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单选题
The quantity of cooled air delivered by an air conditioning unit should （） the sum of the quantity of air re-circulated to the unit and the quantity mechanically exhausted.
A
balance
B
not balance
C
be more than
D
be less than
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Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system?A.Cooling the air to a temperature just above dew pointB.Heating the air to a point at which moisture will boil off ,then re-cooling itC.Cooling the air to a point below dew point, then reheating itD.Heating the air and then cooling it to a point below dew point
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题干材料：Due to the large amount of heat picked up by the air in boiler and engine rooms, it would be impracticable to maintain ambient conditions within the comfort zone by air conditioning or any other means. The normal practice is to provide copious mechanical ventilation; in boiler rooms, the quantity is equated to the combustion requirements, while in a motor ship engine room the supply may be 25-50% in excess of the requirements of the engines.The axial flow fan is particularly suited to handle these large air volumes at the moderate pressures required, while of course the “straight-through” flow feature places it at an advantage over the centrifugal fan.The increasing adoption of automation, with the provision of a separate control room makes less significant the fact that comfort conditions cannot be maintained in the engine room all the time.问题：Which of the following devices should be taken to maintain ambient conditions of the boiler and machinery space?A.air compressorB.air coolerC.air-conditioning plantD.mechanical ventilation plantIn a motor vessel, the air quantity which the engine room need is_______ of the requirements of the engines.A.less than 25-50%B.more than 125-150%C.more than 25-50%D.less than 125-150%According to this passage, which of the following statements is true?A.In boiler and machinery spaces, there is the air conditioningB.In the boiler rooms the requirement of air volume should meet 25-50% of combustion requirementC.To maintain the comfort zone in the separate control room the air conditioning plant should be fittedD.The comfort conditions can be maintained in the engine room all the timeAt the middle pressure and large air quantity,_________ is more suitable.A.an axial flow fanB.a radial flow blowerC.a centrifugal fanD.an auxiliary blower请帮忙给出每个问题的正确答案和分析，谢谢！
考题
In an air conditioning system, moisture is removed from the air by ______.A.filtersB.separatorsC.ducted trapsD.dehumidifiers
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According to this passage, which of the following statements is true?A.In boiler and machinery spaces, there is the air conditioning.B.In the boiler rooms the requirement of air volume should meet 25-50% of combustion requirement.C.To maintain the comfort zone in the separate control room the air conditioning plant should be fitted.D.The comfort conditions can be maintained in the engine room all the time.
考题
Due to the large amount of heat picked up by the air in boiler and engine rooms, it would be impracticable to maintain ambient conditions within the comfort zone by air conditioning or any other means. The normal practice is to provide copious mechanical ventilation; in boiler rooms, the quantity is equated to the combustion requirements, while in a motor ship engine room the supply may be 25-50% in excess of the requirements of the engines.The axial flow fan is particularly suited to handle these large air volumes at the moderate pressures required, while of course the “straight-through” flow feature places it at an advantage over the centrifugal fan.The increasing adoption of automation, with the provision of a separate control room makes less significant the fact that comfort conditions cannot be maintained in the engine room all the time. Which of the following devices should be taken to maintain ambient conditions of the boiler and machinery space?A.air compressorB.air coolerC.air-conditioning plantD.mechanical ventilation plant
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According to the passage, what is one disadvantage of skyscrapers that have mirroredwalls?__________A.The exterior surrounding air is heated
B.The building materials are very expensive
C.Construction time is increased
D.Extra air-conditioning equipment is needed
考题
单选题Due to the large amount of heat picked up by the air in boiler and engine rooms, it would be （） to maintain ambient conditions within the comfort zone by air conditioning.A
possibleB
necessaryC
practicableD
impracticable
考题
单选题In an air conditioning system, moisture is removed from the air by（）A
filersB
separatorsC
ducted trapsD
dehumidifiers
考题
单选题A re-heater in an air conditioning system functions to （）.A
control inlet air temperatureB
control inlet air volumeC
maintain relative humidity at 15%D
restore conditioned air temperature to a comfortable level
考题
单选题A re-heater, as used in an air conditioning system, is designed to control the （）A
chilled water temperatureB
dew point temperatureC
primary air temperatureD
dry bulb temperature
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单选题Refrigerant is normally sub-cooled in a refrigeration or air conditioning system condenser to （）.A
maintain adequate coil back pressureB
prohibit flashing in the liquid lineC
reduce refrigerant volume in the systemD
reduce compressor discharge line loading
考题
单选题请阅读 Passage 1，完成第 21~25小题。Passage 1These days，many large city buildings are equipped with their own air-conditioning systems.These systems help keep the buildings cool，but they can also damage the environment.Since they use a lot of electricity，for instance，they contribute indirectly to global warming.In addition，the water that flows through the systems is often cooled using chemicals called chlorofluorocarbons，or CFCs，that are believed to damage the Earth's ozone layer.Recently，though，a system has been built in the city of Toronto，Canada，that cools buildings with little damage to the environment. In the traditional air-conditioning systems found in most large buildings，water is pumped through the building in a continuous cycle.The water is first cooled to a temperature of 4℃ in machines called chillers.It is then sent to individual units that cool the air in each room.As the water flows through the building，it gradually becomes warmer.Finally，it reaches the roof ，where it is left to cool down naturally in a water tower.After that it is returned to the chillers，where the cycle begins again.Toronto lies on the shore of Lake Ontario，one of North America's Great Lakes，and the new system makes use of cold water taken from about 80 meters below the surface of the lake.At this depth，the water in the lake remains at 4℃ all year round.This is exactly the temperature to which the water in air-conditioning systems is cooled.However，the water from the lake is not pumped directly into the air-conditioning systems.Instead，it is used to cool the water that is already inside the air-conditioning systems.After that，the lake water is added to the city's ordinary water supply.Enwave，the company that developed this deep-lake cooling system，says that it uses 75 percent less energy than traditional air conditioning.And since no CFCs are used，no damage can be caused to the ozone layer.Not every city is located next to a large lake，but experts believe that systems like the one being used in Toronto could be built elsewhere by using other natural sources of cold water.What is the function of the chillers in a traditional air-conditioning system?A
They pump the air continuously to the units in each room.B
They lower the temperature of the water in the system.C
They help the water cool down naturally on the roof .D
They gradually clean the water as it flows through the building.
考题
单选题The pressurized air is usually cooled to increase the charge air （）.A
viscosityB
densityC
velocityD
electricity
考题
单选题Air entering an air-cooled refrigeration system is indicated by （）.A
frosting of the liquid lineB
higher than normal head pressureC
a clear sight glassD
abnormally cold reefer boxes
考题
单选题（）are supplied by main switchboard directly.A
Suez Canal searchlight, air compressor and air conditioning compressorB
Air compressor, boiler blower and refrigeration plantC
Boiler blower, Suez Canal searchlight and refrigeration plantD
Suez canal searchlight, air compressor and boiler blower
考题
单选题Air conditioning is the process of treating air to control （） its temperature, humidity, cleanliness and distribution to meet the comfort requirements of the occupants of the conditioned space.A
instantaneousB
instantaneouslyC
simultaneousD
simultaneously
考题
单选题In reference to air conditioning, when air attains the maximum amount of moisture it can hold at a specific temperature, it is said to be （）.A
superheatedB
saturatedC
condensedD
convected
考题
单选题Most air conditioning units have （） for adjusting the ratio of recirculated fresh airCare must be taken not to reduce the fresh air so that stuffiness or smells arise.A
catch platesB
dampersC
regulating valvesD
fans
考题
单选题With ducted air conditioning systems, the modern tendency is to use（）A
central air conditioning systemB
high velocity systemC
low velocity systemD
single duct system
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单选题请阅读 Passage 1，完成第 21~25小题。Passage 1These days，many large city buildings are equipped with their own air-conditioning systems.These systems help keep the buildings cool，but they can also damage the environment.Since they use a lot of electricity，for instance，they contribute indirectly to global warming.In addition，the water that flows through the systems is often cooled using chemicals called chlorofluorocarbons，or CFCs，that are believed to damage the Earth's ozone layer.Recently，though，a system has been built in the city of Toronto，Canada，that cools buildings with little damage to the environment. In the traditional air-conditioning systems found in most large buildings，water is pumped through the building in a continuous cycle.The water is first cooled to a temperature of 4℃ in machines called chillers.It is then sent to individual units that cool the air in each room.As the water flows through the building，it gradually becomes warmer.Finally，it reaches the roof ，where it is left to cool down naturally in a water tower.After that it is returned to the chillers，where the cycle begins again.Toronto lies on the shore of Lake Ontario，one of North America's Great Lakes，and the new system makes use of cold water taken from about 80 meters below the surface of the lake.At this depth，the water in the lake remains at 4℃ all year round.This is exactly the temperature to which the water in air-conditioning systems is cooled.However，the water from the lake is not pumped directly into the air-conditioning systems.Instead，it is used to cool the water that is already inside the air-conditioning systems.After that，the lake water is added to the city's ordinary water supply.Enwave，the company that developed this deep-lake cooling system，says that it uses 75 percent less energy than traditional air conditioning.And since no CFCs are used，no damage can be caused to the ozone layer.Not every city is located next to a large lake，but experts believe that systems like the one being used in Toronto could be built elsewhere by using other natural sources of cold water.What happens in the end to the water from Lake Ontario?A
It is used by the residents of Toronto.B
It is returned to a place deep in the lake.C
It is cooled down before being used again.D
It is added to the water inside air-conditioning systems.
考题
单选题Which of the following methods is normally used to control the temperature of air distributed from individual cooling coils in an air conditioning system using a chilled water circulation system?（）A
A room thermostat activates an electric heater at each individual chilled air outlet when necessaryB
Varying the number of passes the air makes across the coilsC
Varying the temperature of the water through the coilsD
Varying the quantity of water flowing through the coils
考题
单选题To prevent the unnecessary loading of an air conditioning system while maintaining the designed dry bulb temperature and relative humidity in an air conditioning system, you should （）A
admit only enough fresh outside air to provide proper ventilationB
reduce the air reheating system loadC
lower the compressor head pressureD
operate the purge recovery unit continuously
考题
单选题Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system?（）A
Cooling the air to a temperature just above dew pointB
Heating the air to a point at which moisture will boil off ,then re-cooling itC
Cooling the air to a point below dew point, then reheating itD
Heating the air and then cooling it to a point below dew point
考题
单选题Routine maintenance on a Central Control Room hermetically sealed air conditioning unit should include （）A
changing the air filterB
recharging the systemC
changing compressor lubricantD
renewing container vacuum
考题
单选题请阅读 Passage 1，完成第 21~25小题。Passage 1These days，many large city buildings are equipped with their own air-conditioning systems.These systems help keep the buildings cool，but they can also damage the environment.Since they use a lot of electricity，for instance，they contribute indirectly to global warming.In addition，the water that flows through the systems is often cooled using chemicals called chlorofluorocarbons，or CFCs，that are believed to damage the Earth's ozone layer.Recently，though，a system has been built in the city of Toronto，Canada，that cools buildings with little damage to the environment. In the traditional air-conditioning systems found in most large buildings，water is pumped through the building in a continuous cycle.The water is first cooled to a temperature of 4℃ in machines called chillers.It is then sent to individual units that cool the air in each room.As the water flows through the building，it gradually becomes warmer.Finally，it reaches the roof ，where it is left to cool down naturally in a water tower.After that it is returned to the chillers，where the cycle begins again.Toronto lies on the shore of Lake Ontario，one of North America's Great Lakes，and the new system makes use of cold water taken from about 80 meters below the surface of the lake.At this depth，the water in the lake remains at 4℃ all year round.This is exactly the temperature to which the water in air-conditioning systems is cooled.However，the water from the lake is not pumped directly into the air-conditioning systems.Instead，it is used to cool the water that is already inside the air-conditioning systems.After that，the lake water is added to the city's ordinary water supply.Enwave，the company that developed this deep-lake cooling system，says that it uses 75 percent less energy than traditional air conditioning.And since no CFCs are used，no damage can be caused to the ozone layer.Not every city is located next to a large lake，but experts believe that systems like the one being used in Toronto could be built elsewhere by using other natural sources of cold water.What is one problem with traditional air-conditioning systems?A
The chemicals they use sometimes pollute the water supply.B
They often damage the buildings that they are trying to cool.C
There are not enough CFCs in the world to cool all the buildings.D
The method they use to cool water is thought to harm the ozone layer.
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