ᐅ Pellets combined with solar thermal or photovoltaic systems?
Created on: 15 Jan 2020 09:02
Z
Zigenpeter86
Hello everyone,
I am currently facing a small issue with planning the heating system.
A pellet stove with about 12 kW output is firmly planned. However, it should be supported by solar energy.
The question now is which option makes more sense...
1. Support from solar thermal system
2. Photovoltaics with an electric immersion heater in the buffer tank
Details:
Floor area about 175 sqm (1887 sq ft)
Building style: urban villa with basement
KfW 55 standard
Ventilation with heat recovery
Underfloor heating throughout the house
Orientation: south (10 m (33 ft) roof width facing south)
Roof pitch about 23°
The question is also which combination is best for subsidies/grants.
Thank you very much
I am currently facing a small issue with planning the heating system.
A pellet stove with about 12 kW output is firmly planned. However, it should be supported by solar energy.
The question now is which option makes more sense...
1. Support from solar thermal system
2. Photovoltaics with an electric immersion heater in the buffer tank
Details:
Floor area about 175 sqm (1887 sq ft)
Building style: urban villa with basement
KfW 55 standard
Ventilation with heat recovery
Underfloor heating throughout the house
Orientation: south (10 m (33 ft) roof width facing south)
Roof pitch about 23°
The question is also which combination is best for subsidies/grants.
Thank you very much
Hello,
For a pellet boiler, I would always recommend a thermal solar system. Combined with a buffer tank and intelligently set reheating times, there is no short cycling. I cannot imagine that an electric direct heating system powered by photovoltaic panels would be effective in this case. Both systems should feed into a buffer tank that also supplies the domestic hot water.
With the current subsidies of 35% for biomass, 30% for solar thermal systems, and the possibility of a KfW40 standard with a €24,000 repayment grant, this approach is likely also economically sensible.
I have had good experiences with Oekofen and Solarfocus products. The latter is being installed in our new build as well.
Olli
For a pellet boiler, I would always recommend a thermal solar system. Combined with a buffer tank and intelligently set reheating times, there is no short cycling. I cannot imagine that an electric direct heating system powered by photovoltaic panels would be effective in this case. Both systems should feed into a buffer tank that also supplies the domestic hot water.
With the current subsidies of 35% for biomass, 30% for solar thermal systems, and the possibility of a KfW40 standard with a €24,000 repayment grant, this approach is likely also economically sensible.
I have had good experiences with Oekofen and Solarfocus products. The latter is being installed in our new build as well.
Olli
B
boxandroof15 Jan 2020 11:08Zigenpeter86 schrieb:
What is meant by the domestic hot water heat pump? I’m not familiar with the system. A small heat pump inside the house connected to a separate water storage tank, powered by electricity. In this case, the pellet system does not produce domestic hot water but is used only for heating.
Why do I suggest this? This way, you can turn off the pellet heating in the summer and still avoid limiting the space for photovoltaic panels by installing solar thermal systems on the roof. It has already been mentioned that a regular heat pump might be a more sensible option.
Z
Zigenpeter8615 Jan 2020 11:11@Lumpi_LE
That’s not what I meant. The idea is that the house will have a basement anyway, and except for a hobby room, it is mainly planned for storage rooms and technical installations.
That’s why it’s not very relevant if the heating system requires 2–4 m² (20–43 sq ft) more space because of a pellet bunker or something similar. It just doesn’t bother me.
Groundwater is the real issue; it only appears after about 8 meters (26 feet), and the level seems to fluctuate. In the neighboring community, there have apparently already been problems with ground water heating systems because of this.
@boxandroof
A chimney will always be necessary because a fireplace is planned for the living room.
Is the output of a photovoltaic system sufficient in the summer to cover the demand of a heat pump, or will additional energy need to be purchased?
That’s not what I meant. The idea is that the house will have a basement anyway, and except for a hobby room, it is mainly planned for storage rooms and technical installations.
That’s why it’s not very relevant if the heating system requires 2–4 m² (20–43 sq ft) more space because of a pellet bunker or something similar. It just doesn’t bother me.
Groundwater is the real issue; it only appears after about 8 meters (26 feet), and the level seems to fluctuate. In the neighboring community, there have apparently already been problems with ground water heating systems because of this.
@boxandroof
A chimney will always be necessary because a fireplace is planned for the living room.
Is the output of a photovoltaic system sufficient in the summer to cover the demand of a heat pump, or will additional energy need to be purchased?
B
boxandroof15 Jan 2020 11:23Zigenpeter86 schrieb:
Is the output of a photovoltaic system sufficient in summer to cover the demand of a heat pump? Or is it necessary to buy additional electricity? The days when the output is not sufficient can be counted on one hand. Of course, the preparation of hot water must be scheduled during the day.
boxandroof schrieb:
I can count on one hand the number of days when it wasn’t enough. Of course, hot water production needs to be scheduled during the day. Last year, between March and October, we had 2 days with severe storms and heavy rain all day, so there wasn’t enough sunlight for hot water production.
However, this is hardly significant – it amounts to about 0.40–0.50 euros in losses per year.
Z
Zigenpeter8615 Jan 2020 11:34How many kilowatts of photovoltaic panels are installed? Is there a storage system?
And what is the capacity of the heat pump?
How much buffer storage was filled with this, or how many people are in the household?
And what is the capacity of the heat pump?
How much buffer storage was filled with this, or how many people are in the household?
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