Resource Library

Standard	Organization	Scope	Relevance
ASHRAE 15	ASHRAE	Safety Standard for Refrigeration Systems	Refrigerant safety, ventilation, equipment room requirements
ASHRAE 62.1	ASHRAE	Ventilation for Acceptable IAQ	Outdoor air rates, ventilation system design
ASHRAE 90.1	ASHRAE	Energy Standard for Buildings	Chiller efficiency minimums, part-load requirements
ASHRAE 55	ASHRAE	Thermal Environmental Conditions	Comfort criteria, temperature/humidity ranges
NFPA 70 (NEC)	NFPA	National Electrical Code	Electrical wiring, disconnects, motor protection
NFPA 101	NFPA	Life Safety Code	Egress, fire protection, emergency systems
IIAR 2	IIAR	Ammmonia Refrigeration Systems	Safety, design for ammonia-based chillers

Term	Definition
Approach Temperature	Difference between refrigerant temp and water temp at heat exchanger. Low approach = good efficiency.
Compressor Surge	Unstable flow condition in centrifugal compressors causing reverse flow and vibration.
Condenser	Heat exchanger that rejects heat from refrigerant to cooling medium (air or water).
COP	Coefficient of Performance: ratio of cooling output to energy input.
Evaporator	Heat exchanger that absorbs heat from chilled water into refrigerant.
FLA	Full Load Amps: maximum current draw of compressor motor at full capacity.
Head Pressure	Discharge pressure of compressor; high head pressure indicates condensing problems.
IPLV	Integrated Part Load Value: seasonal efficiency rating for chillers.
Lockout/Tagout	OSHA procedure (29 CFR 1910.147) for isolating energy before maintenance.
Subcooling	Liquid refrigerant cooled below saturation temp; indicates proper charge.
Superheat	Vapor refrigerant heated above saturation temp; indicates proper expansion valve operation.
Ton	Cooling capacity: 1 ton = 12,000 BTU/hr = 3.517 kW.
VFD/VSD	Variable Frequency/Speed Drive: controls compressor motor speed for part-load efficiency.

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