ᐅ Condensing Gas Boiler, Air-to-Water Heat Pump, Fuel Cells – Request for Advice
Created on: 9 Apr 2018 20:46
G
gmt94
Hello everyone,
We are currently in the planning phase for our new home. We are building an urban villa of about 157 m² (1,690 sq ft) according to energy-saving regulations.
My favorite option until this morning was a heat pump with deep geothermal drilling plus a conventional fireplace. However, the drilling company declined the order today due to too high a risk. So I need a new heating alternative.
We are three people: man, woman, and toddler, possibly a fourth child. The child usually takes a bath daily, so there will likely be a relatively high hot water consumption. A rain shower would be desirable.
1. Air-to-water heat pump – somehow I just can’t get comfortable with this option. On one hand, it bothers me that the system is very sensitive to outside temperature, and on the other hand, I’m concerned about the appearance on the house and the noise.
2. Gas condensing boiler with solar hot water support and central ventilation with heat recovery. Since this requires a relatively large water storage tank, I thought of installing a water-bearing (water-carrying) fireplace. This would reduce the risk of overheating the living room, among other things, and the remaining energy could be used for water heating. Woodworking is my hobby. I have a chainsaw license, saw, wood splitter, trailer, and relatively cheap wood is available.
3. My builder also suggested an alternative to the gas boiler: a fuel cell. I haven’t looked into this at all. Does anyone have experience with it?
I hope you can help me. Oh, and ground collectors are not an option due to insufficient space on the plot.
We are currently in the planning phase for our new home. We are building an urban villa of about 157 m² (1,690 sq ft) according to energy-saving regulations.
My favorite option until this morning was a heat pump with deep geothermal drilling plus a conventional fireplace. However, the drilling company declined the order today due to too high a risk. So I need a new heating alternative.
We are three people: man, woman, and toddler, possibly a fourth child. The child usually takes a bath daily, so there will likely be a relatively high hot water consumption. A rain shower would be desirable.
1. Air-to-water heat pump – somehow I just can’t get comfortable with this option. On one hand, it bothers me that the system is very sensitive to outside temperature, and on the other hand, I’m concerned about the appearance on the house and the noise.
2. Gas condensing boiler with solar hot water support and central ventilation with heat recovery. Since this requires a relatively large water storage tank, I thought of installing a water-bearing (water-carrying) fireplace. This would reduce the risk of overheating the living room, among other things, and the remaining energy could be used for water heating. Woodworking is my hobby. I have a chainsaw license, saw, wood splitter, trailer, and relatively cheap wood is available.
3. My builder also suggested an alternative to the gas boiler: a fuel cell. I haven’t looked into this at all. Does anyone have experience with it?
I hope you can help me. Oh, and ground collectors are not an option due to insufficient space on the plot.
markus270310 Apr 2018 07:23ares83 schrieb:
2. But leave out the solar thermal system; that should be fine if you have a mechanical ventilation system with heat recovery.I wouldn’t leave out the solar thermal system; I don’t fully understand that recommendation. From April to September, we get hot water on 75% of the days without any gas costs. And the original poster specifically mentioned that baths are taken daily (like us, at least two bathtubs full daily).
In this case, the solar thermal system definitely benefits us!
Hello,
if possible, I would also skip the solar thermal system. It was still easy for us, but it might be more difficult now after the latest energy saving regulations. It’s not mandatory anyway; you just have to meet certain overall efficiency requirements. How you do that is entirely up to you!
Why skip it?
Simply put: it’s not economically worthwhile (at least for us).
It would have cost us about €5000 and from our old house we know that it does not feed more than a maximum of 10 kWh into the storage per day. It just couldn’t do more because the storage tank would already be at 65-70°C (149-158°F). On top of that, the control system was so badly designed that after the morning shower, it would immediately reheat with gas instead of just waiting for about 3 hours. I was able to reduce that reheating, but couldn’t eliminate it. The builder explained this to me with some rules and regulations. Whether that’s true or he was just incompetent, I don’t know.
Anyway:
The system ended up producing only about 1000 kWh of heat per year. If you use a lot of hot water, it might be 2000 kWh for you. But only if the child bathes during the day, because with morning or evening hot water use, gas reheating kicks in...
2000 kWh of gas consumption means about $100 savings per year. But for the additional €5000 investment, you’d already pay about €60-80 in interest. That makes the ROI roughly between 125 and 250 years.
I’m in very good health (*knock on wood*), but that’s clearly well beyond my personal time horizon.
Best regards,
Andreas
if possible, I would also skip the solar thermal system. It was still easy for us, but it might be more difficult now after the latest energy saving regulations. It’s not mandatory anyway; you just have to meet certain overall efficiency requirements. How you do that is entirely up to you!
Why skip it?
Simply put: it’s not economically worthwhile (at least for us).
It would have cost us about €5000 and from our old house we know that it does not feed more than a maximum of 10 kWh into the storage per day. It just couldn’t do more because the storage tank would already be at 65-70°C (149-158°F). On top of that, the control system was so badly designed that after the morning shower, it would immediately reheat with gas instead of just waiting for about 3 hours. I was able to reduce that reheating, but couldn’t eliminate it. The builder explained this to me with some rules and regulations. Whether that’s true or he was just incompetent, I don’t know.
Anyway:
The system ended up producing only about 1000 kWh of heat per year. If you use a lot of hot water, it might be 2000 kWh for you. But only if the child bathes during the day, because with morning or evening hot water use, gas reheating kicks in...
2000 kWh of gas consumption means about $100 savings per year. But for the additional €5000 investment, you’d already pay about €60-80 in interest. That makes the ROI roughly between 125 and 250 years.
I’m in very good health (*knock on wood*), but that’s clearly well beyond my personal time horizon.
Best regards,
Andreas
Mastermind1 schrieb:
Solar thermal systems are mandatory when using gas or oil. That is not correct. The standard energy saving regulation for houses by many general contractors here in the region does not require solar thermal systems. Many previously had solar thermal but now do not. So it is definitely possible; you just need to consider what makes more financial sense for you. If the child takes many baths, solar thermal might be worthwhile, but if that changes next year, the calculation will look different again.
M
Mastermind110 Apr 2018 08:46ares83 schrieb:
That is incorrect. The standard energy-saving regulation house built by many general contractors around here is without solar thermal (ST); many used to have ST but now they don’t. So it is definitely possible—you just have to see what makes more financial sense for you. If the child takes a lot of baths, ST could be worthwhile, but if that stops next year, the calculation changes again.In that case, a heat pump with air source is clearly being sold (higher profit margin). Or both systems are sold: gas for heating, and for hot water a heat pump with an integrated storage tank (also a good margin).Whether something makes sense nowadays really has to be calculated or questioned individually.
But gas or oil without additional technology is not an option. With the standard energy-saving regulation, controlled ventilation is certainly omitted as well.
So where should the share of renewable energy come from?
PS. I’m not a big fan of solar thermal. I would rather install a photovoltaic system first. But as far as I know, it’s not credited under the energy-saving regulation...
K
Knallkörper10 Apr 2018 08:53Gas and mechanical ventilation with heat recovery is an excellent, economical, and comfortable combination!
Mastermind1 schrieb:
Clearly, an air source heat pump is being sold here (higher profit margin). Or both options are offered: gas for heating, and a heat pump with integrated storage for domestic hot water. (Also a good profit margin).
But gas or oil without additional technology won’t work. With standard energy-saving regulations, controlled ventilation systems are probably also not included.
So where is the share of renewable energy supposed to come from? No, that is completely off. Gas condensing boiler plus controlled ventilation with heat recovery but without solar thermal is the standard in energy-saving regulations.
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