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?
KingJulien25 Oct 2021 12:36lesmue79 schrieb:
The problem is that it’s a standard general contractor / prefab house supplier design. lesmue79 schrieb:
The whole system is designed for a maximum of 30°C (86°F) supply temperature. So what now? 30°C (86°F) supply temperature is actually great!
Why don’t you open everything up as much as possible and lower the heating curve?
H
Hausbau 5525 Oct 2021 12:39Unfortunately, the appropriate TacoSetters are not always installed.
H
Hausbau 5525 Oct 2021 12:48These attachments are useful for adjusting the flow rate.
Does anyone know where to buy these attachments?
Does anyone know where to buy these attachments?
lesmue79 schrieb:
That’s why many thermostatic radiator valves also appear to have zero flow according to calculations. At 20°C (68°F), I can barely get any adjustable flow, and in reality, since I want only 18-19°C (64-66°F), it’s even less. You still don’t understand how the underfloor heating system works.
Finally, give the "unit" the volume flow it needs.
I have now assigned the volume flow rates to the list:
Kitchen 1: 65 m (213 ft), 1.0 L/min
Kitchen 2: 54 m (177 ft), 1.1 L/min
Living/Dining 1: 117 m (384 ft), 0.8–0.9 L/min
Living/Dining 2: 91 m (299 ft), 1.0 L/min
Living/Dining 3: 97 m (318 ft), 0.9 L/min
Bedroom 1: 101 m (331 ft), 0.9 L/min
Bedroom 2: 98 m (322 ft), 0.9 L/min
Bathroom: 73 m (240 ft), 1.0 L/min
Guest 1: 77 m (253 ft), 1.0 L/min
Guest 2: 71 m (233 ft), 1.0 L/min
Hallway 1: 37 m (121 ft), 1.1 L/min
Hallway 2: 35 m (115 ft), 1.1 L/min
WC: 39 m (128 ft), 1.0 L/min
Utility room: 49 m (161 ft), 1.0 L/min
According to the heat pump display, the current flow rate is approximately 768 L/h (203 gal/h).
Heating curve set to 0.1.
Desired temperature is 20°C (68°F).
Now it just needs to get colder again.
Kitchen 1: 65 m (213 ft), 1.0 L/min
Kitchen 2: 54 m (177 ft), 1.1 L/min
Living/Dining 1: 117 m (384 ft), 0.8–0.9 L/min
Living/Dining 2: 91 m (299 ft), 1.0 L/min
Living/Dining 3: 97 m (318 ft), 0.9 L/min
Bedroom 1: 101 m (331 ft), 0.9 L/min
Bedroom 2: 98 m (322 ft), 0.9 L/min
Bathroom: 73 m (240 ft), 1.0 L/min
Guest 1: 77 m (253 ft), 1.0 L/min
Guest 2: 71 m (233 ft), 1.0 L/min
Hallway 1: 37 m (121 ft), 1.1 L/min
Hallway 2: 35 m (115 ft), 1.1 L/min
WC: 39 m (128 ft), 1.0 L/min
Utility room: 49 m (161 ft), 1.0 L/min
According to the heat pump display, the current flow rate is approximately 768 L/h (203 gal/h).
Heating curve set to 0.1.
Desired temperature is 20°C (68°F).
Now it just needs to get colder again.
lesmue79 schrieb:
According to the heat pump display, now about 768 L/h (202 gallons/hour)
Heating curve 0.1
Desired temperature 20°C (68°F)See, it works after all. You can reduce the sleeping temperature to 0.5 each and add 1 liter (0.26 gallons) in the bathroom.
Have you checked the heating curve in your documents?
What output is delivered at 0.1 / 20 with an outdoor temperature of 0°C (32°F)? That’s probably too little.
What are the room temperatures currently?
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