Question

What is the maximal coefficient of performance of a refrigerator which cools down 10 kg of...

What is the maximal coefficient of performance of a refrigerator which cools down 10 kg of water (and then ice) to -6?C. Upper heat source of this refrigerator is surroundings at constant temperature 21?C. Initially water is in equilibrium with surroundings. What is maximal coefficient of performance of heat pump operating in the same configuration. Specific heat of water, specific heat of ice, and latent heat of fusion are equal to 4.19KJ/kg/K, 2.1KJ/kg/K and 335 KJ/kg, respectively.

Engineering   Mechanical-Engineering   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

Water temperature = T1 = - 6 C = 267 K

Surroundings temperature = T2 = 21 C = 294 K

Maximum COP of Refrigerator= T1 / (T2 - T1) = 267 / (294-267) = 9.88

Maximum COP of a Heat pump operating between same temperature conditions is

COP of heat pump = T2 / T2 - T1 = 294 / (294-267) = 10.88

Since here we are asked to find the maximum COP of refrigerator and heat pump with given values of temperature, we should follow Carnot approach. There is nothing to do with Specific heat values given in the problem for finding Maximum COP's of refrigerator and heat pump.

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
The ice maker inside a refrigerator makes ice cubes at 0.0°C from water that is at...
The ice maker inside a refrigerator makes ice cubes at 0.0°C from water that is at 13.2°C when it first enters the ice maker. If this machine is rated at 224 W and has a 3.56 coefficient of performance, what is the maximum amount of ice it can produce in a 24 hourperiod without any interruption or stoppage? Assume that the ice maker works just like a refrigerator. The specific heat of water is 4184 J/(kg · °C), and the...
To change 25 kg of ice -10°C to steam 100°C, how much heat is required? The...
To change 25 kg of ice -10°C to steam 100°C, how much heat is required? The specific heat of water is 4.184 kJ/kg. K. The latent heat of fusion for water at 0°C is approximately 334 kJ/kg (or 80 cal/g), and the latent heat of vaporization at 100°C is about 2,230 kJ/kg (533 cal/g).
A 12kg block of ice at minus 6.5 degrees C is converted to steam/vapour at 100...
A 12kg block of ice at minus 6.5 degrees C is converted to steam/vapour at 100 degrees C in 5 hours. How many KW of heating is required? Given, Specific heat of ice = 2.04 KJ/kg Specific heat of water = 4.2 KJ/kg Latent heat of fusion of ice =335 Kg Latent heat of evaporation = 2256 KJ/kg
If you pour 0.600 kg of 20.0ºC water onto a 1.20-kg block of ice (which is...
If you pour 0.600 kg of 20.0ºC water onto a 1.20-kg block of ice (which is initially at 0 ºC), what is the final temperature? You may assume that the water cools so rapidly that effects of the surroundings are negligible. The specific heat of water is 4 186 J/(kg * ºC), the specific heat of ice is 2 090 J/(kg * ºC), and the heat of fusion of water is 334 x103 J/kg.
How much heat is needed to convert 10 kg of water at 30◦C to: (a) water...
How much heat is needed to convert 10 kg of water at 30◦C to: (a) water at 100◦C? (b) steam? (c) ice? Take: Specific heat capacity of water = 4.186 kJ/kg◦C Latent heat of vaporization of water = 2264 kJ/kg Latent heat of fusion of water = 333 kJ/kg.
I place an ice cube with a mass of 0.223 kg and a temperature of −35°C...
I place an ice cube with a mass of 0.223 kg and a temperature of −35°C is placed into an insulated aluminum container with a mass of 0.553 kg containing 0.452 kg of water. The water and the container are initially in thermal equilibrium at a temperature of 27°C. Assuming that no heat enters or leaves the system, what will the final temperature of the system be when it reaches equilibrium, and how much ice will be in the container...
A 25.0-g glass tumbler contains 200 mL of water at 24.0ºC. If two 15.0-g ice cubes,...
A 25.0-g glass tumbler contains 200 mL of water at 24.0ºC. If two 15.0-g ice cubes, each at a temperature of –3.00ºC, are dropped into the tumbler, what is the final temperature of the drink? Neglect any heat transfer between the tumbler and the room. (Specific heat of water and ice are 4.186 kJ/(kg K) and 2.05 kJ/(kg K), respectively. The latent heat of fusion of water is 333.5 kJ/kg. The specific heat of glass is 0.840 kJ/(kg K )....
How much heat is required to change m=1kg of ice at -6°C into water at 60°C?...
How much heat is required to change m=1kg of ice at -6°C into water at 60°C? cw= 4190 J/kg*K (specific heat of water), Lf= 333 kJ/kg (latent heat of fusion of ice), cice= 2100 J/kg*K
A cup of warm water (0.5 kg at 25*C) is poured into a large vat of...
A cup of warm water (0.5 kg at 25*C) is poured into a large vat of liquid nitrogen at 77K. The mixture is thermally insulated from the surrounding room. The following table of data may be relevant for this problem (all atmospheric pressure): Nitrogen Water Freezing Point(K) Boiling Point (K) 63 77 273 373 Specific Heat Capacity (J/kg.K) 1040 4186(water) 2108(ice) Latent Heat of Fusion(KJ/kg) Latent Heat of Vaporization (kJ/kg) 25.7 200 333 2260 (A) What will the final temperature...
Q3. A cube with side lengths of 2.91 cm is heated to a constant temperature of...
Q3. A cube with side lengths of 2.91 cm is heated to a constant temperature of 720 ◦C at the focal point inside of a parabolic reflector. This has the effect of directing all of the cube’s radiant energy toward a 3.92 kg pack of ice that is initially at −19.0 ◦C. If the emissivity of the cube is 0.466, how long does it take for the ice to completely vaporize? Use the following numbers in your calculation: • The...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT