STATIONARY ENGINEER COMPLETE
DETAILED CASE STUDY
u Cl2 - Chlorine
boiler - equipment that provides hot water or steam for various uses
PRV - PRESSURE RELIEVE VALVE
NOWL - Normal operating water level
BTU - British Thermal Unit
absolute pressure - gauge pressure (psi) + atmospheric pressure (14.7 psi) at sea level
air changes per hour - The hourly ventilation rate divided by the volume of a space. For perfectly mixed
air or laminar flow spaces, this is equal to the number of times per hour that the volume the space is
exchanged by mechanical and natural ventilation.
Air conditioner - An appliance, system, or mechanism designed to dehumidify and extract heat from an
area.
Chiller - A device that removes heat from a liquid via a vapor-compression or absorption refrigeration
cycle. This cooled liquid flows through pipes in a building and passes through coils in air handlers, fan-
coil units, or other systems, cooling and usually dehumidifying the air in the building. Chillers are of two
types; air-cooled or water-cooled. Air-cooled chillers are usually outside and consist of condenser coils
cooled by fan-driven air. Water-cooled chillers are usually inside a building, and heat from these chillers
is carried by recirculating water to a heat sink such as an outdoor cooling tower.
, Condenser - A component in the basic refrigeration cycle that ejects or removes heat from the system.
The condenser is the hot side of an air conditioner or heat pump.
Controller - A device that controls the operation of part or all of a system.
Dry Bulb Thermometer - Dry bulb temperature is the temperature of air measured by a thermometer
which is freely exposed to the air while it is shielded from radiation and moisture. It is usually thought of
as air temperature, and it is the true thermodynamic temperature. It is a measurement of heat intensity
independently of humidity and a dry bulb thermometer is used to measure it.
Economizer - An HVAC component that uses outside air, under suitable climate conditions, to reduce
required mechanical cooling. When the outside air's enthalpy is less than the required supply air during
a call for cooling, an economizer allows a building's mechanical ventilation system to use up to the
maximum amount of outside
Enthalpy - For a given sample of air, a measure of the total heat content (the sum of the heat energy of
the dry air and heat energy of the water vapor within it). It is typically used to determine the amount of
fresh outside air that can be added to recirculated air for the lowest cooling cost.
psychrometric - The study of the behavior of air-water vapor mixtures. Water vapor plays an important
role in energy transfer and human comfort in HVAC design.
Radiation - The transfer of heat directly from one surface to another (without heating the intermediate
air acting as a transfer mechanism)
smoke damper - A damper or adjustable louver designed to augment the ventilation of a space during a
fire.
subcooling - A The condition where liquid refrigerant is colder than the minimum temperature required
to keep it from boiling which would change it from a liquid to a gas phase. Subcooling is the difference
between its saturation temperature and the actual liquid refrigerant temperature.
VAV - variable air volume
DETAILED CASE STUDY
u Cl2 - Chlorine
boiler - equipment that provides hot water or steam for various uses
PRV - PRESSURE RELIEVE VALVE
NOWL - Normal operating water level
BTU - British Thermal Unit
absolute pressure - gauge pressure (psi) + atmospheric pressure (14.7 psi) at sea level
air changes per hour - The hourly ventilation rate divided by the volume of a space. For perfectly mixed
air or laminar flow spaces, this is equal to the number of times per hour that the volume the space is
exchanged by mechanical and natural ventilation.
Air conditioner - An appliance, system, or mechanism designed to dehumidify and extract heat from an
area.
Chiller - A device that removes heat from a liquid via a vapor-compression or absorption refrigeration
cycle. This cooled liquid flows through pipes in a building and passes through coils in air handlers, fan-
coil units, or other systems, cooling and usually dehumidifying the air in the building. Chillers are of two
types; air-cooled or water-cooled. Air-cooled chillers are usually outside and consist of condenser coils
cooled by fan-driven air. Water-cooled chillers are usually inside a building, and heat from these chillers
is carried by recirculating water to a heat sink such as an outdoor cooling tower.
, Condenser - A component in the basic refrigeration cycle that ejects or removes heat from the system.
The condenser is the hot side of an air conditioner or heat pump.
Controller - A device that controls the operation of part or all of a system.
Dry Bulb Thermometer - Dry bulb temperature is the temperature of air measured by a thermometer
which is freely exposed to the air while it is shielded from radiation and moisture. It is usually thought of
as air temperature, and it is the true thermodynamic temperature. It is a measurement of heat intensity
independently of humidity and a dry bulb thermometer is used to measure it.
Economizer - An HVAC component that uses outside air, under suitable climate conditions, to reduce
required mechanical cooling. When the outside air's enthalpy is less than the required supply air during
a call for cooling, an economizer allows a building's mechanical ventilation system to use up to the
maximum amount of outside
Enthalpy - For a given sample of air, a measure of the total heat content (the sum of the heat energy of
the dry air and heat energy of the water vapor within it). It is typically used to determine the amount of
fresh outside air that can be added to recirculated air for the lowest cooling cost.
psychrometric - The study of the behavior of air-water vapor mixtures. Water vapor plays an important
role in energy transfer and human comfort in HVAC design.
Radiation - The transfer of heat directly from one surface to another (without heating the intermediate
air acting as a transfer mechanism)
smoke damper - A damper or adjustable louver designed to augment the ventilation of a space during a
fire.
subcooling - A The condition where liquid refrigerant is colder than the minimum temperature required
to keep it from boiling which would change it from a liquid to a gas phase. Subcooling is the difference
between its saturation temperature and the actual liquid refrigerant temperature.
VAV - variable air volume
