75 Questions
What does refrigeration aim to achieve in terms of temperature?
Extract heat from the space to maintain a lower temperature
Why is control of the environment essential for living and non-living subjects?
To adapt to unpredictable variations in the physical environment
Which variables are mentioned as important in the physical environment?
Temperature, humidity, pressure, and air motion
What is the main focus of refrigeration and air-conditioning?
To provide comfort by controlling environments
Why is adaptation to unpredictable variations challenging for living beings?
Efficiency becomes unfeasible
What is the literal meaning of refrigeration?
Production of cold confinement relative to surroundings
What is the precise meaning of refrigeration?
Cooling down a space
Why do food products spoil less at lower temperatures?
Due to increased molecular motion at lower temperatures
In the context of refrigeration, why is the volume of the space under consideration mentioned?
To explain why the temperature changes more in that space
Why is it uncomfortable to travel in a car during an Indian summer?
Because outside temperatures are very high
How does a refrigerator preserve perishable food products?
By throwing away unwanted heat from the food products
What role does a heat pump play in air-conditioned cars during winter?
It pumps heat into the car
Why does heat need to be supplied inside a car during winter driving in Delhi or Kanpur?
To increase the temperature inside the car
What is one of the primary reasons for using refrigerators in homes, canteens, and hotels?
To preserve perishable food products for a longer duration
Why is it necessary to keep food products at a lower temperature in refrigerators?
To prevent spoilage by reducing bacterial growth
How does refrigeration control the temperature of a space?
By reversing the operation and removing heat from a lower temperature space
What is the precise meaning of air conditioning?
Controlling temperature and humidity
Which parameter is considered most important in air conditioning?
Temperature
What is required for comfort according to the text?
Clean air and air motion
In which type of air conditioning is extra moisture typically removed from the space?
Summer air conditioning
What is added to spaces in winter air conditioning in cold places?
Humidity
What does industrial air conditioning include?
Air conditioning of photographic products
What role does air motion play in air conditioning according to the text?
It helps in temperature control
What additional parameter falls under the purview of air conditioning in some applications?
Control of air pressure
What aspect does refrigeration primarily focus on in air conditioning?
Temperature control
What kind of adjustments are made in industrial air conditioning compared to comfort air conditioning?
Different control parameters influenced
How can a refrigeration system be used as a heat pump?
By changing the direction of flow of the refrigerant
In which century did East Indians start producing ice by dissolving salt in water?
4th century A.D.
Who obtained the first British Patent related to refrigeration?
Thomas Hariss
What was the main working fluid used in Jacob Perkins' hand-operated refrigeration system?
Ether
Who developed the world's first installation of a refrigeration machine for brewery in 1860?
Dr. James Harrison
What did Dr. John Gorrie obtain a patent for in 1851?
Cold air machine for curing high fever
In what century did people start developing methods to produce ice artificially?
19th century
Which refrigeration system used ammonia and water in a vapor-absorption system developed by Ferdinand Carre?
Absorption system
What distinguishes heating operation from cooling operation according to some people?
Heating operation is not associated with refrigeration at all, cooling is.
Why is superheating of the suction vapour advisable in refrigeration and air-conditioning systems?
To ensure complete vaporization of the liquid in the evaporator
What serves as a means of actuating and modulating the capacity of the expansion valve in refrigeration systems?
Suction Vapour Superheat
For which refrigerant is the maximum Coefficient of Performance (COP) obtained with superheating of the suction vapour?
Freon 12
What is the effect of superheating on the specific volume of suction vapour?
Increase in specific volume
How does an increase in condenser pressure affect the refrigerating capacity and power consumption per ton of refrigeration?
Has no effect
What is the heat absorbed by the refrigerant during evaporation called?
Refrigerating effect
What is the formula for Coefficient of Performance (C.O.P.) for a refrigerating system?
(Refrigerating effect) / (Work done)
What happens to the Coefficient of Performance (C.O.P.) when the suction pressure decreases?
Decreases
What effect does an increase in discharge pressure have on compressor work and refrigeration effect?
Increases compressor work, decreases refrigeration effect
What happens to the refrigerating capacity when the evaporator pressure decreases?
Decreases
How does a decrease in evaporator temperature affect the specific volume of suction vapour?
Increase
What is the impact of increasing the condenser pressure on refrigerating capacity and power consumption?
Decreases refrigerating capacity, increases power consumption
What is the relationship between pressure ratio and volumetric efficiency?
Pressure ratio increases with volumetric efficiency
What factor influences power consumption due to increased mass flow in a refrigeration system?
Decreased refrigerating capacity
How does a decrease in evaporator temperature impact the pressure ratio within a system?
Increases the pressure ratio
What was the significant development in refrigeration systems after the 1920s?
Invention of chlorfluor hydrocarbons
Which industry saw stagnation in using NH3 and SO2 as refrigerants around 1930?
Refrigeration industry
What does industrial air conditioning aim to provide for workers?
Comfort in hostile environments
What is the primary focus of comfort air conditioning in buildings?
Creating comfortable conditions for occupants
Why did the refrigeration industry see extensive diversification after the 1920s?
Due to the development of new chlorfluor hydrocarbons
What was an important advantage of chlorfluor carbons over NH3 and SO2 as refrigerants?
Non-toxic properties
In which industry did the invention of new refrigerants take place around 1930?
GE Corporation of USA
What is the primary reason for the development of commercial units utilizing waste heat or solar energy?
"Predicted energy crisis in the future"
What is the main purpose of the evaporator in a vapour compression refrigeration system?
To evaporate the liquid-vapour refrigerant at low pressure and temperature
What is the purpose of the receiver in a vapour compression refrigeration system?
To store the condensed liquid refrigerant
During which process in the cycle is the liquid refrigerant expanded by throttling through the expansion valve?
Expansion process
What happens to the high-pressure and high-temperature vapor refrigerant in the condenser of a refrigeration system?
It is cooled and condensed
What is the function of the expansion valve in a vapour compression refrigeration system?
To allow the liquid refrigerant to pass at a controlled rate
What is the purpose of the condenser in a vapour compression refrigeration system?
To cool and condense the refrigerant
Which part of a vapour compression refrigeration system is responsible for compressing the low pressure and low temperature vapor refrigerant?
Compressor
What does the evaporator of a vapour compression system do with regard to heat?
Absorbs latent heat of vaporization from its surroundings.
Which process in the vapour compression cycle involves changing high-pressure vapor into liquid form?
Condensing Process
What is happening to the refrigerant during throttling through an expansion valve?
Changing phase without heat exchange.
Why is air conditioning important in computer rooms?
To prevent electronic components from overheating
What can happen if humidity is not properly controlled in printing processes?
Static electricity problems
Why are refrigeration and air conditioning crucial for the photographic products industry?
To prevent humidity-related damage to raw materials
In the context of precision metal parts manufacturing, why is air filtration important?
To minimize dust and maintain cleanliness
What is the main purpose of a vapour compression cycle in refrigeration systems?
To circulate and alternate condensing/evaporating refrigerants
How does proper air conditioning benefit textile plants?
By maintaining yarn flexibility and strength
What role does refrigeration play in food storage and distribution?
Extending the storage life of perishable items
Learn about the importance of the physical environment variables like temperature, humidity, pressure, and air motion and their impact on living and non-living beings. Explore how refrigeration plays a crucial role in maintaining suitable conditions for specific applications.
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