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solar heating dilemma
Posted: Sat Jul 15, 2023 10:08 pm
by renewablejohn
With the installation of solar pv I have no problem for summer heating but for winter I am concerned that the amount of solar we get will not be sufficient to heat the house. I could make the electric go further by installing a water source heat pump (air source not available as listed building) but finding an installer is proving difficult so as an alternative I am thinking of installing a large thermal store and heat with excess solar pv when available but having a Lohberger pellet cooking stove also heating the thermal store. The themal store then feeding the upstairs ring of radiators and the downstairs ufh. The ufh could be either water or direct electric as both where put in. So many options I cannot get my head around it so open for suggestions or am I just being mad.
Re: solar heating dilemma
Posted: Sat Jul 15, 2023 11:02 pm
by Joeboy
renewablejohn wrote: ↑Sat Jul 15, 2023 10:08 pm
With the installation of solar pv I have no problem for summer heating but for winter I am concerned that the amount of solar we get will not be sufficient to heat the house. I could make the electric go further by installing a water source heat pump (air source not available as listed building) but finding an installer is proving difficult so as an alternative I am thinking of installing a large thermal store and heat with excess solar pv when available but having a Lohberger pellet cooking stove also heating the thermal store. The themal store then feeding the upstairs ring of radiators and the downstairs ufh. The ufh could be either water or direct electric as both where put in. So many options I cannot get my head around it so open for suggestions or am I just being mad.
Can.you add more solar John? Seems obvious I know but it is where I would start. With a combination of storage heaters on hive plugs, Octopus overnight slots and a wood burning stove with storage heater brick jacket we manage to avoid gas for most of Winter and the thermal store remains a dry modular endeavour.
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Re: solar heating dilemma
Posted: Sun Jul 16, 2023 7:06 am
by Bugtownboy
If you’re making a significant investment to your capabilities, John, additional PV, if feasible, seems the first consideration along with opportunities for increased/improved insulation.
The inclusion of a TS would give you a storage option.
As PV is always going to be marginal during winter, have you invested in either of the Ripple WT projects ? Can you increase your investment?
Vicarious generation is as good as self-generated - unless you’re off-grid.
Re: solar heating dilemma
Posted: Sun Jul 16, 2023 7:34 am
by Ken
winter PV to give heating does not compute.
For me the way forward would be water HP + batt +tou tariff.
Re: solar heating dilemma
Posted: Sun Jul 16, 2023 5:56 pm
by renewablejohn
The only storage heaters we have is the ufh as with being listed and solid 2ft thick walls radiators or storage heaters where frowned upon. that said the ufh is more storage heater than most ufh systems as part of the listing was that if we found sandstone flags they had to be retained which of course we did but at approx 2 inch thick they take a while to heat up but do retain the heat.
Re: solar heating dilemma
Posted: Sun Jul 16, 2023 6:08 pm
by renewablejohn
the TS I was thinking of heating with any excess solar but that would have to be after the battery is charged up and maybe the electric ufh fully up to temperature. But I dont know whether controllers are that sophisticated or whether it would be better to just get more batteries and run the ufh after dark using the batteries. If it gets really cold then just light the wood boiler and pump the heat through the ufh as its already connected to the hot water tank as a mini thermal store.
Re: solar heating dilemma
Posted: Sun Jul 16, 2023 6:13 pm
by renewablejohn
Ken Thats what I have always been told but these bifacial panels are supposed to be better in winter conditions compared to conventional pv. Will see but I dont want to get to the middle of winter and being freezing cold.
Re: solar heating dilemma
Posted: Sun Jul 16, 2023 7:22 pm
by Countrypaul
You don't give any figures for what total amout of heating energy is required - it might help if you could indicate the likely range and would help deciding whether an GSHP would be worthwhile. Depending on your ground conditions and location, would potentially affect the COP you could get from any GSHP.
Since you have both we UFH and electric UFH, assuming the GSHP gave a COP of 3, running the wet system would be roughly 3 times as efficient as the direct electric UFH. In winter when PV generating is minimal this could be a significant benefit. If using a TOU tariff for your electricity then the use of a thermal store might also be beneficial. You could heat the wet UFH and TS on the cheaper electricity using the GSHP, but rely mainly on the TS for more heat during the more expensive periods.
We use E7 at present, and in winter heat the TS from an ASHP, but have the thermostats for the UFH set to slightly higher temperature during the E7 period and allow the temperature in the rooms to fall during the expensive period. This works fine unless it is very cold in which case the ASHP also needs to run for periods during the expensive electricity period. In the shoulder months it is very unlikely that our ASHP comes on during the expensive period, and in summer it is normally turned off.
With a more flexible TOU tariff combined with batteries and your PV you would have many more options about running the GSHP. With a large TS you could also heat is using the wood burning stove, this could obviously get the TS much hotter than the GSHP and would also prevent the GSHP running if the TS was already hot. If you go away for a coupe of days, then the GSHP could be the main heating source.
Re: solar heating dilemma
Posted: Sun Jul 16, 2023 9:19 pm
by renewablejohn
countrypaul. I have never bothered in the past about heat as we are all wood with an Esse wood range cooker heating hob, oven and hot water, A Dunsley Yorkshire boiler heating the radiators and a Dunsley Highlander keeping the snug toastie. With wood being "free" if it gets cold just throw another log on. The question has come about as living beyond the gas main we are targeted and eligible for in theory upto a 38k grant for heating and insulation inprovements. What where supposed to be eligible for is new doors, windows that are currently single glaze (still have 8 of these) wall insulation, floor insulation, solar, heat pump. Me thinking great can I have some of this as where getting older and although logs are free there is still work involved in processing. So assessor came impressed at the grade 2 listed house and it started well. Here are all the plans approved by the council with listed building consent for work to be undertaken. "Doors we could do 2 composite doors" but thats not what is approved. The listed building consent is for outward opening twin rebated sealed oak doors. "Cannot do that"." Windows would be UPVC double glazed for the remaining 8 units you have not done". The Listed Building Consent is for oak frames with triple glazing. "Cannot do that" . We have our own reservoir/silt trap as you can see would be ideal for a water source heat pump. "It would but we only do air source heat pumps" But we cannot have that because we are listed and it would alter the fabric of the building. Well we would like to put some solar on this garage roof as its not within the curtailedge of the Listed Building "Well its a good location and I would put them South rather than E/W but we could not do it as where not MSC registered" So what can you do for us out of this 38k grant then "Nothing really as without the air source heat pump you would not meet the EPC improvement criteria and we dont do any other sort of heat pump. I think the criteria for the grant is below D to qualify and improvement by 2 grades due to the grant. Listed Building EPC is a finger in the air job at the best of times. Back to your question we are very low heat users probably 20kw for the central heating 5kw for the snug and 5kw for the Esse range. Daily electric usage 6 units per day in summer and 10 units per day depths of winter. Sorry for rant but this Cosy Home Assessor did wind me up although a very pleasant man.
Re: solar heating dilemma
Posted: Mon Jul 17, 2023 8:43 am
by richbee
renewablejohn wrote: ↑Sun Jul 16, 2023 9:19 pm
countrypaul. I have never bothered in the past about heat as we are all wood with an Esse wood range cooker heating hob, oven and hot water, A Dunsley Yorkshire boiler heating the radiators and a Dunsley Highlander keeping the snug toastie. With wood being "free" if it gets cold just throw another log on. The question has come about as living beyond the gas main we are targeted and eligible for in theory upto a 38k grant for heating and insulation inprovements. What where supposed to be eligible for is new doors, windows that are currently single glaze (still have 8 of these) wall insulation, floor insulation, solar, heat pump. Me thinking great can I have some of this as where getting older and although logs are free there is still work involved in processing. So assessor came impressed at the grade 2 listed house and it started well. Here are all the plans approved by the council with listed building consent for work to be undertaken. "Doors we could do 2 composite doors" but thats not what is approved. The listed building consent is for outward opening twin rebated sealed oak doors. "Cannot do that"." Windows would be UPVC double glazed for the remaining 8 units you have not done". The Listed Building Consent is for oak frames with triple glazing. "Cannot do that" . We have our own reservoir/silt trap as you can see would be ideal for a water source heat pump. "It would but we only do air source heat pumps" But we cannot have that because we are listed and it would alter the fabric of the building. Well we would like to put some solar on this garage roof as its not within the curtailedge of the Listed Building "Well its a good location and I would put them South rather than E/W but we could not do it as where not MSC registered" So what can you do for us out of this 38k grant then "Nothing really as without the air source heat pump you would not meet the EPC improvement criteria and we dont do any other sort of heat pump. I think the criteria for the grant is below D to qualify and improvement by 2 grades due to the grant. Listed Building EPC is a finger in the air job at the best of times. Back to your question we are very low heat users probably 20kw for the central heating 5kw for the snug and 5kw for the Esse range. Daily electric usage 6 units per day in summer and 10 units per day depths of winter. Sorry for rant but this Cosy Home Assessor did wind me up although a very pleasant man.
Might be a daft question, but can you put the ASHP on the outside of the garage and run insulated pipes to the house? Not sure how far away the garage is