You want the freezer to convert 10.6 kg of water at 21.0°C to 10.6 kg of ice at −8.8°C in 2.00 h. But, in order to keep your electric bill down, you want the power rating of the freezer to stay below 100 W. From these requirements, you determine the minimum COP of the freezer that will satisfy your needs. (Consider that the specific heat of water is 4,186 J/(kg · °C), the specific heat of ice is 2,090 J/(kg · °C), the latent heat of fusion of water is 3.33 ✕ 105 J/kg, and the latent heat of vaporization of water is 2.26 ✕ 106 J/kg.) Find the coefficient of performance (COP)
Latent heat and phase change
A physical process in which a conversion among the basic states or phases of matter, i.e., solid, liquid, and gas takes place under the effect of a certain temperature and pressure is referred to as a phase change. Generally, the phase change of a substance occurs when heat transfer takes place between the substance and its surroundings. Based on the direction in which heat transfer takes place, different types of phase changes can occur.
Triple Point of Water
The branch of physics in which observer deals with temperature related properties is called thermodynamics.
Boiling Point of Water
Everyday examples of boiling is, boiling milk, heating water. One would have observed that when we heat water it goes through various stages and at one point bubbles show in water, and water keeps splashing with bubbles bursting, we in layman terms say that water is boiling.
Freezing Point of Water
In general, the freezing point of water is 0° Celsius, or 32° Fahrenheit. This is the temperature at which water will ordinarily change from its liquid state to its solid state (ice). However, there are certain conditions that can affect the freezing point of water. For example, a liquid may be supercooled or contain impurities so that it does not freeze at the ordinary freezing point.
You wish to buy a new freezer for your basement. The primary use of the freezer will be to prepare ice for family parties. You have a very large family, with grandparents, parents, sisters, brothers, uncles, aunts, cousins, nephews, nieces, and grandchildren. As a result, family birthday parties are held every couple of weeks, and you need lots of ice for drinks. You want the freezer to convert 10.6 kg of water at 21.0°C to 10.6 kg of ice at −8.8°C in 2.00 h. But, in order to keep your electric bill down, you want the power rating of the freezer to stay below 100 W. From these requirements, you determine the minimum COP of the freezer that will satisfy your needs. (Consider that the specific heat of water is 4,186 J/(kg · °C), the specific heat of ice is 2,090 J/(kg · °C), the latent heat of fusion of water is 3.33 ✕ 105 J/kg, and the latent heat of vaporization of water is 2.26 ✕ 106 J/kg.) Find the coefficient of performance (COP).
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