It is commonly recommended that hot foods be cooled first to room temperature by simply waiting a while before they are put into the refrigerator to save energy. Despite this common sense recommendation, a person keeps cooking a large pan of stew twice a week and putting the pan into the refrigerator while it is still hot, thinking that the money saved is probably too little. The average mass of the pan and its contents is 5-kg. The average temperature of the kitchen is 20°C, and the average temperature of the food is 95°C when it is taken off the stove. The refrigerated space is maintained at 3°C, and the average specific heat of the food and the pan can be taken to be 3.9 kJ/kg-K. If the refrigerator has a coefficient of performance of 1.2 and the cost of electricity is Php 21.59 per kW-hr. Determine how much will be saved a year by waiting for the food to cool to room temperature before putting it into the refrigerator. Ans: Php 170.66

It is commonly recommended that hot foods be cooled first to room temperature by simply waiting a while before they are put into the refrigerator to save energy. Despite this common sense recommendation, a person keeps cooking a large pan of stew twice a week and putting the pan into the refrigerator while it is still hot, thinking that the money saved is probably too little. The average mass of the pan and its contents is 5-kg. The average temperature of the kitchen is 20°C, and the average temperature of the food is 95°C when it is taken off the stove. The refrigerated space is maintained at 3°C, and the average specific heat of the food and the pan can be taken to be 3.9 kJ/kg-K. If the refrigerator has a coefficient of performance of 1.2 and the cost of electricity is Php 21.59 per kW-hr. Determine how much will be saved a year by waiting for the food to cool to room temperature before putting it into the refrigerator. Ans: Php 170.66

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter3: Transient Heat Conduction

Section: Chapter Questions

Problem 3.12P

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