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?
Just for fun, I set the minimum heating circuit temperature/flow temperature to 23°C (73°F), and it was immediately displayed as the target flow temperature. I'm curious to see if the heat pump controller will maintain this until the heating curve demands more than 23°C (73°F). If that's the case, it would basically be just a base level increase (and not a parallel shift that raises the entire heating curve, which would happen if you adjust it via the desired temperature).
OWLer schrieb:
My heating engineer installs ventilation systems and air handling units from Zewotherm. Heat pumps from Daikin and Vaillant.
So it seems we don’t have a match there. 😉 Alright then :-D I guess there aren’t that many with the Fujitsu heat pump.
I have now set my heating curve to 0.2. All rooms with a 1 l/min (0.26 gal/min) flow rate reach about 21-22°C (70-72°F), which is great. However, the guest toilet only gets to 20°C (68°F) with a 3 l/min (0.79 gal/min) flow rate, and the bathroom just barely reaches 21°C (70°F) even with the same flow rate. The bathroom is too cold for my girlfriend, so I need to raise the heating curve.
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