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 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 What we call a refrigeration cycle depends on its function The objective of a refrigerator is to remove heat (QL) from the cold medium; the objective of a heat pump is to supply heat (QH) to a warm medium
15 TEAMPLAY If the evaporating pressure were reduced to 0.10 MPa in the previous problem, how would the following be affected (up, down, remain the same): Evaporating Temperature? Cooling capacity? Work input to the compressor? Explain why.