designer will coordinate with chiller manufacturers
prior to specifying a minimum full or part load
efficiency for a gas-engine driven chiller.
Gas-engine driven chiller can be provided with
compressors of the centrifugal type (typically
larger than 2460 kW (700 tons)), the rotary screw
type (intermediate sizes), the reciprocating type
(typically up to 703 kW (200 tons)), and the scroll
type (small system).
Projects which include vapor-compression type liquid
chillers (this excludes absorption chillers) will
comply with the safety standards defined in ASHRAE
15. Designers will be responsible for thoroughly
researching and implementing the ASHRAE 15 safety
requirements. For refrigerant-containing parts
(excluding piping) located within an indoor space, a
designer can use the following 6-step synopsis as a
guide in determining "System Application
Requirements" from ASHRAE 15.
Step 1. Identify the safety group
classification of the refrigerant anticipated to be
used in the new liquid chilling equipment.
Refrigerants R-22 and R-134a are considered Group A1
refrigerants. Refrigerant R-123 is considered a
Group B1 refrigerant.
Step 2. Identify the occupancy classification
of the facility which will house the new liquid
chilling equipment. Occupancies include
institutional, public assembly, residential,
commercial, large mercantile, industrial, and mixed
types.
Step 3. Determine the system probability (high
or low) of the new liquid chilling equipment.
Liquid chillers are typically considered
low-probability systems according to ASHRAE 15.
Step 4. Estimate the quantity of refrigerant
(grams or pounds) in the largest single liquid
chiller or largest refrigerant circuit of the new
equipment. The designer will research catalog data
from a minimum of 2 different liquid chiller
manufacturers in order to get an approximation.
Step 5. Determine the volume (cubic meters or
cubic feet) of the indoor space which is planned to
house the new liquid chilling equipment.
Step 6. Identify the "System Application
Requirements" from the applicable table in ASHRAE 15
based upon the information identified in the
previous steps (e.g., safety group, occupancy,
system probability, refrigerant quantity, and indoor
space volume). The "System Application
Requirements" will dictate applicable refrigerant
limitations as well as occupied space or mechanical
SECTION 15620A
Page 15
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