ORC project with compressor working as a expander
ORC project with compressor working as a expander
(OP)
Hi everybody!
I´m project engineer. We are working in a new ORC (Organic RAnkine Cycle) project and our porpouse is to recover thermal power from a low temperature source. The inlet conditios in the expander (is not defined yet) are: T=82ºC and P=8,3 bar. The oulet conditions are different depending if we are in winter or summer resort (T=33ºC and T=14.5ºC). Working fluid is a refrigerant; R245fa
We are looking for a machine to expand the fluid and generate electricity. After reading some literature we know that compressors in a reverse mode are used in those applications, that is; screw compressor as a screw expander, scroll compressor as a scroll expander, air motors,etc. We are trying to choose the most suitable machine for our application. Could someone tell me what is the best one for this application? Could someone tell me what kind of compressors can be used as an expander?
And the last question, does anybody now manufacturers of Screw EXPANDER and Scroll EXPANDERs?
Thank you in advance
Best regards
I´m project engineer. We are working in a new ORC (Organic RAnkine Cycle) project and our porpouse is to recover thermal power from a low temperature source. The inlet conditios in the expander (is not defined yet) are: T=82ºC and P=8,3 bar. The oulet conditions are different depending if we are in winter or summer resort (T=33ºC and T=14.5ºC). Working fluid is a refrigerant; R245fa
We are looking for a machine to expand the fluid and generate electricity. After reading some literature we know that compressors in a reverse mode are used in those applications, that is; screw compressor as a screw expander, scroll compressor as a scroll expander, air motors,etc. We are trying to choose the most suitable machine for our application. Could someone tell me what is the best one for this application? Could someone tell me what kind of compressors can be used as an expander?
And the last question, does anybody now manufacturers of Screw EXPANDER and Scroll EXPANDERs?
Thank you in advance
Best regards





RE: ORC project with compressor working as a expander
You also need to set the outlet pressure too to help select what the equipment is going to look like and how much energy you can get back. Also, is it two phase flow? or sat vapor or liquid?
RE: ORC project with compressor working as a expander
I have some questions, what "high bypass rate" means? I don´t understood what do you want to say.
The outlet pressures are 1 bar or 2 bar depending if we are in winter or in summer conditions. We are talking about a global efficiency of 11 percent in winter conditions (best ones), assuming 70% of issoentropic efficiency in the expander. Do you know a solution to this "expander"? For us is the most difficult part of the project.
Regars
RE: ORC project with compressor working as a expander
RE: ORC project with compressor working as a expander
Ge Rotoflow (www.ge
and Texas Turbines (www.txturbine.com) can also do the job.
I estimate the expander will give you 5Kj/mole of energy at 1 bar and 3.5 Kj/mol at 2 bar. The outlet temperature will 30 C at 1 bar and 45 C at 2 bar.
RE: ORC project with compressor working as a expander
I don´t understand the concept of "keeping the gas of bypassing", could you explain me that?
And the last question, what is the range of efficiency in screw compressors?
Thanks for all
regards
RE: ORC project with compressor working as a expander
In an oil-flooded screw, the oil has three functions: (1) seal between the rotor and the case to reduce bypassed flow; (2) lubricate the metal-to-metal parts; and (3) remove the heat of compression.
David
RE: ORC project with compressor working as a expander
After you read about screws and see a video, you'll see what I mean about bypassing. Kobelco makes big dry types. We use mostly Sullaire and Frick oil types in my business.
RE: ORC project with compressor working as a expander
What about air motors? how do they operate? and what about their efficiency? could be another possibility, I think. I contacted with a manufacturer but he didn´t give any technical data about efficiency, operating mode, coupling to the alternator, etc. So before going on with this proposal I would like to know your opinion.
Thanks again
RE: ORC project with compressor working as a expander
IR makes air motors, there are a couple of others. Most have a MAOP of 7 bars. Most models can run on hydrocarbons.
go here to see curves. you can generate random ac and convert to dc then back to exact frequency ac.
h
RE: ORC project with compressor working as a expander
RE: ORC project with compressor working as a expander
RE: ORC project with compressor working as a expander
Thanks again
RE: ORC project with compressor working as a expander