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...
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)...
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?
Over a period of time, a hot object cools to the temperature of the surrounding air....
Over a period of time, a hot object cools to the temperature of the surrounding air. This is described mathematically by Newton's Law of Cooling T=C+(To-C) e-K, where t is the time it takes for an object to cool from temperature To to temperature T, C is the surrounding air temperature, and k is a positive constant that is associated with the cooling object. A cake removed from the oven has a temperature of 210°F and is left to cool...
A halloon containing air has an initial temperature of 300 K. The baloon is heated and...
A halloon containing air has an initial temperature of 300 K. The baloon is heated and expands a polytropic process wit, n-(-2) until譨hits a rigid spherKal wire cage and can't expand any more. When the balloon first hits the 2 m' wire eage the conditions in the balloon are 1000 K and 200kPa. The heating then continues until finally the temperature in the balloon is 1200 K Wire Cage What is the mass of the air in the balloon?. 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
Over a period of time, a hot object cools to the temperature of the surrounding air. This is described mathematically by Newton's Law of Cooling T=C+(To-C) e-K, where t is the time it takes for an object to cool from temperature To to temperature T, C is the surrounding air temperature, and k is a positive constant that is associated with the cooling object. A cake removed from the oven has a temperature of 210°F and is left to cool...
A halloon containing air has an initial temperature of 300 K. The baloon is heated and expands a polytropic process wit, n-(-2) until譨hits a rigid spherKal wire cage and can't expand any more. When the balloon first hits the 2 m' wire eage the conditions in the balloon are 1000 K and 200kPa. The heating then continues until finally the temperature in the balloon is 1200 K Wire Cage What is the mass of the air in the balloon?. What...
Most questions answered within 3 hours.
-
A local
electronic company primarily manufactures four highly technical
telecommunication products. Each product must be processed...
asked 35 minutes ago -
•Describe the basic structure of collagen monomers •Explain how
amino acid composition of collagen contributes to...
asked 2 hours ago -
Compute the sample correlation coefficient
r for each of the following data sets.
(Use 3 decimal...
asked 2 hours ago -
5a. What are the advantages and disadvantages of Proxy ARP?
b. What is the TTL field...
asked 2 hours ago -
An ice cube (density = 900[kg/m3]) with a side length of
2.54[cm] is held by a...
asked 4 hours ago -
would you say that leaders in the international context are born
or made? That is, can...
asked 4 hours ago -
Instructions
Read the Digital Trends article "Solid state drives are speedier
than hard disk drives. Are...
asked 4 hours ago -
A multiple-choice test consists of 29 questions with possible
answers of a, b, c, d. Estimate...
asked 4 hours ago -
Question 1: Ethanol is the active ingredient of alcoholic
beverages. It is also s a possible...
asked 4 hours ago -
In the process of a simple distillation, the substances in the
still head tube are in...
asked 4 hours ago -
In a normal distribution with mean 3 and standard deviation of
7, what are the upper...
asked 5 hours ago -
A big block stone with mass M explodes and splits in two pieces
with mass 0.40M...
asked 5 hours ago