HVAC BOMA Pre-Quiz Latest Version with Complete Solutions

HVAC BOMA Pre-Quiz Latest Version with Complete Solutions Two basic categories of chillers are the _____. Compression cycle and absorption The five requirements for comfort are proper temperature, humidity, filtration, _____. Circulation The primary function of an expansion device is to _____. All of the above (produce a reduction in the pressure on the liquid refrigerant, regulate the flow of refrigerant into the evaporator and lower the boiling point of the refrigerant far enough below the temperature of the load to get the needed heat transfer rate. The wet-bulb depression is _____. The difference between the dry-bulb and wet-bulb temperatures. The dew-point temperature is the _____. Temperature when the moisture begins to condense out of the air. How many Btu are required to change one pound of ice at 20°F to steam at 220°F 1,304 Btu/h If an R-12 refrigeration system is operating with a 25.4 psig suction pressure, what is the evaporator superheat if the evaporator outlet temperature is 34°F 9 On an R-11 or R-123 system, the refrigerant removal process normally starts with the removal of _____. Liquid refrigerant The condenser in a refrigeration system _____. All of the above (desuperheats the vapor from the compressor, condenses the vapor from the compressor and subcools the liquid refrigerant before it leaves the condenser) The human body gives off heat by which of the following? All of the above (convection, radiation and conduction) If the temperature remains constant and the volume that a gas occupies increases, the pressure will _____. decrease Transformers are rated using _____. Volt-amperes Measuring velocity pressure in a duct indicates the _____. Speed at which the air is moving A solid material exerts a pressure or force _____. Downward only Pure water boils at temperature of 213°F, at which of the following standard conditions? 14.967psi Which of the following would allow a system to operate more efficiently? Condenser that had refrigerant leaving with 15°F of subcooling One watt of electrical energy is equal to _____. 3.413 Btu Rotary compressors are used primarily in _____. Domestic refrigerators The water circuit in shell and coil and coil-type tube-in-a-tube condensers must be cleaned _____. Chemically When a water regulating valve is used to control the head pressure of the water-cooled system, the valve's spring is acting against which pressure to modulate the waterflow? Head pressure of the system The standard atmospheric pressure at sea level is _____. 29.92" The steps to aggressively controlling the contamination of indoor air would involve _____. All of the above (locating and eliminating the source of contamination, providing adequate ventilation and providing methods for cleaning the air) If the resistance against a propeller fan is doubled, the cfm output decreases, but the amperage draw of the motor _____. Increases Which of the following re-presents a different temperature than the other three? 475K The best method of leak checking is when the refrigeration system is _____. Standing with dry nitrogen pressure of 150 psig in the system