Forums

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

Good heat loss calculator for ASHP with UFH?

 
Page 3 / 3
Air Source Heat Pumps (ASHPs)
Last Post by Johnmo 4 weeks ago
29 Posts
4 Users
4 Reactions
447 Views
RSS
 ash2020
(@ash2020)
Eminent Member Member
85 kWhs
Joined: 1 month ago
Posts: 12
Topic starter 14/08/2024 8:12 am  

@johnmo Excellent. I'm going to try and re-instate my Part P electrical qualification which lapsed when I retired.


   
ReplyQuote
Jancold
 Jancold
(@jancold)
Estimable Member Member
1101 kWhs
Joined: 2 years ago
Posts: 66
15/08/2024 3:46 pm  

@johnmo I revisited the Heatpunk project which I did back in May and put in the data for the floor and ceilings which I had not done and revised the heat loss up to 5070 or 70W/m2.  Does that seem reasonable?


   
ReplyQuote
 Johnmo
(@johnmo)
Prominent Member Member
1654 kWhs
Joined: 2 years ago
Posts: 317
15/08/2024 5:01 pm  

Posted by: @jancold
↑

@johnmo I revisited the Heatpunk project which I did back in May and put in the data for the floor and ceilings which I had not done and revised the heat loss up to 5070 or 70W/m2.  Does that seem reasonable?

Seems high to me

Take a look here

https://www.heatgeek.com/how-to-size-my-heat-pump-or-boiler-heat-loss-cheat-sheet/

 

Maxa i32V5 6kW ASHP (heat and cooling)
6.5kW PV
13.5kW GivEnergy AIO Battery.


   
ReplyQuote



Jancold
 Jancold
(@jancold)
Estimable Member Member
1101 kWhs
Joined: 2 years ago
Posts: 66
15/08/2024 5:50 pm  

@johnmo Thanks, yes I have that cheat sheet and was a bit surprised it was higher than expected. Maybe I should start the Heatpunk project again. Still awaiting Octopus report promised this week but we will see.


   
ReplyQuote
 Johnmo
(@johnmo)
Prominent Member Member
1654 kWhs
Joined: 2 years ago
Posts: 317
15/08/2024 6:17 pm  

There is a lot said about perfect sizing of heat pump to heat loss, but if you run open loop, there is flexibility. Our house heat loss at -3 is about 3kW at 7 degs about 1 to 1.5kW, but we have 6kW heat pump. It cycles, at min load and I get about 10 to 12 mins on and off an hour. So doesn't short cycle. We are currently doing cooling it has been a mostly wet day so almost no load required and the heat pump compressor has started 8 times in 18 hrs.

Opposite to what a lot will say - I think you are better to be slightly big on heat demand, your radiators end up bigger, so you can run lower flow temperature, your heat pump has some flexibility, if it gets really cold outside. Get it the other way round, you end up running higher temps and the immersion on if it gets really cold.

No zones (well one) is the best for flexibility, and oversized, you may get a very slight CoP hit when it's mild, but not much, when it's cold it runs fine.

So I wouldn't fret to much, 5kW or 4kW you really should be running a 6kW ASHP. Remember you still need 2 to 3 hrs for DHW each day mid winter 

Maxa i32V5 6kW ASHP (heat and cooling)
6.5kW PV
13.5kW GivEnergy AIO Battery.


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



Share:

Join Us!

Latest Posts

Members Online

x Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
Shield Security →