Mechanical Specifications - York YPC Engineering Manual

Mechanical Specifications

GENERAL
The YORK YPC Two-Stage Steam Fired Absorption
Liquid Chiller is completely factory-packaged, including
a first-stage (high temperature) generator, solution heat
ex changers, main shell, microprocessor controls and all
interconnecting unit piping and wiring.
All models are shipped as a single piece with a nitrogen
charge to eliminate the possibil ity or air entering the ma-
chine during shipment. LiBr solution, de-ionized water
(refrigerant), purge pump, chilled water flow switch, and
steam control valve shall ship loose for field installation.
The purchase price includes services of a Johnson
Controls fac tory-trained, field service representative to
supervise the initial start-up of the machine.
SOLUTION FLOW
The solution flow is divided into two parallel paths, one
leading to the first-stage generator and one to the second-
stage generator. In this way, each stream is concentrated
only once, allowing for a more safe and efficient operation.
The balance of flow between the two streams is factory-set
ensuring maximum efficiency for any given application.
MAIN SHELL
The main shell consists of four separate shell and tube
heat exchangers: the absorber, evaporator, condenser
and second-stage (low temperature) generator, all housed
in a single carbon steel shell divided into low pressure
and intermediate pressure sections. The shell is fabri-
cated from formed carbon steel plates with fusion welded
seams. Carbon steel tube sheets, drilled and reamed to
accommodate the tubes, are welded to the end of the
shell. Intermediate tube supports are fabri cated of carbon
steel plates. Each tube is roller ex panded into the tube
sheets to provide a leak tight seal; each tube is individually
replaceable. The solution side of the shell is designed for
a working pressure of 60 mm Hg absolute.
The portion of the main shell opposite the generator
houses the low pressure section of the machine which
includes the evaporator and the absorber. Both the ab-
sorber and the evaporator are drip-type heat ex changers
with 5/8" (16 mm) OD, 0.025" (0.635 mm) wall, copper
tubing for the 14SC and 3/4" (19 mm) OD, .028" (0.71
mm) wall copper tubing for the 16SL and larger. Tubes are
externally enhanced where necessary to achieve desire
capacity. The absorber and evaporator are sepa rated by
finned eliminator baffles designed to allow only water in
the vapor state to pass to the absorber.
The side of the main shell closer to the generator contains
the intermediate pressure section of the machine consist-
8
ing of the condenser and second-stage generator. The
second-stage generator is a drip-type heat exchanger
with 5/8" (16 mm), 0.025" (0.6 mm) wall, copper tubing
for the 14SC, and 3/4" (19 mm) OD, 0.028 (0.7 mm) wall
for the 16SL and larger. Generator and condenser are
separated by baffling which prevents liquid carryover to
the condenser. Condenser tubing is 5/8" (15.9 mm) 0.025"
(0.6 mm) wall copper tubing for the 14SC, and 3/4" (19.05
mm) OD, 0.028" (0.7 mm) wall for the 16SL and larger.
The removable compact water boxes are fabricated of
steel. The design working pressure is 150 PSIG (10.3 bar)
and the boxes are tested at 195 PSIG (13.4 bar). Integral
steel water baffles are located and welded within the water
box to provide the required pass arrangements. Stub-out
water nozzle connections with ANSI/AWWA C-606-style
grooves are welded to the water boxes. These nozzles
are suitable for ANSI/AWWA C-606 couplings, welding or
flanges, and are capped for ship ment. Plugged vent and
drain connections and lifting lugs are provided on each
water box.
FIRST‑STAGE GENERATOR
The first-stage generator is a single flooded shell and tube
heat exchanger. The shell side is fabricated from carbon
steel plate with fusion welded seams, and is designed for
a working pressure of 13.5 psia (0.9 bar) (the unit bursting
disk is designed to fail at 10 PSIG (0.7bar)). Carbon steel
eliminator baffles laid out in a serpentine fashion pre vent
solution carryover over with the refrigerant vapor. The
generator has a single drilled and reamed carbon steel
tube sheet and uses a "U" shaped tube bundle to minimize
thermal stress. The "U" tubes are 5/8" (16 mm) OD, .035"
(0.9 mm) wall, 70/30" cupro-nickel and are roller expanded
into the tube sheets. The tube side of the generator is
designed for working pressures up to 150 PSIG (10.3 bar)
and is ASME approved and stamped in accordance with
ASME Boiler and Pressure Vessel Code, Section VlII. The
high temperature generator contains a solution float valve
which controls the level of solution in the gener ator. This
limits the amount of sensible heating at part load condi-
tions, resulting in much better performance.
SOLUTION HEAT EXCHANGER
The solution heat exchanger is a shell and tube design
with geometrically-enhanced 5/8" (16 mm) OD for the
14SC and 0.58" (14.7 mm) OD for the 16SL and larger,
90/10 cupro -nickel tubing. The shell is formed from carbon
steel plate with fusion welded seams. Tubes are roller
expanded into carbon steel tube sheets.
DRAIN COOLERS
YPC Absorption steam units come equipped with a con-
densate drain cooler, eliminating the need for a separate
FORM 155.19-EG3 (1011)
JOHNSON CONTROLS