Refrigerant Piping Handbook - Icemeister

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Refrigerant Piping HandbookbyGarth DenisonRefrigerant Piping Handbook.ppt

Suva refrigerantsAcknowledgementsThe author wishes to acknowledge the contribution of variousfriends, co-workers and former colleagues. Gino DiFebo,Nick Reggi, Wesley Taylor and Laurence White enriched thepages of this work with their perspectives and knowledge. Itwas their participation, discussions, review and comments thatmade this publication possible.DedicationTo the advancement of the profession and its members.

Suva refrigerantsTable of ContentsEngineering Data .Section OnePiping Losses .Section TwoNomographs .Section ThreePiping Procedures .Section FourExpansion / Contraction .Section FiveBest Practices .Section SixQuick Pick Criteria .Section SevenHFC Quick Pick Tables .Section EightHCFC Quick Pick Tables .Section NineCFC Quick Pick Tables .Section Ten

Engineering DataSection 1

Suva refrigerantsEngineering DataSection 1 page . 1

Suva Engineering Data Section OneDesign Goals .page3Application Considerations .page 5Code Regulationspage refrigerants6General Design Principles page 7Capacity versus Pressure Drop page 8Equivalent Lengths .page 9Copper Tubing Specifications .page 10Weight of Refrigerant in Copper .page 11Refrigerant Receivers .page 12Temperature / Pressure tables .page 13Refrigeration Piping Schematics .page 14TEL Work Sheets page 16Glossary of Terms .page 18Section 1 page . 2

Suva refrigerantsRefrigerant PipingDesign GoalsA common goal is to size the Suction, Hot Gas and Liquidlines for about 1Fº pressure drop at design capacity.A Suction line must:The Hot Gas Discharge line must: return oil from the evaporator to thecompressor at minimum system capacity. avoid oil trapping at minimum systemcapacity. prevent oil draining from an active to aninactive evaporator when more than oneevaporator is used in a single system. prevent backflow of oil or liquidrefrigerant to the compressor during lowcapacity or shutdown. dampen or eliminate line vibrations and noisecause by compressor vibration. minimize line sweating from condensation.dampen or eliminate line vibration andnoise caused by gas pulsations andcompressor vibration. prevent unnecessary heat gain into therefrigerant.continued .Section 1 page . 3

Suva Refrigerant PipingrefrigerantsDesign GoalsThe Liquid line must prevent: formation of flash gas upstream of the meteringdevice. heat gain to the refrigerant.The Hot Gas Defrost line must: maintain sufficient refrigerant flow rate. Thevelocity determined at saturated conditionswill result in a conservative line size. be properly sized to handle the calculatedneeded hot gas load, this is based on twice theevaporator flow rate. prevent condensed liquid refrigerant frombackflow to the compressor while on defrost orshutdown.The refrigerant Condensate line must: provide sewer-type flow; that is, free draining ofliquid refrigerant in one direction, whilerefrigerant vapour flows adjacent to the liquid inthe other direction.Good refrigeration piping design requires that the refrigeration lines be pitched in the direction of flow atapproximately 1/2 inch per 10 feet or 1 inch per 20 feet.Refrigerant velocities in vertical lines should be at least 1500 ft/min to ensure good oil return;velocities in horizontal lines should be at least 750 ft/min.Section 1 page . 4

Suva Refrigerant PipingrefrigerantsApplication Considerations System design for MINIMUM pressure drop.Pressure loss results in:a. decrease in thermal capacityb. increase power requirements (see page 8) Refrigerant being piped DOES NOT change state. Lubricants are miscible with refrigerants. minimize the accumulation of liquidrefrigerant in compressor crankcase oil returns to compressor at same ratewhich it leavesSection 1 page . 5

Suva Refrigerant PipingrefrigerantsCode RegulationsDesign should conform to all codes, law and regulations thatapply at the “SITE” of the installation.Examples:Mechanical Refrigeration Code . CSA B52Canadian Building CodeASHRAE 15Municipal / State / Provincial CodesOEM’s Recommended Installation GuidelinesSection 1 page . 6

Suva Refrigerant PipingrefrigerantsGeneral Design Principles Ensure proper feed to evaporators. Practical line sizes without excessive pressure drop. Protect compressor by: preventing excessive oil from being trapped in asystem. minimizing oil loss from the compressor. preventing liquid refrigerant or oil from entering thecompressor while operating or while on the off cycle. maintaining a clean and dry system.Section 1 page . 7

Suva refrigerantsRefrigerant PipingCapacity Versus Line Pressure DropVapour LinesLiquid LinesCapacity % HP/Ton %Pressure drop not as critical as in vapour lines.No line loss100.0100.02F º Suction line95.7103.5 vapour formation in line2F º Hot gas discharge line 98.4103.5 insufficient liquid pressure at DX device92.2106.84F º Hot gas discharge line 96.8106.84F º Suction linePressure drop should not cause:Typical liquid line pressure drop no greaterthan 1Fº change in refrigerant temperature.Section 1 page . 8

Suva refrigerantsRefrigerant PipingEquivalent Lengths of Nonferrous Valves and FittingsEquivalent Length is expressed in Feet of PipeLine SizeODGlobe /SolenoidValveAngle /CheckValve90 º SRElbow1/2951.40.95/81261.53/41477/8151 1/890 º LRElbow45 ºElbowEnlarging Coupling1/23/4Reducing Coupling1/23/4Tee Line 71.80.91.54.54.73.01.02.31.81.01 3/828153.62.41.21.86.05.83.61.22.92.21.21 5/835174.22.81.42.07.08.04.81.64.03.01.62 1/845225.93.91.83.010.0106.12.05.03.82.02 5/851266.94.62.23.512.0138.02.66.54.92.63 1/865347.75.52.74.515.0159.23.07.76.03.03 5/880409.86.53.05.017.017113.89.06.83.81/4dMuller Brass Co. DataNote: General accepted industry practice for determining the equivalent lengths for both P traps andU Bends is to add two 90 LR elbows of the specific OD tubing size for each component used.1/4DDdCarrier Engineering Manual number 3Enter table for losses at smallest diameter “d”Section 1 page . 9

Suva Refrigerant PipingrefrigerantsCopper Tubing SpecificationsNominal (OD)DiameterType3/8DiameterOD InID InFlow Areasq. In.WeightLb/Lin 0.7850.4360.4840.6410.4551 1/8KL1.1251.1250.9951.0250.7780.8250.8390.6551 3/8KL1.3751.3751.2451.2651.221.261.0400.8841 5/8KL1.6251.6251.4811.5051.721.781.361.142 1/8KL2.1252.1251.9591.9853.013.102.061.752 5/8KL2.6252.6252.4352.4654.664.772.932.481967 ASHRAE Guide and Data Book3 1/8KL3.1253.1252.9072.9456.646.814.003.33{ Maximum allowable hanger distanceas per CSA B52 code3 5/8KL3.6253.6253.3853.4259.009.215.124.294 1/8KL4.1254.1253.5573.90511.712.06.515.38Maximum Spacing Between PipeSupports for Copper TubingNominal (OD)DiameterMax. Spanin Ft.5/87/81 1/81 3/81 5/82 1/82 5/83 1/83 5/84 1/8567891011121314{Based on ASTM B-88 standardSection 1 page . 10

SuvaWeight of Refrigerant in Copper Tubing refrigerantsPounds per 100 feet of Type K & L Tubing( Weight at 77ºF / 25ºC )Flow AreaTube O.D. (2) sq. in1/25/83/47/81 1/81 3/81 5/82 1/82 5/83 1/83 5/84 1/8KLKLKLKLKLKLKLKLKLKLKLKLCu ft /100ftR-1281.84 2.32L (1) VR-134aR-401AR-402A R-404A 16V75.28L2.02V74.52L1.81V71.86L4.32 65.45 4.00VL (3) 6115.40.960.63 11.40.3113.30.3812.10.4511.70.3711.70.67 487.43.2481.95.09171.34.86 156.05.78 151.04.79159.08.71 157.64.23 156.03.79 150.49.04137.08.37 148.25.48 138.88.62175.94.99 160.25.93 155.15.93163.28.94 161.84.34 160.13.89 154.49.28140.78.60 152.15.63 142.58.85264.77.50 241.08.93 233.47.41 245.6 13.45 243.56.53 241.05.85 232.413.97211.7 12.94229.08.47 214.413.327.59 251.7 13.79 249.56.69 247.06.00 238.114.32216.9 13.26234.68.68 219.813.659.31 343.58.34 331.219.90 301.7 18.43 326.3 12.10 305.718.99271.27.69 247.09.15 239.1377.210.70 343.512.72 332.610.55350.1 19.17347.0387.210.98 352.613.06 341.413.06359.3 19.68356.19.56 352.68.56 340.020.43 309.6 18.92 345.0 12.40 313.819.49511.414.50 465.717.25 450.914.31 474.6 25.99 470.412.62 465.711.31 449.126.99 409.0 25.00 442.416.37 414.425.7526.36523.614.84 476.817.66 461.714.65 485.9 26.62 481.612.92 476.811.58 459.827.64 418.7 25.59 453.016.76 424.3664.018.82 604.722.39 585.518.58616.3 33.75 610.816.39 604.714.68 583.135.10 531.1 32.46 547.521.26 538.133.43680.719.30 619.922.95 600.219.05631.7 34.60 626.116.80 619.815.05 597.735.93 544.3 33.27 588.821.79 551.634.27NOTES: (1). L . saturated liquid & density, V . saturated vapour & density, (2). Copper Tubing as per ASTM – B88, (3). for R-507 use R-404A valuesSection 1 page . 11

SuvaRefrigerant Receivers refrigerants( R-22 capacities at 90º F and 90% full. )Density of R-22 at 90º F is 72.71 lbs per cubic footVertical ReceiversHorizontal Receivers( R-22 capacity in lbs. )( R-22 capacity in lbs. )Dia. length lbs.Dia. length lbs.Dia.3.5 x 7.5 23.5 x 10 35x 28 189 3/4 x 22 5166x 30 28x 36 3410 3/4 x10 3/4 x10 3/4 x10 3/4 x10 3/4 x3648607296 10514217921629012 3/4 x12 3/4 x12 3/4 x12 3/4 x48607296 1962482994044x 10 455x 10x 20 6 136 5/8 x 38 43lengthlbs.7 5/8 x 28 416666xxxx12182430 101622288 5/88 5/88 5/88 5/88 5/8Note: Dia. and Length are in inchesxxxxx2836424860 53 69 81 93 117Dia. length lbs.1414x 72 363x 96 489161616x 60 388x 72 470x 96 63318x 72 597202020x 72 736x 84 866x 96 996Note: Dia. and Length are in inchesFor alternate refrigerant storage capacities in pounds for R-22 rated receiversmultiply the rated capacity by the following conversion factors.Example: A receiver that measures 12 3/4" x 72" has a R-22 rated capacity of 299 lbs.What is its revised capacity if this receiver is used with R-407C ?299 lbs x 0.9473 283 lbs.R-22 .R-123 .R-124 .R-134a .86820.94730.88531.0278R-410A . 0.8794R-507 . 0.8674Notes: Receivers capacities source . Standard Refrigeration Company.All dimensions are expressed in inches and all weights are expressed in pounds.Densities sourced from E.I. DuPont Thermodynamic Tables,R-507 . AlliedSignal Inc., computer program,R-408A and R-409A . Elf Atochem, computer program.Section 1 page . 12

SuvaTemperature / Pressure Chart CompleteRange of Temperature ApplicationsHigh, Medium and Low Temperature ApplicationsºFR-12R-22R-502R-134aR-404AR-407C refrigerantsVery Low Temperature 59-18-15-12- 9- 7434855626989991091211326673819099- 4- 5282302324347372445479510543577Bubble / 101- 98- 96- 93- 909”5”1”251471013036913- 87- 84- 82- 79- 76-100-95-90-85-8071114182317222632381721263238- 73- 71- 68- 66- 2606877- 59- 57- 54- 51- 9285951071191328798110122135- 46- 43- 40- 37- 136149146160176193211150165181198217- 32- 29- 26- 23- 21Bubble / DewNote: Pressure / ºC temperature values are rounded off to the nearest whole number, and the values are expressed in PSIG or inches Hg.Section 1 page . 13

Suva refrigerantsRefrigerant Line IdentificationCondenserLiquidCondensate lineRoof LineHot Gas Binding LineDischarge LineReceiverLiquid LineHot Gas By-pass LineLiquidBy-pass lineCompressorHot GasDefrost LineTXVSuction LineEvaporatorSection 1 page . 14

Typical Refrigeration Piping SchematicTXV((((((((refrigerantsTXV(( (TXVSuva()))Evaporator # 1SEvaporator # 2Evaporator #3Refrigerant in useSaturated Suction Temperature (SST)Saturated Condensing Temperature (SCT)Design LoadMinimum LoadType L copper tubing and all long radius elbowsFilter / DrierAir Cooled Condenser((((((OilseparatorReceiverVapour Lines equivalent lengths;Suction line . H , V , R /Discharge line . H , V , R /Hot Gas Defrost line . H , VLiquid Line equivalent lengths;Liquidline . H , V , R /Note: H is horizontal, V is vertical, R is riserSection 1 page . 15

Suva Determining Total Equivalent LengthsSuction LineEquivalentft./unitDischarge LineTotal Eq.FeetEquivalentft./unitrefrigerantsLiquid Condensate LineTotal Eq.FeetQuantitySizeEquivalentft./unitTotal Eq.FeetActual run of pipe in feet(riser #1)N/AN/AN/AN/AActual run of pipe in feet(riser #2)N/AN/AN/AN/AShort radius elbows (1st)N/AN/AN/AN/AShort radius elbows (2nd)N/AN/AN/AN/ALong radius elbows (3rd)N/AN/AN/AN/ALine Flow teeN/AN/AN/AN/ABranch Flow teeN/AN/AN/AN/AN/AN/AN/AN/AComponent Description QuantitySizeQuantitySizeActual run of pipe in feet(main)Long radius elbows (1st)Long radius elbows (2nd)45º elbowsGlobe / Solenoid valveAngle / Check valveFilterN/AN/AN/AN/AMisc:Equivalent length ofSuction Lineft.Equivalent length ofDischarge Lineft.Equivalent length ofLiquid Condensate Lineft.Sub total # 1page 1 of 2ft.Section 1 page . 16

Suva Determining Total Equivalent LengthsLiquid LineHot Gas Bypass LinerefrigerantsHot Gas Defrost LineQuantitySizeEquivalentft./unitTotal Eq.FeetQuantityActual run of pipe in feet(main #2)N/AN/AN/AN/AN/AN/AN/AN/ASight glass / N/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AComponent Description QuantitySizeEquivalentft./unitTotal Eq.FeetEquivalentft./unitSizeTotal Eq.FeetActual run of pipe in feet(main)Short radius elbows (1st)Short radius elbows (2nd)Long radius elbows (1st)Long radius elbows (2nd)Long radius elbows (3rd)Line Flow teeBranch Flow tee45º elbowsGlobe / Solenoid valveAngle / Check valveFilterMisc:Equivalent length ofLiquid Lineft.Equivalent length ofHot Gas Bypass Linepage 2 of 2ft.Equivalent length ofHot Gas Defrost Lineft.Sub total # 2ft.Sub total 1 2 GRAND TOTALft.

Suva refrigerantsGlossary of Terms ACR: Air Conditioning Refrigeration tubing, this tubing has been internally cleaned, sealed and presserizedwith dry nitrogen. The specification are either type K or L copper tubing.Access Fitting: a fittings that allows a means of accessing the internal pressures within a system.Ancillary Devices: auxiliary devices pertaining to the system. Examples include but are not limited to thefollowing; sight glasses, mufflers, ORI/ORD, oil separators, receivers, accumulators etc:.Base Trap: a " P " trap located at the foot of a riser or vertical lift.Cap Tube: a fixed orifice metering device of various lengths and inside diameter.Distributor: located after the TXV and will distribute refrigerant through various feeder tubes to activelyfeed the refrigerant to the evaporator.Fixed Orifice Device: various forms of metering devices such as; capillary tube, accurators, orifice plates etc:.Hangers: devices that are located at a pre determined distance apart that support and secure the refrigerantpiping system.Insulation: a material installed around the outside diameter of refrigerant tubing that retards the transfer of heat.Inverted Loop: a loop at the top of a vertical rise that will turn the flow of refrigerant 180 degrees.continued .Section 1 page . 18

Suva refrigerantsGlossary of Terms LR elbow: Long Radius elbow.NRE: Net Refrigeration Effect. The refrigeration work completed in the evaporator.OD: the Outside Diameter of the ACR refrigerant tubing being used or specified.“ P ” Trap: a 180 degree return bend loop located at the bottom of a pipe riser to help insure oil return or helpprevent a liquid from settling on the heads of the compressor during it’s off cycle.Piping: the act of doing / installing the required system piping or describing the completed piping system.Pitch: the slope / grade, 1/2 inch per 10 feet, of the piping run that is pitched in the direction of refrigerant flow.Pull Box: an enclosed box usually located in the floor, where joints are made when long runs of tubing are used.SCT: Saturated Condensing Temperature.Service Valves: valves so located that a service technician using the proper tools will have access to therefrigeration circuit.Side Inlet T: a device located after the thermostatic expansion valve, before the distributor that will allowfor the introduction of hot gas into the evaporator as a means of capacity control.continued .Section 1 page . 19

Suva refrigerantsGlossary of Terms SR elbow: Short Radius elbow.SST: Saturated Suction Temperature.TEL: Total Equivalent Length, referring to the individual refrigerant piping run.TEV / TXV: Thermostatic Expansion Valve.THR: Total Heat of Rejection, usually the condensers capacity.Tubing: the actual physical material of construction of a refrigerant piping system. This materialis usually ACR tubing and is measured / known by its outside diameter.Section 1 page . 20

Guide Notes:Suva refrigerantsSection 1 page . 21

Guide Notes:Suva refrigerantsSection 1 page . 22

Piping LossesSection 2

Suva refrigerantsRefrigerant Piping LossesSection 2 page . 1

Suva refrigerantsPiping Losses Section TwoCause and Effect .page 3Section 2 page . 2

Suva refrigerantsCause and Effect of Pressure DropPressure Loss Results in:Decrease in Thermal CapacityIncreased Power RequirementsSection 2 page . 3

Suva Cause and Effect of Pressure DroprefrigerantsPressure drop occurs during fluid flow as a result of frictional forces within the fluid and frictional forcesbetween the moving fluid stream and the stationary pipe walls. The amount of pressure drop depends on anumber of variables, including:****type of flow, e.g., laminar, turbulent, etc.physical properties of fluid, e.g., viscosity, density, etc.pipe characteristics, e.g., diameter, roughness, etc.velocity of flow in pipePressure drop increases in proportion to the length of pipe. Pressure drop is also increased by anythingwhich disturbs the flow, such as valves, tees, elbows and other fittings.compressorliquid tem pressuredischarge lineTXVsystem pressureIn refrigerant piping, some pressure drop occurs in both vapour and liquid lines. These pressure drops canhave a significant impact on system performance. The effect of these pressure drops must be anticipatedand compensation made in the total design.suction lineSystem pressures actual pressure changes including the effects of pressure dropSection 2 page . 4

NomographsSection 3

Suva refrigerantsRefrigerant Piping Nomograph’sSection 3 page . 1

Suva refrigerantsNomographs Section ThreeWhat is a nomograph .page 3 page 4Velocity nomograph page 5Pressure nomograph page 6Using a nomographSection 3 page . 2

Suva refrigerantsNomographA graph having three parallel straight lines, each graduated for a differentvariable so that a straight line cutting all three intersects the related valuesof each variable. A chart representing numerical relationships.Before using a refrigerant nomograph you must know the following facts:******The system refrigerant type (example R-22)System design capacity (example 6.0 tons)Saturated Suction Temperature (SST) (example - 20 F)Saturated Condensing Temperature (SCT) (example 100 F)Maximum allowable pressure drop for each refrigeration lineMinimum allowable velocity for each refrigeration lineContinued .Section 3 page . 3

Suva refrigerantsNomographUsing the Refrigerant Pressure Drop or Velocity Nomograph1. Select the proper nomograph chart.2. Enter at the design refrigeration capacity at the top of the chart.3. From the refrigeration capacity location drop vertically untilintersecting the saturated evaporator temperature (SST) line,the discharge lines and ending at the saturated liquid line.4. At this evaporator temperature location draw a horizontal lineintersecting the diagonal tubing lines.5. Select the desired pressure drop or velocity on the saturatedcondensing temperature line at the bottom of the chart and drawa vertical line to intersect the previously drawn horizontal line.6. Select the proper suction line tubing size from where these twolines intersect.7. Confirm the pressure drop in psi per 100 feet or velocity of selectedtubing just below the saturated condensing temperature (SCT) line.8. Repeat the above outline steps for the discharge and liquid lines.Section 3 page . 4

Refrigeration CapacityTon of refrigeration0.1 0.5 1 2 4 6 10 20 40 60 8tubi ng1/2{" Velocity "Evaporator TemperatureapEv-60F-atorortemreturaep ExampleF40Discharge Line0F- 2 0FeF20 F40erglinhaiscDLiquid LineNOTE: This is a graphicrepresentation only, usespecific nomograph forspecified 6080100LiquidlineRefrigerant Line SizesLoad 17 tons {SST 0 F SCT 120 F }Design Liquid line is 200 fpmDesign Suction line is 2000 fpmLiquid line is 1/2 inchSuction line is 7/8 inchAt 80 F CondensingAt 100 F CondensingRefrigerant VelocityAt 120 F 0100}Condensing TemperaturesVelocity in feet / minuteSection 3 page . 5

Refrigeration CapacityTon of refrigeration0.1 0.5 1 2 4 6 10 20 40 60 100Nomograph{21/825/831/8" Pressure "Example15/8EvapO.D.orattypor teLempcoppereraturetubi ngEvaporator TemperatureDischarge Lineee linhargDisc7/813/811/8- 60- 40 F- 20 F0 F F2040 FF 204060801002468100.60.813/81/2Refrigerant Line SizesLiqui5/8d line3/4Liquid LineLoad 20 tons {SST minus 20 F SCT 100 F }Suction line P 1.5 psi / 100 ft.Liquid line P 7.5 psi / 100 ft.Suction line is 1 5/8 inchLiquid line is 5/8 inchNote: is this case the liquid linepressure drop would be okay ifliquid line was only 20 ft. Long.NOTE: This is a graphicrepresentation only, usespecific nomograph forspecified refrigerantAt 80 F Condensing}Pressure dropAt 100 F CondensingCondensing Temperatures204060801002468100.60.81At 120 F CondensingPressure drop in psi per 100 feetSection 3 page . 6

Piping ProceduresSection 4

Suva refrigerantsPiping ProceduresRefrigerant piping should be designed and installed to accomplish the "Design Goals"as outlined in this Refrigerant Piping Handbook.Section 4 page . 1

Suva refrigerantsPiping Procedures Section FourRecommended Procedure .page 3Heat Rejection Factors . .page 5Double Risers . . page 6Double Riser Examples page7Typical Condenser Piping page8Liquid Condensate Piping page 10Effects of Height on Pressure .page 11Pipe Hanger Spacing page 12Section 4 page . 2

Recommended Procedure for Determining the Proper RefrigerantPipe Sizes for Typical Refrigeration and Air Conditioning SystemsTo carry out these objectives you will require the following:1.2.3.4.5.6.7.8.9.10.11.This check list.A pressure / temperature chart for the specified refrigerant.DuPont’s Refrigerant Piping "Quick Pick" Handbook.The minimum and maximum design load conditions for this specific refrigeration / air conditioningsystem.Obtain the saturated suction temperature, saturated condensing temperature for this specific system.Determine the maximum allowable pressure drops expressed in psig for this specific refrigerantat the stated design conditions.Using the accepted industry standard of plus 50 %, determine the approximate equivalent length bymaking a reasonable estimate of the total equivalent length of tubing for each piping run.Find the preliminary tubing size for each selected piping run.Determine the actual equivalent tube length of each piping run including its fittings andancillary devices.Calculate the allowable pressure drop based on a maximum of 2 F degrees for suction vapourlines and 1 F degree for liquid lines.Add the actual tube length plus the equivalent lengths for all the various fittings and componentsfor each individual pipe run.continued .Section 4 page . 3

Recommended Procedure for Determining the Proper RefrigerantPipe Sizes for Typical Refrigeration and Air Conditioning Systemscontinued .12. Select the suggested tube size from the appropriate "Quick Pick" table for thedesired pipe run.13. Divide the total equivalent length obtained in step 11 above into 100 and multiply by theallowable pressure drop, to determine the pressure drop per 100 feet for the selected linesize. Note: the DuPont pressure drop charts are based on 100 feet.14. If desired plot the actual design situation of the appropriate refrigerant pressuredrop and velocity chart. Keep in mind that the pressure drop chart is based on 100equivalent feet per selected piping run.15. When the actual pressure drop per 100 feet is determined, divide 100 into the calculatedtubing length and multiply by the actual pressure drop per 100 feet. The result will be theactual pressure drop of this selected piping run. The sum of these pressure drops per pipingrun will determine the total system friction losses.The above outlined procedure is for FULL LOAD conditions. For part load conditions alwayscheck your pipe run to insure that you have maintained the minimum recommended velocity of1500 feet per minute. Keep in mind that double risers can be used on either or both the Hot GasDischarge Line and the Suction Line to maintain the minimum acceptable velocity of 1500 feetper minute when PART LOAD conditions exist.Section 4 page . 4

Suva Heat Rejection FactorsrefrigerantsCondenser Load Compressor Capacity x FactorIf heat of rejection figures are not obtainable from the compressor manufacturer, the factors shown in the tablebelow may be used to determine the Total Heat of Rejection (THR).For systems outside the normal limits of single stage compressor applications, such as compound and cascaderefrigeration systems, the following formulae may be used to arrive at the Total Heat of Rejection requirementsfor the selection of the condenser:Open Compressors:Total Heat of Rejection Compressor Capacity (Btuh) (2545 x BHP).Suction cooled Hermetic Compressors:Total Heat of Rejection Compressor Capacity (Btuh) (3413 x kW).EvaporatorTemperatureCondensing Temperature90 F (32 C) F COpen-30-20-1001020304050-34-29-23-18-12- 7- 491.421.361.311.261.221.181.14100 F (38 C)110 F (43 C)120 F (49 30 F (55 C)140 F (60 .551.491.421.351.29Notes:* Outside normal limits of single stage compressor applications.For two stage applications use formulae shown above.Section 4 page . 5

Suva refrigerantsDouble RisersA double riser gives the effect of a downsized riser at minimum load, while providing about thesame pressure drop as a full sized line at full load. The smaller riser is sized to insure oil returnat the minimum capacity step; the larger riser is sized so that the combined “flow areas” of bothof these risers are approximately equal to the main suction or discharge line.1 5/87/8Riser # 21 3/8Riser # 1EvaporatorFull load capacityODarea7/81 1/81 3/81 5/82 1/82 5/83 1/8(0.48)(0.83)(1.26)(1.78)(3.1

Refrigerant Piping Capacity Versus Line Pressure Drop Vapour Lines No line loss 2F º Suction line 2F º Hot gas discharge line 4F º Suction line 4F º Hot gas discharge line Capacity % 100.0 95.7 98.4 92.2 96.8 HP/Ton % 100.0 103.5 103.5 106.8 106.8 Liquid Lines Pressure drop not as cri

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