Designing a General Purpose Heat Pump Controller

[AC_Hacker]

Originally Posted by takyka

AC,

With the smallest sufficient DC cap, the arduino can survive few hundred ms without power. I have never tried, but read in a book, the compressor can stop, or at least slows down so much, it will not spin up again without Pressures equalize. With optocoupler you can count each individual AC cycle.
It's cheap, and really just 4-5 components to add.

The flow sensor has some resistance, sure. I didn't measure it. I have the 1" version it has proximately half of the crossection blocked. The wheel turns so easy, if you blow into it gently it immediately spins up. For me, the small penality in COP would be acceptable for the added safety. I know about flow switches, but 5-10 times more expensive, and having a tongue in de way of the flow which generates resistance too.

T.

T,

I just ordered two of THESE_FLOW_SENSORS form ebay.

As BBP indicated, these will make it easier to calculate COP.

Here we go...

-AC