Stefan Weiss
13-02-2014, 09:52 PM
We are simulating an organic rankine cycle on a small scale, but we are unable to find a tiny expander for work output (opposite of compressor work input). At this scale, we are mostly just testing a heat exchanger for the generator (evap) so we plan on putting in an expansion valve between the generator (evap) and the condenser.
The only problem is that since the cycle is running "backward" with a liquid refrigerant pump (in lieu of a vapor compressor), after the generator (evap) the refrigerant would normally be going to the turbine/expander but instead we need a way to expand vapor 400psia @ 239degF to 154psia @ 195degF (constant enthalpy) doing no work. In this dummy cycle, the only work being done is on the heat exchangers. Could I just use some kind of needle valve to dial in the pressure drop?
The only problem is that since the cycle is running "backward" with a liquid refrigerant pump (in lieu of a vapor compressor), after the generator (evap) the refrigerant would normally be going to the turbine/expander but instead we need a way to expand vapor 400psia @ 239degF to 154psia @ 195degF (constant enthalpy) doing no work. In this dummy cycle, the only work being done is on the heat exchangers. Could I just use some kind of needle valve to dial in the pressure drop?