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2. For next time:Class projects due Wednesday, December 3, 2003.Outline:Refrigeration cycleIdealized cycle devicesExampleImportant points:Distinguish between heat pumps and refrigeratorsKnow what devices make up the refrigeration cycle.. 3. Refrigeration affects many areas of your life. The
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1. 1 Lec 27: Refrigeration
2. 2 For next time:
Class projects due Wednesday, December 3, 2003.
Outline:
Refrigeration cycle
Idealized cycle devices
Example
Important points:
Distinguish between heat pumps and refrigerators
Know what devices make up the refrigeration cycle.
3. 3 Refrigeration affects many areas of your life The obvious:
Refrigerator/Freezers allow food preservation
Air conditioning makes Texas inhabitable between July 4 and mid-September
Refrigerated fishing boats allow preservation of catch
Refrigerated trucks are used to ship fruits/meats
Refrigeration makes possible medical procedures that call for lowering body temperatures
4. 4 What we call a refrigeration cycle depends on its function
5. 5 Schematic of the cycle
6. 6 Four processes in cycle Isentropic compression (1 to 2)
Constant pressure condensation (2 to 3)
Isenhalpic expansion (3 to 4)
Constant pressure evaporation (4 to 1)
7. 7 Refrigeration cycles are often displayed on pressure-enthalpy diagrams
8. 8 Performance of refrigeration cycles is measured by the Coefficient of Performance
9. 9 COP for heat pumps:
10. 10 TEAMPLAY
11. 11 TEAMPLAY Show that the performance of a heat pump and a refrigerator are related by the expression COPHP = COPR + 1.
12. 12 Simple view of household refrigerator
13. 13 Heat Pump Heats a House in Winter and Cools it in Summer
14. 14 TEAMPLAY
15. 15 TEAMPLAY