MERM Error?

[navyasw02]

I was trying to work a 6MS MD #78 and I think I found an error in the MERM regarding the NTU Method equations. I think eq 36.81 and 36.82 are reversed, meaning that 36.81 where it says Cmin = Ccold should be for Cmin = Chot. Same goes for 36.82, Cmin = Ccold. Otherwise, the C terms would cancel in the equations.

Can anybody else verify that? I just want to make sure I'm not messing something up.

 

[Sschell]

which edition do you have? mine (12th edition) appears to be correct:

36.81 (Cmin=Ccold):

[Chot(Thot,in-Thot,out)]/[Cmin (Thot,in-Tcold,in)]

 

[navyasw02]

which edition do you have? mine (12th edition) appears to be correct:
36.81 (Cmin=Ccold):

[Chot(Thot,in-Thot,out)]/[Cmin (Thot,in-Tcold,in)]

Weird, I have the 12th edition also and mine's reversed. My 36.81 is:

Cmin = Ccold

E = Ccold(Tcold out - Tcold in) / Cmin(Thot,in - Tcold, in). If Cmin = Ccold, it would just simplify to (Tcoldout-Tcoldin)/(Thotin-Tcoldin) which is not correct.

Your version is correct. That's really odd that the same edition can have different eqns.

 

[Sschell]

Quick somebody call Lindeburg!

 

[navyasw02]

Quick somebody call Lindeburg!

Oh I did. I already informed the state board as well.

 

[Relvinim]

which edition do you have? mine (12th edition) appears to be correct:
36.81 (Cmin=Ccold):

[Chot(Thot,in-Thot,out)]/[Cmin (Thot,in-Tcold,in)]

Weird, I have the 12th edition also and mine's reversed. My 36.81 is:

Cmin = Ccold

E = Ccold(Tcold out - Tcold in) / Cmin(Thot,in - Tcold, in). If Cmin = Ccold, it would just simplify to (Tcoldout-Tcoldin)/(Thotin-Tcoldin) which is not correct.

Your version is correct. That's really odd that the same edition can have different eqns.

My edition (12th) has the same error as yours. Thanks for bringing this up because i thought I was losing my mind.