ᐅ Add wood gasification boilers, hydronic fireplaces, and solar systems to gas heating.
Created on: 20 Jan 2024 13:08
J
Jansepp
Dear forum community,
I would like to ask for advice regarding the upgrade of our heating system. I am quite skilled in some areas of DIY, but not when it comes to heating. Please excuse me if my questions seem amateurish. Ultimately, a professional will carry out the work, but I would like to better understand the topic myself in order to be able to assess everything.
I am attaching sketches of the current and planned setups, as well as pictures of the buffer storage tank.
Currently, we heat our house (an old building from 1930 with an extension from the 1970s) with a Viessmann Vitodens 300 condensing boiler connected to a simple 300 L (79 gallons) domestic hot water tank. Additionally, there is a wood stove with an external chimney.
The house is now being energy renovated, and to avoid dependence on gas, the primary energy source is intended to be wood combined with solar thermal energy.
This means:
- Installation of an Atmos wood gasifier with 25 kW output
- Installation of two water-jacketed wood stoves, each with 12 kW output (7 kW room air, 5 kW water jacket)
- Installation of a 550 L (145 gallons) buffer storage tank
- Installation of a 15 m² (161 sq ft) solar thermal system
The two stoves will be regularly fired during the day and evening.
We basically have free access to wood.
So far, so good, but I still have the following issues / questions:
- I would like not to have to reload the wood gasifier constantly but rather bring the buffer tank up to temperature once a day. Are 550 L buffer tanks sufficient for 270 m² (2,906 sq ft) of living space? If not, how many liters would be recommended?
- Is the buffer tank suitable for this setup in terms of connections? Unfortunately, I have no data on this. It came together with one of the water-jacketed stoves. The flange still has three inlets and outlets. For example, I do not know if it is suitable for domestic hot water production (it of course has insulation, which is not shown in the photos). I would also appreciate alternative purchase recommendations.
- I assume that the current 300 L (79 gallons) tank can be removed completely, as it will no longer be needed? Or will I need a tank for domestic hot water in the future, with the buffer tank only used for heating water?
- Is it advisable to place the buffer tank in the outbuilding or would it be better located in the basement next to the gas boiler? Or does the location not matter?
- How / by which device (controller?) can the system be set up so that the gas boiler starts automatically when the temperature in the buffer tank drops too low? The gas boiler should remain as a backup in case the stoves, wood gasifier, and solar thermal system fail to provide sufficient heat for any reason.
- What share of the energy supply can the solar thermal system roughly be expected to contribute?
- Now a difficult question: approximately how high might the costs be for the connection work / piping?
Thank you very much and best regards,
Josef
I would like to ask for advice regarding the upgrade of our heating system. I am quite skilled in some areas of DIY, but not when it comes to heating. Please excuse me if my questions seem amateurish. Ultimately, a professional will carry out the work, but I would like to better understand the topic myself in order to be able to assess everything.
I am attaching sketches of the current and planned setups, as well as pictures of the buffer storage tank.
Currently, we heat our house (an old building from 1930 with an extension from the 1970s) with a Viessmann Vitodens 300 condensing boiler connected to a simple 300 L (79 gallons) domestic hot water tank. Additionally, there is a wood stove with an external chimney.
The house is now being energy renovated, and to avoid dependence on gas, the primary energy source is intended to be wood combined with solar thermal energy.
This means:
- Installation of an Atmos wood gasifier with 25 kW output
- Installation of two water-jacketed wood stoves, each with 12 kW output (7 kW room air, 5 kW water jacket)
- Installation of a 550 L (145 gallons) buffer storage tank
- Installation of a 15 m² (161 sq ft) solar thermal system
The two stoves will be regularly fired during the day and evening.
We basically have free access to wood.
So far, so good, but I still have the following issues / questions:
- I would like not to have to reload the wood gasifier constantly but rather bring the buffer tank up to temperature once a day. Are 550 L buffer tanks sufficient for 270 m² (2,906 sq ft) of living space? If not, how many liters would be recommended?
- Is the buffer tank suitable for this setup in terms of connections? Unfortunately, I have no data on this. It came together with one of the water-jacketed stoves. The flange still has three inlets and outlets. For example, I do not know if it is suitable for domestic hot water production (it of course has insulation, which is not shown in the photos). I would also appreciate alternative purchase recommendations.
- I assume that the current 300 L (79 gallons) tank can be removed completely, as it will no longer be needed? Or will I need a tank for domestic hot water in the future, with the buffer tank only used for heating water?
- Is it advisable to place the buffer tank in the outbuilding or would it be better located in the basement next to the gas boiler? Or does the location not matter?
- How / by which device (controller?) can the system be set up so that the gas boiler starts automatically when the temperature in the buffer tank drops too low? The gas boiler should remain as a backup in case the stoves, wood gasifier, and solar thermal system fail to provide sufficient heat for any reason.
- What share of the energy supply can the solar thermal system roughly be expected to contribute?
- Now a difficult question: approximately how high might the costs be for the connection work / piping?
Thank you very much and best regards,
Josef
Winniefred24 Jan 2024 10:35bortel schrieb:
Are you actually aware of the cost of heating water with gas? I need 20m³ (706 cubic feet) per month, a large family maybe three times that...
You could heat water with gas for many years before a solar thermal system pays off^^
1500L (400 gallons) buffer tank?!?! For what? Renewable energy systems are unfortunately rarely cost-effective. Anyone who can do the math will realize that they don’t pay off. We are aware of this—especially for people like us with well-insulated older buildings and low gas consumption. It is purely an “ideological” decision. Gas prices would have to become exorbitantly high or the purchase prices for solar thermal systems, heat pumps, etc. would have to drop drastically for it to make financial sense. So don’t worry, you’re not the only one who has noticed this.
What on earth do you use 20m³ (706 cubic feet) of water per month for?? There are four of us with pets and a garden, and we use around 80m³ (2,825 cubic feet) per year on average.
Winniefred schrieb:
Unfortunately, renewable energy is hardly economical. Anyone who can do the math will realize that it doesn’t pay off. We are aware of that—especially for people like us with well-insulated older buildings and low gas consumption. It’s purely an “ideological” decision. Gas prices would have to become exorbitantly high, or the purchase costs for solar thermal/heat pumps, etc., would have to drop significantly for it to make financial sense. So don’t worry, you’re not the only one who has noticed this.
What on earth do you use 20m³ (707 cubic feet) of water per month for?? We are four people with pets and a garden and use around 80m³ (2,825 cubic feet) per year on average. Sorry, I obviously meant 20m³ (707 cubic feet) of gas for hot water preparation.
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