Hello everyone,
I would like to introduce myself briefly. We started building a new single-family house five years ago. We moved in about 2.5 years ago.
Unfortunately, after the first few weeks, we had to part ways with the architect and construction management, as their services (planning, etc.) were a disaster, and some of the craftsmen were far from professional (just my personal opinion).
But this is not meant to be a story about our struggles; by now, we are living very satisfactorily in our home.
However, we plan to build again in the near future. To avoid going through the same issues, we want to form our own opinion as thoroughly as possible beforehand.
Now, onto the topic:
Heat pump
Water-circulating stove (to provide support during cold temperatures)
No solar panels (energy saving regulations are met)
Heating load approximately 7000 kWh per year excluding hot water
Flow temperature 26-32°C (79-90°F), temperature spread is 5°C (9°F)
Room volume approximately 600 m³ (21,200 ft³)
These values are based on our current house; the new house will be built almost the same but possibly with better insulation. So I think it can be used as a reference.
Example: At 0°C (32°F) outside and 23°C (73°F) inside, we have a flow temperature of 30°C (86°F) and a return temperature of 25°C (77°F), which equals a 5°C (9°F) spread.
In summary:
- The heat pump should be able to heat and cool the house independently.
- The concrete ceiling should be actively cooled (down to the dew point), possibly also the floor heating.
- The water-circulating stove is intended to provide supplementary heating and create a cozy atmosphere.
- Solar panels are not to be installed (optional).
I have drawn a simple schematic with two storage tanks (1000-liter buffer / 300-liter domestic hot water tank).
How it works:
- Normally / summer, the heat pump heats the domestic hot water tank to 50°C (122°F), starting at a certain time (yellow).
- When the stove is turned on, it first heats the domestic hot water tank via the lower heat exchanger and then cools down the buffer tank (red).
- When the stove is off, water from the buffer tank is circulated until the domestic hot water tank reaches 60°C (140°F) or the same temperature as the buffer (blue).
- Solar panels could possibly be connected to the upper heat exchanger of the domestic hot water tank (brown). Additionally, the buffer tank might also be heated via the lower heat exchanger.
- If the domestic hot water tank is cold, the stove is off, and hot water is needed quickly, the heat pump switches on and an electric heating element in the domestic hot water tank supports heating. Otherwise, heating is controlled normally by the heat pump according to the schedule.
- The underfloor heating and ceiling heating are supplied by the heat pump or via the buffer tank.
The control system is very simple and would be managed by a programmable controller. Also, there are few components, which reduces potential failures or troubleshooting complexities.
I do not want a combined unit / combined storage tank, as I consider them relatively expensive, and they always require a service technician if something goes wrong.
If problems do occur, the valves can be switched manually, and the heat pump will operate independently.
This is very important to me.
The domestic (fresh) water is not connected to the heating circuit.
Please do not discuss the type of heat source (heat pump, solar, etc.) at this time. I would like to do that later, unless it’s related to the system’s function. Thank you.
The control system for underfloor and ceiling heating needs to be discussed in a second step, but that can only happen after the system is installed.
Thank you very much for the support.

I would like to introduce myself briefly. We started building a new single-family house five years ago. We moved in about 2.5 years ago.
Unfortunately, after the first few weeks, we had to part ways with the architect and construction management, as their services (planning, etc.) were a disaster, and some of the craftsmen were far from professional (just my personal opinion).
But this is not meant to be a story about our struggles; by now, we are living very satisfactorily in our home.
However, we plan to build again in the near future. To avoid going through the same issues, we want to form our own opinion as thoroughly as possible beforehand.
Now, onto the topic:
Heat pump
Water-circulating stove (to provide support during cold temperatures)
No solar panels (energy saving regulations are met)
Heating load approximately 7000 kWh per year excluding hot water
Flow temperature 26-32°C (79-90°F), temperature spread is 5°C (9°F)
Room volume approximately 600 m³ (21,200 ft³)
These values are based on our current house; the new house will be built almost the same but possibly with better insulation. So I think it can be used as a reference.
Example: At 0°C (32°F) outside and 23°C (73°F) inside, we have a flow temperature of 30°C (86°F) and a return temperature of 25°C (77°F), which equals a 5°C (9°F) spread.
In summary:
- The heat pump should be able to heat and cool the house independently.
- The concrete ceiling should be actively cooled (down to the dew point), possibly also the floor heating.
- The water-circulating stove is intended to provide supplementary heating and create a cozy atmosphere.
- Solar panels are not to be installed (optional).
I have drawn a simple schematic with two storage tanks (1000-liter buffer / 300-liter domestic hot water tank).
How it works:
- Normally / summer, the heat pump heats the domestic hot water tank to 50°C (122°F), starting at a certain time (yellow).
- When the stove is turned on, it first heats the domestic hot water tank via the lower heat exchanger and then cools down the buffer tank (red).
- When the stove is off, water from the buffer tank is circulated until the domestic hot water tank reaches 60°C (140°F) or the same temperature as the buffer (blue).
- Solar panels could possibly be connected to the upper heat exchanger of the domestic hot water tank (brown). Additionally, the buffer tank might also be heated via the lower heat exchanger.
- If the domestic hot water tank is cold, the stove is off, and hot water is needed quickly, the heat pump switches on and an electric heating element in the domestic hot water tank supports heating. Otherwise, heating is controlled normally by the heat pump according to the schedule.
- The underfloor heating and ceiling heating are supplied by the heat pump or via the buffer tank.
The control system is very simple and would be managed by a programmable controller. Also, there are few components, which reduces potential failures or troubleshooting complexities.
I do not want a combined unit / combined storage tank, as I consider them relatively expensive, and they always require a service technician if something goes wrong.
If problems do occur, the valves can be switched manually, and the heat pump will operate independently.
This is very important to me.
The domestic (fresh) water is not connected to the heating circuit.
Please do not discuss the type of heat source (heat pump, solar, etc.) at this time. I would like to do that later, unless it’s related to the system’s function. Thank you.
The control system for underfloor and ceiling heating needs to be discussed in a second step, but that can only happen after the system is installed.
Thank you very much for the support.
T
toxicmolotof24 Dec 2017 09:10Good morning and Merry Christmas.
I haven’t reviewed your drawing, as that is the job of the plant engineer or, even better, a heating system engineer.
What I can tell you is this:
As nice and ideal as the concept is, you will probably never recover your investment.
The buffer tank reduces the efficiency of the heat pump, only to reheat with wood afterwards. Maybe it makes sense with an air-to-water heat pump and free wood.
I haven’t reviewed your drawing, as that is the job of the plant engineer or, even better, a heating system engineer.
What I can tell you is this:
As nice and ideal as the concept is, you will probably never recover your investment.
The buffer tank reduces the efficiency of the heat pump, only to reheat with wood afterwards. Maybe it makes sense with an air-to-water heat pump and free wood.
T
toxicmolotof24 Dec 2017 09:48Then have a professional explain it to you. I am not an expert.
A heat pump, when properly planned, does not require a buffer tank. The buffer tank therefore wastes energy through unnecessary waste heat and heating.
A heat pump, when properly planned, does not require a buffer tank. The buffer tank therefore wastes energy through unnecessary waste heat and heating.
Why is it not possible to have a normal discussion in forums?
It is clear that a heat pump does not need a buffer tank.
If you had read my post even once and looked at my diagram even once, you would have seen that the buffer tank in the diagram is only for the stove. The heat pump heats the underfloor heating and domestic hot water directly, and then the reply that you are not an expert *shaking my head*.
I would appreciate it if reasonable answers were posted here instead of comments made out of boredom... I won’t elaborate further.
Sorry.
It is clear that a heat pump does not need a buffer tank.
If you had read my post even once and looked at my diagram even once, you would have seen that the buffer tank in the diagram is only for the stove. The heat pump heats the underfloor heating and domestic hot water directly, and then the reply that you are not an expert *shaking my head*.
I would appreciate it if reasonable answers were posted here instead of comments made out of boredom... I won’t elaborate further.
Sorry.
Hello!
First of all: It’s a strange approach to try to limit others’ opinions and statements in an open forum. That rarely works.
A fundamental question from me: what is your intention in discussing a layout first and then the type of heat generation? Maybe you will invest weeks or months in an idea that might collapse for some reason?
Background knowledge is essential to provide meaningful advice.
First of all: It’s a strange approach to try to limit others’ opinions and statements in an open forum. That rarely works.
A fundamental question from me: what is your intention in discussing a layout first and then the type of heat generation? Maybe you will invest weeks or months in an idea that might collapse for some reason?
Background knowledge is essential to provide meaningful advice.
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