SailNet Community - View Single Post - water flow GPM per HP of an engine?
View Single Post
  #9  
Old 05-05-2012
SlowButSteady's Avatar
SlowButSteady SlowButSteady is offline
Senior Slacker
 
Join Date: Feb 2010
Location: SoCal
Posts: 4,223
Thanks: 0
Thanked 17 Times in 15 Posts
Rep Power: 5
SlowButSteady is on a distinguished road
Re: water flow GPM per HP of an engine?

Here's a very rough estimate:

Twenty hp is about 15 kW. If we assume about 30% efficiency, the engine would need about a 50 kW input. The difference, 35 kW, ends up as heat (one way or another). Converting 35 kWHr to kcal we get about 30,000 kcal. It takes 1 kcal to raise the temperature of a liter of water 1˚C. If we set the intake water to 20˚C and the output water to 40˚C, each liter of water will conduct 20 kcal away from the system. So, getting rid of 30,000 kcal/hr will require 1500 l/hr = 25 l/min = 6.6 gal/min. Of course, the efficiency of the engine may be somewhat higher or lower; the water temps may be higher or lower; and we haven't accounted for the heat transfer from the engine to the air surrounding it (remember, your engine compartment heats up quite a bit, particularly with the engine running at or near full load). But that's my rough estimate.
__________________
Never forget them. Do something to prevent it from happening again.
Charlotte Bacon, Daniel Barden, Rachel Davino, Olivia Josephine Gay, Ana M. Marquez-Greene, Dylan Hockley, Dawn Hochsprung, Madeleine F. Hsu, Catherine V. Hubbard, Chase Kowalski, Jesse Lewis, James Mattioli , Grace McDonnell, Anne Marie Murphy, Emilie Parker, Jack Pinto, Noah Pozner, Caroline Previdi, Jessica Rekos, Avielle Richman, Lauren Rousseau, Mary Sherlach, Victoria Soto, Benjamin Wheeler, Allison N. Wyatt
Reply With Quote Share with Facebook