Homework Help: Counter flow heat exchanger lab

1. Nov 26, 2007

azzamut

1. The problem statement, all variables and given/known data
in practice is is assumed well insulated heat exchangers are adiabatic. With reference to this heat exchanger, carry out the necessary calculations and then give an opinion as to the validity of this assumption.

2. Relevant equations

Observation
Thotin 55.88, Thotmid 51.84 Thotout 22.47 Tcoldin 29.37 Tcoldmid Tcoldout 47.41
Hot water flow rate 2800 cold water flow rate 1750

internal tube external diameter 15mm wall thickness 0.7mm
outer tube external dia 22mm, wall thickness 0.9mm
insulation wall thickness 20mm
heat transmission length 1.5m
heat transmission area 0.067m squared

3. The attempt at a solution

can someone point me in the right direction with this question thanks

2. Nov 26, 2007

MechanicalMan

If it is well insulated and adiabatic (no heat transfer out of the system), then all of the heat energy in the hot fluid will be gained by the cold fluid.

Find the heat lost by the hot fluid and gained by the cold fluid. If they do not match up (which they won't), then talk about possible losses in the system.

3. Nov 26, 2007

azzamut

any equations to use?

4. Dec 2, 2007

Gokul43201

Staff Emeritus
What do you think? What are the equations that describe the total heat gained or lost by a body?

Also, what are the units on the various quantities in the question (you're missing some units)?