ᐅ Do photovoltaic systems and heat pumps share similar performance characteristics or operational experiences?
Created on: 9 Mar 2016 22:27
T
toxicmolotof
Hello dear forum members,
Since Monday afternoon, my photovoltaic system has been up and running, and I have to say... I can’t stop smiling.
Here are the details:
Today’s performance:
The gray line represents household consumption, the blue and red areas show production, where the blue part was self-consumed and the red part was sold.
You can clearly see the washing machine running in the morning, the regular starts of the heat pump, midday consumption, and even the not-so-optimally started dishwasher after 6 p.m.
For a (very good) day in March, I’m more than satisfied. The only thing is that the heat pump in the early morning isn’t yet running as efficiently as I’d like. But I guess only a battery would help with that, and that still seems uneconomical to me.
Since Monday afternoon, my photovoltaic system has been up and running, and I have to say... I can’t stop smiling.
Here are the details:
- 5.4 kWp (18 modules at 300 W each)
- Peak power limitation 70% soft
- Flat roof, mounting angle 10°
- Orientation southwest, about 45° off south
- Feed-in to household electricity including heat pump
- Surplus energy sale
- no battery storage
Today’s performance:
The gray line represents household consumption, the blue and red areas show production, where the blue part was self-consumed and the red part was sold.
You can clearly see the washing machine running in the morning, the regular starts of the heat pump, midday consumption, and even the not-so-optimally started dishwasher after 6 p.m.
For a (very good) day in March, I’m more than satisfied. The only thing is that the heat pump in the early morning isn’t yet running as efficiently as I’d like. But I guess only a battery would help with that, and that still seems uneconomical to me.
T
toxicmolotof10 Mar 2016 22:54Uwe82 schrieb:
Reducing from 70 to 55 is also possible, but no interim payments must have been made yet.However, this is only allowed if at least 6 months have passed since the initial application. Everything else is subject to goodwill.
T
toxicmolotof10 Mar 2016 23:21Regarding KfW and Limit Values:
We did not perform calculations without photovoltaic systems. Instead, we relied on the energy consultant’s statement that we would definitely achieve KfW 70. Then, the photovoltaic system was sized so that we met the values for KfW 55.
Our building: 47.9 kWh/(m²a) and 0.250 W/(m²K)
Reference: 88.7 kWh/(m²a) and 0.358 W/(m²K) (allowed would also be 0.400)
KfW 70: 62.1 kWh/(m²a) and 0.304 W/(m²K)
KfW 55: 48.8 kWh/(m²a) and 0.251 W/(m²K)
KfW 40: 35.5 kWh/(m²a) and 0.197 W/(m²K)
As you can see, achieving KfW 55 was a very close call; the photovoltaic system had to produce 2,000 kWh annually with a self-consumption share of 39.5%, meaning just under 800 kWh. Since we now expect an annual yield of over 4,000 kWh, the self-consumption share of 800 kWh should be significantly exceeded.
We did not perform calculations without photovoltaic systems. Instead, we relied on the energy consultant’s statement that we would definitely achieve KfW 70. Then, the photovoltaic system was sized so that we met the values for KfW 55.
Our building: 47.9 kWh/(m²a) and 0.250 W/(m²K)
Reference: 88.7 kWh/(m²a) and 0.358 W/(m²K) (allowed would also be 0.400)
KfW 70: 62.1 kWh/(m²a) and 0.304 W/(m²K)
KfW 55: 48.8 kWh/(m²a) and 0.251 W/(m²K)
KfW 40: 35.5 kWh/(m²a) and 0.197 W/(m²K)
As you can see, achieving KfW 55 was a very close call; the photovoltaic system had to produce 2,000 kWh annually with a self-consumption share of 39.5%, meaning just under 800 kWh. Since we now expect an annual yield of over 4,000 kWh, the self-consumption share of 800 kWh should be significantly exceeded.
T
toxicmolotof14 Mar 2016 23:14And this is what it looks like when you aim to optimize self-consumption around 9 AM. Unfortunately, by 2 PM, the last electrical appliances like the washing machine, dryer, dishwasher, and vacuum cleaner had also stopped running...
toxicmolotow schrieb:
And this is what it looks like if you aim to optimize self-consumption around 9 a.m. Unfortunately, by around 2 p.m., the last power consumers like the washing machine, dryer, dishwasher, and vacuum cleaner had all stopped...
Check the individual consumption of your appliances.
As far as I remember (don’t hold me to it if I’m wrong), the dishwasher uses less power compared to the washing machine, while the dryer has the highest consumption. So, I would start the dishwasher between 9:00 and 10:00 a.m., then add the washing machine between 10:00 and 11:00 a.m., and begin the dryer from 12:00 noon (by then the dishwasher should be off and the washing machine possibly finished or about to finish so the dryer has something to dry). Vacuum cleaners or similar devices don’t run for long and can be fitted in between.
This whole theory becomes irrelevant if the sun decides to take a nap during the day.
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toxicmolotof15 Mar 2016 12:48That was just an experiment over the weekend... I can’t use as much as is generated by the sun without clouds on an ongoing basis. The peak loads were caused by the heat pump anyway.
In that sense, what you have is what you have. Everything else has to be sold or bought.
Basically, just a great technical gadget.
In that sense, what you have is what you have. Everything else has to be sold or bought.
Basically, just a great technical gadget.
B
Bauexperte15 Mar 2016 17:45toxicmolotow schrieb:
Basically just a great technical gadget.You wouldn’t even notice SCNR
Regards, Bauexperte
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