ETL 1110-1-181
12 Jan 98
chiller represents a single numeric representation of part load
efficiency at different load points. The different load points of a
chiller are determined based upon standard ARI rating conditions. The
standard rating conditions are defined in ARI 550, ARI 560, or ARI 590
as applicable. IPLV values are expressed either as kW/ton or are
dimentionless
d. Application Part-Load Value (APLV). The APLV rating of a
liquid chiller represents a single numeric representation of part load
efficiency at different load points. The different load points of a
chiller are determined based upon site specific rating conditions. APLV
values are expressed either as kW/ton or are dimentionless.
B-4. LIQUID CHILLER TYPES. Liquid chiller designs are either the vapor
compression type or the absorption type. Both designs rely on a cycle
of condensation and evaporation to produce cooling. Refer to the
"ASHRAE HANDBOOK, Refrigeration Systems and Applications" for a thorough
explanation of each type of chiller system.
B-5. CURRENT ENERGY MANDATES. Minimum energy performance standards
for electrically-driven liquid chillers (vapor compression type) in
federal buildings are defined in 10 CFR 435.108 and ASHRAE 90.1. The
energy parameters are based upon the standard rating conditions
established in ARI 550 and ARI 590. At the time of publication of this
ETL, minimum energy performance standards for other types of liquid
chillers (i.e., absorption type chiller, gas engine-driven type
chillers, etc.) were not specifically mandated by any federal
regulations.
B-6. CHILLER EFFICIENCIES. Because of typical manufacturing practices,
most liquid chillers are not available in multiple efficiencies for each
available capacity. Only one model, and therefore, only one efficiency
is available from a manufacturer for a given capacity. This is not the
case; however, for large electrically-driven, water-cooled rotary screw
or centrifugal type chillers (typically larger than 200 tons capacity).
These type chillers can be supplied by manufacturers in numerous
efficiencies for each capacity.
B-7. CURRENT ARMY CRITERIA. The Corps of Engineer's Guide
Specification (CEGS) 15650 "Central Refrigerated Air-Conditioning
System" contains the Army's current recommendations for minimum energy
efficiencies for all types of liquid chillers. The recommendations in
CEGS 15650; however, are not based upon the best commercially available
chiller efficiencies. The recommendations are intended to meet or
exceed any current energy mandates while also allowing competitive
bidding among multiple manufacturers.
B-8. CHILLER PROCUREMENT. In the procurement process of a liquid
chiller, minimum specification requirements (including efficiency) will
be developed using CEGS 15650. In addition, the procurement contract
should include a bid option that will allow each bidding Contractor the
ability to supply an additional proposal(s) at no additional cost to the
Government for providing a more efficient chiller than is specified.
The Contractors must identify the first cost and efficiency of each
additional proposal. In review of the Contractors' proposals, a
B-2
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