Hot well size

[DetroiTug]

Running two noncondensing systems, I'm not understanding the concern with hotwell temperature. Other than removing some oxygen from the water.
My systems don't have hot wells and the feedwater starts out at ambient temperature. To ensure better temperatures at feedwater introduction, this is done through feedwater heaters, The US navy used around five feedwater heaters.

One could make a condenser with zone partitions to regulate the amount of condensing and temperature drop going on, but that really would be really complicated with varying demand.

If you simply want to raise the hotwell temp: On my steam car the water tank goes around the boiler about half the circumference, the water stay about 120 degrees. A hotwell could be fashioned in that manner. Or experiment with cutting down the size/surface area of the condenser.

If none of this applies, please disregard

-Ron

[Lopez Mike]

As I'm sure you are aware, there are penalties for running a non-condensing system. Besides putting really dubious water in your boiler, the efficiency penalty is significant. Whether you dump it straight in or heat it up first, you are expending energy heating it.

As you say, oxygen retention is well worth thinking about but not letting the condensed exhaust cool down more than necessary is a more my goal. If I could figure out a way to pump it without cavitation, it would be great to put it back in at the temperature of the engine exhaust.

I have pretty much decided to put aside schemes to reduce the volume of the hot well. I'm still plotting on a good way to insulate at least the sides and bottom of it and not have it look like hell but I think that I will make it a priority to sort out the bits for an exhaust feed water heater to be plumbed in right after the pump.

With any luck I will find that I can, indeed, reduce the size of my condenser. It's only a hunk of 5/8" copper pipe perhaps five feet long and rather rudely built at that. If I were a bit more of a fanatic I would have some more sophisticated construction like two pipes in parallel such that I could switch in two when running hard. Or, as some do, have an condenser inside the boat with a coolant pump and all that. Not likely given my proclivities for keeping things simple!

[Mike Rometer]

Mike, simple, we all like. How about fitting a lenth of foam domestic pipe insulation over part of your condenser? You could shorten or extend it as required very easily. It would let you get a handle on how much alteration is required. I suspect it might even become semi-permanent..

[Lopez Mike]

Good idea. Especially since I trailer the boat.

I will have to be careful not to run the engine more than a few seconds on the trailer before launching lest I melt the pipe insulation. All of the launching ramps near me have the dock far enough from the ramp that I need to be able to steam before I back the boat down. Dumb.

So here's a theoretical question. If I do a trial insulation of the condenser will it make any difference whether I insulate the front half or the rear half. I'm thinking that I should insulate the rear half as then I'm less likely to melt the foam. The uninsulated front half will have cooled down the condensate more before it gets to the insulated part.

[dhic001]

Mike,
You could antifoul a section of the condenser to help cut down on the cooling effect. One of the boats I work with had the condenser antifouled, and after a very long voyage with almost boiler water coming back to the hotwell (and very little vacuum), I spent a few hours under the boat removing the antifoul. The change was dramatic.
Daniel

[Mike Rometer]

So here's a theoretical question. If I do a trial insulation of the condenser will it make any difference whether I insulate the front half or the rear half. I'm thinking that I should insulate the rear half as then I'm less likely to melt the foam. The uninsulated front half will have cooled down the condensate more before it gets to the insulated part.

Probably best at the back, but once in the water that should keep the whole thing cool enough.

Next option could be a narrower condenser tube, down from 5/8" to 1/2", reducing the surface area.

[Mike Cole]

Mike, simple, we all like. How about fitting a lenth of foam domestic pipe insulation over part of your condenser? You could shorten or extend it as required very easily. It would let you get a handle on how much alteration is required. I suspect it might even become semi-permanent..

I have been following this thread as my return to the hot well is cold , will be trying this for the next outing
Thanks

Mike

[DetroiTug]

Quote: "there are penalties for running a non-condensing system. Besides putting really dubious water in your boiler, the efficiency penalty is significant. Whether you dump it straight in or heat it up first, you are expending energy heating it."

It would seem that way, but if one looks at how they are implemented, there is actually a performance boost with exhaust feedwater heaters in addition to the advantage of hot feedwater. Not much is free with anything, but flue and exhaust feedwater heaters are free to operate, owing to the fact that steam engines ran without them are very inefficient - lots of extra heat to play with. The flue feedwater heater or economizer is simply collecting heat that would normally be vented to atmosphere. In the case of the exhaust feedwater heater, it acts much like a condenser and drops the steam back pressure on the engine exhaust thereby providing some performance boost.

-Ron

[Lopez Mike]

All of those arguments apply to condensing systems as well. And it still doesn't help with feed water of unknown properties.

And yes, an exhaust feed water heater is the way to go. Mine needs some expert brazing and is going over to the welder this week. Then it's just some plumbing.

I need the gains. When I try to go more than ten or fifteen miles I can't see over the bags of wood!

[cyberbadger]

And it still doesn't help with feed water of unknown properties.

If I can drink it, I call it good enough for my boiler to drink.
-CB