CEMP-E
TI 810-10
1 February 1999
CHAPTER 5
EQUIPMENT
5-1. LOCATION OF EQUIPMENT. Specify air-conditioning equipment, including air handlers,
compressors, pumps and associated equipment that is suitable for outdoor installation where
life cycle cost effective. When comparing interior and exterior equipment installations in life
cycle cost analysis, include all associated building costs required to house interior equipment in
the analysis. Provide details on the drawings necessary to ensure drainage for "winterizing"
equipment where appropriate.
5-2. CHILLERS. Individual reciprocating machines will not exceed 700kW (200 tons) capacity,
and the total capacity of all reciprocating machines or packaged air-conditioning units equipped
with reciprocating compressor used for air conditioning a single facility will not exceed 1400kW
(400 tons). A single packaged unit will not contain more than eight compressors. Where
multiple chillers are specified, provide a chilled water pump and a condenser pump for each
chiller. With the exception of the criteria listed herein, the number of chillers specified will be
optimized in the life cycle cost analysis. Where there is a combination of normal summer air-
conditioning loads and year-round air-conditioning loads optimize system zones and size
system components to support the entire facility load during warm weather and a portion of the
equipment may be essentially fully loaded during winter operations. In facilities when, because
of the small size of the off-hours or the small winter load, it is impractical to operate the primary
equipment in the central plant, an auxiliary refrigeration system may be provided. Use heat
recovery where it is life cycle cost effective.
a. Reciprocating Compressors.
(1) For chillers over 35 kW (10 tons), use capacity control which reduces the power
requirement as the load varies.
(2) Compressors operating in parallel will have the normal oil level at the same
elevation for all machines and the crankcases of these compressors will be provided with gas
and oil equalizing lines. When compressors are connected in parallel, arrange the hot-gas
discharge lines so that the oil from the common discharge line will not collect in an idle unit
while the other units are running, and size the lines to provide an equal pressure drop between
each machine and its respective condenser. The suction lines will return refrigerant gas and oil
from the evaporator to the compressor during operation of the system, and will not allow oil or
liquid refrigerant to be returned as slugs at any time. Provide means for trapping oil in the
common suction header to prevent oil slugs from collecting in the idle compressor.
b. Centrifugal Compressors. When a two-stage centrifugal compressor is selected, a
refrigerant intercooler will also be required. For low-temperature applications, where
compressors with four or more stages may be needed, two-stage intercoolers will be used.
Use capacity control methods to reduce energy consumption as the load is reduced to minimize
life cycle costs.
c. Helical Rotary (Screw) Compressor. Screw compressors will use oil injection. An oil
separator or sump and oil cooler will be included in the system. Oil coolers assist the
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