The Steamboating Forum

Forgive my ignorance, but i have to ask, does the condenser exhaust into the hot well? Or is it a closed system. Ive only been in one condensing boat and it discharged the condensate overboard.

Hey Johnp

The condenser is usually, but not always, evacuated by an air pump and the condensate is fed back into the hot well. The whole point of using a condenser in the first place is to recover the water for reuse. Maybe the boat of which you speak was discharging bilge water? Or maybe the condenser system was not finished or?

Scott

i ask about the discharge, he said he wasn't worried about recycling he just wanted the benefit of the vaccum.

The two major benefits of a condenser, condensate recovery, and engine performance increase with high vacuum exhaust conditions. A steam plant condenser system can have both features, or either one.

Condensing to recover condensate only will not require a vacuum pump (wet air pump) and condensate will be forced into the hotwell by a slight positive pressure in the condenser. The recovered condensate is nearly pure and oxygen free water, the best thing to feed into a boiler. HOWEVER if there is oil mixed with the condensate, it must be removed before feeding into the boiler. Oil feeding into a boiler is generally very bad, and needs to be avoided.
Separation of the oil from the condensate is often a very daunting task, virtually impossible unless pure (non-compounded, non-detergent) mineral or synthetic oil is used to lubricate the engine cylinders.

Condensing to reduce engine back pressure will require a vacuum pump (wet air pump) and condensate will be forced into the hotwell by this pump. The recovered condensate is nearly pure and oxygen free water, the best thing to feed into a boiler. HOWEVER if there is oil mixed with the condensate, often better to discard the condensate rather than risk the boiler contamination with oil. If this oil laden condensate is discharged overboard, then environmentally acceptable oil, or bio-degradable oil should be used.

As it is with all steam engine systems, a gain one place can result in losses in efficiency elsewhere. Instead of condensing for a vacuum only, it may be better to send the exhaust up the stack and create an induced draft for a hotter fire/higher steam output. Iron Chief exhausts up the stack and it is a marked improvement over exhausting through the hull/no induced draft. A good comparison would be a home heating woodstove and a forge.

-Ron