Solar power works great in my calculator.
Of course, but not for your refrigerated air conditioner.
The advent of extremely low power CMOS IC’s and LCD displays have made solar powered calculators a no brainer.
My first calculator was a Remington/Rand with nixie tubes. (not kidding) and I paid over $60 for it back in the 1970’s. It would add/subtract/multiply/divide, nothing more. I still have it somewhere, probably in my electronic shop. Last I checked it, it still worked.
I also still have a collection of slide rules. Some were mine, others my father-in-law’s. (he was an EE)