Yeah, pretty much everywhere here. I got one too. Very easy to install since it's only one unit so no messing with refrigerant - just connect inlet and outlet.
ideas for hydronic heating with a solar powered water heater
- Thread starter 11thhourfabrication
- Start date
Yeah, pretty much everywhere here. I got one too. Very easy to install since it's only one unit so no messing with refrigerant - just connect inlet and outlet.
11thhourfabrication
New Member
Gas tankless water heater for domestic. Wanted to try the Hybrid Hot Water Heater before I stepped up to a high temp air to water heat pump.How are you heating your domestic water (not used for your heating) now? If it is a tank off of your boiler, you could get an electric water heater and put it before/after/in-place of that tank.
Another method would be to get an electric boiler and switch between gas and electric based on time/fuel cost/net metering excess bank.
I use a 6kW electric boiler to heat my garage - haven't had an excess banked since I turned it on!
Thermolec
Dual-energy standard boilers for fossil fuel backup or standalone installations. Standard models include great features like a modulating electronic controller with outdoor sensor as well as integrated load management control.www.thermolec.com
11thhourfabrication
New Member
Hi
Yes you are correct it would solve the problem I have but I was trying to see if the hybrid hot water heater would do something similar for a far cheaper cost.
11thhourfabrication
New Member
I was looking at the high temp air to water heat pump which would act more like my boiler. Trouble is they are not readily available here in California and most dealers will only sell to a trained installer.
11thhourfabrication
New Member
Thanks for the info on Thermolec. I will give them a call and see what they could recommend.How are you heating your domestic water (not used for your heating) now? If it is a tank off of your boiler, you could get an electric water heater and put it before/after/in-place of that tank.
Another method would be to get an electric boiler and switch between gas and electric based on time/fuel cost/net metering excess bank.
I use a 6kW electric boiler to heat my garage - haven't had an excess banked since I turned it on!
Thermolec
Dual-energy standard boilers for fossil fuel backup or standalone installations. Standard models include great features like a modulating electronic controller with outdoor sensor as well as integrated load management control.
WindWizard
Solar Enthusiast
If you are good at plumbing and electrical solutions, then your could take your hybrid hot water tank and then run it into the hydronic tank and then circulate the water. It would take some fancy controls to make sure that your gas heater does not turn on. You would also have to add a circulator pump with controls. If you are very creative and don't mind a bit of plumbing, then it could be done. If you have to hire it out, then I would not recommend it.
Another idea that I just thought of would be to purchase your hybrid water heater and then use that as a preheater to your gas heater. You could just put it into the loop where the gas heater supplies the heat to your hydronic baseboard and then returns it into your hybrid water heater. You would need to turn down the temperature on the gas water heater to match your hybrid water heater, but it just may work.
I did something similar to that. My house uses a baseboard hydronic heating where the water is heated with oil or through a wood boiler. I did not like the oil boiler coming on in the middle of the night and burning oil when we have wood. I made the controls for it so that if the house requires heat in the middle of the night, then it uses the heat in the water tanks to supply the heat. The tanks are indirect so I can heat the tanks with wood in the day and then use the heat in the tanks to heat the house. Basically, I do not have to get up in the night and feed the boiler with wood and the oil tanks are not used and our electric bill is zero except Nov-Jan we use around $162 total. I have another 12 panels that are going up soon to see if I can be energy independent of the grid.
It would be much simpler to just do a mini split.
Another idea that I just thought of would be to purchase your hybrid water heater and then use that as a preheater to your gas heater. You could just put it into the loop where the gas heater supplies the heat to your hydronic baseboard and then returns it into your hybrid water heater. You would need to turn down the temperature on the gas water heater to match your hybrid water heater, but it just may work.
I did something similar to that. My house uses a baseboard hydronic heating where the water is heated with oil or through a wood boiler. I did not like the oil boiler coming on in the middle of the night and burning oil when we have wood. I made the controls for it so that if the house requires heat in the middle of the night, then it uses the heat in the water tanks to supply the heat. The tanks are indirect so I can heat the tanks with wood in the day and then use the heat in the tanks to heat the house. Basically, I do not have to get up in the night and feed the boiler with wood and the oil tanks are not used and our electric bill is zero except Nov-Jan we use around $162 total. I have another 12 panels that are going up soon to see if I can be energy independent of the grid.
It would be much simpler to just do a mini split.
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DIYrich
Solar Wizard
Tl;dr
I was looking into how to use solar with my current boiler system. Pre heating the water using solar can cause problems with boiler efficiency and operations. It is designed for a certain incoming water temp for the flue and condensation to work properly.
In any case, the easiest option is heat pumps. I have central air, so heat pump for that is easy, and when Temps get too low (and heat pumps are not efficient), the boiler kicks in. In your case, if you burn through your credits, just turn off the heat pump until you have enough credits again.
You can also add minisplits for additional spot control.
I was looking into how to use solar with my current boiler system. Pre heating the water using solar can cause problems with boiler efficiency and operations. It is designed for a certain incoming water temp for the flue and condensation to work properly.
In any case, the easiest option is heat pumps. I have central air, so heat pump for that is easy, and when Temps get too low (and heat pumps are not efficient), the boiler kicks in. In your case, if you burn through your credits, just turn off the heat pump until you have enough credits again.
You can also add minisplits for additional spot control.
idreadnought
New Member
115k btu is a lot of heat. If you have 100 gallons of water at 160 degrees. Then use it until it reaches 80 degrees. This will create 66,720 Btu's of energy. Plus the system would run inefficient because it is designed to work at a constant temperature, not a reducing temperature. At most you will get 1/2 hour of heating. Why not a heat pump mini split? Heat pumps are 3x more efficient at heating compared to resistive heating.
zanydroid
Solar Wizard
Seems like this has been over complicated thus far in this thread
The style of Hybrid HPWH in the U.S. only output 4000 or so BTU/h, except for the 12000 BTU/h 120V one from Rheem. And they are not designed for cold weather operation (since they require water to be plumbed into them, vs a split A2W)
The above reason disqualifies standard HPWH based way of providing winter heat in Marin county.
Otherwise you have to go to niche things like SanCO2 (which may even disavow use for hydronic).
Unless you are willing to go custom or pay large markup for low volume (in North America) A2W system. The answer is A2A heatpumps (minisplits as mentioned above) or wait 5-10 years for A2W to be common in the U.S. Actually it’s very questionable whether A2W would talk hold in the U.S. with the smaller installed base of hydronic here versus Europe. IE not a technology issue but a market ecosystem issue.
The style of Hybrid HPWH in the U.S. only output 4000 or so BTU/h, except for the 12000 BTU/h 120V one from Rheem. And they are not designed for cold weather operation (since they require water to be plumbed into them, vs a split A2W)
The above reason disqualifies standard HPWH based way of providing winter heat in Marin county.
Otherwise you have to go to niche things like SanCO2 (which may even disavow use for hydronic).
Unless you are willing to go custom or pay large markup for low volume (in North America) A2W system. The answer is A2A heatpumps (minisplits as mentioned above) or wait 5-10 years for A2W to be common in the U.S. Actually it’s very questionable whether A2W would talk hold in the U.S. with the smaller installed base of hydronic here versus Europe. IE not a technology issue but a market ecosystem issue.
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For cold climates, you don't put Glycol into them?
zanydroid
Solar Wizard
These hybrid HPWH are the highest installation number water HP in the U.S. residential market and are for domestic water IE open loop; cooking, showering, which I think each disqualifies addition of glycol
Unless you’re into refilling it and letting it on your skin
No, we just use a heat exchanger for the domestic hot water, with the glycol in the underfloor heating and buffer vessel (closed system).
zanydroid
Solar Wizard
I guess if monobloc units become common here that would be a consideration.
I don’t relish finding subs to switch to hydronic LOL. Plus it would be a design challenge to find space in a house that wasn’t designed for all the support equipment.
I don’t relish finding subs to switch to hydronic LOL. Plus it would be a design challenge to find space in a house that wasn’t designed for all the support equipment.
zanydroid
Solar Wizard
Few months back I heard there were some more legit monobloc HPWH (IE not direct imported from AliExpress, which I've heard people have success with). Found this one.
www.ecomfort.com
Maximum output temp is 149F
LG KPHTC551M - 55k BTU - Therma V Monobloc - Air-to-Water Outdoor Heat Pump - R32
Buy LG KPHTC551M Today. Free Shipping. Check the LG - 55k BTU - Therma V Monobloc - Air-to-Water Outdoor Heat Pump - R32 ratings before checking out.
www.ecomfort.com
Maximum output temp is 149F
zanydroid
Solar Wizard
Why hasn't a parallel resistive boiler been proposed yet? + a controls panel to select between the resistive boiler and gas boiler. It probably doesn't need to be complicated, just flip between Gas and Electric it based on the expected remaining electricity surplus.
I corrected your calculation of gas energy usage - 14.5MWh, compared to your 9MWh surplus.
You can cut the bill in half with resistive boiler.
Monobloc is a lot more up front money, and adds complexity of self-support. It'll be hard to breakeven with an approved monobloc before you go off NEM2. If you import one yourself, you might have a chance. Since it's probably going to be hard to find an installer in California to service the approved LG monobloc anyway, might as well be naughty and import one.
I corrected your calculation of gas energy usage - 14.5MWh, compared to your 9MWh surplus.
You can cut the bill in half with resistive boiler.
Monobloc is a lot more up front money, and adds complexity of self-support. It'll be hard to breakeven with an approved monobloc before you go off NEM2. If you import one yourself, you might have a chance. Since it's probably going to be hard to find an installer in California to service the approved LG monobloc anyway, might as well be naughty and import one.
That's the thing - the device itself isn't really that expensive (I got mine for 1900 Euro including shipping from China), but of course installed it myself. I don't get why the regulations need to make everything so expensive over there. Even if I would have 'outsourced' this to a plumber, it would only have cost a few hundred to do the install, no permits needed.
zanydroid
Solar Wizard
That LG is the only monobloc eComfort has. It's a pretty immature market. You can look up SanCO2 prices if you want, it's likely even worse (and likely requires a HVAC license to install since it uses CO2 refrigerant, being a split system).
A lot of plumbers already give F-U quotes for the simpler Gas -> HPWH installs ($1000 labor is normal, $3000 labor = F-U price), and I'm not sure a standard plumber would touch something even more niche.
OffGridForGood
Catch, make or grow everything you can.
IIRC, San Anselmo is just near San Franscisco - from a search:
San Anselmo, the summers are long, comfortable, arid, and mostly clear and the winters are short, cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 5 °C to 24 °C and is rarely below 1 °C or above 29 °C.
With year around weather like that, a mini split is the only way that makes sense to me. Will do the tiny bit of heating you will need plus all the cooling that your hydronic will not do. The downfall with the plan is the cloudy winter weather in the region.
San Anselmo, the summers are long, comfortable, arid, and mostly clear and the winters are short, cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 5 °C to 24 °C and is rarely below 1 °C or above 29 °C.
With year around weather like that, a mini split is the only way that makes sense to me. Will do the tiny bit of heating you will need plus all the cooling that your hydronic will not do. The downfall with the plan is the cloudy winter weather in the region.
zanydroid
Solar Wizard
My point about climate was, Marin County is likely too cold in the winter to reliably hack together an outdoor HPWH to try to use it for hydronic -- you're going to put it in an weather enclosure, which will rapidly cool the enclosure starting from 2-3C and make it fight itself.
Maybe it's viable during the day.
A standard tier inverter minisplit is fine in this climate, I have one (and I'm 2 counties over). But, it doesn't integrate with the hydronic system. The hydronic system may be superior to a minisplit in, I dunno, heating bathrooms, floors, etc, and is a significant sunk cost invested into the house.
OffGridForGood
Catch, make or grow everything you can.
If a minisplit provides heating, as a dump load, the hydronic doesn't need to run as hard = lower heating cost as intended.
Zwy
Emperor Of Solar
Gas tankless takes more gas than one might think. A heat pump water heater will use less Kw than the gas tankless. Why do you ask? It takes X number of Kw to heat a volume of water. It can be in the form of gas, oil, electric. The heat pump has the advantage of outputting 3 Kw of heat for each Kw of energy consumed. If the electricity is free excess, the heat pump water heater wins hands down even if the price of natural gas is around $0.05/Kwh.
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