Counter flow heat exchanger lab

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Discussion Overview

The discussion revolves around the assumptions and calculations related to a counter flow heat exchanger in a lab setting. Participants are exploring the validity of the assumption that well-insulated heat exchangers are adiabatic, as well as the necessary calculations to analyze heat transfer between hot and cold fluids.

Discussion Character

  • Homework-related
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant questions the validity of assuming that a well-insulated heat exchanger is adiabatic, suggesting that heat energy in the hot fluid should equal the heat gained by the cold fluid.
  • Another participant emphasizes the need to calculate the heat lost by the hot fluid and the heat gained by the cold fluid, noting that discrepancies may indicate losses in the system.
  • A participant requests clarification on which equations to use for the calculations involved in the heat exchanger analysis.
  • There is a prompt for discussion about the equations that describe total heat gained or lost by a body, along with a request for clarification on the units of various quantities mentioned in the problem.

Areas of Agreement / Disagreement

Participants appear to have differing views on the assumption of adiabatic conditions, with some suggesting it may not hold true based on expected calculations. The discussion remains unresolved regarding the specific equations to use and the implications of potential heat losses.

Contextual Notes

Participants have not provided specific equations or detailed calculations, and there are mentions of missing units for various quantities, which may affect the clarity of the discussion.

azzamut
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Homework Statement


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.


Homework 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





The Attempt at a Solution




can someone point me in the right direction with this question thanks
 
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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.
 
any equations to use?
 
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)?
 

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