air Source Heat Pum...
Good heat loss calc...
 
Notifications
Clear all

Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!

Good heat loss calculator for ASHP with UFH?

 
Page 1 / 3
Air Source Heat Pumps (ASHPs)
Last Post by Anonymous 2 years ago
29 Posts
4 Users
4 Reactions
6,059 Views
RSS
 ash2020
(@ash2020)
Active Member Member
Joined: 2 years ago
Posts: 12
Topic starter 07/08/2024 10:41 am   [#1649]

Hi all, new here and very excited to be starting on our project. We are buying a modern-ish bungalow with good insulation in Cornwall and are going to install an ASHP with underfloor heating. Long story but the property shares an oil tank with the vendors next door and currently has an oil boiler and rads. We told them we didn't want them to install a new oil tank so from the day we move in, will have no heating or hot water. Therefore I want to try and get all the design work done so we can hit the ground running on day one.
Is there a good calculator, maybe an Excel spreadsheet I can use?

Thanks, looking forward to lots of interactions here.

Andrew

 

 



   
👍
1
Quote
 Anonymous 5011
(@Anonymous 5011)
Joined: 4 years ago
Posts: 562
07/08/2024 1:11 pm  

This is one from buildhub. I have left my house figures in to give you a starter for 10.

UFH design - see attached.

Lots of insulation otherwise your downwards losses will make you cry. So 150mm PIR and above. Not the 40mm UFH outlets want to sell you. It works best with loops in concrete or screed. If you can't do that you may be better with radiators or fan coils.

 

Maxa ufh calc

 

Maxa Heat loss calculator - Sleepieshill.xlsx
Maxa ufh calc2


   
👍
2
ReplyQuote
 ash2020
(@ash2020)
Active Member Member
Joined: 2 years ago
Posts: 12
Topic starter 07/08/2024 1:17 pm  

@johnmo Hey thanks for that. It'll give me a good head start. I'm assuming we have plenty of insulation under the chipboard floor but I can't check until we actually own the place and I can lift some floors.



   
ReplyQuote
 Judith
(@judith)
Prominent Member Member
Joined: 3 years ago
Posts: 548
07/08/2024 8:17 pm  

Hi Ash, 

when was your soon to be new home built? Because it will only be as good as building regs were at the time.

When you get into details lots of floor covering say suitable for ufh but then they say nothing above 29C temperature on the glue. Only ceramic tile can go higher in temperature. 
To keep temperatures low and hence efficiency high you probably need spacing between pipes of 100mm. A couple of plumbers would have put in 150-250mm spacing which coupled with the floor covering temperature limit would have left us cold. They basically didn’t do a room heat loss at all.


2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with SCOP >4) open system operating on WC


   
ReplyQuote
 ash2020
(@ash2020)
Active Member Member
Joined: 2 years ago
Posts: 12
Topic starter 08/08/2024 10:44 am  

Thanks Judith. It was built in 2008 so should have some floor insulation. It would appear to be suspended timber with chipboard but it could be beam and block. I'm trying to find out what plans were submitted to Building Control.
We're going to be using Marmoleum Click flooring which does have the temperature limit so thanks for the spacing advice. We'll be doing the pipework ourselves so heat loss calcs will be essential.



   
ReplyQuote
 Anonymous 5011
(@Anonymous 5011)
Joined: 4 years ago
Posts: 562
08/08/2024 12:30 pm  

Posted by: @ash2020
↑

We'll be doing the pipework ourselves so heat loss calcs will be essential.

You can download a free copy of LoopCad on a trial basis for a month. Well worth the effort.



   
ReplyQuote
 ash2020
(@ash2020)
Active Member Member
Joined: 2 years ago
Posts: 12
Topic starter 08/08/2024 6:59 pm  

@johnmo Thank you. That'll be useful.

 



   
ReplyQuote
 Judith
(@judith)
Prominent Member Member
Joined: 3 years ago
Posts: 548
08/08/2024 8:53 pm  

Heatpunk is pretty good for a house heat loss, which you need to start. https://heatpunk.co.uk/home It’s easier than many tools and with reasonable output displays. It allows ufh to be entered in W/m^2


2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with SCOP >4) open system operating on WC


   
ReplyQuote
 ash2020
(@ash2020)
Active Member Member
Joined: 2 years ago
Posts: 12
Topic starter 08/08/2024 9:41 pm  

@judith Thank you again. I've downloaded it and played around but I can't see anywhere where you can design UFH.



   
ReplyQuote
 Judith
(@judith)
Prominent Member Member
Joined: 3 years ago
Posts: 548
08/08/2024 10:10 pm  

@ash2020 sorry to mislead you. You can’t design your ufh in it but once your house is entered you can check your ufh design matches your room heat loss.

It is is the heat pump section of task pull down and looks like this

IMG 0538

Personally I would  start with the house heat loss so you know the scale of the ufh design needed. You enter the ufh in W/m^2 in heatpunk for the room and iterate until you have enough heat and it is cost effective.

You could design a system using the smallest pipe inter loop gap, lots of length etc but it would cost more to install but allow a lower operating temperature. It’s a trade off between up-front costs and on-going operation cost.


2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with SCOP >4) open system operating on WC


   
👍
1
ReplyQuote
 ash2020
(@ash2020)
Active Member Member
Joined: 2 years ago
Posts: 12
Topic starter 09/08/2024 1:28 pm  

@judith Thanks again. I'll stick with it.

 



   
ReplyQuote
 Anonymous 5011
(@Anonymous 5011)
Joined: 4 years ago
Posts: 562
09/08/2024 2:46 pm  

Posted by: @ash2020
↑

design UFH

Download a free copy (trial) of LoopCad.



   
ReplyQuote
Page 1 / 3
Forum Jump:
  Previous Topic
Next Topic  

Currently viewing this topic 1 guest.

Share:

SPONSORS

Join Us!

Installer Finder

Degrees of Separation

Latest Posts

SPONSORS

Members Online

 No online members at the moment

Click to access the login or register cheese
Protected By
Shield Security PRO