Air-water heat pump current consumption and data

2021-02-09 22:42:15

That actually fits quite well with my observations. We currently have a heat demand of 40-50 kWh. The district heating shows between 1.5-2 kW output when I check.
Outdoor temperature on average at -12 (24h average)

Additionally electricity consumption 8-12 kWh.
With a COP of about 3.5, that fits with Zaba.

What kind of houses do you have??? A normal KFW55 loses significantly more heat and has a heat demand of more like 100 kWh at such temperatures (actually even more theoretically). That would be a COP of 7 and something like that is impossible.

2021-02-09 23:15:41

A normal KFW55 loses significantly more heat there and has a heat demand of about 100 kwh at such temperatures (calculatively rather more..).

How do you come to such a value?

2021-02-09 23:41:59

What kind of houses do you have??? A normal KFW55 loses significantly more heat and at such temperatures rather has a heating demand of 100 kwh (actually even more in calculation..). That would then be a COP of 7 and such a thing is impossible.

Here KFW40, window ventilation. About 150sqm in Hamburg. Temperature between -1 and -7°C. Temperature inside the house 22.5-23°C. Domestic hot water 49°C with 5K hysteresis, 300l hot water buffer. Circulation during the day 30min in the morning and 60min in the evening, pulsed. Hot water is prepared once a day, rarely twice on weekends. Unfortunately, there is a 70l buffer fixed in the heat pump return circuit (compact unit, only the hot water buffer is not integrated). Of course, all ERR removed and without power, overcurrent valve closed. Blower door just above Passive House standards.
Total heat production 55-60kWh per day for heating and hot water. I'm satisfied...

2021-02-10 06:01:27

how is that possible? Our heat pump is already at ~24.5kWh today, total consumption ~42kWh.

Supply temperature is at ~30 degrees, currently -8.2 outside temperature.

There has been no 3rd heating cycle in the 24-hour window. That means today there will be a 3rd heating cycle again and since it is getting even colder, the total house consumption will probably be 35kWh today. You just must not forget, I believe you heat your full 250 sqm. I only heat 1/3 of the 210 sqm passively.

It was actually 22.5kWh yesterday. But what I have noticed is that the hot water looks extremely power-consuming in the dat file (long cycle and rising more gradually than usual). aren’t you feeling like bathing daily? Would narrowing that down be an option?

2021-02-10 06:52:35

We have, similar to Daniel-Sp, a Kfw40+, 150sqm. Temperature in the house averages between 21-22, hot water at 47C with a 180L tank.

From 8 pm last night until now, we have used 22 kWh of heat, the temperature in the house has dropped by 0.5C due to the night setback. It is now 21.4 in the house. Outside it is currently -22C with a 24h average of -14.3C.

Not everything is optimal yet, but I am actually quite satisfied.

If you have >30% more area, different insulation standard(?), you should be able to achieve this as well.

2021-02-10 07:10:26

At AIT/Novelan there is also a hydraulic diagram from the manufacturer without buffer and mixing stuff, officially with warranty. I don't know why this works in that group and why not at Brötje, it's the same technology. About the calculated COP of Brötje. How is it calculated? Is the consumption of the circulation pumps also measured? How is the amount of heat measured? There are many inaccurate methods that are mostly installed by the heat pump manufacturers. Some also calculate it only from the power consumption in relation to the volume flow and other values. I don't trust the stated values at first. COP of 5 at a flow temperature of almost 35°C and an outdoor temperature of 1.3°C would be a super rocket pump...

yes, the consumption of the circulation pump is included in the total consumption. How exactly the COP is measured at Brötje I don't know either. The most important thing for me, as mentioned, is the coordination of the flow rates through the circulation pump and compressor. My compressor also has a performance curve that is controlled by the outdoor temperature, so I have to coordinate a total of 3 "heating curves" with each other :p I am always amazed at how different the consumptions are here and that it depends solely on the amount of pipe length installed in the rooms. That the energy saving ordinance prescribes an ERR but no max flow temperature is quite surprising!

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Air-water heat pump current consumption and data

Bookstar

nordanney

Daniel-Sp

Zaba12

teh_M

Alessandro