microhydro
Civil/Environmental
- Sep 30, 2009
- 17
I'm extracting heat from a 37°F stream flowing at 220 gpm. I plan to use copper coils immersed in the open flow as an evaporator. Conventional wisdom suggests that I keep the evaporator temperature high enough to prevent icing. However, the limiting convection heat transfer coefficient is on the refrigerant side [23.4 BTU/(hr•ft^2•°R)]. The water side of the evaporator is much better[758 BTU/(hr•ft^2•°R)]. So, I'm thinking that I could run the evaporator much colder, say 0°F. My guess is that ice would form until an equilibrium between ice formation and ice melting occurs. Thus I would see much higher heat transfer with the larger delta T (37°F versus 6°F). Does anyone have ideas or experience with this?