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krusty
30-04-2002, 06:29 PM
:confused:

Hi folks.....first off, I am computer engineer, not a mechanical one! Hope you will bare with me.

Suppose I want to design a propane powered 'cooling device' (some more technical folks would call it a fridge), albeit a small one, RV size.

What are the considerations in going with an intermittent absorption VS continuous-cycle absorption systems. The latter is what I have seen in the past and I like the idea of a unit running with a constant low heat.

Also, are there catalogues available out on the net for small RV sized burners, condensors & evaps?

Would there be 1 book you would recommend that would have all of the required example analysis in it?

Oh yes, I will be meeting with a PhD mech eng type next week to help in the design, but I wanted to pick your brains as well to get a better understanding of the issues involved. I have a product idea and am looking for help in a prototype design, so I can cost model it in production to see what type of price point could be met and whether or not I can build a viable business case around it.

Mucho gracias........Bruce

Prof Sporlan
30-04-2002, 07:19 PM
Gas absorption a/c units have been around for quite some time, and the Prof notes that there is an alliance to promote its use as an alternative to vapor compression systems using HCFCs Gas Absorption Alliance. (http://www.hvacrnews.com/editorials/gascompanydec.htm)

You don't hear much about absorption refrigeration, though. Efficiencies no doubt become a problem. Wouldn't a conventional refrigeration system work in this application?

krusty
30-04-2002, 07:37 PM
thx for the followup!

It would be used in an environment without electricity so a traditional compressor driven design would not work.

Are their any ballpark estimates on efficiencies between gas/fuel powered units VS compressor driven models?

Prof Sporlan
30-04-2002, 07:55 PM
Chapter 1 of the 2001 ASHRAE Fundamentals Handbookprovides examples of absorption cycles with state points specified and efficiencies calculated. The same is done for the vapor compression cycle, and it is compared to the Carnot cycle.

A direct comparison between the vapor compression and absorption cycle is not made, but the efficiency numbers seem to favor vapor compression substantially.