Calculation of a photovoltaic system regarding economic efficiency

  • Erstellt am 2021-08-17 13:01:59

konibar

2021-08-17 14:31:02
  • #1

Electric heating (even indirectly via heat pump) is the most unfavorable scenario imaginable.
Especially since you always need to heat more when it is dark outside.
The efficiency of good commercially available solar panels is currently about 25% max
(monocrystalline, better panels are in the lab stage).
But only with optimal orientation in summer and always free of dirt.

For solar heating, solar thermal (parallel to photovoltaics) would be much more efficient.
And possibly a 500-liter hot water tank for this purpose.
 

Ypsi aus NI

2021-08-17 14:31:12
  • #2
220 sqm far away from the Zugspitze :p As I said: alone 4,000 kwh for the air-water heat pump, two e-cars, air conditioning. I could look up the rest if needed. Maybe it will only be 9,000 kwh, but 3,500 kwh all-in as mentioned by the OP is definitely too little!
 

Grobmutant

2021-08-17 14:37:28
  • #3
The feed-in tariff is currently 7.36 cents and not 9.
 

driver55

2021-08-17 14:39:45
  • #4
Of course, the calculation looks different then… nobody really knows that at first… And sure, the higher the total consumption, the quicker the investment pays off… (As long as there are no defects/repairs…) At 20 degrees in the house and “the kitchen stays cold because no HO and therefore cafeteria” that can be about right… for 90 sqm in the Rhine valley… :D
 

RotorMotor

2021-08-17 16:32:46
  • #5
Sorry, but where did you get that nonsense from? To back it up with numbers again: Heat pump at least COP of 3, rather 4 Realistic photovoltaic efficiency of 20% Overall makes at least 60-80%. While solar thermal energy rarely if ever reaches over 50%, is very expensive and significantly more maintenance-intensive (photovoltaics are maintenance-free) Also, solar thermal energy can only "produce" heat that is often not needed in that quantity. Photovoltaics generate electricity that can be used in many ways! And what should an average household do with a 500l tank?! Conclusion: Photovoltaics + heat pump always beats solar thermal energy.
 

Hangman

2021-08-17 16:51:17
  • #6


... sure, solar thermal really kicks in when it’s dark :cool:
 

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