Heat pump in combination with photovoltaic system

Hi,

we commissioned a photovoltaic system without storage last month. Currently, we are not receiving any remuneration because a bidirectional meter has not yet been installed. The current meter has a reverse flow lock, so we are giving away all surplus electricity for free.

I had set our heat pump for the first 2-3 years after moving in so that it operated without ERR and only responded to the outside temperature. Differences between day and night operation were not adjusted. This has been running more or less without changes for 7-8 years.

To avoid giving away electricity at the moment, I have been tweaking the heat pump a bit over the last two weeks – shifting domestic hot water production more to the daytime and also adjusting the heating curve upwards during the day and downwards at night through parallel shift. Initially, this led to it being clearly too warm in the evening last week in combination with the sun. So, I lowered the curve a bit during the day again. This morning, however, it was a bit too cold as a result. Nothing dramatic, but not as consistent as before.

How do you handle this?

How do you handle that?

set so that it worked without ERR and only oriented itself to the outside temperature.

That is completely fine for heating operation. Feeling comfortable in the house is more important to me than saving a few cents (which is not much anyway).

Hot water production rather scheduled for the day

This way you can really take advantage of the sun. Thanks to working from home, I almost always do hot water manually when the sun allows it (then you can nicely "play" with when and at what hot water temperature the preparation is started). If automatically due to appointments/business trips, then during the day.

So you don't make any distinction between day and night operation at all? Tending to be, more heating will be done at night at colder temperatures than during the day if the [SOLL-Temperatur] is based on the outside temperature. That was what I wanted to at least partially offset with the parallel shift. I probably shifted too much in both directions.

So you don’t make any distinction between day and nighttime operation at all?

Of course not.

Tendency is that significantly more heating is done at night at colder temperatures,

That only makes a marginal difference in the new house. In fact, for example, the heat pump currently only starts to draw somewhat more power in the late night/early morning hours (power consumption then increases by 100-150 watts). Therefore, it’s really not worth it (for me) to implement a nighttime setback. And in the morning, the sun in my (10 kWp) system is still not sufficient. Especially in winter, since most days it isn’t enough all day. So we are talking about autumn and spring, where, for example, today at nice sunshine from around 09:30, the demand of the house and the heat pump is only then covered. With clouds, even much later. And before I fiddle with the system to save 500 watts or 1 kWh of electricity during the day (autumn/spring) (= 15 cents "profit", increased heating consumption due to nighttime setback not considered), which over the season adds up to 7.86€, I prefer a house heated exactly to the point.

You definitely have a modern and modulating heat pump and also an extremely low consumption, if I remember correctly.

So far, I only had a normal intermediate meter. Now with the smart meter, you can quite clearly see that the heat pump mainly operates at night.
I already wanted to cover part of that with the photovoltaic system.
The technology has advanced quite a bit in the last 12 years since we have had it.
Mine always draws 2000W when it switches on. Since the heat pump is a direct evaporator with a surface collector, it probably has to switch off occasionally and also for regeneration and cannot run continuously.

You surely have a current and modulating heat pump and also an extremely low consumption, if I remember correctly. I only had a normal submeter until now. Now with the smart meter, you can clearly see that the heat pump mainly operates at night. I already wanted to cover part of that with photovoltaics. The technology has developed quite a bit in the last 12 years since we have had it. Mine always takes 2000W when switching on. Since the heat pump is a direct evaporator with a flat collector, it probably has to switch off now and then for regeneration and cannot run continuously.

All right. I hadn’t considered that. For me, around 500 watts run for heating at night at about the freezing point currently.