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Late night musings.
I have a heat source.
I have an requirement for cooling.
I don't have a compressor.
Can I use the heat to impart energy to a refrigerant gas, say R134a and use this added energy to start the refrigeration process.
Like a adsorption fridge but without the ammonia.
Any suggestions or links to any articles would be appreciated.
Cheers
Why use R134a? - this refrigerant have no future together with R404, R407C, R410a and similar in EU! they going to phase out completely in 3-10 year period for new equipment and sales-banned after this time...
look on Baltzar von Platen and Carl Georg Munters about absorption process for cooling
They make on _very_ clever way heat driven cooling process based on ammonia, hydrogen and water without any moving part inside except fluids itself and gravity as help and going commercial success via Elektrolux in early time refrigerator and still used on camping/caravan refrigerator feed with LGP and electricity.
COP is not compare to modern compressor-system but works a lot better than thermoelectric cooler (and termoelement-cooler can only use high quality energy as electricity) and ammonium absorptions process can use low quality heat around 200 degree C from different sources
Einstein make similar process based on n-butan and ammonia but not going in working commercial products
if you want make new process - try understand above process and other absorptions process carefully... and thinking hard and out of boxes if you want find way not already are invented or/and patented...
good old fashioned evaporative cooling. you can get 10degC td out of it.
Amonium Absoprtion refridgeration cycle is horroribly inefficient though.
As to your question as stated NO you can not, you need a thermal gradient. With that said a guy did build an interesting system:
He made several big heat colectors out of 1 inch copper and painted them black, these where out said facing the sun
up stairs he made the evap and set it into 2 55 gallon drums of glycol mix.
pulled a vacuum and charged with R12 (Old system), during the day the pipes heated and drove all the gas to the evaps, at night the gass would boil and go back to the out side collector. he used the sun for his thermal gradient. One idea for you to try, Only instead of R-12 try Butane or propane
Thanks for the replies.
And in turn.
I have no desire to start messing around with ammonia again....R134a is what is available to me.
Evaporative will be no good in this application sorry
Thermal gradient ? heat source is at +85'C so I have at least 60'C TD to work with
Any other ideas?
Cheers
If you stick R134a as only choice as refrigerant, you newer find solution depend you not open minded enough to find any solution...
If you digging via google you can find lot of document about absorption refrigerate in different way, and many of them using more scary chemical than ammonia...
Find compatible pair of vapour and absorbent for used temperature and temperature difference is absolute necessary for absorptions process - and this pair is not necessary same as refrigerant
For Einsteins cycle (example absorption pair and refrigerant not a same) look:
http://www-old.me.gatech.edu/energy/andy_phd/
and to replace ammonia in water, try HCl, Sulfur dioxide, hydrogen sulfid and Methyl-bromide if you think is better than ammonia in term of toxic risks...
I think I see more learning to be don on your end.
chlorine
dilithium
R sdhf
R 12
R 134
R134a it all does the same thing, the system I discribed where they used r-12 will work with propane for all it cares.
I like the idea of the "solar" collector powering the system, in my scenario I will be using waste automotive heat.Quote:
Originally Posted by The MG Pony
Thanks for your input it gives my something to ponder.
I not like HCF ie. high GWP and Europa not allowed HCF above 150 GWP to use in near future...
but for interest i find:
http://www.sciencedirect.com/science...12609012000039
R134a - DMAC absorption refrigeration system
but still need temperature 140 - 180 degree C on heat source side, ie. similar as ammonium absorption process and not fit for 85 degree C source...
jet refrigeration, with thermal vapour recompressor
jet refrigeration need high quality steam > 100 degree C
One alternative is using water and silicagel (and small vacuum pump)
http://www.gbunet.de/outgoing/nak-prospect.pdf
fit for 85 degree C heat range but cold side not lower than 4 - 8 degree C
Do you have a basic diagram made?, and the process a bit more hashed out?
It is an interesting project, and would enjoy assisiting you on it.