ᐅ Heat pump, hot water storage tank, tankless water heater, heat recovery ventilation (HRV), underfloor heating, heating and cooling
Created on: 20 Jun 2023 14:37
H
Havanna86
Hello everyone,
I’m looking for advice on the design of our renovation project.
Key details: built in 1930, ground floor area 90 m² (970 ft²), upper floor area 40 m² (430 ft²), basement used only for storage, semi-detached house, extensive renovation planned (including basement ceiling, facade, windows, roof – all to qualify for BEG EM funding).
We are converting the entire ground floor to underfloor heating. On the upper floor, the plan is to use wall heating installed in the space between the rafters. According to calculations, after renovation the heating demand will be 5.3 kW. A air-to-water heat pump (Vitocal 252 – the 08 model) will be used. This heat pump does not have an integrated water storage tank.
The system will be combined with a hydronic fireplace, which delivers 2 kW of heat directly into the room and 8 kW to the water circuit. Additionally, one or more buffer tanks will be integrated to
a) store the heat from the fireplace,
b) use a heating element to feed in excess solar energy from a photovoltaic system during peak times,
and thus provide hot water for heating and domestic hot water.
Due to limited space in the basement, I will most likely need to place two buffer tanks side by side. I am targeting a volume of 800 to 1000 liters (210 to 265 gallons). To avoid having to constantly store hot domestic water during winter, I will integrate a tankless water heater (solar-compatible). The idea is to use the temperature level in the domestic hot water tank and only raise it by about 15 degrees Celsius (27 degrees Fahrenheit) if needed, preferably less.
This is the basic theory, which I have discussed with the heating engineer. However, I want to fully understand the system and I’m stuck on some points, so I hope for your support.
1.) What is the best way to connect the buffer tanks? From my point of view, a series connection seems suitable, with the domestic hot water tank with the DHW loop as the rear, warmer tank, is that correct?
2.) Where is the best place for the heat pump to feed in? Ideally in the middle, right? But where would the middle be with two tanks?
3.) Where should the hydronic fireplace connect?
4.) Up to what temperature in the buffer tank does it make sense to operate the heat pump?
An additional thought, which is not a priority: There is the possibility of a cooling function in summer. Does it make sense to consider the buffer tanks in this regard or would that only complicate things further? Otherwise, in summer it could be possible to have one cold and one hot buffer tank: one for domestic hot water and one for heating water.
Thank you very much for your interest!
I’m looking for advice on the design of our renovation project.
Key details: built in 1930, ground floor area 90 m² (970 ft²), upper floor area 40 m² (430 ft²), basement used only for storage, semi-detached house, extensive renovation planned (including basement ceiling, facade, windows, roof – all to qualify for BEG EM funding).
We are converting the entire ground floor to underfloor heating. On the upper floor, the plan is to use wall heating installed in the space between the rafters. According to calculations, after renovation the heating demand will be 5.3 kW. A air-to-water heat pump (Vitocal 252 – the 08 model) will be used. This heat pump does not have an integrated water storage tank.
The system will be combined with a hydronic fireplace, which delivers 2 kW of heat directly into the room and 8 kW to the water circuit. Additionally, one or more buffer tanks will be integrated to
a) store the heat from the fireplace,
b) use a heating element to feed in excess solar energy from a photovoltaic system during peak times,
and thus provide hot water for heating and domestic hot water.
Due to limited space in the basement, I will most likely need to place two buffer tanks side by side. I am targeting a volume of 800 to 1000 liters (210 to 265 gallons). To avoid having to constantly store hot domestic water during winter, I will integrate a tankless water heater (solar-compatible). The idea is to use the temperature level in the domestic hot water tank and only raise it by about 15 degrees Celsius (27 degrees Fahrenheit) if needed, preferably less.
This is the basic theory, which I have discussed with the heating engineer. However, I want to fully understand the system and I’m stuck on some points, so I hope for your support.
1.) What is the best way to connect the buffer tanks? From my point of view, a series connection seems suitable, with the domestic hot water tank with the DHW loop as the rear, warmer tank, is that correct?
2.) Where is the best place for the heat pump to feed in? Ideally in the middle, right? But where would the middle be with two tanks?
3.) Where should the hydronic fireplace connect?
4.) Up to what temperature in the buffer tank does it make sense to operate the heat pump?
An additional thought, which is not a priority: There is the possibility of a cooling function in summer. Does it make sense to consider the buffer tanks in this regard or would that only complicate things further? Otherwise, in summer it could be possible to have one cold and one hot buffer tank: one for domestic hot water and one for heating water.
Thank you very much for your interest!
H
HeimatBauer26 Jun 2023 16:46I’d say, “what isn’t installed can’t break,” and besides, you don’t have to pay for it, install it, maintain it, or deal with permits.
Every fireplace is a luxury hobby; there’s no way to justify it easily by adding a water jacket. Using an electric heating element just to use up excess solar power? I have solar panels too, but even when there’s surplus solar energy, I don’t increase the flow temperature because what’s the point of taking three hot baths in summer?
So yes, many things are possible, but not everything makes sense.
Every fireplace is a luxury hobby; there’s no way to justify it easily by adding a water jacket. Using an electric heating element just to use up excess solar power? I have solar panels too, but even when there’s surplus solar energy, I don’t increase the flow temperature because what’s the point of taking three hot baths in summer?
So yes, many things are possible, but not everything makes sense.
Similar topics