User Manual

ManualsBrandsCarrier ManualsRefrigerators16JB

Carrier

Application Data

Application Detail

16JB

5qP£È.S<£ù£5 ¡sy

Hermetic Absorption Liquid Chillers

GENERAL

Application details in this publication cover

various methods of applying the 16JB absorption

machine to meet liquid chilling needs. Throughout

this publication, the chilled liquid will be water.

Subjects covered are chilled water temperature

control, condenser water temperature control,

system design for steam and hot water machines,

and general information.

CHILLED WATER TEMPERATURE CONTROL

The absorption machine is basically a water

chiller that can be connected to any conventional

open or closed system. However, circulation of

chilled water must be continuous during operation

of the machine and during the shutdown dilution

cycle. Chilled water flow may be restricted at

partial load.

For fine chilled water temperature control

within narrow limits, such as required in precision

control of industrial processes or maintenance of

laboratory conditions, the chilled water system

may require additional storage volume to allow the

machine to adjust slowly to changes in load.

Normal air-conditioning applications are not

subject to such requirements.

Systems having large storage volumes of chilled

water transmit load changes to the machine slowly,

allowing accurate chilled water temperature con

trol. Small storage systems transmit load changes

rapidly, making temperature control more diffi

cult. For fine temperature control, the chilled

water system volume should be at least ten times

the gpm flow through the cooler. If a tank is added

to the system for extra storage volume, it should

be located in the line from the load to the cooler.»

Two-Pipe Cooling-Heating Systems — When

machines are used in conjunction with a two-pipe

cooling-heating system, certain precautionary steps

should be taken during changeover from heating to

cooling.

Maximum water temperature permitted thru

the evaporator is 130 F because of the possibility

of tube stress. If system water temperature is above

80 F but less than 130F at changeover time,

evaporator flow should be throttled to prevent

machine overload.

It is recommended that hot water temperatures

be reset, based on outside air temperature. If a

reset-type control is used, the entering hot water

temperature at changeover will normally be lower

than 130 F.

STEAM MACHINES

Boilers — Generally, any boiler capable of modu

lating its input to maintain design operating steam

pressure within 1 psi under varying loads, is suit

able for application with the absorption machine.

This generally includes all gas- and oil-fired boilers.

Some oil-fired boilers are conversions from

coal-fired to oil-fired and may have control systems

which are too sluggish to give proper response to

machine load changes. Direct control of oil feed

rate normally ensures proper response.

Coal-fired boilers, due to slow buildup and

shutdown characteristics, should be used only

when the absorption machine represents less than

15% of boiler operating load. This generally limits

coal-fired boiler applications to large industrial jobs

where process steam is generated in large quantities

year-round.

BOILER CAPACITY — Minimum boiler capacity

for use with the absorption machine is equal to full

load steam consumption, plus sufficient capacity

to offset piping radiation losses. In the absence of a

detailed study of radiation and vent losses, a

minimum 10% safety factor should be used.

Pressure Reducing Valves — Maximum unit ratings

are based on 14 psig steam pressure at the

generator inlet. Operation at higher inlet pressures

or with more than 100 F superheat is not per

missible. Higher inlet pressures may lead to over

concentration.

Where steam supply pressures are above 15 psig

(14 psig + 1 psig for control) and below 20 psig,

the steam control valve can be used to reduce the

pressure. If steam supply is above 20 psig, a

pressure reducing valve must be provided between

the steam supply and the control valve inlet. A

safety relief valve should be provided between the

steam control valve and the generator inlet. This

valve must be set in accordance with paragraph

UG-133 (f) of the ASME code to relieve at a

pressure not exceeding 17 to 18 psig or the setting

determined by apphcable local codes.

Further specific details relative to pressure

reducing stations should follow accepted standards,

such as the ASHRAE Guide and manufacturer’s

recommendation. For applications on high-pressure

district heating, the steam utility should be con

sulted for local codes or standards.

Steam Piping should be sized to avoid excessive

pressure drop or excessive velocities. Recommenda

tions and pipe sizing tables are given in the Carrier

System Design Manual. It is recommended that

lines be sized on the basis of design system flow for

the machine plus a 10 to 20% safety factor to

allow for normal radiation losses.

Form 16JB-2XA

Summary of content (11 pages)

PAGE 1
Application Data Carrier 16JB Application Detail 5 qP£È.S<£ù£ 5 ¡sy Hermetic Absorption Liquid Chillers GENERAL STEAM MACHINES Application details in this publication cover various methods of applying the 16JB absorption machine to meet liquid chilling needs. Throughout this publication, the chilled liquid will be water. Subjects covered are chilled water temperature control, condenser water temperature control, system design for steam and hot water machines, and general information.
PAGE 2
Start-Up Demand — Steam demand by the absorp tion machine is greatest at start-up (see Table 1 for values). Table 1 — Maximum Condensate Flow (Ib/hr) VALVE SIZE (in.) 2 2Y2 3 4 5 VALVE INLET STEAM PRESSURE 20 psig 14 psig 12 psig 10 psig 2450 4825 8175 14540 21650 2025 4000 6760 12025 17900 1880 3710 6285 11190 16655 1750 3430 5810 10350 15400 When boiler capacity is unable to keep up with start-up demand, the steam pressure will fall off.
PAGE 3
FROM SEMERATOR (LEFT END) MACHINE Sizes 16J8077 THRU IZA Fig. 3 — Typical Atmospheric (Vented) Condensate Return System outlet, and trap outlet pressure. A vacuum breaker is factory installed to ensure that operating steam pressure in the generator does not fall below atmospheric pressure. Use the following formulas to determine available trap pressure drop: Trap pressure drop = trap inlet ~ trap outlet psig. Trap inlet pressure = 0 psig + hydrostatic head to trap inlet -- condensate leg pressure drop.
PAGE 4
At this time, pressure drop across the steam control valve is maximum. If boiler capacity is large enough, the control valve inlet pressure will stay at design, then flow rate will be limited by control valve capacity. Table 1 gives maximum condensate flow for different inlet steam pressures. Interpolate for intermediate pressures. If steam demand on start-up can be held within a controlled limit, the trap(s) may be sized accordingly.
PAGE 5
# into the vacuum pump condensate return system. If this method is used, it is desirable to use either cold boiler feed water or any other cold water source which will benefit by heat rejected from hot condensate. CLOSED CONDENSATE RECEIVER TO lA S П r~ 1------------------------------------- 1 NOTE' Each J5IKÌ 5s similar t o O f ) CLOSED CONDENSATE (PRESSURIZED) RETURN CLOSED CONDENSATE RECEIVER 1 1 til TO L-b^-eoa^ l&lóOliKSeS machìnes.
PAGE 6
cw ASR ncfTmTSR <5cJ«3RA70R PlPtNS rOR MACHINE SiZES 16>® 077 THRO 124, OR TWO St^íGt£-£^íO MACHINES fN PARAiXEL. P(PiN<3 FOR MftCHiNE SIZES 077 THRU OR TWO SiNGL£-EN0 MACHINES iNRARALLEL t24 “Acid for 3-way vaive usaae. Pipe MC port (when 3-way valve useO) to generator irvieris). Fig. 6 — Suggested Piping For Hot Water Machines Using Supply Hot Water 300 F or Below A three-way valve is recommended to ensure a constant system flow of hot water supply re gardless of load.
PAGE 7
VALVE SIZING — The hot water capacity control valve CV2, should be sized to handle full design flow on machine sizes 010-068. Valves CV2 and CVS on machine sizes 077-124 are each sized at one-half design flow. The pressure drop and sizing formula used in sizing the valve(s) should be consistent with valve manufacturer’s recommenda tions. The three-way diverting valve should be sized to handle the design supply of high-temperature hot water (HTHW) and must be suitable for high temperature duty.
PAGE 8
The generator shell and some of the machine piping will become hot during operation. If insula tion is to be used as a safety precaution, or to reduce ambient temperature in the machine room, we recommend insulating the surfaces shown in Fig. 9. Hot-surface dimensions are given in Table 3. Generator insulation can be either blanket-type or low-pressure boiler insulation. Insulation used for piping is generally standard low-pressure steam pipe insulation.
PAGE 9
The integral shipping skids, or base rails, are normally left on the machine. However, the base rails may be removed, if desired, but not until the machine is in final position. When isolation pads are used, they should be located under the corners of the machine, atop soleplates with 1/2-in. min imum thickness (see Fig. 10). The soleplate ensures machine contact on the floor only at the corners when base rails are left on. Shims may be inserted under the soleplates for leveling the machine.
PAGE 10
Tube Removal — Clearance for tube removal the need arise. Refer to Fig. 11 for tube pulling clearance dimensions and data. Evaporator, absorber and condenser tubes may be pulled from either end. should be considered when planning a piping system. The 16JB machines are designed so all tubes are accessible for cleaning or servicing should UNIT 16J8 010,0i2.0U 0t8,02t 024,028 032,036 041,047 054,057 061,068 077,084 097,107 115,124 COVER PLATE WEIGHTS* (lb) — in.
PAGE 11
Manufacturer reserves the right to change any product specifications without notice. CARRIER AIR CONDITIONING COMPANY • SYRACUSE, NEW YORK Tab 15 Form 16JB-2XA New Printed in U.S.A. 6-71 Codes MA and ML Catalog No.