Calculations of Refrigeration/Heat Pump Cycles

STUDENT
NAME:
TUTOR NAME: Prof R A Bickerton
PROGRAMME: B Eng / M Eng Mechanical Engineering MODULE CODE:
EGR3030M
MODULE
TITLE: Machines and Energy Conversion
SUBJECT: CALCULATIONS OF REFRIGERATION/HEAT PUMP CYCLES
COURSEWORK
TITLE:
ENGINEERING REPORT ON THE USE OF THERMODYNAMIC PRINCIPLES
TO CALCULATE CONDITIONS THROUGHOUT VAPOUR POWER CYCLES
COURSEWORK
WEIGHTING (%):
40% OF 25% FOR
COURSEWORK
(SEE LECTURE
ZER0)
Issue Date:
04/07/18
Due Date:
6/8/18
Feedback Date:
PERFORMANCE CRITERIA:
TARGETED LEARNING OUTCOMES
Technical report writing.
Mechanical & thermodynamic concepts of refrigerants and vapour power cycles
Application of thermodynamic principles
Use of vapour P-h diagrams.
Important Information – Please Read Before Completing Your Work
All students should submit their work by the date specified using the procedures specified in the Student Handbook.
An assessment that has been handed in after this deadline will be marked initially as if it had been handed in on
time, but the Board of Examiners will normally apply a lateness penalty.
Your attention is drawn to the Section on Academic Misconduct in the Student’s Handbook.
All work will be considered as individual unless collaboration is specifically requested, in which case this should be
explicitly acknowledged by the student within their submitted material.
Any queries that you may have on the requirements of this assessment should be e-mailed to . No queries will
be answered after respective submission dates.
You must ensure you retain a copy of your completed work prior to submission.
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COURSEWORK BRIEF:
EGR3030M
Assignment 4 re-sit Refrigeration
a) Draw the diagram for a simple refrigeration circuit identifying the 4 major constituents [4
marks]
The chemical compositions of refrigerant gasses have changed over the
years from Ammonia (R717) to fluorocarbon blends such as R134a, R
245fa and RF1234yf etc.
b) Using the P-h diagrams for the 4 refrigerants given below calculate the coefficient of
performance (CoP) when these are used as a refigerant between the following
temperatures.
Cold box -20°C outside temperature for the condenser 30°C
Assume a 5°C temperature (delta T) for both heat exhangers, evapourator
and condenser
[40 marks]
Comment on the differences in CoP and on the performance effects of
changing from NH4 to flurocarbons.
[1 mark]
c) A company wishes to use a refrigerator/ heat pump for food processing where an initial high
temperature heat exhanger is set to produce steam at 100⁰C. For this the condenser pressure is
set to give 105⁰C at heat exchager input and this pressure is then maintained in the normal air
condenser. The processed food is then to be chilled to -20°C
Assume a 5°C temperature (delta T) for all heat exhangers, steam
generator ( ie 105⁰C pressure setting) evapourator and condenser
Draw a modified refrigertion diagram shown this new configuration [5 marks]
Cold box -20°C, outside temperature for the condenser 30°C, steam
generator (105⁰C)
Using the P-h diagrams for the 4 refrigerants given below calculate the
coefficient of performance (CoP) for:-
i) The refigeration heat input
ii) The heat rejected for steam generation
iii) The remaining heat rejected by the condenser to atmosphere
[40 marks]
Pepare a short engineering report on your findings and explain how you
could improve design of the refigerator/heatpump system
[10 marks]
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Pressure enthapy R717 Ammonia NH4
Pressure enthalpy RF1234YF
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HAND IN OF REPORT AND ANY APPENDICES IE SPREADSHEET CALCULATIONS, SKETCHES
AND GRAPHS ETC NEEDS TO BE BY TURNITIN AS PER SCHOOL PROCEEDURES.
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