Carrier 30GB060 User Manual

4.5 (2)

Advance

Packaged

Product

Air-Cooled

Flotronic™

Data

Liquid Chiller

Nominal 60-Ton Capacity

30GB060

 

 

Features

Unit nominal capacity serves virtually any large com­ mercial or institutional air conditioning need or industrial process cooling requirement.

High-tech solid-state electronic control circuitry tested to U.S. Government Space Agency standards.

Microprocessor control maintains total control over chiller functions, permitting intelligent control of the refrigerant cycle.

Diagnostic module with digital display included to permit rapid troubleshooting just by pressing a button.

Electronic expansion valves (EXV) operate down to ISpsig (103 kPa) pressure differential. (Ordinary ther­ mostatic expansion valve typically requires lOOpsig [690 kPa] differential.) This reduces compressor motor power requirements and improves the unit EER.

Flotronic™ chiller provides up to 28% efficiency im­ provement over standard 30GB chillers on an annual basis.

Additional operating cost savings with precise multiplestep compressor capacity control.

Multiple compressors and dual refrigerant circuits help to protect against the possibility of loss of total capacity.

Semi-hermetic 06E compressors are serviceable in the field.

Designed for outdoor installation to minimize required mechanical room space.

Air-cooled condenser design saves condenser water and eliminates cooling tower.

Domestic units will operate to 115 F (46 C).

Protection against freeze-up — low water temperature cutoff and electric heaters protect cooler.

Available as standard with aluminum fins and copper tubes for normal applications, or with all-copper coils.

Field-installed accessories

Demand limit control module (required for remote ON/OFF control)

Leaving chilled water temperature reset accessory board

Sensor kit assembly for outdoor or space temperature reset of chilled water temperature

Ground current refrigeration circuit protection

Discharge and suction pressure gage panel

Oil pressure switch package includes oil pressure switches (2) for unit

Capacity control: accessory electric suction cutoff unloader

Motormaster® head pressure control (requires unit modification for low-ambient operation)

Factory-Installed option (FlOP)

Thermal expansion valves — For those situations where energy savings of the EXV are secondary and equipment first costs are most important. With this option, the electronic expansion valve and controls related to the EXV function, head pressure control and its related part-load energy savings, are deleted from unit and are replaced by thermal expansion valves and liquid line solenoid valves. Minimum operating ambient for FlOP TXV-equipped units with standard head pressure control is 32 F. Contact your Carrier representative for details on operation at temperatures below 32 F. The FlOP model continues to have microprocessor features and diagnostic capability. Standard accessories are useable.

2-87

Form 30GB-1APD

Table of contents

Features

Page

Dimensions

Page

1

10

Field-Installed Accessories ...............................................

1

Mounting Weights .........................................................

10

Factory-Installed Option (FIOP)......................................

1

Electrical Data ...............................................................

11

Model Number Nomenclature ..........................................

2

Controls .......................................................................

11,12

Physical Data....................................................................

2

Control Sequence ..........................................................

13

Application Data ............................................................

2-6

Typical Installation ........................................................

14

Selection Procedure ..........................................................

6

Guide Specifications....................................................

15,16

Performance Data ...........................................................

7-9

 

 

Model number nomenclature

30GB-AIR-COOLED

30GB 060 - 6

 

— 1 575-3-60

OUTDOOR LIQUID CHILLER

— 5

208/230-3-60

 

— 6

460-3-60

UNIT SIZE (approximates chiller capacity in tons)

Physical data

MODEL 30GB

060

APPROX OPER WT - lb

4900

REFRIG CHG — lb

65

Circuit 1

Circuit 2

85

COMPRESSORS, Type...Rpm

Reciprocating,

 

Semi-Hermetic 1750

(No.) Circuit 1*

(1) 6275

(No.) Circuit 2

(1) A299

Capacity Control Steps

4

Circuit 1 (%)

43

Circuit 2 (%)

57

Minimum Step Capacity (%)

29

CONDENSER FANS — Type

Propeller, Direct Drive

Fan Speed — Rpm

1080

No. Biades...Diameter-in.

 

Circuit 1/Circuit 2

4...26/3 ..30

No. Fans...Total kW

6. 1 92

Totai Airfiow — Cfm

46500

CONDENSER COiLS — Type

Plate Fins (Aluminumf)

Tubes (Copper), OD-in.

'/2

Fins/in. Circuit 1/Circuit 2

14 2/15.0

No. Rows Circuit 1/Circuit 2

%

Face Area (sq ft) Circuit 1

57 5

Circuit 2

57.5

Max. Working Pressure

450

Refrig psig

 

COOLER — No. ...Type

One...Direct Expansion,

Modei 10HA400—

Shell & Tube

824

No. Refrigerant Circuits

2

Net Water Volume — Gal.

17 7

(includes nozzles)

 

Max. Working Press. — psig

Refrigerant Side-235,

 

Water Side-150

WATER CONNECTIONS

MPT

Inlet and Outlet — in.

3

Drain — in. FPT

%

 

 

*6 prefix indicates one electric unioader. "A” prefix indicates no unloader. tCopper fins aiso avaiiabie

Application data

Leveling unit

Unit must be level when installed to ensure proper oil return to the compressors.

While most outdoor locations are suitable for 30GB units, the roof is a common site that presents a problem if roof has been pitched to aid in water removal. To assure proper oil return, be sure that unit is level, particularly in its major lengthwise dimension, as com­ pressor oil return piping runs in that direction.

It should be determined prior to installation if any special treatment is required to assure a level installation.

Cooler temperature

1. Maximum leaving chilled water temperature (LCWT) for Model 30GB is 70 F (21 C). Unit can start and pull down with up to 95 F (35 C) entering water tempera­ ture due to MOP (maximum operating pressure) feature of the expansion valve. For sustained opera­ tion, it is recommended that entering water temperature not exceed 85 F (29.4 C).

2. Minimum LCWT for standard Model 30GB is 40 F (4.5 C). It is permissible to use a standard micro­ processor-controlled Flotronic chiller with leaving water temperatures in the range of 34 F (1°C) to 39.9 F (4.4 C) only if a protective brine solution (20% antifreeze solution, or greater) is used and microprocessor dip switch is properly set. (See Controls and Trouble­ shooting book for further information.) Special order medium temperature brine units must be ordered for operation with leaving water temperatures in the range of 34 F (1°C) to 15 F (-9C). For ratings below 40 F

4.5 C) LCWT, contact your local Carrier representative.

Application data (cont)

MINIMUM COOLER WATER FLOW RATES

AND MINIMUM LOOP VOLUME

UNIT 30GB

MINIMUM

PRESSURE

MINIMUM

FLOW (1)

DROP

VOLUME (2)

 

Gpm

ft of water

Gallons

060

67

3.8

180

NOTES.

1. Minimum flow based on 1 5 fps veiocity in cooier without special cooler baffling

2.Minimum Loop Volumes: Gallons = V X ARl Cap (tons)

APPLICATION

Normal Air Conditioning Process Type Cooling

Low Ambient Unit Operation

Leaving water temperature reset

Accessory board* may be installed in 30GB chillers to provide reset of LCWT in constant water flow systems. Reset reduces compressor power usage at part load when design LCWT is not necessary. Humidity control should be considered since higher coil temperatures resulting from reset will reduce latent heat capacity. Three reset options are offered;

From return water temperature* — Increases LCWT temperature set point as return (or entering) water tem­ perature decreases (indicating load decrease). Option may be used in any application where return water provides accurate load indication. Limitation of return water reset is: LCWT may only be reset to value of design return water temperature. Return reset is the simplest of 3 reset acces­ sories available, as return water sensor is already installed.

From outdoor temperature* — Increases LCWT as outdoor ambient temperature decreases (indicating load decrease). This reset should be applied only where outdoor ambient is an accurate indication of load. An accessory thermistor is required.

From space temperature* — Increases LCWT as space temperature decreases (indicating load decrease). This reset should be applied only where space temperature is an accurate indication of load.

For details on applying a reset option, refer to 30GB Controls and Troubleshooting Instructions.

*Obtain ordering part numbers from current price pages.

Cooler flow range

 

this publication are

Ratings and performance data in

for a cooling range of 10°F or 6°C. Flotronic^" chillers with

microprocessor control may be operated at a different

temperature range provided flow limits are not exceeded.

For minimum flow rates, see Table. High flow rate is limited

by pressure drop that can be tolerated. If another range is

used, apply LCWT correction as given in selection example.

Minimum cooler flow

(maximum

cooler

temperature

range) for standard units is shown in Table. When gpm

(L/s) required is lower (or range higher), follow recom­

mendations below:

 

 

 

a. Multiple smaller chillers may be applied in series, each

providing a portion of the design temperature range.

b. Cooler water may be recirculated to raise flow rate.

However, mixed temperature entering

cooler must

be maintained a minimum of at least 5°F (2.8°C) above the leaving chilled water temperature.

c.Special cooler baffling is required to allow minimum flow rate to be reduced 12%.

CHILLER COOLER

RECIRCULATION

SUPPLY

RETURN

Maximum cooler flow (> 5 gpm/ton or < 5 F range [>0.09 L/s . kW or <2.7 C range]) results in practical maximum pressure drop through cooler.

a. Return water may bypass the cooler to keep pressure drop through cooler within acceptable limits. This permits a higher AT with lower water flow through cooler and mixing after the cooler.

b. Special cooler baffling is available by special order, to permit a cooler flow rate increase of 10%.

CHILLER COOLER

BYPASS

SUPPLY

RETURN

Variable cooler flow rates may be applied to a standard 30GB chiller. Unit will, however, attempt to maintain a constant leaving chilled water temperature. In such cases, minimum flow must be in excess of minimum flow given in Table and flow rate must change in steps of less than 10% per minute. Apply 6 gallons per ton (6.5 liters per kW) water loop volume minimum if flow rate changes more rapidly.

Water loop volume — In circulation must equal or exceed 3 gallons (11.4 liters) per nominal ton of cooling (3.25 liters per kW) for temperature stability and accuracy in normal air conditioning applications. (For example, a 30GB060 would require 180 gallons in circulation in system loop — see Table.) For process jobs where accuracy is vital or for operation at ambient below 32 F (0°C) with low unit loading conditions, there should be from 6 to 10 gallons

Carrier 30GB060 User Manual

Application data (cont)

per ton (6.5 to 10.8 liters per kW). To achieve this volume, it is often necessary to install a tank in the loop. Tank should be baffled to insure that there is no stratification and that water (or brine) entering tank is adequately mixed with liquid in the tank.

GOOD

GOOD

Cooler fouling factor used to calculate tabulated ratings was 0.0005 ft2. hr. °F/Btu (0.000088 m^. K/W). As fouling factor is increased, both unit capacity and compressor power decrease. Standard ratings should be corrected using following multipliers:

FOULING FACTOR

CAPACITY

COMPRESSOR

ENGLISH

SI

MULTIPLIER

POWER

((F . hr. °F/Btu)

(m*. K/W)

 

MULTIPLIER

0.0005

0.000088

1.00

1 00

0.001

0.000176

0.97

0.98

0.002

0.000352

0.91

0.91

Cooler protection in form of ethylene glycol (or other suitable brine) is recommended when operating in areas which experience temperatures below 32 F (0°C) to protect cooler should there be a loss of cooler heater power. Even though unit cooler is protected with insula­ tion and an electric heater that protects the cooler down to 10 F (-12 C), it does not protect water piping external to unit. Use only antifreeze solutions approved for heat exchanger duty. Use of automotive antifreezes is not recommended because of the fouling that can occur once their relatively short-lived inhibitor breaks down.

Draining cooler and outdoor piping is recommended if system is not to be used during freezing weather condi­ tions. See section below for low-ambient operation.

Condenser

Altitude correction factors must be applied to standard ratings at altitudes above 2000 ft (610m) using following multipliers:

ALTITUDE

 

CAPACITY

COMPRESSOR

ENGLISH

 

SI

MULTIPLIER

POWER

(ft)

 

(m)

 

MULTIPLIER

0

 

0

1 00

1.00

2000

 

610

0 99

1.01

4000

 

1220

0 98

1.02

6000

 

1830

0,97

1.03

8000

 

2440

0.96

1.04

10000

 

3050

0.95

1.05

Condenser airflow restrictions will affect the unit capacity, condenser head pressure and compressor power input. Correction factors to be applied for external static restrictions up to 0.2 in. wg (50 Pa) are shown below.

EXTERNAL

 

 

 

STATIC

 

CAPACITY

COMPRESSOR

RESISTANCE

POWER

MULTIPLIER

ENGLISH

 

SI

MULTIPLIER

 

 

(in. wg)

 

(Pa)

 

 

0.0

 

0.0

1 00

1.00

0.1

 

25

0 986

1 01

0.2

 

50

0 968

1.03

High-ambient temperature — Standard 30GB chillers can operate to 115 F (46 C) ambient temperature.

Low-ambient operation

Flotronic^“ 30GB chillers with electronic expansion valves (EXV) will start and operate at ambients down to 0°F (-18 C) with following field provisions:

Wind baffles must be added for operation below 32 F (0°C).

A WARNING

Operation at low ambient is not recommended if minimum load on chiller is below minimum step of unloading.

Protection against freeze-up — It is recommended that field-installed chilled water piping be protected at lower ambient temperatures by wrapping with field-supplied heating cable and covering with 2-in. (50-mm) thick closed­ cell insulation.

Antifreeze solution must be added to water loop to protect loop down to 15 F (8 C) below minimum operating ambient temperature.

For operation of EXV-equipped chillers below 0°F (-18 C) and for operation of TXV-equipped (factoryinstalled option) chillers below 32 F (0°C), down to -20 F (-29 C), the Carrier Motormaster® condenser head pres­ sure control and its associated components must be added. Consult your local Carrier representative for complete details.

Provide sufficient volume in the chilled water loop — At least 6 gallons per ton of refrigerant (6.5 liters per kilowatt) is recommended minimum, provided there is a moderate system load.

Capacity Correction (Antifreeze)

Ethylene glycol (or other suitable brine) should be used in installations where subfreezing temperatures are ex­ pected. Unit performance data must be corrected for the addition of ethylene glycol as shown in following example. Correction factors may be derived from follow­ ing curves.

Example: Where a 5 F outdoor temperature is anticipated, determine concentration of ethylene glycol to protect system to -10 F ambient temperature at zero flow.

Enter the solution crystallization point curve at -10 F, read 40% concentration of ethylene glycol is required to prevent crystals from forming in solution.

Consider the 30GB060 unit from the Selection Pro­ cedure (Water) example (refer to correction curves at 40% solution).

Application data (cont)

Correct

unit

capacity

On

glycol performance

capacity correction curve, read 0.95.

 

 

Corrected capacity = 0.95 x determined capacity

 

 

 

- 0.95 X 61.3

 

 

Correct chilled

= 58.2 tons

 

 

water flow

— On the gpm correction

factor curve, read 1.15.

 

 

 

 

Chilled water flow (at corrected capacity)

 

 

24 X corrected capacity

= U.S. gpm

 

 

temperature rise

 

 

 

24 X 58.2 tons

99.8 U.S. gpm

 

 

14 F

 

Chilled water flow (40% solution) = 1.15x99.8

 

 

 

 

 

= 114.7 U.S. gpm

Correct cooler pressure drop — On cooler pressure

drop correction curve, read 1.33.

 

 

On cooler pressure drop curve, for 114.7 gpm, read

PD = 10 ft water gage. The pressure drop for 40% solution =

1.33 X 10.0 = 13.3 ft water.

 

 

 

Correct compressor power input (kW) — On power

correction

curve, read 0.97

correction factor

at 40%

EG concentration.

Selection

Procedure

example

Power

input

from

= 71.1 kW.

Corrected power input = 0.97 x 71.1 = 68.9 kW.

ETHYLENE GLYCOL PERFORMANCE CORRECTION FACTORS AND SOLUTION CRYSTALLIZATION POINTS

Oversizing chillers

Oversizing chillers by more than 15% at design conditions must be avoided as the system operating efficiency would be affected adversely (resulting in greater/excessive electrical demand). When future expansion of equipment is anticipated, it is strongly recommended that a single chiller be installed to meet present load requirements and a second chiller added to meet the additional load demand.

It is also recommended that the installation of 2 smaller chillers be considered where operation at minimum load is critical. The operation of a smaller chiller loaded to a greater percent of minimum is preferred to operating a single chiller at or near its minimum recommended value.

Multiple chillers

Where chiller capacities greater than 200 tons (703 kW) are required, or where stand-by capability is desired, chillers may be installed in parallel. Units should be of equal size to ensure balanced water flows. Where a large temperature drop (>25F [13.9 C]) is desired, chillers may be installed in series. Water temperature sensors need not be moved for multiple chiller operation. A 10-ft (3-m) separation is required between units for airflow, and a 6-ft (1.8-m) distance is required from units to obstructions. See figure. See Physical Data for service clearances.

 

 

 

(3m)

 

 

 

(I.Sm)

 

 

 

10 FT

 

 

 

6 FT

 

 

 

 

 

 

 

* MINIMUM

 

 

 

MINIMUM

 

 

 

 

 

 

 

 

 

 

/ / / / / /

/

/

 

 

 

 

 

 

 

 

 

 

MULTIPLE UNIT SEPARATION

 

 

 

 

(F)

(C)

 

 

 

 

-40

r-40

 

 

 

 

-20

c -30

 

 

 

 

-10

-20

 

 

 

 

0

 

 

 

 

 

 

 

 

 

+20

-10

 

 

 

 

0

10

20

30

40

50 40

 

% CONCENTRATION (BY WEIGHT)

ETHYLENE GLYCOL

Electrical/utility interests

Energy management — See 30GB Controls and Trouble­ shooting manual and accessory installation instructions for details.

Demand limiting (also called load shedding) — When utilities demand for electricity exceeds a certain level, loads are shed to keep electricity demand below a pre­ scribed maximum level. Typically, this happens on hot days when air conditioning is most needed.

Load shedding must be done intelligently. Demand may be limited on Model 30GB by resetting water tem­ perature, or by using a demand limit accessory that unloads the chiller to a given predetermined percent of the load. Both features require signal from an intelligent central control. Do not cycle demand limiter for less than 10 minutes on and 5 minutes off.

Duty cycling cycles electrical loads at regular intervals regardless of need. This reduces electrical operating costs of a building by “fooling” demand indicating devices. Duty cycling of compressors or fans is not recommended since motor winding and bearing life suffer from constant cycling.

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