20
JOHNSON CONTROLS
FORM 155.19-EG3 (1011)
GENERAL
Provide YORK Millennium YPC Two-Stage Absorption
Steam-Fired Chiller(s) capable of producing chilled water
per the capacities shown on drawings and sched ules.
Each chiller shall be of hermetic design, leak tested, and
factory performance tested.
Chiller shall ship as a one-piece assembly ready for con
-
nection to the building water, fuel, and electrical systems.
Purge pump, chilled-water flow switch, LiBr solution,
deionized water (refrigerant), and steam valve shall be
shipped loosed for filed installation.
Chiller to ship with a nitrogen gas holding charge to elimi
-
nate the possibility of air entering unit during transport and
to permit the verification of a leak-tight unit upon delivery.
Purchase price to include parts and labor warranty for a
period of one year from start up or eighteen months from
delivery, whichever occurs first.
CONSTRUCTION
The chiller-heater unit to consist of one first-stage (high
temperature) generator, solution heat exchangers, and
main shell. The main shell shall include the condenser,
second-stage (low temperature) generator, evaporator,
and absorber.
Crossover routing cooling water from the absorber to the
condenser shall be shipped loose from the factory, elimi-
nating the need for a customer supplied crossover pipe.
The flow of solution shall be initiated by a hermetic solution
pump, located beneath the absorber, and shall be divided
into two parallel paths, one leading to the first-stage gen
-
erator and the other to the second-stage generator. This
parallel flow design shall permit each stream of solution
to be concentrated only once in order to limit the maxi
-
mum concentration of LiBr and thus minimize the risk of
crystallization.
TUBE MATERIALS
The first-stage generator tubes shall be 70/30 cupro-
nickel, 0.035 inch (0.89 mm) wall thickness and shall be
“U -shaped” to minimize thermal stress, prolong tube life,
and increase unit efficiency. The drain cooler tubes shall
be 90/10 cupro-nickel, .030” (0.76 mm) wall thickness.
The second-stage generator evaporator, absorber, and
condenser shall be seamless copper 5/8” (15.875 mm),
OD, 0.025” (0.635 mm) wall, copper tubing for the 14SC,
and 3/4” (19.05 mm) OD, 0.028” (0.71 mm) wall for the
16SL and larger, with enhanced surface as required to
meet given capacity.
WATER BOXES
Water boxes shall be removable to permit tube cleaning
and replacement. Water-circuit tubing to be replaceable
from either end of the chiller-heater unit. Stubout water
connections having ANSI/AWWA C-606 grooves shall
be provided as standard (ANSI flanged connections are
optional). All water boxes and associated water-circuit
nozzles and tube bundles shall be designed for 150 PSIG
(1MPa) working pressure and shall be hydrostatically
tested to 195 PSIG (1.3 MPa). Vent and drain connec
-
tions shall be provided on each water box.
SIGHT GLASSES
Unit shall be equipped with no fewer than six (6) sight
glasses to permit exact adjustment of solution and refrig
-
erant levels under full load conditions to ensure efficient
and trouble free operation. Sight glasses to be located as
follows: upper evaporator, lower evaporator, first-stage
generator, second-stage generator, ab sorber, oil trap.
SPRAY DISTRIBUTION
Solution and refrigerant distribution shall be accom plished
by use of a drip apparatus which produces a fine, laminar
film on the outside of the tube bundles.
PUMPS
Solution and refrigerant pumps shall be hermetically
sealed, self lubricating, totally enclosed, liquid-cooled,
factory-mounted, wired and tested. Suction and dis charge
connections of solution and refrigerant pumps shall be
welded to chiller-heater unit piping. Flanged pump con
-
nections are not acceptable. Pumps shall be designed for
a total of 55,000 hours between service inspections.
ISOLATION VALVES
Suction and discharge connections for the solution and
refrigerant pumps shall be equipped with factory welded
isolation valves to permit the servicing of hermetic pump
assemblies without any loss of solution or leakage of air
into the chiller-heater.
SOLUTION VALVES
Valves used for adjusting solution flow shall be fully
welded or brazed to prevent leakage of air into unit. Valve
operator shall be covered with a seal cap to eliminate the
possibility of stem leakage. Fittings be tween valve body
and unit piping to be welded. Threaded valve connections
are not acceptable.
PURGING SYSTEM
Chiller-heater shall be equipped with a purge system
which will constantly remove noncondensible vapors
Guide Specifications
