Heat recovery from engine exhaust while testing
Heat recovery from engine exhaust while testing
(OP)
My company manufactures ( and tests, ofcourse!) IC engines. While testing for a few hours, there is a possibility of heat recovery from flue gases at 400 C, which can be used for heating water.
My question is:
If a use a concentric heat exchanger to recover heat from flue gases to water, and a water tank ( with a vent connection) placed at a higher elevation than the heat exchanger, will it work? I mean, if I provide a pipe from the bottom of the tank to the inlet of the heat exchanger and the outlet pipe from the heat exchanger to the top of the tank. Is there a requirement of a pump? ( which I don't wan't unless it is really required!)
Thanks
My question is:
If a use a concentric heat exchanger to recover heat from flue gases to water, and a water tank ( with a vent connection) placed at a higher elevation than the heat exchanger, will it work? I mean, if I provide a pipe from the bottom of the tank to the inlet of the heat exchanger and the outlet pipe from the heat exchanger to the top of the tank. Is there a requirement of a pump? ( which I don't wan't unless it is really required!)
Thanks





RE: Heat recovery from engine exhaust while testing
For the water system to operate efficently, you will need to use a circulation pump.
Cooky.
RE: Heat recovery from engine exhaust while testing
If you do not want to vaporize water, a pump is required. But this does not mean that you don't have a water hammer concern, either. If the system pressure is below Psat at 400 C and you cannot maintain a certain minimum flow rate requirement, then water will vaporize. If your intent is to preheat the combustion air, why don't you forget about water and exchanger duty from exhaust gas to air itself?
RE: Heat recovery from engine exhaust while testing
RE: Heat recovery from engine exhaust while testing
Typical engine application use the jacket water in series with a heat exchanger to recover heat out of the exhaust gas flow.
Basically what you are looking for is called an economizer.
RE: Heat recovery from engine exhaust while testing
Waste heat boilers for steam or hot water are available in many sizes from 100,000btu/hr absobtion to...bigger HRSG's,
on smaller unitsthehorizontal (scotch type is more effective)and less expensive. email engine heat output details to generalblr1@netzero.net
ER
RE: Heat recovery from engine exhaust while testing
Make sure the hot water from the exchanger enters towards the top of the elevated tank, but submerged, and the cold water feed is from the bottom of the tank. Size the lines according to the density difference, friction/inertial loss and circulation rate. Some like to insulate the hot riser and leave the cold downcomer bare. No pump required. No vaporization required. You could dispense with the tank and make the tank and exchanger in one if you liked.
a concetric exchanger wont pick up much heat though; your will need multi tubes.
As for the economics, thats another question.
Cheers
Steve
RE: Heat recovery from engine exhaust while testing
The engineering manager was more worried about safety and insisted on having a circulation pump. So, a forced circulation system is being fabricated.
Thanks once again!
RE: Heat recovery from engine exhaust while testing