Air CooledCondenser Units

Design FeaturesOptional EquipmentModel NomenclatureSelection ProcedureCapacitiesPhysical DataElectrical DataTypical PipingDimensionsPipe PositionApplication ConsiderationStandard EquipmentGuide Specifications

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Table of Contents

1

Design Features that AssureEconomical OperationGeneral

Model RAR-4 air-cooled condenser units meets therequirements of commercial, industrial and residentialapplications. All units are factory assembled, wired andtested and are provided with a holding nitrogen charge.

TAHVIEH air-cooled condenser units provide a clean, andarchitecturally attractive appearance suitable for rooftopor ground level installation. Condenser air intake is fromthe sides of the unit rather than from underneath. Allcomponents are enclosed within the cabinet and thecondenser discharge grilles are fully recessed.

A mild ambient temperature control, which permits theunits to start and operate at temperatures down to 25 ºC(-3.9 ºF), is option on all models.

All models of RAR condenser units are tested and rated inaccordance with ARI 520 and conform to ANSI B9.1 Safety

Code.

Versatility

RAR-4 new design series condenser units feature upto 2 refrigerant circuits, and can be matched with awide variety of air-cooled chiller units.

Weather Resistant Construction

Aluminum extruded structure with heavy gage hot-dipped galvanized steel panel make unit proper forcorrosive environment. For high corrosive ambientconditions, aluminum sheet panels could be used asan optional feature.To facilitate installation, the units are mounted on asteel base channel equipped with lifting lugs. The basechannels are coated with 3 layers of epoxy painting formild humidity ambient condition (as standard) and forhigh humidity ambient air, hot-dipped galvanizedcoating is used. Galvanized steel internal bracing, limitthe noise and vibration transmission.

Automatic Mild Ambient TemperatureControl

A mild ambient temperature control, factory installedon each unit, automatically stages the condenser fans,allowing the unit to start and operate at ambient

temperatures as low as 25 ºF (-3.9 ºC ). It consists oftemperature & pressure-actuated switches that shut offa number of condenser fans when the condensingpressure drops to a predetermined setting. As thepressure rises, the control automatically restarts thefans to maintain an optimum condenser pressure range.

Complete Operating Protection

A control circuit virtually protects the machine underany operating condition. Safety lockout circuitswith manual reset, automatically shut down the unitsignal from the motors safety devices. For immediateshut down, there is a separate main switch.

Condenser Coils

Aluminum plate fins are mechanically bonded onseamless 3/8” OD copper tubes in a staggeredconfiguration for maximum heat transfer efficiency.Copper plate fins is another coil option which is properfor moderate coastal ambient condition. This willimprove cooling capacity of the units, too. (To discoverthe exact difference value contact TAHVIEH)Condenser coils are factory leak tested at 470 psig(33.0 Kg/cm2) air pressure underwater and vacuumdehydrate. Over 10 ºF of liquid subcooling may beobtained, depending upon the difference betweencondensing temperature and the outside ambienttemperature. Subcooling adds to the efficiency of thesystem and assures liquid refrigerant at the expansionvalve even though vertical lifts or long runs of pipingmay be necessary.

Direct Driven Condenser Fans

Propeller-type condenser fans are direct driven. Usingspecial propeller fan with airfoil shape blades causereduction of noise as well as electrical energyconsumption. There are no belts to adjust, no pulleys toalign. Fan motors are three phase with permanentlylubricated ball bearings.

High Starting Torque Motors

The direct driven fan motors are designed to providemore than sufficient starting torque to overcomewindmilling . These motors are specifically selected toproduce trouble-free,consistent performance for this rigorousduty.

2

Optional EquipmentAutomatic Mild Ambient TemperatureControl

A mild ambient temperature control, factory installedon each unit, automatically stages the condenser fans,allowing the unit to start and operate at ambienttemperatures as low as 25 ºF (-3.9 ºC ). It consists oftemperature & pressure-actuated switches that shutoff a number of condenser fans when the condensingpressure drops to a predetermined setting. As thepressure rises, the control automatically restarts thefans to maintain an optimum condenser pressurerange.

Storage Receivers

Normally, receivers are not required in the RAR-4refrigerant circuit. In those instances where thetotal system refrigerant circuit, the refrigerant chargeexceeds the pump-down capacity of the condensercoil, storage receivers with capacities from 95 to576 lbs. ( 43.1 to 261.3 Kg ) are available for fieldinstallation. These are for refrigerant storage duringoff season or service operations and are manuallyoperated. Each receiver is ASME constructed, witha working pressure of 425 psi ( 29.9 Kg/cm2 ), andincludes a relief valve, saddles, drain valveconnection and purge valve.

Isolator PadsLaminated neoprene and cork isolator pads areavailable to minimize operating noise and vibration.

Anti-Windmilling Design

A specific design target for this product has been toremove fan windmilling as a threat to trouble-freeperformance. This requirement was accomplished infour basic ways. First, the fans were recessed belowthe top profile of the unit to eliminate wind effects.Secondly, the multiple fans were arranged to besequenced in-groups such that the static pressuredifferential at start-up is at a minimum. Thirdly, fanswith blades least likely to “turbine” were selected.These steps, plus high starting torque fan motors,minimize windmilling problems.

Condenser Coil Guards

Inlet guards are available to protect the condensercoils from damage. They are fabricated from heavygage steel mesh configuration, hot-dipped galvanizedcoated for corrosion resistance and painted to matchthe condenser coils.

3

Altitude CorrectionApply the multipliers shown to the charted tonnage figures when using RAR-4 units at high altitude.

ReceiversIn those instances where the total system refrigerantcharge exceeds the storage capacity of thecondenser coil and the liquid to the evaporator

Example (English shown, Metric similar) :1 . Given following requirements :A Capacity requirement 41 tons.B Design condensing temperature 125º F.C Outside design ambient = 95º F.D Unit located at 5000 ft above sea level.

2 . RAR4046 will produce 45.8 tons at sea level so :Total unit cooling capacity at 5000 ft ( 1524 m ) = 45.8 x 0.933

= 44.6

Feet of altitude

Tonnage multiplier

KW input multiplier

0

1.0

1.0

5000

0.933

1.015

10000

0.843

1.026

Model Nomenclature

Basic equipment, options and accessories are codedin fourteen positions by letters and numbers.Inaddition to the basic equipment,options should beindicated. The standard equipment coding key forRAR condenser units is listed below. Complete modelnomenclature must be furnished with each order.

position 1-3 :

Position 4 :

Position 5-7 :

Position 8 :

Position 9 :

Position 10-12 :

Product Name

Design Generation

Nominal Tonnage016,024,029,046,055,068,083,097,122,141,163

Condenser fin materialA : Aluminum fin plateC : Copper fin plate

Panel materialG : Galvanized steel sheet panelA : Aluminum steel sheet panel

Accessories- : Standard ( No accessories )R : Storage receiver & relief valveS : Isolator padL : Low ambient control

R A R 4 0 2 5 A G R S LExample:Position : 1 2 3 4 5 6 7 8 9 10 11 12

Selection Procedure

solenoid valve, pump down receivers are offered forf i e ld ins ta l l a t ion . These a re fo r re f r i ge ran tstorage during off season or service operations and aremanually operated.

4

CapacitiesH

eat

Rej

ecti

on (

Ton

s )

Temperature Difference ( Condensing Temp. Minus Ambient Temp. ºF )

163

141

122

097

083

068

055

046

029

024

016

15 20 25 30 35 40

010

2030

4050

6070

8090

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

5

Physical Data

LEGEND :

** Nominal Capacity is at a 30 ºF temperature difference between condensing temperature and ambient air entering condenser ( includes the effect of subcooling )¥ All data based on units without liquid receivers and at 100 ºF liquid temperature and 90% full.

6

LEGEND :

** Nominal Capacity is at a 30 ºF temperature difference between condensing temperature and ambient air entering condenser ( includes the effect of subcooling )¥ All data based on units without liquid receivers and at 100 ºF liquid temperature and 90% full.

Physical Data

7

LEGEND :

** Nominal Capacity is at a 30 ºF temperature difference between condensing temperature and ambient air entering condenser ( includes the effect of subcooling )¥ All data based on units without liquid receivers and at 100 ºF liquid temperature and 90% full.

Physical Data

8

Electrical Data

LEGEND :

RLA - rated Load AmpsFLA - Full Load AmpsMFS - Maximum Fuse SizeMCA - Minimum Circuit Amps

9

Typical PipingRAR Unit With Single System

1. Hot gas lines should rise above refrigerant level incondenser circuit. double riser may be required;check compressor minimum capacity.

2. Trap should be installed on hot gas lines toprevent condenser oil and refrigerant vaporfrom accumulating on compressor headsduring off cycle.

3. Pitch all horizontal lines downward in the directionof refrigerant flow.

4. For piping length greater than 50 ft, provide supportto liquid and gas lines near connection to coil.

5. All must follow standard refrigerant pipingpractices.

10

DimensionsRAR4016

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

11

DimensionsRAR4024

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

12

DimensionsRAR4029RAR4046RAR4055

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

13

DimensionsRAR4068

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

14

DimensionsRAR4083

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

15

DimensionsRAR4097

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

16

DimensionsRAR4122

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

17

DimensionsRAR4141RAR4163

Note: All fixing basement holes are ø16mm (5/8”).

ACCESS SPACE

18

Pipe PositionRAR4016THRU RAR4163

19

Application Consideration

Certain application constraints should be consideredduring sizing, selecting and installing TAHVIEH air-cooled condenser. Unit reliability is dependent uponthese considerations. Where your application varies fromthe guidlines presented, it should be reviewed withTAHVIEH sales engineers.

Unit Placement

A base of foundation is not required if the selected unitlocation is level and strong enough to support the unit`soperating weight. Refer to the weights section for theweight of individual units. ( as listed on page 7 thru 9 ).

Isolation and Sound Emission

The most effective method for noise isolation is proper unitlocation. Unit should be placed away from noise sensitiveareas. Stracturally transmitted noise can be reduced withthe use of spring isolators and they are recommendedfor acoustically sensitive applications. Flexible electricalconduit, for maximum isolation effectiveness, will reducesound transmitted through electrical conduit.State and local codes on sound emissions should alwaysbe considered. Since the environment in which a soundsource is located affects sound pressure, unit placementmust be carefully evaluated.

Servicing

Recommended minimum space envelopes for servicinghave been shown in the dimensional data section and serve asguidelines for providing adequate clearance. The minimumspace envelopes also allow for control panel door swingand routine maintenance requirements.

Unit Location

Unobstructed flow of condenser air is essential tomaintaining capacity and operating efficiency. Whendetermining unit placement, careful consideration mustbe given to assure a sufficient flow of air across thecondenser heat transfer surface. Two detrimentalconditions are possible and must be avoided. Warm airrecirculation and coil starvation. Warm air recirculationoccurs when discharge air from the condenser fans isrecycled back at the condenser coil inlet. Coil starvation

occurs when free airflow to the condenser is restrictedboth warm air recirculation and coil starvation causereductions in unit efficiency and capacity because of thehigher head pressures associated with them. In moreserver cases, nuisance unit shutdowns will result fromexcessive head pressures. Cross winds, those perpendicularto the condenser, tend to aid efficient operation in warmerambient condition. However, they tend to be detrimentalto operation in lower ambient of when hot gas bypass isused due to the accompanying loss of adequate heatpressure. As a result, it is advisable to protect air-cooledcondensers from continuous direct winds exceeding10 miles per hour. Debris, trash, supplies, etc should notbe allowed to accumulate in the vicinity of the air-cooledcondenser. Supply air movement may draw debris in tothe condenser coil, blocking spaces between coil finsand causing coil starvation. Special consideration shouldbe given to low ambient units. Condenser coils and fandischarge must be kept free of snow or other obstructionsto permit adequate airflow for satisfactory unit operation.

Clearance

Vertical condenser air discharge must be unobstructed.While it is difficult to predict the degree of warm airrecirculation, a unit installed with a ceiling or otherobstruction above it will lose capacity and the maximumambient operation will be reduced. Nuisance high headpressure tripouts may also occur. The inlet to the coilmust also be unobstructed. A unit installed closer thanthe minimum recommended distance to a wall or othervertical riser may experience a combination of coilstarvation and warm air recirculation resulting in unitcapacity and efficiency reductions, as well as possibleexcessive head pressures. The recommended lateraldistances are listed in the Dimensional Data section.

Effect of Altitude

The tables in the Performance Data section are for useat sea level. At elevations substantially above sea level,the decreased air density will decrease condenser capacity.Refer to selection procedure to correct performance atother altitudes.

20

Standard Equipment

Condenser Section

Copper Tube and Aluminum fin condenser coilsPropeller airfoil blade shape fanProtected motors with permanently lubricated bearingsRefrigerant PipingCondenser coil filter and guard

Controls

On-Off reset switchPhase protection controlFan Motor FusesFan motor safety switches

Guide Specifications

General

Units shall be tested and rated in accordance with ARI520 and conform to ANSI B9.1 Safety Code.

Air Cooled Condenser

Condenser coils shall be 3/8” OD copper tube,aluminum fin type Coils shall include a subcoolingsection and shall be designed for use with Refrigerant22. Coil circuits shall be factory leak tested at 470 psigunder water.

Fans

The propeller fans shall have air foil blade shape andbedirectly driven by three phase motors. Motors shallrun at 900 rpm and shall permanently lubricated type.They shall be dripproof with built-in overload protection.(Condenser coils shall be protected by factory installedaluminum fine mesh filter with steel mesh cover. Guardsshall be hot-dipped galvanized coated for corrosionresistance and painted to match the coils.)

Operating and Safety Controls

Machine shall include a control panel containing anon-off reset switch, phase protection and terminal board.

Cold Weather Control

An automatic mild ambient control shall be factoryinstalled to provide satisfactory operation at minimumambient temperature down to 25 ºF (-3.9 ºC).