efficiency factor of heat pump brands
is there any way to find out actual efficiency of heat pump brands and models at a given range say 7-9kw?
the reason im asking is im thinking of possibly fitting it myself or going Octopus to keep costs within my budget.
so far ive had quotes of between £4500-7500 for just a heat pump and cylinder no rads. octopus are £3800 with 5 rad changes.
id much rather fit a Vaillant and a more efficient tank to be honest and have done all the prep work to the point where i even have 28mm primaries going to a new plant room with 13mm insulation on them, even though they are inside the house.
but rather than follow the crowd that seems to be behind Vaillant id like to check why they are using these? hence the question.
id rather start with a efficient heat pump then tweak stuff to improve my scop like larger rads as i go.
@adamk - I think it is fair to say that the consensus is that the greatest performance* gains are achieved by good system design and running with a low a flow (leaving water) temperature as possible, rather than finding a heat pump that somehow has better performance than others.
Most manufacturers publish performance data in their technical literature (for a Midea heat pump it is in the Engineering Data book) but of course this can be seen as the manufacturer marking its own homework, and furthermore the data is efficacy (tightly controlled conditions) data rather than real messy world efficiency or rather (see below) performance data.
* I prefer to use the word performance rather than efficiency for heat pumps. Very strictly speaking, efficiency is the useful energy returned from the energy put in, which by definition cannot exceed 100% (you can't get something for nothing). A heat pump does something different, it extracts heat from the outside air, making, at least for me, the word performance seem better to describe how the heat pump, err, performs. COP also uses the P word.
Midea 14kW (for now...) ASHP heating both building and DHW
I agree it's probably going to be difficult to obtain like for like data, and even if you can (and trust that data), it's unlikely that you will actually be running under those exact conditions (e.g, how often are you running with a 35C flow temp when it's exactly 7C outside?).
Heat pumps aren't new technology, so I prefer to think (maybe naively) that given they all contain similar parts, their performance should be similar. As with @cathoderay, I think far more substantial variations in performance will come from really good system design and operation. I think if you design with good system volume and flow rates, and large emitters proportionally sized to the heat loss of each room, then which metal box you install at the end of the 28mm primaries in the garden should have little overall effect.
I think what really sets the brands apart is their control panels / software (and customer service/warranty), as what's in the metal box is the same for all.
Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 3.645kWp solar (south facing), Fox ESS inverter.
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.
Posted by: @old_scientistI think what really sets the brands apart is their control panels / software (and customer service/warranty), as what's in the metal box is the same for all.
I think that's the same for a lot of modern-day 'Tech'. A lot of people seem to focus on lowest price and ROI, ignoring things like fitness for purpose, useability, etc.
All heat pumps, using the same gas, will have a verry simmalr perfomance, you cammot beat the rules of thermodynamics, the biggest effect on heat pump performance is the system design and how that system is opperated.Posted by: @adamkis there any way to find out actual efficiency of heat pump brands and models at a given range say 7-9kw?
the reason im asking is im thinking of possibly fitting it myself or going Octopus to keep costs within my budget.
so far ive had quotes of between £4500-7500 for just a heat pump and cylinder no rads. octopus are £3800 with 5 rad changes.
id much rather fit a Vaillant and a more efficient tank to be honest and have done all the prep work to the point where i even have 28mm primaries going to a new plant room with 13mm insulation on them, even though they are inside the house.
but rather than follow the crowd that seems to be behind Vaillant id like to check why they are using these? hence the question.
id rather start with a efficient heat pump then tweak stuff to improve my scop like larger rads as i go.
Director at Heacol | Expert Heat Pump Consultant | Book a one-to-one consultation for pre- and post-installation advice, troubleshooting and system optimisation.
Posted by: @heacolAll heat pumps, using the same gas, will have a verry simmalr perfomance, you cammot beat the rules of thermodynamics, the biggest effect on heat pump performance is the system design and how that system is opperated.
I dont doubt you are right.
That said I did some calculations a few days ago of the ratio (for a Vaillant heat pump) between the theoretical maximum COP as defined by the Carnot equation, and quoted COP. Unless I made a mistake, which is of course possible, its close to 50%, falling to a little over 40% at higher OATs. This table suggests that electric motors (which underpin the compressor) can be expected to be between 80 and 90% efficiency, so there is still quite a lot to be accounted for. I imagine some gets lost in gas leaking past the seals and doubtless there are other sources of lost energy. However it does suggest that there is theoretically room for improvement (and variation between manufacturers), albeit that compressors are pretty mature technology so probably all perform very similarly, if indeed they aren't all made in the same factory!
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
Posted by: @jamespaThis table suggests that electric motors (which underpin the compressor) can be expected to be between 80 and 90% efficiency, so there is still quite a lot to be accounted for.
Rotary compressors usually have the electric motor in the refrigerant, as the refrigerant is used to cool the motor. Therefore the waste heat is reclaimed and becomes productive heat.
Posted by: @robsPosted by: @jamespaThis table suggests that electric motors (which underpin the compressor) can be expected to be between 80 and 90% efficiency, so there is still quite a lot to be accounted for.
Rotary compressors usually have the electric motor in the refrigerant, as the refrigerant is used to cool the motor. Therefore the waste heat is reclaimed and becomes productive heat.
Interesting. COP of only 1 though for the reclaimed heat!
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
@jamespa There are many hundreds of other variables in the vapour compression circuit, miss one and the calculations are irrelivant. Every time I thnk I have cracked it, another rairs it's ugly head and back to the beginning you go. Like playing snakes and ladders, with just snakes.🤣
Director at Heacol | Expert Heat Pump Consultant | Book a one-to-one consultation for pre- and post-installation advice, troubleshooting and system optimisation.
- 22 Forums
- 2,057 Topics
- 44.9 K Posts
- 48 Online
- 3,299 Members
Join Us!
Trusted Installers
Struggling to find a reliable heat pump installer? A poor installation can lead to inefficiencies and high running costs. We now connect homeowners with top-rated installers who deliver quality work and excellent service.
✅ Verified, trusted & experienced installers
✅ Nationwide coverage expanding
✅ Special offers available
Latest Posts
-
RE: Rate the quality of your heat pump design and installation
Ideal HP290 installed by a sub contractor of CB Heating...
By Davesoa , 6 minutes ago
-
RE: IVT Greenline high pressure switch and electrical cassette errors
OK, so when the HP comes on it becomes obvious.It's on ...
By tdudgeon , 3 hours ago
-
RE: Is Your 6kW Air Source Heat Pump Really a 6kW?
@johnmo I think we’ve been trudging through the same...
By SUNandAIR , 4 hours ago
-
RE: Heat Pump Manufacturers Recommending Buffer Tanks
One manufacturer Viessmann has to have their buffer, as...
By Johnmo , 11 hours ago
-
RE: How To Balance Radiators & the Role of the Lockshield Valve: A Homeowner's Guide
Good luck, I hope it all works out!
By JamesPa , 1 day ago
-
@johnd it's a difficult one, because we've seen instanc...
By Mars , 1 day ago
-
RE: Is your heat pump insured?
@johnmo sorry it comes across like that. The post is au...
By KevinPotts , 1 day ago
-
RE: Getting the best out of a heat pump - is Homely a possible answer?
@johnmo Perhaps a little detail might explain my reason...
By Toodles , 1 day ago
-
Win a 6-panel PV courtesy of egg and Renewable Heating Hub
Our epic giveaway just went live! Want to win a 6-pan...
By Mars , 2 days ago
-
RE: Yes, the "zoning with ASHP" topic again...
James, thanks again for your thoughtful and persistent ...
By HarryRea , 2 days ago
-
RE: Is this normal? Click of the DHW returning to space heating
So the Lone Ranger returned today! Even though we thoro...
By Grantmethestrength , 2 days ago
-
RE: Vaillant & OVO partner up to offer Heat Pump Plus
Hopefully iv done the right thing today by signing up t...
By Westkent , 2 days ago
-
RE: Battery sizing - How low can you go!
My own experience with connecting four batteries to thr...
By Transparent , 2 days ago
-
RE: Plate heat exchanger considerations
Work on 2-3 percent per degree. This is a reasonable e...
By JamesPa , 3 days ago
-
RE: Advice for ground source heat pump in new build with PV and batteries
The useful bit is the bit that specifies the heat loss ...
By JamesPa , 3 days ago
-
RE: Volumisers in Heat Pump Systems: Does Placement Matter?
You’re absolutely right that during defrost the refrige...
By Mars , 3 days ago
-
@editor thanks Mars that’s the same table I found in th...
By Gary , 3 days ago
-
RE: Tariff and charging strategy advice please
They haven't asked me to prove that I have an EV (I do)...
By JamesPa , 3 days ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
Took a while to find on the OFGEN site: ”The FIT sche...
By AgentGeorge , 3 days ago