1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I am confused as to which streams I should use for the log mean temperature difference. I am pretty sure it should be the difference in temperature between the two streams on the same side, so I think it's (700-450)-(1100-960) / ln [(700-450)/(1100-960)], but I am not sure. The term wasn't well defined, and my search on wikipedia gave the definition as ''The LMTD is a logarithmic average of the temperature difference between the hot and cold streams at each end of the exchanger.'' This is too vague, which end of the exchanger??