ᐅ Fuel cell or operating costs, photovoltaic systems and solar thermal energy?

Greetings,

I am currently working on the heating system.
We are taking over the house and property of my grandparents, built in 1948.
I don’t need to describe the current condition here, as we are planning a complete renovation anyway.
A gas heating system is installed.

The plan includes roof refurbishment, exterior insulation, new windows with triple glazing, underfloor heating in the bathroom, and a new heating system in general.

I am weighing my options.

I have come across fuel cell heating systems from manufacturers like Buderus and Viessmann and find the technology really impressive. However, I wonder if it is wise to remain dependent on natural gas. In the end, it is a great technology but still based on natural gas. My electricity would also come from fossil fuels, and I’m not really comfortable with that idea.

As an alternative, I have considered simply replacing the old gas heating system with a condensing boiler and installing a sizeable solar thermal system and photovoltaic panels on the roof. Combined with a large buffer tank and a battery in the basement, I should be able to cover the emission-free heating demand during the sunny months. In winter, the fuel cell system would probably still trigger the boiler to handle peak heating demand.
However, the roof slopes face east-northeast and west-southwest, which is not ideal.
The property is quite large, though, so there is the possibility to place the modules somewhere in the garden.

I really like the idea of combined heat and power (CHP), but in the end, the power would still go out if the gas supply is cut off.

Does anyone have an opinion for me?

Thank you

WSW is great. Power in the afternoon when you're usually at home anyway, rather than in the morning. I would go for photovoltaic panels but skip solar thermal.

And there are even more options. Combined heat and power unit, wood log boiler, pellet heating system, water-bearing fireplace in the living room, a small heat pump for the warmer months.

Are you planning to install underfloor heating?

It seems to me that you only skimmed through the text.

First of all: the fuel cell also counts as a combined heat and power unit, so your statement is a bit confusing in relation to my question.
Otherwise, as I mentioned, underfloor heating is only planned for the bathroom, meaning a mixed system.
Solar thermal is important to me. I don’t want the gas boiler to turn on for every small amount of hot water.

Thanks for the opinion on domestic hot water (DHW); I hadn’t looked at it that way before.

When I think of a combined heat and power (CHP) unit, I imagine a diesel engine running in the basement, but yes, fuel cells are also considered CHP systems.

A hybrid operation usually means a high supply temperature – so that basically rules out a heat pump (even as just part of the solution).

The problem I clearly see with solar thermal (ST) is that in winter it doesn’t deliver much, while in summer there’s an excess of hot water. ST is basically a relic from the times when photovoltaic panels were still very expensive, and it was a way to build cheaply with a gas boiler in new construction.

Is wood heating – also alongside other systems – an alternative? You mentioned a yard; do you have a forest and the equipment to manage firewood?

I actually have 4,000m² (43,000 sq ft) of forest on the property.
However, I’m somewhat skeptical about fireplaces. Recent reports over the past few months indicating that they release a significant amount of pollutants into indoor air, especially fine dust particles, make me cautious. If I end up with indoor exhaust levels comparable to a busy street, the idea of a crackling fire no longer seems so appealing. On the other hand, I want to plan the renovation to be as age-friendly as possible from the start. Right now, it might not be a problem for me to handle firewood, but whether I’ll still feel the same at 70 is uncertain. And who knows what the situation will be in 30 to 40 years.

Hmm, I’m undecided.

It would be ideal if a fuel cell heating system could later be converted to run directly on hydrogen. That way, the concept would at least be future-proof.

In any case, thanks for sharing your impressions.

Jupiter1234 schrieb:

[..] but in the end, my lights also go out when the gas valve is turned off.

Who the heck is supposed to turn off the gas valve?

Jupiter1234 schrieb:

It would of course be convenient if you could later switch such a fuel cell heating system to run directly on hydrogen. That would at least make the concept future-proof.

Take a look at where the hydrogen for these systems actually comes from: natural gas.

What is the service life of such fuel cell heating systems anyway? The only figure I could find was from Focus Online, which mentioned about 10 years, with a trend toward longer life.

I don’t know what your expectations are regarding future viability and so on, but a lot will have to be renewed anyway in 20 to 30 years.

If you really care about topics like environment, future, and independence, the only sensible option is to go completely with underfloor heating and a heat pump. Plus photovoltaics. Would that be feasible for your renovation / full refurbishment?