1005 unit 11,12,17
What process takes advantage of the fact that some chemicals have an affinity for other chemicals? Question content area bottom Part 1 A. Absorption process B. Refrigeration process C. Compression process D. Thermoelectric process
A
When comparing coil design between older, less efficient air conditioning systems and newer high-SEER air conditioning systems, the newer coils use _____ temperature and pressure difference than the older systems. Question content area bottom Part 1 A. Less B. Similar C. More D. None of the above
A
Where is evaporative cooling the most effective? Question content area bottom Part 1 A. Dry climates B. Soggy climates C. Humid climates D. Fertile climates
A
Which of the following are compatible with mineral oil? Question content area bottom Part 1 A. CFCs and HCFCs B. CFCs and HBFSs C. CFCs and HCFB D. HFCs and HGFH
A
Which of the following best describes what comprises a thermocouple device? Question content area bottom Part 1 A. It is comprised of two metal wires joined on both ends, but separated or insulated from each other in between. B. It is comprised of two metal wires joined on both ends. C. It is comprised of two metal wires separated or insulated from each other in between. D. It is comprised of two disconnected metal wires joined on both ends, separated or insulated from each other in betwe
A
Which of the following is a contaminant that is frequently found in refrigerant? Question content area bottom Part 1 A. Carbon B. Oil C. Chlorine D. Fluorine
A
Which of the following is not a type of compressor? Question content area bottom Part 1 A. Shell and coil B. Rotary C. Screw D. Reciprocating
A
Which of the following is the correct order of the components of a typical evaporative cooler? Question content area bottom Part 1 A. A water sump, a pump, wetted media, and a blower B. A pump, wetted media, a blower, and a water sump C. A pump, a blower, wetted media, and a water sump D. A wetted media, a blower, a pump, and a water sump
A
Which of the following refrigerant lines carries the high-pressure, hot, superheated gas from the compressor to the condenser? Question content area bottom Part 1 A. Discharge line B. Suction line C. Liquid line D. None of the above
A
Which oil does not have significant issues with material compatibility? Question content area bottom Part 1 A. Alkyl benzene B. Glycol-based oil C. Polyol ester D. Mineral oil
A
Which two refrigerant lines connect the inside and outside units of a split system? Question content area bottom Part 1 A. Suction line and liquid line B. Suction line and discharge line C. Suction line and refrigerant line D. Liquid line and discharge line
A
Why is boiling considered a cooling process? Question content area bottom Part 1 A. Boiling extracts heat from whatever it is touching. B. Boiling transfers the heat it touches to the atmosphere. C. Boiling requires pressure. D. Boiling requires condensation.
A
How does the compression system differ from the absorption system? Question content area bottom Part 1 A. The systems differ in how the water is transferred. B. The systems differ in how the low and high pressures are created. C. The systems differ in how the evaporator functions. D. The systems differ in how the generator functions.
B
A liquid receiver is used after the condenser on the _____ side. Question content area bottom Part 1 A. High B. Low C. Suction D. Bottom
A
A reciprocating compressor uses pistons in a cylinder. Question content area bottom Part 1 True False
A
Explain how an evaporative cooling system works. Question content area bottom Part 1 A. Water flows over media and air is pulled across the wetted media. Some of the water evaporates, cooling off the air. B. Water evaporates over wetted media to produce condensation. C. Liquid flows over media and water is pulled across the wetted media. Some of the water evaporates, cooling off the air. D. Air flows over media while water is pulled across the media. The air dissipates.
A
Explain the difference between a bubble point and a dew point. Question content area bottom Part 1 A. Bubble point is the temperature where small bubbles first start to form in saturated liquid; dew point is the temperature where small droplets of liquid first start to form in a saturated gas B. Bubble point is the temperature where small bubbles first start to form in superheated liquid; dew point is the temperature where small droplets of liquid first start to form in a superheated gas C. Bubble point is the temperature where small bubbles first start to form in saturated gas; dew point is the temperature where small droplets of liquid first start to form in a saturated liquid D. Bubble point is the temperature where small bubbles first start to form in sub-cooled liquid; dew point is the temperature where small droplets of liquid first start to form in a subcooled gas
A
How are refrigerants with a lower toxicity labeled? Question content area bottom Part 1 A. Letter "D" B. Letter "C" C. Letter "A" D. Letter "B"
A
Question content area top Part 1 Compounds consisting of carbon atoms tied to each other in chains surrounded by hydrogen atoms are considered: Question content area bottom Part 1 A. Hydrocarbons. B. Chemical compounds. C. Molecular carbons. D. Elemental chains.
A
Question content area top Part 1 How can a liquid's boiling point be lowered? Question content area bottom Part 1 A. By lowering the pressure B. By lowering the humidity C. By raising the humidity D. By raising the pressure
A
Question content area top Part 1 How is heat absorbed from the space being cooled? Question content area bottom Part 1 A. By keeping the refrigerant at a low pressure and temperature B. By keeping the refrigerant at a high pressure and the temperature low C. Heat is absorbed by keeping the refrigerant at a low pressure and the temperature high D. Heat is absorbed by keeping the refrigerant at a high pressure and the temperature high
A
Question content area top Part 1 What are the two cycles that make an absorption system work? Question content area bottom Part 1 A. The refrigeration cycle and the solution cycle B. The heating cycle and the cooling cycle C. The defrost cycle and the solution cycle D. The refrigeration cycle and the duty cycle
A
Question content area top Part 1 What type of system most effectively uses thermoelectric refrigeration? Question content area bottom Part 1 A. Electronic systems B. Home air conditioning systems C. Large restaurant refrigerators D. Large manufacturing cooling plants
A
The basic refrigeration cycle system consists of how many components? Question content area bottom Part 1 A. 4 B. 1 C. 3 D. 2
A
The four major components of the compression refrigeration cycle, listed in order, are: Question content area bottom Part 1 A. Compressor, condenser, metering device, and evaporator. B. Metering device, condenser, compressor, and evaporator. C. Evaporator, compressor, metering device, and condenser. D. Condenser, compressor, metering device, and evaporator.
A
The refrigerant is a high-pressure, warm, _____________ liquid at the inlet of the metering device. The state of the refrigerant is 100% liquid. Question content area bottom Part 1 A. Subcooled B. Saturated C. Vaporized D. Superheated
A
The refrigerant is saturated in most of the evaporator except for the very end. It is also saturated in most of the condenser except for the very beginning and very end. Question content area bottom Part 1 True False
A
The refrigerant is subcooled from the _____ of the condenser up to the metering device. Question content area bottom Part 1 A. Outlet B. Middle C. End D. Top
A
The refrigeration cycle is a practical application of the gas laws. Question content area bottom Part 1 True False
A
The refrigeration cycle is called a cycle because it is a circle. Question content area bottom Part 1 True False
A
The _____ picked up in the evaporator + the _____ of compression = the _____ rejected in the condenser. Question content area bottom Part 1 A. Heat B. Vapor C. Liquid D. Temperature
A
The ___________ is a mechanical device for pumping refrigerant vapor from the low-pressure evaporator to the high-pressure condenser. Question content area bottom Part 1 A. Compressor B. Evaporator C. Condenser D. Coil
A
What chemical family is the basic building block for most modern refrigerants? Question content area bottom Part 1 A. Hydrocarbons B. Carbons C. Hydrogens D. Halogens
A
What is a halogenated refrigerant? Question content area bottom Part 1 A. A refrigerant that has been made by replacing hydrogen atoms on hydrocarbon molecules with chemicals from the halogen family of chemicals B. A refrigerant that has been made by assigning hydrogen atoms on hydrocarbon molecules with new atoms C. A refrigerant that has been made by adding hydrogen atoms on hydrocarbon molecules D. A refrigerant that has been made by discarding hydrogen atoms on hydrocarbon molecules
A
What is the device that rejects heat from the refrigeration system? Question content area bottom Part 1 A. Condenser B. Evaporator C. Compressor D. None of the above
A
A screw compressor compresses gas by squeezing it between the roller and a spring-loaded vane. Question content area bottom Part 1 True False
B
EPA regulations for preventing the release of ozone-depleting substances divide refrigerants into four categories based on what property? Question content area bottom Part 1 A. Physical state B. Operating pressure C. Chemical composition D. Operating temperature
B
Each refrigerant is assigned a safety rating consisting of a letter and a: Question content area bottom Part 1 A. Symbol. B. Number. C. Word. D. Code.
B
Refrigerant is superheated from the _____ of the evaporator. Question content area bottom Part 1 A. Middle B. End C. Top D. Beginning
B
Superheating the refrigerant leaving the evaporator ensures that _____ liquid enters the compressor. Question content area bottom Part 1 A. Little B. No C. All D. None of the above
B
The basic refrigeration cycle system consists of how many components? Question content area bottom Part 1 A. 3 B. 4 C. 2 D. 1
B
The only two chemicals that should be inside a refrigeration system are refrigerant and: Question content area bottom Part 1 A. Refrigeration carbons. B. Refrigeration oil. C. Compressor liquid. D. Evaporator liquid.
B
The refrigerant is __________________ as it enters the condenser. Question content area bottom Part 1 A. Subcooled B. Superheated C. Vaporized D. Saturated
B
There are three types of air-cooled condensers. Which of the following is not an air-cooled condenser? Question content area bottom Part 1 A. Induced draft B. Reduced draft C. Forced draft D. Natural draft
B
There are three types of water-cooled condensers. Question content area bottom Part 1 True False
B
The ______________ is the component that cools by absorbing heat from its surroundings. Question content area bottom Part 1 A. Condenser B. Evaporator C. Compressor D. Expansion device
B
The _______________ carries the high-pressure, warm, subcooled liquid from the condenser to the metering device. Question content area bottom Part 1 A. Suction line B. Liquid line C. Discharge line D. None of the above
B
What components are responsible for maintaining the high and low pressures in a compression refrigeration system? Question content area bottom Part 1 A. The condenser and metering device B. The compressor and metering device C. The metering device and evaporator D. The compressor and evaporator
B
What does the refrigerant number assigned to single-component halogenated refrigerants describe? Question content area bottom Part 1 A. The number of isomers in the refrigerant molecule B. The number of each type of atom in the refrigerant molecule C. The number of bonds in the refrigerant molecule D. The number of chlorine atoms in the refrigerant molecule
B
What is the difference between a compound and a zeotrope? Question content area bottom Part 1 A. A compound is a chemical composed of two or more hydrocarbons with its own unique physical and chemical properties; zeotropes are mixtures of two or more hydrocarbons that are not chemically bonded B. A compound is a new chemical composed of two or more chemicals with its own unique physical and chemical properties; zeotropes are mixtures of two or more chemicals that are not chemically bonded C. A compound is a new chemical composed of two or more molecules with its own unique chemical properties; zoetrope's are mixtures of two or more molecules that are not bonded D. A compound is a mixture of two or more chemicals that are not chemically bonded; zoetrope's are new chemicals composed of two or more chemicals with its own unique physical and chemical properties
B
What is the purpose of refrigerant in a refrigeration system? Question content area bottom Part 1 A. To power the system B. To transfer heat C. To lubricate D. To absorb heat
B
What is the purpose of refrigeration? Question content area bottom Part 1 A. To remove frost from objectionable areas B. To move heat from where it is not wanted to where it is unobjectionable or can be used C. To move heat in a circular path D. To remove heat entirely
B
When the compressor squeezes gas into a small volume where does the superheated gas travel next? Question content area bottom Part 1 A. To the expansion device B. To the condenser C. To the evaporator D. Stays in the compressor
B
Which components are responsible for maintaining the high and low pressures in a compression refrigeration system? Question content area bottom Part 1 A. Condenser and metering device B. Compressor and metering device C. Evaporator and metering device D. Evaporator and compressor
B
Which of the following is not one of the three common refrigerant lines found on compression systems? Question content area bottom Part 1 A. Discharge line B. Split system line C. Liquid line D. Suction line
B
Which of the following is not true of refrigerant? Question content area bottom Part 1 A. Refrigerants absorb heat by evaporating from a liquid to a vapor. B. Refrigerants absorb heat by condensing from a vapor back to a liquid. C. Refrigerant is the fluid used in a refrigeration system for transferring heat. D. Refrigerants in mechanical refrigeration systems change their physical state.
B
Which of the following is true of refrigerants heat transfer ability? Question content area bottom Part 1 A. Refrigerants absorb the most heat when condensing from a liquid to a vapor. B. Refrigerants absorb the most heat when evaporating from a liquid to a vapor. C. Refrigerants absorb the most heat when condensing from a vapor to a liquid. D. Refrigerants absorb the most heat when its temperature changes.
B
Which of the following systems uses heat and the process of absorption to move refrigerant? Question content area bottom Part 1 A. Evaporative system B. Absorption system C. Mechanical compression system D. Thermoelectric system
B
Which refrigerant line is the larger of the two lines going to the compressor? Question content area bottom Part 1 A. Discharge line B. Suction line C. Compression line D. Liquid line
B
A much larger amount of heat can be absorbed and transferred when a liquid is vaporized to a gas, due to the advantage of a refrigerant's: Question content area bottom Part 1 A. Specific heat characteristics. B. Sensible cooling. C. Latent heat characteristics. D. Cooling operations
C
An accumulator is located on the _____ side just before the compressor. Question content area bottom Part 1 A. Bottom B. Suction C. Low D. High
C
Explain how a thermoelectric refrigeration system works. Question content area bottom Part 1 A. AC current passes through a thermocouple made of two dissimilar metals; one junction absorbs heat and the other releases heat B. DC current passes through a thermocouple made of metal to absorb and release heat C. DC current passes through a thermocouple made of two dissimilar metals; one junction absorbs heat and the other releases heat D. DC current passes through a compressor made of two m
C
In which part during the absorption cycle is heat is absorbed? Question content area bottom Part 1 A. The condenser B. The solution pump C. The evaporator D. The generator
C
Question content area top Part 1 Where does the heat required to evaporate the water in evaporative cooling originate? Question content area bottom Part 1 A. The water B. The sump C. The air D. The blower
C
Question content area top Part 1 Why should the refrigerant in a system be the first component determined? Question content area bottom Part 1 A. It has to be ordered in advance of all other components. B. It is governed by the law. C. Its chemical and physical properties will play a large role in selecting all other components. D. Its operating temperature needs to be found before the refrigeration system will operate.
C
The refrigerant leaving the compressor is superheated as it enters the: Question content area bottom Part 1 A. Evaporator. B. Coil. C. Condenser. D. Metering device.
C
There are two large classes of metering devices. Which type of metering device provides the most efficient operation? Question content area bottom Part 1 A. Light meter B. Double pipe C. Thermostatic expansion valve D. Fixed restriction
C
The _____________ carries the low-pressure, cool, superheated vapor from the evaporator coil to the compressor inlet. Question content area bottom Part 1 A. Liquid line B. Discharge line C. Suction line D. None of the above
C
What action occurs when a liquid boils? Question content area bottom Part 1 A. It expels a large amount of heat. B. It lowers the pressure of the air around it. C. It absorbs a large amount of heat. D. It raises the pressure of the air around it.
C
What acts as the refrigerant in a thermoelectric refrigeration system? Question content area bottom Part 1 A. Air B. Heat exchanger C. Electric current D. Water
C
What does an air conditioner do with the heat in a house? Question content area bottom Part 1 A. It increases the humidity in the house. B. It converts the heat into cold air. C. It moves the heat from inside the house to outside the house. D. It circulates the heat in the house.
C
What is the advantage of the Maisotsenko Cycle? Question content area bottom Part 1 A. It reduces more air pressure B. It improves overall system efficiency C. It reduces the air temperature more than standard evaporative coolers D. It reduces the relative humidity
C
What is the composition of a refrigerant labeled HFC-134a? Question content area bottom Part 1 A. Two hydrogen atom, two fluorine atoms, four chlorine atoms B. One carbon atom, three hydrogen atoms, four fluorine atoms C. Two carbon atoms, two hydrogen atoms, four fluorine atoms D. One hydrogen atom, three fluorine atoms, four chlorine atoms
C
What organization has established the number designation for refrigerants? Question content area bottom Part 1 A. AHRI B. ASME C. ASHRAE D. ASES
C
When an azeotropic mixture boils, components of the mixture will ____. Question content area bottom Part 1 A. The temperature will rise B. You cannot boil an azeotrope C. Behave as a single compound D. Separate into their original components
C
Which is not considered a principle of the compression refrigeration cycle? Question content area bottom Part 1 A. Gasses give off large amounts of heat when they condense to a liquid. B. Heat travels from hot to cold. C. The temperature at which a liquid boils is controlled by its area. D. Liquids absorb large amounts of heat when they boil off to a gas.
C
Which of the following best describes the Peltier effect? Question content area bottom Part 1 A. The Peltier effect states that small amounts of electrical current flow through wires at different junction points. B. The Peltier effect states that small amounts of electrical current flows through wires if the two junction points are at different temperatures. C. The Peltier effect states that if a current is imposed on the thermocouple, one end will heat up and the other will cool off, as reversing the direction of the current will sap the hot and cold junctions. D. The Peltier effect states that if a current is imposed on the thermocouple, one end will heat up and the other will cool off.
C
Which of the following can cause fractionation? Question content area bottom Part 1 A. Overheating B. Freezing C. Leaking D. Depressurization
C
Which of the following is an example of a compound? Question content area bottom Part 1 A. Butane B. Methane C. Water D. Carbon
C
Which of the following statements is true regarding the low-side pressure and high-side pressure in a system? Question content area bottom Part 1 A. The low side of the system rejects heat and the high side of the system absorbs heat. B. The low side of the system has a low temperature and the high side of the system has a high temperature. C. The low side of the system absorbs heat and the high side of the system rejects heat. D. The low side of the system has low-pressure and rejects heat and the high side absorbs heat.
C
Which of the following systems uses metal wires that are insulated from each other? Question content area bottom Part 1 A. Mechanical compression system B. Evaporative system C. Thermoelectric system D. Absorption system
C
Which type of cooling mechanism is used in the most applications? Question content area bottom Part 1 A. Condensation cycle B. Expansion cycle C. Compression cycle D. Conversion cycle
C
An appliance listed in the low-pressure category uses a refrigerant that boils at a pressure of below ________. Question content area bottom Part 1 A. 65 psia B. 75 psia C. 55 psia D. 45 psia
D
Contaminants are often introduced to the system through service practices or through compressor failure and poor: Question content area bottom Part 1 A. Airflow B. Water flow C. Tubing D. Installation
D
Define the term "glide" when referring to zeotropic refrigerants. Question content area bottom Part 1 A. The temperature between the bubble point and the dew point of a zoetrope refrigerant at low pressure B. The temperature difference between the bubble point and the dew point of a zoetrope refrigerant at atmospheric pressure C. The temperature difference between the bubble point and the dew point of a zoetrope refrigerant at low pressure D. The temperature difference between the bubble point and the dew point of a zoetrope refrigerant at any particular pressure
D
Describe the difference between latent heat and sensible heat. Question content area bottom Part 1 A. Latent heat causes a change in the refrigerant temperature, while sensible heat causes a change in the refrigerant state B. There is no difference. C. Sensible heat causes a change in the refrigerant pressure, while latent heat causes a change in the refrigerant composition D. Sensible heat causes a change in the refrigerant temperature, while latent heat causes a change in the refrigerant state
D
How do EPA regulations divide refrigerants regarding regulations focused on preventing the release of ozone-depleting substances? Question content area bottom Part 1 A. By physical state B. By operating temperature C. By chemical composition D. By operating pressure
D
List the four major components of the compression refrigeration cycle in order. Question content area bottom Part 1 A. Condenser, evaporator, metering device, compressor B. Compressor, metering device, condenser, evaporator C. Condenser, compressor, metering device, evaporator D. Compressor, condenser, metering device, evaporator
D
Question content area top Part 1 Which is not a component that helps maintain the high and low pressures in an absorption refrigeration system? Question content area bottom Part 1 A. Generator B. Absorber C. Solution pump D. Evaporator
D
Question content area top Part 1 Which of the following is not an optional component that can be found on the high side of a refrigeration system? Question content area bottom Part 1 A. Liquid receiver B. Discharge line muffler C. Oil separator D. Oil level control
D
Question content area top Part 1 Why do both the compression cycle and absorption cycle have a high-pressure side and a low-pressure side? Question content area bottom Part 1 A. The low-pressure side allows refrigerant to boil at a temperature below the temperature of the space being cooled, releasing heat; the high side pressure allows the refrigerant to condense at a temperature higher than the outdoor temperature, absorbing heat B. The low-pressure side allows water to bo
D
Refrigerants can be divided into how many different chemical categories? Question content area bottom Part 1 A. 6 B. 3 C. 2 D. 5
D
The behavior of a zeotropic refrigerant can be compared to a mixture of which of the following? Question content area bottom Part 1 A. Fluorine and water B. Salt and water C. Oxygen and water D. Alcohol and water
D
What is the safety code for mechanical refrigeration? Question content area bottom Part 1 A. ASHRAE Standard 36 B. ASHRAE Standard 37 C. ASHRAE Standard 39 D. ASHRAE Standard 34
D
What series number is used for all zoetrope designations? Question content area bottom Part 1 A. 200 B. 100 C. 500 D. 400
D
Which of the following are compatible with mineral oil? Question content area bottom Part 1 A. HFCs and HGFH B. CFCs and HCFB C. CFCs and HBFSs D. CFCs and HCFCs
D
Which of the following best describes the concept of "cold?" Question content area bottom Part 1 A. Cold is the pressure in the air. B. Cold is how air travels. C. Cold is the temperature of the air. D. Cold is the lack of heat.
D
Which of the following is a true statement about evaporative cooling? Question content area bottom Part 1 A. For Correct operation, the area being cooled must be airtight. B. A one-stage system is most effective. C. It works very well in humid climates. D. System efficiency increases as air temperature increases.
D
Which refrigerants receive a 400 series number? Question content area bottom Part 1 A. Azeotropic B. Isomeric C. Halogenic D. Zeotropic
D
Which of the following are optional components that can be found on the low side of a refrigeration system? Question content area bottom Part 1 A. Suction to liquid heat exchanger B. Evaporator pressure regulator C. Suction line filter D. None of the above E. All of the above
E
