Just out of curiosity, to better understand the slope of the heating curve, what flow temperatures do you typically run at 0°C (32°F) outdoor temperature, given a certain indoor temperature and insulation level, when using a combination of underfloor heating and a heat pump?
Background of the question:
My logic tells me that if I want, for example, 22°C (72°F) room temperature, the flow temperature must be at least 22°C (72°F) or higher, since I learned that there needs to be a temperature difference for heat transfer to occur.
So if my heating system turns on at 12°C (54°F) outdoor temperature, my flow temperature should logically start somewhere around 22°C–25°C (72°F–77°F). Accordingly, at only 5°C (41°F) outside, it should be around 27°C (81°F), and at 0°C (32°F) close to 30°C (86°F).
The system design usually takes the location and outdoor temperature down to about –12°C (10°F). If at 0°C (32°F) flow temperature is already 30°C (86°F) according to my logic, then at –12°C (10°F) the flow temperature should be about 40°C (104°F). But most underfloor heating designs for heat pumps are based on a maximum flow temperature of 35°C (95°F).
Of course, the insulation of the house and the indoor temperatures still play a role. Or is the increase in flow temperature actually so gradual that it only rises by about 0.5–1°C (1–2°F) for outdoor temperature drops in 0–5°C (0–9°F) increments?
Background of the question:
My logic tells me that if I want, for example, 22°C (72°F) room temperature, the flow temperature must be at least 22°C (72°F) or higher, since I learned that there needs to be a temperature difference for heat transfer to occur.
So if my heating system turns on at 12°C (54°F) outdoor temperature, my flow temperature should logically start somewhere around 22°C–25°C (72°F–77°F). Accordingly, at only 5°C (41°F) outside, it should be around 27°C (81°F), and at 0°C (32°F) close to 30°C (86°F).
The system design usually takes the location and outdoor temperature down to about –12°C (10°F). If at 0°C (32°F) flow temperature is already 30°C (86°F) according to my logic, then at –12°C (10°F) the flow temperature should be about 40°C (104°F). But most underfloor heating designs for heat pumps are based on a maximum flow temperature of 35°C (95°F).
Of course, the insulation of the house and the indoor temperatures still play a role. Or is the increase in flow temperature actually so gradual that it only rises by about 0.5–1°C (1–2°F) for outdoor temperature drops in 0–5°C (0–9°F) increments?
A
Alessandro1 Nov 2021 14:09Buy an IR thermometer and check the temperature difference on each circuit. What I discovered is that the HTHK, which was criticized as a short circuit, had a temperature difference of 5K (9°F). That’s why it runs at the highest flow rate in my bathroom. Only with that do I reach 23°C (73°F).
You have to experiment with the heat pump for a long time to achieve a perfect result. Although by perfect, I actually mean minimizing the damage caused by the underfloor heating system installed by the heating engineer :p
You have to experiment with the heat pump for a long time to achieve a perfect result. Although by perfect, I actually mean minimizing the damage caused by the underfloor heating system installed by the heating engineer :p
KingJulien1 Nov 2021 16:12lesmue79 schrieb:
The base temperature / desired temperature is 21°C (70°F) if both are the same.At least for Stiebel Eltron, these are not the same. While the base temperature only shifts the heating curve along the Y axis (a 1K change in base temperature equals a 1K change in the target heating curve), the desired temperature changes the target value disproportionately.In any case, I would first experiment with these two parameters (above 0°C (32°F), I believe). Otherwise, in winter, you’ll just end up increasing the slope again.
There are menu options for minimum/maximum heating circuit temperature.
I haven't tried it yet, but if the Vaillant heating curve is based on 20°C (68°F) flow temperature at 20°C (68°F) outdoor temperature, then setting the minimum heating circuit temperature to, for example, 22°C (72°F) would basically be a floor boost of 2°C (4°F), right? Although I rather suspect that it simply adds 2°C (4°F) overall to the target flow temperature, based on my experience with the Vaillant controller so far.
I haven't tried it yet, but if the Vaillant heating curve is based on 20°C (68°F) flow temperature at 20°C (68°F) outdoor temperature, then setting the minimum heating circuit temperature to, for example, 22°C (72°F) would basically be a floor boost of 2°C (4°F), right? Although I rather suspect that it simply adds 2°C (4°F) overall to the target flow temperature, based on my experience with the Vaillant controller so far.
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