What are the parameters for an Organic Rankine Cycle waste heat recovery system?

  • Thread starter Thread starter TheBigBiscuit
  • Start date Start date
  • Tags Tags
    Heat
AI Thread Summary
The discussion focuses on modeling a waste heat recovery system using an Organic Rankine Cycle (ORC) with exhaust gas from a natural gas engine as the heat source. Key parameters include exhaust gas temperature, which is approximately 1000 Kelvin for a 1.5 MW engine, and specific heat values ranging from 1 to 1.3 kJ/kgK. Participants suggest verifying exhaust gas composition to accurately determine heat capacity, noting that water vapor increases it compared to nitrogen. A lean burn engine's stack temperature is recommended to be between 450 to 550 degrees Celsius with a specific heat of 1.1 kJ/kg.K. The conversation also touches on natural processes, like countercurrent heat exchangers in birds, as potential inspiration for the project.
TheBigBiscuit
Messages
4
Reaction score
0
Hello, I'm new to these forums and hoping I can get some help with a project I'm undertaking in college. The project is to model a waste heat recovery system using an Organic Rankine Cycle (ORC). What I'm currently looking at is my waste heat source (exhaust gas from a natural gas engine). The parameters I'm considered with at present are the exhaust gas temperature and the specific heat of the exhaust gas.
Searching these parameters on the internet provisionally, I seem to be getting exhaust gas temperatures of approximately 1000 Kelvin for a 1.5 MW MAN gas powered engine, and specific heat seems to be between 1 - 1.3 kJ/kgK.
However these sources aren't as reliable as I'd like (not that they aren't accurate, but I'd like a bit more concrete proof or references if that's possible).
Any help would be greatly appreciated as I haven't looked at the gas engine side of the project in more detail as it's only the exhaust port of this that concerns the ORC, so it's likely I'm going about it the wrong way.
 
Engineering news on Phys.org
You can perfectly check the composition of the exhaust gas and add the heat capacity of the constituents. H2O will increase it over N2. In the maximum case, all O2 burns CH4.
 
450 to 550 deg C, with a Cp of 1.1 kJ/kg.K in the stack would be a good starting point for a lean burn engine.
 
TheBigBiscuit, Welcome to Physics Forums!

There may be a process in nature that might apply to your project. May I suggest that you have a look at how birds in frigid climates use a countercurrent heat exchanger between blood vessels in their legs to keep heat concentrated within their bodies? You may be surprised to discover how often some variation of this process is used by modern industry.

http://en.wikipedia.org/wiki/Countercurrent_exchange

Cheers,
Bobbywhy
 
Thanks for taking time to reply. It's given me some food for thought. I may need to get back to ye at some point but thanks very much for this base.
 
Thread 'I need a concave mirror with a focal length length of 150 feet?'
I need to cut down a 3 year old dead tree from top down so tree causes no damage with small pieces falling. I need a mirror with a focal length of 150 ft. 12" diameter to 36" diameter will work good but I can't think of any easy way to build it. Nothing like this for sale on Ebay. I have a 30" Fresnel lens that I use to burn stumps it works great. Tree service wants $2000.
Hi all, i have some questions about the tesla turbine: is a tesla turbine more efficient than a steam engine or a stirling engine ? about the discs of the tesla turbine warping because of the high speed rotations; does running the engine on a lower speed solve that or will the discs warp anyway after time ? what is the difference in efficiency between the tesla turbine running at high speed and running it at a lower speed ( as fast as possible but low enough to not warp de discs) and: i...
Thread 'Where is my curb stop?'
My water meter is submerged under water for about 95% of the year. Today I took a photograph of the inside of my water meter box because today is one of the rare days that my water meter is not submerged in water. Here is the photograph that I took of my water meter with the cover on: Here is a photograph I took of my water meter with the cover off: I edited the photograph to draw a red circle around a knob on my water meter. Is that knob that I drew a red circle around my meter...
Back
Top