Hybrid heating options?

Air source, ground source and associated systems for heating homes
Post Reply
AE-NMidlands
Posts: 1828
Joined: Wed Jun 02, 2021 6:10 pm

Hybrid heating options?

#1

Post by AE-NMidlands »

Does anyone have any experience or reports of hybrid heat pump / gas boiler systems?
I am in a large old semi in a town and the gas boiler running the small-bore central heating will need replacing soon. I understand that heat pumps don't usually produce water hot enough to run the radiators as they are, and the disruption from replacing the whole system would be unacceptable. It is also pretty reliable, touch wood. The house is being progressively insulated and draught-proofed, but I can't imagine a heat pump ever being enough on its own.

Fitting a modern condensing boiler would be the simplest option (although the condensate disposal route would not be straightforward) but a heat pump as the primary stage could work...
https://www.daikin.co.uk/en_gb/product- ... svEALw_wcB seem to be promoting them.
I don't know whether the return water temperature at the boiler is too high for the heat pump to make a useful contribution in those circumstances. Some "hybrid" systems just seem to have a boiler to take over when air temp is too low for the heatpump.
A
2.0 kW/4.62 MWhr pa in Ripples, 4.5 kWp W-facing pv, 9.5 kWhr batt
30 solar thermal tubes, 2MWhr pa in Stockport, plus Congleton and Kinlochbervie Hydros,
Most travel by bike, walking or bus/train. Veg, fruit - and Bees!
User avatar
Stinsy
Posts: 2640
Joined: Wed Jun 02, 2021 1:09 pm

Re: Hybrid heating options?

#2

Post by Stinsy »

I've seen them. I don't know anyone with one but I'm very wary of such "best of both worlds" devices.

For me, you'd be better fitting an air-to-air heat pump and/or a storage heater or two, completely independent of your wet central heating.
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
5x 2.4kWh Pylontech batteries (12kWh)
LuxPower inverter/charger

(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
User avatar
nowty
Posts: 5167
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: Hybrid heating options?

#3

Post by nowty »

I simply added my heatpump in parallel with the existing combi gas boiler but I don't use them together although I have tested them both working together and it still works and nothing bad happens. I do limit the the heating water temp from the gas boiler to 55 degrees and I have fitted a check valve to the output of the gas boiler heating circuit so the heatpump cannot force water backwards through the gas boiler heat exchanger. And I have a zone valve on the heatpump which prevents the gas boiler forcing water through the heatpump.

In the past winters, I ran the heatpump on the cheap rate, then switched from the heatpump to the gas boiler. This year with my cheap rate storage heater boost I have managed to so far keep the gas boiler switched off completely by running the heatpump on my battery bank during peak rate times.

I have to say Nowty Towers needs one hell of an operating manual which is still on the ToDo list in case of my demise.
15.2kW PV > 101MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 19MWh generated
5 Other RE Coop's
105kWh EV storage
60kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 490 m3
User avatar
Fintray
Posts: 1297
Joined: Mon May 31, 2021 6:37 pm
Location: Aberdeenshire

Re: Hybrid heating options?

#4

Post by Fintray »

nowty wrote: Sun Dec 05, 2021 2:05 pm I have to say Nowty Towers needs one hell of an operating manual which is still on the ToDo list in case of my demise.
I'm the same, my wife keeps saying she wouldn't have a clue what to do with all the "systems" :)
3.87kWp PV
10.24kWp PV SolarEdge system
Tesla Powerwall 2
100 x 47mm Navitron tubes (still being installed!) Now likely to be removed for more PV.
MK2 PV router DHW diverter
Morso 5kW WBS
Vaillant AroTherm 10kW ASHP
Nissan Leaf
Bugtownboy
Posts: 920
Joined: Tue Jun 01, 2021 12:35 pm

Re: Hybrid heating options?

#5

Post by Bugtownboy »

I think it does raise a, perhaps, difficult issue. Whilst the systems - PV, wet, wind, that many of you have installed, how much depends on you as individuals ?

How easy would it be for a partner/family member to maintain ?

Doesn’t have to be a terminal situation :shock: , a dose of flu or COVID could be enough to incapacitate for a couple of weeks.

I think the principle of usability, effectiveness and robustness is proven. Is it time to start to develop systems for the non-expert ?
Tinbum
Posts: 1030
Joined: Mon May 31, 2021 9:55 pm

Re: Hybrid heating options?

#6

Post by Tinbum »

Fintray wrote: Sun Dec 05, 2021 4:02 pm
nowty wrote: Sun Dec 05, 2021 2:05 pm I have to say Nowty Towers needs one hell of an operating manual which is still on the ToDo list in case of my demise.
I'm the same, my wife keeps saying she wouldn't have a clue what to do with all the "systems" :)
Ditto
85no 58mm solar thermal tubes, 28.5Kw PV, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, 8kWh Growatt storage, 22 x US3000C Pylontech, Sofar ME3000's, Brosley wood burner and 250lt DHW
User avatar
Stinsy
Posts: 2640
Joined: Wed Jun 02, 2021 1:09 pm

Re: Hybrid heating options?

#7

Post by Stinsy »

I try very hard to make everything “dead mans handle” so my input is more “optimising” rather than anything essential to keep the system running.

Eg if a very sunny summer day is forecast I might set the batteries to charge to 80% rather than 100% in the cheap period. While being left on the “wrong” setting is sub-optimal it isn’t a catastrophe.
Last edited by Stinsy on Sun Dec 05, 2021 6:14 pm, edited 1 time in total.
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
5x 2.4kWh Pylontech batteries (12kWh)
LuxPower inverter/charger

(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
spread-tee
Posts: 569
Joined: Mon May 31, 2021 7:16 pm
Location: ville of spiky things

Re: Hybrid heating options?

#8

Post by spread-tee »

Boiler cascade systems are nothing new and can be made to work with many varied heat sources, that's kind of what we have here at spiky-ville, wood stove-gasser-solar thermal.
It can be as simple as a few change-over and pipe/appliance stats.A plan of the logic is very helpfull when trying to work out a fault. Or it could be all apps and smart phones, nests and etc, in which case when it fails you are bazookered.

It's a shame the GOVT are short on neuron power with heat pump legislation, as a heat pump and a gasser could make good partners.

Desp
Blah blah blah
Mr Gus
Posts: 3813
Joined: Sun Jun 13, 2021 9:42 pm
Location: Tofu eaters paradise (harrumph)

Re: Hybrid heating options?

#9

Post by Mr Gus »

Stinsy wrote: Sun Dec 05, 2021 1:39 pm I've seen them. I don't know anyone with one but I'm very wary of such "best of both worlds" devices.

For me, you'd be better fitting an air-to-air heat pump and/or a storage heater or two, completely independent of your wet central heating.

YUP, i'd prefer the ability to have a chance to have some heating rather than everything go down (well, power cuts excepted, y'know what I mean)
1906 ripplewatts @wind Turb-ine-erry
It's the wifes Tesla 3 (she lets me wash it)
Leaf 24
Celotex type insulation stuffed most places
Skip diver to the gentry
Austroflamm WBS
A finger of solar + shed full more
AE-NMidlands
Posts: 1828
Joined: Wed Jun 02, 2021 6:10 pm

Re: Hybrid heating options?

#10

Post by AE-NMidlands »

Mr Gus wrote: Sun Dec 05, 2021 6:15 pm
Stinsy wrote: Sun Dec 05, 2021 1:39 pm I've seen them. I don't know anyone with one but I'm very wary of such "best of both worlds" devices.
For me, you'd be better fitting an air-to-air heat pump and/or a storage heater or two, completely independent of your wet central heating.
YUP, i'd prefer the ability to have a chance to have some heating rather than everything go down (well, power cuts excepted, y'know what I mean)
I'm thinking of keeping the gas CH and having batteries to keep the house (CH) control and lighting working.
A heat pump would be a bonus and cut gas consumption in normal circumstances, but when the grid goes down (like flooding of a big sub-station) I would like to thnk that the battery would keep the background GCH and lights going.
Resilience!
A
2.0 kW/4.62 MWhr pa in Ripples, 4.5 kWp W-facing pv, 9.5 kWhr batt
30 solar thermal tubes, 2MWhr pa in Stockport, plus Congleton and Kinlochbervie Hydros,
Most travel by bike, walking or bus/train. Veg, fruit - and Bees!
Post Reply