Compressor Types
Mechanical device that increases the pressure of a gas by reducing its volume.
Compressor
What component prevents refrigerant migration and mixing with crankcase oil when the unit is off.
Crankcase Heater
Temperature difference of the inlet to the outlet of a water recirculating system. Referred to as "Tower Range"
10F
What do you use to lift a heavy RTU onto a building.
Crane
Total heat content in the air.
Enthalpy
Multiple small compressors used instead of larger ones. Utilizes pistons like a car engine.
Reciprocating Compressor
Component used to move water through the condenser and cooling tower. (most common type of water pump)
Centrifugal Pump
Temperature difference of the inlet to the outlet of a waste-water system. Referred to as "Tower Range"
20F
A raised frame that is attached to the roof of a building and designed to support roof-mounted equipment. Has to be atleast 14inch high.
Curb
Insufficient water flow through a cooling tower can result in?
High system operating pressures/High head pressure & high suction pressure.
Capacity control done with a slide valve. Two Types: semi-hermetic compressors and open-drive compressors. Positive displacement pump able to handle some liquid refrigerant without damage.
Rotary Screw Compressor
A device used in HVAC systems to reheat air that has already been cooled.
Reheat coil
How many gallons per minute (gpm) does a waste-water system use.
1.5 gallons per minute (gpm)
Mixed air is best described as the combination of ___ and ___?
Return Air and Outside Air
Encapsulation and Electroporation are two methods that can be used to control.
Bacteria Growth.
Welded, hermetic, positive displacement compressor. Advantages: Efficiency, quietness, fewer moving parts, size and weight, and ability to pump small amounts of liquid refrigerant without compressor damage.
Scroll Compressor
Electronically alter the frequency of alternating- current (AC) sine waves through a device called an inverter.
Variable-Frequency Drive (VFD)
Galvanized steel does not readily rust because the steel is coated with ___??
Zinc
Help provide the correct amount of ventilation air to the structure. Helps reduce cooling costs by allowing outside air into the air conditioning equipment.
Economizer
The process of running electronic probes through the length of various types of tubes or along the surfaces of materials in order to find flaws in them.
Eddy Current Test
Has an impeller that can spin at 30,000RPM into a volute. Capacity control is achieved by guide vanes.
Centrifugal Compressor
The most common valve used in water and steam circuits which has a replaceable seat is the ____ valve.
Globe Valve
Water evaporates from a cooling tower leaving behind solid materials. What is it called when we bleed off a portion of the water in circulation to eliminate these solid materials.
Blowdown
Estimates the occupancy level by measuring the levels of carbon dioxide.
Demand Control Ventilation (DCV)
How can a technician verify waterflow through the condenser of a chiller?
Checking the Pressure/Temperature drop from the inlet to the outlet.