Hybrid oil and ashp experiences please
Hi
I’m looking for anyone who has combined these two different heating methods as a seamless, integrated way to heat their property please. How well did that work and did the installer really understand how to undertake that installation to maximise heat efficiency and lower cost?
As quick background I have 2 buildings on the one property. The building that I’m looking to install a hybrid solution is a 100 year old stone barn with low insulation levels and a lot of cold bridging...approx 300m2 in floor space. Neither GSHP nor ASHP will do it on their own. The second property is a 6 year old full barn conversion with very high levels of insulation, GSHP and MVHR which work very well...so am very familiar with HP technology
Appreciate hybrid experiences please
many thanks
Judd
Welcome to the forums @juddmay.
We have a bivalent system running an ASHP alongside an oil boiler. We never really used the oil in any significant quantities - it was a back up and did the odd defrost. This year, we are trialing a new biofuel in the oil boiler and so we’ve been using our bivalent system.
The major takeaway is that many ASHPs don’t have sufficient controls to cooperate with an oil boiler. Even with our system we’ve had to tweak settings to trick the ASHP into relinquishing control. We addressed these points in a video we posted recently which may help you, and have also spoken about efficiency. Even though the video is about the fuel, we speak at length about our system.
In closing, hybrid/bivalent systems are definitely possible - it’s about finding the right heat pump (from a settings and controls perspective) that will allow them to work seamlessly, and for the system to be designed accordingly.
I’ll ask installers which ASHP brands they recommend for hybrid setups.
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
The largest ever trial of heat pumps in the UK which is currently underway has installed a lot of hybrid heat pumps.
Not yet published much in the way of findings which will come later.
I expect many are mains gas/heat pump setups but some of the learnings would be relevant.
Many thanks for your very prompt reply and I looked at your Home Farm site. A few things pop out
Firstly, did you insulate your property given its age, or change rad sizes given you ran first year on just ashp (sorry, couldn’t see this detail)?
Secondly, there was an extensive Dept of Business report in 2017
which highlighted that under many conditions a HHP system could be the most practical solution for properties like mine, though the main driver of the report was to consider electricity usage and emissions....but a lot of its conclusions were ahead of available technology at the time...which is why I’m chasing experiences now. There are off the shelf systems ready to go (Grant for example) but again detailed performances references are scant.
Lastly, I wondered what SCOP you’re getting from your HP in single or bivalent mode given the report I mention summarised “If the heat pump contributes to meeting DHW demand, this would be likely to reduce the overall efficiency of the heat pump, as well as increasing the average and peak electricity demand. If the DHW demand is spread throughout the day, for a continuous heating schedule the DHW and space heating demand will coincide, resulting in an increased load and an increased flow temperature compared to that required to meet the space heating demand. This will reduce the COP of the heat pump. Also, the temperature for DHW is at least 40 degrees Celsius7, which is above the optimal flow temperature of a typical air- source heat pump, meaning that even if there is no space heating demand, the heat pump will be operating to meet the DHW demand under non-optimal conditions.
Due to these factors, several manufacturers selling HHPs shared the view that in a hybrid configuration, using the boiler to provide DHW is the most practical option, and that using the heat pump for this would not be recommended.”
We’re all on a journey to learn.....By the time I get there I’ll be in my dotage. Cheers. Judd
@juddmay, I’ll reply to your post above later this afternoon.
In the time being, I received a message about the best heat pump options for hybrid systems from Graham Hendra: “RED is easiest, Hitachi is the most programmable, it can do literally anything. Samsung is horrible. Mitsubishi is worse. Midea is OK.”
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
The guys at Daikin sent us some manuals explaining the controls on Daikin systems for hybrid systems. Look from page 72 onwards, and it'll hopefully provide you with a few more answers.
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
For Grant the heatpumps are made by Chofu who provide a much more detailed manual. See section 8.3, page 111 onwards:
In particular, 8.3.2 describes 'Backup heater in Supplementary mode' where it'll run both at the same time, using the oil burner to boost up the temperature when the ASHP can't do it all.
Note that the heatpump has its own room temperature compensation/control system which Grant completely ignore by using classical on/off thermostats as if it's a traditional boiler. It is possible this supplementary mode doesn't work if you use them as Grant indicate.
I don't have a hybrid setup so no direct experience. In general, when people talk about hybrid setups are they running both at the same time, or just turning off the heat pump and firing up the boiler?
Oops, missed the edit window. It's section 8.4 on page 120 (External Heat Source) not 8.3 (electric backup heater) - it appears you can have both and they work in the same way, just the settings for each can be different.
@prunus Many thanks for that
the schematic on page 118, suggests that the EHS has no direct impact on DHW, and access to it is via a buffer tank. That flies in the face of the govt report which highlights DHW is best done by traditional heating source (oil in my case), but that doesn’t look like an out the box solution from Grant. Will speak to them Monday
@editor Many thanks for this. I’m finding not quite the flexibility of installation I would like. Worcester Bosch offer hybrid solution but you’ve got to add an additional interior unit to achieve it. Theoretically I’m well placed in that my oil boiler required hot Water tank....rather than condensing route...but practically just adding ashp and software controller is not so easy. By using the govt recommended route of DHW from oil boiler means I could keep my existing HW tank, but the setup for most of the systems look like adding either a sizeable piece of kit I don’t want, or moving away from the out the box install that it comes with. I’m preferring the Grant option in that everything can move outside and into one box if required, but that means overriding the default setup options...so I’m exploring that today with a Grant installer. Keep you posted.thanks again.
@editor hi Mars. How much is HVO per litre?
Daikin Altherma 3H HT 12kWh ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and new Hyundai Ioniq 5 N electric vehicles with Myenergi Zappi mk1 charger
@julianc, last year it was £1/per litre, but as with all things it's gone up to around £1.30/litre. As far as I know, it's not really available everywhere at the moment though. The reason it's so bloody expensive is because it's loaded with levies, duties and taxes – if they were stripped away, it would be same price as kerosene, about 51p/litre (that's our rate for this week).
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
- 21 Forums
- 1,986 Topics
- 43.3 K Posts
- 23 Online
- 2,311 Members
Join Us!
Heat Pump Dramas?
Thinking about installing a heat pump but unsure where to start? Already have one but it’s not performing as expected? Or are you locked in a frustrating dispute with an installer or manufacturer? We’re here to help.
✅ Pre-Installation Planning
✅ Post-Installation Troubleshooting
✅ Performance Optimisation
✅ Complaint Support (Manufacturer & Installer)
Latest Posts
-
RE: Plug and play solar. Thoughts?
I’ve seen our mains voltage very high on occasion, but ...
By robl , 28 minutes ago
-
Sorry for the delay in replying. We are now able to acc...
By Simon and Zoe , 2 hours ago
-
RE: Adding data centre electricity costs to domestic energy bills?
I forgot to ask - did anyone else who responded to the ...
By Lucia , 4 hours ago
-
RE: Can I add an EV charger to a full consumer unit by coupling with a garage DB?
It might be technically possible to run an EV charger f...
By Transparent , 5 hours ago
-
RE: In the middle of an ASHP installation - a few questions (and issues)
@editor sure. The 12kW Clivet.
By benson , 7 hours ago
-
RE: Database of heat pump performance data?
I cant agree more. You need a heat pump that is ri...
By JamesPa , 12 hours ago
-
RE: Newbie out of her depth – Samsung AE120RXYDEG 12kW heat pump
Update for those following this thread.Finally got the ...
By BAMi , 12 hours ago
-
Dont worry about this. Long story and discussion but d...
By JamesPa , 14 hours ago
-
@eliuccio I was wondering how things are going with t...
By JamesPa , 14 hours ago
-
😆 I would have been tempted to see how good the...
By Mars , 24 hours ago
-
RE: Volumisers in Heat Pump Systems: Does Placement Matter?
No not auto adapt running hotter at cheaper times coole...
By Gary , 1 day ago
-
RE: Ecodan Auto Adapt Questions
Hi @richard24738 we weren’t happy with our FTC Contr...
By SUNandAIR , 1 day ago
-
RE: To relocate or add extra PV panels..advice required
You can't forecast the annual generation by simple extr...
By JohnR , 1 day ago
-
RE: Are MCS are finally improving (some of) their guidelines?
@johnr I think OE argue that the lower running costs as...
By Toodles , 1 day ago
-
RE: Additional Battery v Wind Turbine v Ripple
@lucia Yes, that is the response to which I referred ea...
By Toodles , 1 day ago
-
RE: Is it worth siting panels on an East facing roof?
Yes. Thanks all. I have used the guides and have found ...
By Carpenterstation , 2 days ago
-
RE: The EPC Dilemma: How Current Ratings Fail Heat Pumps
I've commented earlier in this thread, finding the same...
By Mike Patrick , 2 days ago
-
RE: SolarPV tables / online calculator
This guy did a good analysis in summary go down a...
By Judith , 2 days ago
-
RE: ASHP Ecodan L9 error - No Heating but Hot Water
@dnagre delayed reply! It worked again for a bit but ha...
By Phoenix15 , 2 days ago
Latest Topics
-
Plug and play solar. Thoughts?
By Lucia 3 days ago
-
By JamesPa 3 days ago
-
Vaillant water pressure gauge vs Analogue gauge
By jeegnesh 3 days ago
-
Database of heat pump performance data?
By madbilly 4 days ago
-
By madbilly 4 days ago
-
Confused about Samsung Gen6 Hot Water Controller
By ntruby 5 days ago