Flow temperature & weather compensation. Impact on efficiency
Having had my heat pump for about 18 months I have gradually got to grips with understanding the controls and functions. I'm sure everyone's experience is different as it depends on so many factors including property efficiency, whether lived in all day, wfh, geographic location and more.
The most simple conclusions I came to are that the setup has best efficiency/cost with: Lowest flow temperature possible which is best managed with weather compensation. This requires a different mindset from my previous Oil central heating experiences! Target room temperatures are mostly around 21deg in main living room and kitchen but much cooler in secondary/less used rooms & bedrooms.
I came across a very useful tool that allows comparison of the impact on SCOP (Seasonal Coefficient of Performance) of different flow temperatures.
In my case using the exact model LG Therma V HM161M.U33
I can see the impact of the flow temperature and added benefit of using weather compensation. I am now using both and see that the flow temp is often as low as 30deg! But the house is reaching and holding the target 21deg without difficulty. The house is very old & generally inefficient but with underfloor heating and modern extension. At night I drop the temp just 1 degree (if more it would take a long time to warm up and/or need higher flow temp)
As can be seen in the screenshot the efficiency is around 375% at 35deg with weather compensation down to 200% at 55deg without weather compensation.
A very graphic and clear view of why flow temp should be as low as possible and weather compensation functionality should be used.
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
@tim441 this is really useful info and a great find. Your experience of converting from oil to ASHP mirrors mine. I'm only 3 months into the journey however. My system design temperature was 50degC but I'm finding with climatic compensation on, a maximum of 42degC flow at 0degC ambient and 30degC flow at 20degC ambient is providing efficient operation. I'm using hugely less energy than I was when I had CH and HW from kerosene, hugely less emissions, and saving around 20% on my fuel bills over the most expensive and energy intensive months. As the days draw longer and the weather warms, the ASHP efficiency and solar PV should really start to kick in and save energy.
-
Daikin Octopus installation update - I saw my first defrost. 😍😂
5 days ago
-
Warm weather and heat pumps.
5 months ago
-
What happens when the outside temperature exceeds the upper WC point?
6 months ago
-
Savings - using Weather Compensation & Time of Use Tariffs
8 months ago
-
Servicing LG Therma V
1 year ago
- 26 Forums
- 2,221 Topics
- 49.3 K Posts
- 161 Online
- 5,881 Members
Join Us!
Podcast Picks
Latest Posts
-
RE: New Fogstar 15.5kWh upright solution
As it happens, electronics was part of my uni curriculu...
By Batpred , 7 minutes ago
-
RE: What crazy nonsense are inverter limits and why are they imposed?
@transparent Thank you for a very comprehensive, tim...
By Batpred , 1 hour ago
-
RE: Isolating the system for a planned power cut
@transparent 😊 I may have lost you there.. I ...
By Batpred , 2 hours ago
-
RE: How good is the app support for your heat pump?
We have a Grant Aerona 290 15.5kW heat pump with their ...
By GrahamF , 3 hours ago
-
RE: Automation options to maximuse efficiency & ToU tariffs
I would extend that, @jamespa. Homely, Havenwise and Ad...
By Majordennisbloodnok , 4 hours ago
-
RE: Grant 13kW Aerona3 - issues getting zones to temp
He may need to tweak a couple of settings. There is de...
By JamesPa , 5 hours ago
-
-
RE: Low COP and unevenly heated rooms with 12kW Samsung AE120MXTPEH / AE260TNWTEH
Where is the noise coming from. If its the pump then p...
By JamesPa , 6 hours ago
-
RE: Should Our Water Circulation Pump Be Configured to Run All The Time?
@kenbone thanks for this input. It sounds like a bette...
By GrahamF , 7 hours ago
-
The Mars and Richard Kitchen Show
Just stopping by to say: 1) Mars I'm so sorry that yo...
By Lucia , 16 hours ago
-
Yes, you make a good point and beyond servers, engineer...
By Batpred , 19 hours ago
-
RE: Electricity price predictions
Without getting too much into politics, given that the ...
By Batpred , 1 day ago
-
UK Consumer Law Reality Check (for anyone dealing with ...
By DREI , 1 day ago
-
@dgclimatecontrol Thanks... this was resolved back in M...
By Sandman1600 , 1 day ago
-
RE: Help me keep the faith with my air source heat pump installation
That's the problem with the UK, in comparison with Amer...
By DREI , 1 day ago
-
Electrical is the only way forward.. But until we get...
By Batpred , 1 day ago
-
RE: Air source heat pump roll call – what heat pump brand and model do you have?
Manufacturer: Panasonic Model: WH-WXG12ME8 Type: AS...
By Andy-e , 1 day ago
-
In our installation, we actually have an LLH but any di...
By Toodles , 1 day ago
-
RE: Large heat pump options for church building
This church project has more in common with a commercia...
By GrahamF , 1 day ago
-
RE: External wall insulation - your experience
So our house is in SE England. We mainly had mixed w...
By Batpred , 2 days ago