Efficiency loss going from low pressure steam to hot water

J. Besold

Our school has a 25 year old heating system that uses natural gas to create low pressure steam which is then passed through a heat exchanger to create hot water for heating. If the boiler is at 82% efficiency when producing low pressure steam what are the likely losses we are experiencing in efficiency when converting the low pressure steam to hot water? Thank you

Mike T., Swampeast MO

I may be wrong, but as long as you're returning the condensate back to the boiler for re-heating it shouldn't be too much. You'll have transmission loss of the steam to the HX, some jacket losses from the HX itself and transmission loss of the condensate back to the boiler.