1. By: Trevor Stephens ME 340 4/7/2014

2.  Conventional Design  Cools via free convection  Fast Freezing Design  Cools via free convection plus conduction H20H20 Freezer Shelf Ice Tray Lining (Plastic) H20H20 Freezer Shelf Ice Tray Lining (Plastic) Conductive Base  Purpose: To determine experimentally if a conductive base around a conventional ice tray will cool water faster than a conventional ice tray by itself.

3.  Ice was used as the conductive base  Four thermocouples with LabQuest digital readout were used to measure transient temperature 1 st Thermocouple: Freezer Air Temperature 2 nd Thermocouple: Conductive Base (Ice) Temperature 3 rd Thermocouple: Water Temperature in Conventional Ice Tray Design 4 th Thermocouple: Water Temperature in Fast Freezing Ice Tray Design

5.  Approximated water as a sphere (r = 2.5 cm) experiencing free convection  Used lumped capacitance and transient conduction (1 term approximation)  Lumped capacitance has questionable validity (Bi = 0.103)  Transient conduction valid for t > 14.5 minutes (F 0 > 0.2 for t > 14.5 min.)  Neither method was extremely effective in modeling the experimental results because both ignored the conduction due to the freezer shelf.

6.  Combination of conduction and free convection contribute to cooling—model becomes much more complex.  Dimensions of experimental setup are given if future work on this analytical model is to be conducted. H20H20 Freezer ShelfIce Tray Lining (Plastic) Ice R 1 = 3.20 cm R 2 = 4.54 cm H 1 = 2.30 cm H 2 = 11.50 cm

7.  Using ice as a conductive base is not the best choice, but it showed potential in the fast freezing ice tray design.  Other experiments should be done with different conductive bases: aluminum, steel, other frozen liquids.  Current analytical model for conventional ice tray has several limitations Ignores conduction due to freezer shelf Freezer air was not constant (T ∞ ≠ constant) Water was not truly spherical shape  Future work is needed to develop accurate analytical models, especially with the fast freezing ice tray design.  Conclusion: The fast freezing ice tray design shows promise, but further work is necessary to develop a marketable product.