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 09:14With an electric heat pump, you will certainly operate more economically in the long run.
What I meant to say is that it doesn’t make sense to push over 3 liters per minute into the bathroom.
Are you running the heat pump directly to the underfloor heating or to a buffer tank?
What I meant to say is that it doesn’t make sense to push over 3 liters per minute into the bathroom.
Are you running the heat pump directly to the underfloor heating or to a buffer tank?
OWLer schrieb:
I have something similar under the actuator, but not a hexagon; instead, it’s the "radiator square" for the part below the actuator pin. If I turn this, does it increase the flow, or does it just adjust the limit of the actuator’s travel?
With my valve, I adjusted it on the return side, but didn’t notice any change in flow.
Put differently, what exactly needs to be adjusted to remove the throttle? You can definitely regulate the flow with that square piece, but I haven’t seen any detailed drawings.
That square should be fully opened, and the rest adjusted on the Taco valve. If the flow doesn’t increase anymore, you would theoretically need to throttle other circuits or increase the pump capacity, which could have a negative impact on energy consumption.
Alessandro schrieb:
With an electric heat pump, you will definitely operate more economically in the long run.
What I meant is that it doesn’t make sense to push more than 3 L/min (0.8 gallons per minute) into the bathroom.
Are you running the heat pump directly into the underfloor heating or into a buffer tank?Small inline buffer tank on the return side with an 18-liter (4.8 gallons) volume.
The nominal flow rate of the heat pump is definitely reached, whether I fully open all heating circuits or throttle them to increase the flow rate in the bathroom.
For now, I’m leaving all circuits as open as possible except for the rooms I want 1-2°C (2-4°F) cooler than the rest. The heating curve can’t be set any lower anyway.
A
Alessandro1 Nov 2021 11:20Wait until the outdoor temperature drops. Right now, it is difficult because there are large daily fluctuations.
KingJulien1 Nov 2021 13:18lesmue79 schrieb:
The heating curve can’t be set any lower anyway.What about the flow temperature? I think at these temperatures it’s still the more effective adjustment...Alessandro schrieb:
What I meant is that it doesn’t make sense to push over 3 L/min into the bathroom.Besides, then there’s the risk of a hydraulic short circuit and frequent cycling.KingJulien schrieb:
What about the floor temperature? I think that’s probably the more practical option given the temperatures anyway...
Also, there’s the risk of a hydraulic short circuit and cycling.The floor temperature / target temperature is set at 21°C (70°F), assuming they mean the same thing.
The hydraulic short circuit risk surely depends on the length of the heating circuit, right? If I push 3 liters per minute (3 l/min only as an example, in reality it’s much lower) through a 30-meter (98 feet) circuit, that’s equivalent to an open bypass valve. But with an 80-meter (262 feet) circuit, the risk should be significantly lower. Ultimately, you can find out by measuring the return temperature.
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