Waste Heat Recovery
Waste Heat Recovery
(OP)
I’m looking for a good manufacturer & supplier of waste heat recovery equipments, i.e. exhaust gas boilers, absorption chillers, fresh water generators etc..
I’ll appreciate it if anyone can post the names & web site addresses of such manufacturers. May thanks, WR.
I’ll appreciate it if anyone can post the names & web site addresses of such manufacturers. May thanks, WR.





RE: Waste Heat Recovery
RE: Waste Heat Recovery
On a personal basis it is probably worth the effort but if you bought the installation, paid to operate and maintain it, the economics won't be there.
RE: Waste Heat Recovery
RE: Waste Heat Recovery
how about this nifty little product?
http://www.hi-z.com/websit07.htm
RE: Waste Heat Recovery
The efficiency of a diesel engine is approximately 33% with 30% heat rejected to the cooling water, 30% heat rejected to the exhaust gas and the remaining 7% is radiated to atmosphere. Theoretically, we are able to recover all the heat rejected to the cooling water and only 50% of the heat rejected to the exhaust gas and that is to say, the recoverable waste heat of a diesel engine represents almost 45% of input energy which is a great amount of energy and should give a reasonable return of investment provided that it is efficiently utilized.
My question now to Jimkden and others, your statement “if you bought the installation, paid to operate and maintain it, the economics won't be there” is it based on practical experience with existing installations or just based on mathematical work ? WR.
RE: Waste Heat Recovery
What is your application, or how are you planning to capture and use the heat? Is this a year around need, or is it seasonal?
RE: Waste Heat Recovery
RE: Waste Heat Recovery
We are talking here on large diesel engines of over 3000 Kw output. WR
RE: Waste Heat Recovery
The exhaust waste heat of an IC engine is difficult to recover. This is because it is hard, but not impossible, to transfer heat into or out of a gas due to the low thermal conductivity of the gas. Heat exhangers used to cool gases often have liquid on one side of the heat exhanger and gas on the other. Gas to gas heat exchange requires large surface areas to get reasonable heat transfer rates. Regenerators are occasionally used to recover heat from a gas and send it to another gas.
Also, if you successfully get the heat out of the engine exhaust, condensation of the water vapor in the exhaust can be a problem. The condensate is usually acidic and corrodes most metals used in heat exchangers.
There are some SAE papers from the 1970's on bottoming cycles for IC engines. These papers would probably have some info on recovering the engine exhaust heat.
When I was in the Navy, we had a lithium bromide absorption type chiller. It worked well but that particular model required a skilled operator.
RE: Waste Heat Recovery
The heat available in the exhaust gases of a diesel engine isn’t in fact difficult to recover, an exhaust gas boiler would utilize the heat available in the exhaust gases and generate hot water or steam. In order to avoid formation of sulphuric acid, the temperature of the exhaust gases is always maintained above the temperature at which the water vapor in the exhaust gases will begin to condensate and therefore a chemical reaction between sulphur & water would be avoided. WR
RE: Waste Heat Recovery
After all, there is a production naturally aspirated spark ignition engine that manages 37%.
Cheers
Greg Locock