This is interesting.

From attached presentation:

Working Fluid Selection

The efficiency of the WHR Rankine cycle is dependent on the thermodynamic properties of the working fluid. R245fa (C3H3F5), water and ethanol were selected as three candidates from more than 30 working fluids reported in a literature review. Water was eliminated from the candidate list due to having a low condensation pressure (0.3 bar) leading to sealing concerns and a high freezing point. Ethanol has advantages over R245fa in reduced system pressure, volumetric flow rate through the expander and size of the recuperator. Higher system pressure has significant impact to the cost of the WHR system for mobile applications because the working fluid pump and the heat exchanger’s costs increase. Higher volumetric flow rates and comparatively lower pressure are desirable from a system perspective. The above mentioned considerations led to the selection of ethanol as a working fluid.

Comments?

26

Hi Sångfors 

Some useful references on attachment 1

https://energy.gov/sites/prod/files/2014/03/f13/ace088_subramanian_2013_o.pdf

2

https://energy.gov/sites/prod/files/2014/07/f17/ace088_subramanian_2014_o.pdf

3

https://energy.gov/sites/prod/files/2016/06/f32/ace097_subramanian_2016_o_web.pdf

4

https://books.google.com/books?isbn=0081005113

5

http://www.refrigeration-engineer.com/forums/showthread.php?9356-Compressor-as-Expander-for-power-(Rankine-Cycle)

6

https://www.calnetix.com/access-energy-thermapower-orc-systems

7

https://www.sciencedirect.com/science/article/pii/S0196890417302595

8

https://www.mdpi.com/1996-1073/9/8/606/pdf

9

https://sciencedirect.daneshgostar.org/science/article/pii/B9780081005101000120

10

https://www.imp.gda.pl/files/transactions/131/131_14_.pdf

11

http://www.springer.com/cda/content/document/cda_downloaddocument/9783662456224-c2.pdf?SGWID=0-0-45-1490324-p177095631

12

https://orbi.ulg.ac.be/bitstream/2268/202577/1/PhD_Thesis_JF.Oudkerk.pdf

13

http://eprints.nottingham.ac.uk/28990/1/INVESTIGATION%20OF%20ENVIRONMENTALLY%20FRIENDLY%20POWER%20GENERATION%20SYSTEMS%20FOR%20LOW-GRADE%20WASTE%20HEAT%20RECOVERY.pdf

q

https://www.envaenergy.de/en/

w

https://repository.tudelft.nl/islandora/object/uuid:3232af97-a958-4b0f-a3fc-6d1514a31673/datastream/OBJ/download

r

http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2467175

we

https://www.osti.gov/scitech/servlets/purl/1091781

c

https://www.asme-orc2015.be/proceedings/documents/72.pdf

d

http://www.dcamm.dk/-/media/Sites/DCAMM/S-Reports/S190-Jorrit-Wronski-PhD-Thesis.ashx?la=da

g

https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-362a4126-0ad6-4e4f-bd32-b344ebe6fd49/c/173-188.pdf

Hi Laith Al-Ani,

Thanks a lot for all interesting papers you sent about this matter.

Kind regards

Bo

www.bosangfors.se

Actually I was looking for expanders having built-in volume ratio = 1.

Having built-in volume ratio = 1 means that the generated power can be high.

The disadvantage is that the adiabatic efficiency is low.

If you will have an expander with optimized efficiency you must decrease the generated power.

Then it's a matter of cost. One might perhaps have to compromise.

If you for example design a machine with say 1 % efficiency below the optimum

you can get out more power from the expander.

See attached graph.