ᐅ Is it still worthwhile to install a solar thermal system when you already have an air-to-water heat pump and photovoltaic panels?
Created on: 16 Dec 2019 13:08
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ludwig88sta
Hello everyone,
We are planning to install a photovoltaic system on the fully south-facing pitched roof of our planned house. Since we also want underfloor heating, an air-to-water heat pump is currently our preferred heating option.
I have read here in the forum that with an air-to-water heat pump, a solar thermal system— which heats water using solar energy—would be unnecessary. In other words, on sunny days, the air-to-water heat pump powered by photovoltaic electricity heats the water more efficiently and cost-effectively, right?
Is this still the current understanding as of 2019, so that with a photovoltaic system plus an air-to-water heat pump, the roof is covered only with photovoltaic panels instead of leaving space for a solar thermal system? How did you approach this?
Thanks in advance and have a great start to the week,
ludwig88sta
P.S.: Side question: if you plan a photovoltaic system on the entire south-facing roof, what type of roof tiles do you use? Naturally, as affordable as possible. What do you think about photovoltaic roof tiles (tiles with integrated photovoltaic modules)? Probably more expensive than installing regular photovoltaic panels on a tiled roof, right?
We are planning to install a photovoltaic system on the fully south-facing pitched roof of our planned house. Since we also want underfloor heating, an air-to-water heat pump is currently our preferred heating option.
I have read here in the forum that with an air-to-water heat pump, a solar thermal system— which heats water using solar energy—would be unnecessary. In other words, on sunny days, the air-to-water heat pump powered by photovoltaic electricity heats the water more efficiently and cost-effectively, right?
Is this still the current understanding as of 2019, so that with a photovoltaic system plus an air-to-water heat pump, the roof is covered only with photovoltaic panels instead of leaving space for a solar thermal system? How did you approach this?
Thanks in advance and have a great start to the week,
ludwig88sta
P.S.: Side question: if you plan a photovoltaic system on the entire south-facing roof, what type of roof tiles do you use? Naturally, as affordable as possible. What do you think about photovoltaic roof tiles (tiles with integrated photovoltaic modules)? Probably more expensive than installing regular photovoltaic panels on a tiled roof, right?
The supply line is for the underfloor heating, but here we are talking about the hot water tank. We have 230 liters (61 gallons) integrated into the heat pump, which is more than enough for bathing and showering afterwards, but still small enough to ensure constant circulation.
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ludwig88sta18 Dec 2019 21:37ares83 schrieb:
The flow temperature you mentioned is for the underfloor heating, but here we are talking about the hot water tank. We have a 230 liter (60 gallon) tank integrated into the heat pump, which is more than enough for bathing and showering afterwards, but still small enough to keep the water circulating regularly. Yeah, that's right, thanks!
Although I understand there are people here on the forum who don’t need 60°C (140°F) as the target temperature (not the flow temperature) for hot water, but only heat it to just above 40°C (104°F)? Nevertheless, the risk of Legionella in a single-family house is very, very unlikely.
Do you also have underfloor heating without a separate thermal storage tank, just your 230 liter (60 gallon) hot water tank integrated in the heat pump?
ludwig88sta schrieb:
There are also people in this forum who don’t need 60°C (140°F) as the target temperature (not the flow temperature) for domestic hot water, but only heat just above 40°C (104°F), as far as I understand?
Do you also have underfloor heating and no thermal storage there, just your 230-liter (61-gallon) domestic hot water tank integrated into the heat pump, right? We’re in the 41-42°C (106-108°F) range, which is completely sufficient for us.
Yes, exactly, with the underfloor heating we have a large buffer tank; other solutions would kill the efficiency. Otherwise, only the 230-liter (61-gallon) hot water storage tank.
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ludwig88sta19 Dec 2019 21:19ares83 schrieb:
Yes, exactly, with the underfloor heating we have a large buffer tank; other solutions would reduce efficiency. Otherwise, just the 230-liter (61-gallon) hot water storage tank. Why is the buffer tank for the underfloor heating beneficial for efficiency in your case? Usually, a buffer tank for underfloor heating is generally discouraged here.
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ludwig88sta20 Dec 2019 08:50That's what I wanted to hear!
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