A mini-fridge needs to maintain a temperature of 277 K. The air outside the mini-fridge has...
A mini-fridge needs to maintain a temperature of 277 K. The air outside the mini-fridge has a temperature of 303 K. Every fifteen minutes, 2.88
Homework Answers
1a. Power output of compressor=[Heat transferred out of mini fridge-heat transferred into surrounding]/time
=[3.6*105-2.88*105]/[15*60]=80J/sec
2a. COP= [Heat transferred out of refrigerator]/[Heat transferred out of mini fridge-heat transferred into surrounding]
=2.88*105/[3.6*105-2.88*105]
=4
3a. COPrefrigerator=TH/TH-Tc=303/[303-277]=11.65
4a. Heat transferred out= COP*Power of compressor*time in sec
=11.65*80*15*60=8.39*105 J
1b. COP=TH/[TH-TC]=302/[302-291]=27.45
2b. Heat transferred into the house= Work done*(COP+1)=1300*(27.45+1)=36.990*103 J
3b. Heat transferred into the house= Work done*(COP+1)=1300*[4+1]=6.5*103 J
1C. COP=TH/[TH-TC]=302/[302-276]=11.62
2c. Heat transferred into the house= Work done*(COP+1)=1300*(11.62+1)=16.4*103 J
3c. Heat transferred into the house= Work done*(COP+1)=1300*[4+1]=6.5*103 J
Add Answer to:
A mini-fridge needs to maintain a
temperature of 277 K. The air outside the mini-fridge has...
An air conditioner is used to maintain a house at 400C when the temperature outside is...
An air conditioner is used to maintain a house at 400C when the temperature outside is 850C. The house gains heat through the walls and the windows at a rate of 2130kJ/kg/min, and heat generation rate within the house from people, lights and appliances amounts to 120kJ/min. Determine the minimum power required for the air conditioner and cost of its operation over a three month summer at a rate of $0.15Kw Hr.
A manufacturing building is being ventilated to maintain air temperature, air moisture levels and air quality....
A manufacturing building is being ventilated to maintain air temperature, air moisture levels and air quality. The following is known about the situation: • The desired inside conditions are 68°F db with a maximum of 60% RH. • The average outside conditions are 42°F db and 35°F wb. • The building has an overall heat loss factor of 454 BTU/(h·ºF) with a total volume of 76,000 ft3. • Inside the building, people and equipment generate sensible heat at a rate...
roblem #17: A hot drink is taken outside on a cold winter day when the air...
roblem #17: A hot drink is taken outside on a cold winter day when the air temperature is --9°C. According to a principle of physics called Newton's Law of Cooling, the temperature T (in degrees Celsius) of the drink 1 minutes after being taken outside is given by TI) = -9 + Ae where A and k are constants. (a) Suppose that the temperature of the drink is 88°C when it is taken outside. Find the value of the constant...
2. The temperature of the air in a room needs to be adjusted (from room temperature...
2. The temperature of the air in a room needs to be adjusted (from room temperature and pressure, 298 K and latm). The room is 10.0 m wide, 22.0 m deep, and 3.0 m high. The approximate constant pressure heat capacity of air is Cp 1.0 kJ/(K*kg)1. Assume the air in the room is an ideal gas. 2.1 What is the approximate mass of the air in the room? (Use molar volume and molar weight of air) 2.2 How much...
1.A Carnot air conditioner keeps the temperature in a house at 297 K on a day...
1.A Carnot air conditioner keeps the temperature in a house at 297 K on a day where the outside temperature is 311 K. What is the coefficient of performance of this air conditioner? 2.A Carnot engine has an efficiency of 22.0%. It is operating between two reserves at constant temperature that differ by 750C. What is the minimum temperature (TL) and the maximum temperature (TH)?
A thermometer is taken from an inside room to outside of the building where the air temperature is 5' F
#1). A thermometer is taken from an inside room to outside of the building where the air temperature is 5' F. After 1 minute, the thermometer reads 55° F and after 5 minutes, the thermometer reads 30°F. What was the initial temperature of the room?#2). A thermometer is removed from a room where the air temperature is 70°F to outside the building where the temperature is 10° F. After minute, the thermometer reads 50°F. What is the reading at t...
3. A cold storage facility is maintained at 20°F when the outside air temperature is 90°RF...
3. A cold storage facility is maintained at 20°F when the outside air temperature is 90°RF by an air conditioning unit operating as a cycle at steady state. The unit must remove 120,000 Btu/h continuously from the facility to maintain the required indoor temperature, and has a power input of 20 hp Determine: the actual coefficient of the air conditioning unit the minimum theoretical horsepower that would be required to operate a cooling unit under these conditions. (1hp 2545 Btu/h)...
1. Air in a thundercloud expands as it rises. If its initial temperature is 294 K...
1. Air in a thundercloud expands as it rises. If its initial temperature is 294 K and no energy is lost by thermal conduction on expansion, what is its temperature when the initial volume has tripled? 2.Fifteen identical particles have various speeds: one has a speed of 2.00 m/s, two have speeds of 3.00 m/s, three have speeds of 5.00 m/s, four have speeds of 6.00 m/s, three have speeds of 9.00 m/s, and two have speeds of 11.0 m/s.Find...
104. An air-water vapour mixture has a dry-bulb temperature of 333 K and a dew-point temperature...
104. An air-water vapour mixture has a dry-bulb temperature of 333 K and a dew-point temperature of 313 K. The total pressure is 101.3 kPa and the vapour pressure of water at 313 K is 7.3 kPa and that at 333 K is 19.91 kPa. The humidity of air expressed as kg of water vapour per kg of dry air is (a) 0.048 (b) 0.079 (c) 0.122 (d) 0.152
A piston-cylinder device contains 0.5 m3 air at 100 kPa and 1000 K. Because the outside...
A piston-cylinder device contains 0.5 m3 air at 100 kPa and 1000 K. Because the outside is cooler (at 300 K), the hot air starts losing heat to the surroundings and the volume of air starts decreasing. Over a certain period of time the volume is observed to shrink by 50%. The final temperature is lower or higher? Determine the boundary work transfer (absolute value). in KJ was W positive and Q negative? or what?
roblem #17: A hot drink is taken outside on a cold winter day when the air temperature is --9°C. According to a principle of physics called Newton's Law of Cooling, the temperature T (in degrees Celsius) of the drink 1 minutes after being taken outside is given by TI) = -9 + Ae where A and k are constants. (a) Suppose that the temperature of the drink is 88°C when it is taken outside. Find the value of the constant...
2. The temperature of the air in a room needs to be adjusted (from room temperature and pressure, 298 K and latm). The room is 10.0 m wide, 22.0 m deep, and 3.0 m high. The approximate constant pressure heat capacity of air is Cp 1.0 kJ/(K*kg)1. Assume the air in the room is an ideal gas. 2.1 What is the approximate mass of the air in the room? (Use molar volume and molar weight of air) 2.2 How much...
3. A cold storage facility is maintained at 20°F when the outside air temperature is 90°RF by an air conditioning unit operating as a cycle at steady state. The unit must remove 120,000 Btu/h continuously from the facility to maintain the required indoor temperature, and has a power input of 20 hp Determine: the actual coefficient of the air conditioning unit the minimum theoretical horsepower that would be required to operate a cooling unit under these conditions. (1hp 2545 Btu/h)...
104. An air-water vapour mixture has a dry-bulb temperature of 333 K and a dew-point temperature of 313 K. The total pressure is 101.3 kPa and the vapour pressure of water at 313 K is 7.3 kPa and that at 333 K is 19.91 kPa. The humidity of air expressed as kg of water vapour per kg of dry air is (a) 0.048 (b) 0.079 (c) 0.122 (d) 0.152
Most questions answered within 3 hours.
-
Where is the error in this code sequence?
String s1 = "Hello";
String s2 = "ello";...
asked 10 months ago -
Financial data for Joel de Paris, Inc., for last year
follow:
Joel de Paris, Inc.
Balance...
asked 10 months ago -
Consider this reaction:
Al2(SO4)3 (aq)+ BaCl3
(aq) Al2Cl6 (aq)- +
3BaSO4(s) . What is the...
asked 10 months ago -
Suppose that Savneet is considering increasing her
recent random sample from 20 car rentals to 40...
asked 10 months ago -
Trucks arrive at an unloading terminal at an average rate of 120
per hour.
Trucks arrive...
asked 10 months ago -
Why are methanol and ethanol completely soluble in water while
octanol is not very little soluble....
asked 10 months ago -
A facilities manager at a university reads in a research report
that the mean amount of...
asked 10 months ago -
When the CuSO4 is rehydrated by adding water to the anhydrous
compound, is this an endothermic...
asked 10 months ago -
A ray of sunlight is passing from diamond into crown glass; the
angle of incidence is...
asked 10 months ago -
A block of mass 0.249 kg is placed on top of a light, vertical
spring of...
asked 10 months ago -
how do the kidneys compensate in the presences of acidosis
a) trigger hyperventilate
b) reserve acid...
asked 10 months ago -
Question 501 pts
The rental rate of capital to the firm increases. Which of the
following...
asked 10 months ago