Can we make electricity from heat?

I am a refrigeration technician with a fascination for heat pumps. I wonder if we can make two systems in parallel. The Carnot heat engine is used to describe the steam locomotive. I want to use a different fluid with a lower boiling point to create a heat engine using a refrigeration cycle.

Imagine a common natural chemical Isoprene because it boils at 94 degrees Fahrenheit. the roof of the house is heating up and the isoprene boils inside a hermetically sealed system. A nozzle sprays a mixture of silicone oil and liquid isoprene and turns the turbine and an alternator pulls electrons from the earth and powers a pump and compressor and two fans. Air from the building absorbs the heat from the isoprene and it condenses back into a liquid and the cycle begins. A battery , compressor and capacitors will be useful to start the process. A small flame might be beneficial to control the boil.

Once the process begins, it should proceed in the mythical fashion of a perpetual motion machine. We are cheating because the heat of the building adds fuel . Heat is energy and it is often thought of as waste in the refrigeration process.
 
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I can't comment on the efficiency or otherwise of the Isoprene cycle but I don't know what you mean by an "alternator pulling electrons from the earth". Electrical power is not generated that way at all.
Furthermore I would be very surprised if there would be enough heat difference to to generate any useful power. Just look at the heat and pressure required in a coal fired power station to generate a useful quqntity of power.
 

russ_watters

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Sorry, but perpetual motion machines are not possible and we do not discuss them here. If you look at the efficiency equations for heat pumps and heat engines, you will see they are inverses of each other; the maximum efficiency of such a system is exactly 100%: no more.

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