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?
H
Hausbau 5529 Oct 2021 14:49Try setting night-time lockout periods for the heat pump during the transitional seasons. This way, the heat pump is forced to operate during the day when outdoor temperatures are higher. Using this method, you can set slightly higher room temperatures during the day (1 to 2 degrees Celsius (2 to 4 degrees Fahrenheit), while still maintaining comfort and well-being). This also helps you understand the potential of your house as a thermal storage system.
In general, with Vaillant systems, the operating time of the heat pump can be influenced via the energy integral.
In general, with Vaillant systems, the operating time of the heat pump can be influenced via the energy integral.
R
RotorMotor29 Oct 2021 19:01Durran schrieb:
Without reading everything here, I can say that my current supply temperature is 60 degrees Celsius (140°F).
Only the kitchen, downstairs bathroom, and one child's bedroom are being heated. That's it. You forgot to mention the insulation standard!
Hausbau 55 schrieb:
Try setting night-time lockout periods for the heat pump during transition seasons. This forces the heat pump to operate during the day when outdoor temperatures are higher. Using this method, you can set slightly higher indoor temperatures during the day (1 to 2 degrees lower, while considering comfort and wellbeing). This way, you can take advantage of your house’s thermal storage capabilities.
Generally, with Vaillant systems, the runtime of the heat pump can be adjusted via the energy integral. I have already limited the heat output of the heat pump using whisper mode and turn it off at night in the transition period, as you suggested. This results in a ratio of about 1.5 hours of runtime per compressor start. The compressor hysteresis is also set to maximum, as is the energy integral. Unfortunately, on my heat pump, the energy integral can only be set up to 120 minutes (up to 2 hours), whereas other Vaillant heat pump models allow up to 180 minutes (3 hours). When temperatures drop to around -5°C (23°F) or lower, it runs continuously 24/7.
So my house doesn’t meet any specific insulation standard. Insulation is applied where it makes sense.
The exterior walls are 36 cm (14 inches) Poroton blocks with lime-cement plaster on both inside and outside, resulting in a total wall thickness of about 40 cm (16 inches). It has an unheated attic.
The spaces between the rafters are insulated with 16 cm (6 inches) of expanded polystyrene insulation. The ceiling to the attic is insulated with 20 cm (8 inches) of mineral wool.
It actually works quite well. I use about 1,000 liters (264 gallons) of heating oil and around 6 solid cubic meters of wood per year. Domestic hot water is electric, and in the future, I plan to use my own solar system with a 10 kW battery storage.
There is no triple glazing and no underfloor heating, except in the bathroom. Instead, there are two chimneys in the house: a wood kitchen stove, a living room fireplace with 18 kW (61,400 BTU), and an oil heating system. The hot water is provided by a boiler.
The exterior walls are 36 cm (14 inches) Poroton blocks with lime-cement plaster on both inside and outside, resulting in a total wall thickness of about 40 cm (16 inches). It has an unheated attic.
The spaces between the rafters are insulated with 16 cm (6 inches) of expanded polystyrene insulation. The ceiling to the attic is insulated with 20 cm (8 inches) of mineral wool.
It actually works quite well. I use about 1,000 liters (264 gallons) of heating oil and around 6 solid cubic meters of wood per year. Domestic hot water is electric, and in the future, I plan to use my own solar system with a 10 kW battery storage.
There is no triple glazing and no underfloor heating, except in the bathroom. Instead, there are two chimneys in the house: a wood kitchen stove, a living room fireplace with 18 kW (61,400 BTU), and an oil heating system. The hot water is provided by a boiler.
lesmue79 schrieb:
Unfortunately, with my heat pump, you can only set the energy integral up to a maximum of 120 minutes, whereas other Vaillant heat pump models apparently allow up to 180 minutes. When temperatures drop to around -5°C (23°F) or lower, it runs continuously 24/7. With Vaillant? What exactly do these values mean? My heating technician thinks everything is working perfectly and at the same time set the storage tank offset to 25 K. The result was a supply temperature setpoint for hot water of over 70°C (158°F).
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