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
Z
Zigenpeter8615 Jan 2020 09:54The heating capacity is currently only an estimate. A precise calculation will follow.
It has not yet been decided which rooms in the basement will be heated.
The 175 m² (1,884 sq ft) are calculated excluding the basement.
It has not yet been decided which rooms in the basement will be heated.
The 175 m² (1,884 sq ft) are calculated excluding the basement.
We have just under 220 m² (2,368 sq ft) of heated area built to KfW 55 standard, with a heating demand of 18.9 kWh/m². Even including domestic hot water, you are nowhere near 12 kW.
In terms of costs, pellet heating is probably the most expensive method for a new building built to KfW standard. And the solar thermal system is just a means to an end with new gas buildings; otherwise, no one chooses that voluntarily.
In terms of costs, pellet heating is probably the most expensive method for a new building built to KfW standard. And the solar thermal system is just a means to an end with new gas buildings; otherwise, no one chooses that voluntarily.
I wouldn’t go for pellets; in my opinion, that option is outdated.
Photovoltaic systems work in winter as well, even with clouds and fog. A heat pump really only makes sense if you don’t need much heating anyway, just a bit of hot water – which fits well with the heating system you’ve chosen.
Photovoltaic systems work in winter as well, even with clouds and fog. A heat pump really only makes sense if you don’t need much heating anyway, just a bit of hot water – which fits well with the heating system you’ve chosen.
A 12 kW heating system for a 175 sqm (1,883 sq ft) KFW55 house is clearly oversized.
A pellet heating system in a new build is also quite questionable – why?
Solar thermal systems are only installed with gas heating (to meet building permit / planning permission requirements) – they are not cost-effective.
A pellet heating system in a new build is also quite questionable – why?
Solar thermal systems are only installed with gas heating (to meet building permit / planning permission requirements) – they are not cost-effective.
D
Deliverer15 Jan 2020 10:10I consider 12 kW quite large for a new build—but how “small” can pellet systems actually be? When it burns, it burns, right? I assume these heating systems are usually installed with a large buffer tank to make efficient use of the high heat output without cycling on and off 20 times a day. But I’m not a heating engineer...
Regarding heat pumps and the crystal ball: Eventually, due to overlogging in Eastern Europe (without reforestation), all the forests will be cleared, or the governments of these countries will find an effective solution. By that time, pellets will be even more expensive, and heat pumps will become attractive again. The fact that, thanks to new subsidies, a high percentage of older buildings will probably switch to pellets does not improve the situation.
However, with a well-designed underfloor heating system, renovation costs remain reasonable. Or maybe my crystal ball is cracked anyway—if so, you can safely disregard this whole post.
Regarding heat pumps and the crystal ball: Eventually, due to overlogging in Eastern Europe (without reforestation), all the forests will be cleared, or the governments of these countries will find an effective solution. By that time, pellets will be even more expensive, and heat pumps will become attractive again. The fact that, thanks to new subsidies, a high percentage of older buildings will probably switch to pellets does not improve the situation.
However, with a well-designed underfloor heating system, renovation costs remain reasonable. Or maybe my crystal ball is cracked anyway—if so, you can safely disregard this whole post.
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