Microchannel REMOTE AIR COOLED CONDENSER WITH ELECTRONICALLY COMMUTATED AXITOP MOTORS Technical Bulletin Products that provide lasting solutions.
Krack Corporation has a long tradition of leadership and product innovation in the refrigeration industry. Krack s new Microchannel Remote Air Cooled Condenser incorporates a new patented modular assembly. n Smaller size and less weight reduces cost in the building construction. n The new coil has less internal volume resulting in a significant reduction in refrigerant charge. Less refrigerant is environmentally friendly. n Coil slabs are easily replaced from the rear of the unit. Environmentally Friendly Benefits n Reduced Coil Internal Volume - Resulting in a significant reduction in condenser operating and flooding charge. n AxiTop Fan Diffuser - Compared to a standard fan blade and guard, the AxiTop increases CFM 10% while lowering energy consumption 5%. n EC Motor - Continuously variable speed operation provides vastly greater energy savings than traditional fan cycling. California Energy Commission n Models compliant with CEC Title 24 are offered. Table of Contents Benefits and Features 1 System Selections 2 Model Key 2 Applications 3 Performance Data 4 California Energy Commission Title 24 Performance Data 5 Dimensional Data - Standard Model 6 - Receiver Model 7 Receiver Data 8 Control System 8 Electrical Data 9 Control Panel Nomenclature 10 Condenser Control Panel 1 1
Benefits and Features Remote Air-Cooled Condenser Patented Microchannel Condenser Modular Assembly Design (Patent #6988538) n Arranged for vertical air discharge. n Multi-fan sections compartmented to allow individual fan cycling while preventing off-fan windmilling. n Removable end panel for clean out and service access. Corrosion Resistant n All models employ mill galvanized steel fan sections and coil side baffles. n Legs are heavy mill gauge galvanized steel. n Corrosion resistance is improved with an all aluminum microchannel coil, reducing the chance for galvanic corrosion that exists on traditional copper tube and aluminum fin coils. Additionally, the microchannel tubes are coated with a sacrificial metallic layer that is less noble than the tube, fin, and braze material. Protective Cover Panels Compact Design n Lighter weight. - Up to 35% weight reduction compared to traditional condenser design. n Modular construction and fewer parts. - Available in 2 to 14 fan models. AxiTop Fan Diffuser n Design provides a clean path for air to exit and reduces turbulence. n Compared to a standard fan blade and guard, the AxiTop increases CFM 10% while lowering energy consumption 5%. n Sound levels are also reduced thanks to the lowered turbulence. Optional Features n Electro-Fin coated coils. n Mounted receiver. n Reusable air filter. n Module isolation ball valves. Electronically Commutated Motors n Continuously variable speed operation results in significant savings in energy usage. n More accurate airflow control prevents wear and tear on the coil, extending condenser life. n Integral phase-loss, locked rotor, and overheat protection. n Electrical enclosures are protected with labyrinth seals, gaskets, and liquid tight connections for all-weather operation. Versatile Fan Control Methods n Electronic relay boards. n Temperature or pressure speed controls. n No controls. Replaceable High Efficiency Coil n Extruded aluminum microchannel coil construction increases coil efficiency, while reducing refrigerant operating charge, unit weight and footprint. n Unit design allows for coil replacement from rear of unit. US 1
System Selections THR - Total Heat of Rejection n Condenser total heat of rejection (BTU/h) is the sum of the evaporator refrigeration effect and the heat of compression which varies with compressor type and operating conditions. THR Calculation Method n THR = Open Reciprocating Compressor Capacity (BTU/h) + (2545 x BHP) n THR = Suction Gas Cooled Hermetic Reciprocating Compressor Capacity (BTU/h) + (3413 x kw) THR Estimated Method n THR may be estimated by multiplying the rated compressor BTU/h capacity by the compressor operating condition factor shown in Table 1 or 2. Multiply result by altitude factor when applicable. EVAPORATOR TEMP ( F) -30-20 -10 0 10 20 30 40 50 TABLE 2 OPEN COMPRESSOR CONDENSING TEMPERATURE ( F) 90 100 110 120 130 140 1.33 1.28 1.21 1.17 1.14 1.12 1.09 1.42 1.32 1.28 1.20 1.17 1.15 1.12 1.47 1.42 1.32 1.28 1.20 1.17 1.14 Beyond the normal limits for single-stage compressor application. 1.47 1.42 1.32 1.28 1.20 1.17 1.47 1.41 1.36 1.32 1.27 1.23 1.20 1.47 1.42 1.32 1.28 EVAPORATOR TEMP ( F) -40-30 -20-10 0 5 10 15 20 25 30 40 50 FEET 1,000 2,000 3,000 4,000 TABLE 1 HERMETIC COMPRESSOR CONDENSING TEMPERATURE ( F) 90 100 110 120 130 140 1.66 1.57 1.49 1.42 1.36 1.33 1.31 1.28 1.26 1.22 1.18 1.14 FACTOR 1.02 1.05 1.07 1.10 1.73 1.62 1.53 1.46 1.40 1.34 1.32 1.29 1.27 1.25 1.21 1.17 1.80 1.68 1.58 1.50 1.44 1.41 1.38 1.35 1.33 1.31 1.28 1.20 Beyond the normal limits for single-stage compressor application. TABLE 3 ALTITUDE FEET 5,000 6,000 7,000 8,000 2.00 1.80 1.65 1.57 1.50 1.46 1.43 1.40 1.35 1.32 1.27 1.23 1.64 1.56 1.52 1.49 1.46 1.43 1.40 1.31 1.26 1.62 1.59 1.55 1.52 1.49 1.45 1.42 1.35 1.29 FACTOR 1.12 1.15 1.17 Model Key MX H - 06 M UNIT TYPE: MX = Microchannel FAN/MOTOR COMBINATION: H=1020 RPM 2.5 HP EC MOTOR VOLTAGE: K= 208/230/3/60 M= 460/3/60 U= 380/3/50 TOTAL NUMBER OF FANS: 02 10 04 12 06 14 08 2
Applications n Locate Condensers no closer than their width from walls or other condensers. Avoid locations near exhaust fans, plumbing vents, flues or chimneys. n Parallel Condensers should be the same model resulting in the same refrigerant side pressure drops. Compressor discharge lines should have equal pressure drops to each condenser. n Condenser Refrigerant Charge for Summer conditions are listed on the Performance Data Table. The additional Winter Flooding charge required is difficult to predict with fan cycling and is maximized with holdback; however, the maximum additional refrigerant charge is also listed on the Performance Data Table for Winter conditions at -20 F. The Summer operating and Winter maximum flooding charge is substantially less than that required for traditional tube and fin condensers due to the reduced internal volume of the microchannel coils. n Receiver Capacity should be sized to store condenser summer charge, plus the condenser low ambient allowance, plus the evaporator charge, plus an allowance for piping and heat reclaim coil charges. n Compressor Discharge lines should be sized to minimize pressure drops and maintain oil return gas velocities. Each connection should be looped to the top of the condenser. n gravity Liquid Drain Lines should drop from each outlet as low as possible before headering or running horizontally. Pitch downhill to receiver. REFRIGERANT LINE CAPACITY DATA COPPER LINE SIZE O.D. 5/8 7/8 1-1/8 1-3/8 1-5/8 2-1/8 2-5/8 COMPRESSOR LINE CAPACITY IN TONS CONDENSER TO RECEIVER LBS. OF REFRIGERANT LIQUID PER 100 DISCHARGE LINE LIQUID LINE 100 OF LENGTH R-404A R-407A R-134a R-404A R-407A R-134a R-404A R-407A R-134a 0.5 1.0 0.5 3.0 3.6 3.7 11.0 13.0 13.0 2.0 3.0 2.0 6.0 7.4 7.7 22.0 25.0 26.0 4.5 6.5 4.5 10.4 12.7 13.0 36.0 42.0 43.0 7.0 15.0 7.0 16.0 19.2 20.0 55.0 64.0 65.0 15.0 20.0 11.0 23.0 29.0 28.5 78.0 90.0 92.0 30.0 45.0 28.0 40.0 47.0 46.0 138.0 160.0 163.0 45.0 75.0 43.0 62.0 73.0 72.0 212.0 245.0 250.0 Capacity is compressor suction tons for application between -40ºF and +40ºF suction at condensing temperatures between 80ºF and 120ºF sat. For multiple or unloading compressor application, the vertical discharge riser from the compressor may need to be one size smaller. This table data is only to be used as a guide. For exact values, please calculate to your specific job line lengths and design pressure/temp values using ASHRAE handbook or ARI refrigerant tables. 3
Performance Data TOTAL HEAT OF REJECTION (MBH) MX MODEL R-404A / R-507 R-407A TEMP DIFFERENCE TEMP DIFFERENCE 10 F 15 F 20 F 25 F 10 F 15 F 20 F 25 F AIR FLOW (CFM) CONDENSER CHARGE R-404A (LBS) SUMMER WINTER EST. SOUND 10'(dBA) SHIP WEIGHT (LBS) MXH-02 171.1 256.7 342.2 427.8 167.0 250.5 334.0 417.5 27100 4 12 60 674 MXH-04 342.2 513.3 684.4 855.5 334.0 501.0 668.0 835.0 54200 15 26 63 1398 MXH-06 513.3 770.0 1026.6 1283.3 501.0 751.5 1002.0 1252.5 81300 23 40 65 2047 MXH-08 684.4 1026.6 1368.8 1711.0 668.0 1002.0 1336.0 1670.0 108400 40 55 66 2736 MXH-10 855.5 1283.3 1711.0 2138.8 835.0 1252.5 1670.0 2087.5 135500 52 77 67 3420 MXH-12 1026.6 1539.9 2053.2 2566.5 1002.0 1503.0 2004.0 2505.0 162600 80 88 68 4069 MXH-14 1197.7 1796.6 2395.4 2994.3 1169.0 1753.5 2338.0 2922.5 189700 108 106 68 4718 Note: Ratings are based on 85 F - 115 F entering air temperature and 0 F sub-cooling. The temperature difference is between the saturated condensing temp. and the entering air temp. to the condenser. See Electrical Motor Amp Data Table on page 9. CORRECTION FACTOR FOR OTHER REFRIGERANTS CHARGE CORRECTION FACTOR CAPACITY FACTOR REFRIGERANTS MULTIPLY R-404A BY: SUMMER WINTER R-404A 1.00 1.00 1.00 R-134A 0.97 1.17 1.11 R-22 1.02 1.14 1.09 R-407A See R-407A Chart 1.10 1.08 R-407C 0.98 x R-407A 1.09 1.07 NOTE: 1. Ship weight includes ship loose leg weights. 2. Sound data is an estimate only. It can be greatly affected by surroundings. 4
California Energy Commission (CEC) Title 24 n Title 24 is an energy efficiency mandate that applies to equipment sold for use in warehouse and retail food store applications in California. n Air-cooled condensers must meet efficiency standards set in this mandate. n To comply, AxiTop-equipped units operate with a slightly reduced maximum speed. This results in a small drop in capacity and a far larger reduction in energy usage. n The design and controls of the unit remain the same, with only the motor programming changing. California Energy Commission Title 24 Performance Data TOTAL HEAT OF REJECTION (MBH) MX MODEL R-404A / R-507 R-407A TEMP DIFFERENCE TEMP DIFFERENCE 10 F 15 F 20 F 25 F 10 F 15 F 20 F 25 F AIR FLOW (CFM) CONDENSER CHARGE R-404A (LBS) SUMMER WINTER EST. SOUND 10'(dBA) SHIP WEIGHT (LBS) MXH-02 155.8 233.7 311.6 389.5 159.1 238.7 318.2 397.8 24255 4 12 60 674 MXH-04 311.6 467.4 623.2 779.0 318.2 477.3 636.4 795.5 48510 15 26 63 1398 MXH-06 467.4 701.1 934.8 1168.5 477.3 716.0 954.6 1193.3 72765 23 40 65 2047 MXH-08 623.2 934.8 1246.4 1558.0 636.4 954.6 1272.8 1591.0 97020 40 55 66 2736 MXH-10 779.0 1168.5 1558.0 1947.5 795.5 1193.3 1591.0 1988.8 121275 52 77 67 3420 MXH-12 934.8 1402.2 1869.6 2337.0 954.6 1431.9 1909.2 2386.5 145530 80 88 68 4069 MXH-14 1090.6 1635.9 2181.2 2726.5 1113.7 1670.6 2227.4 2784.3 169785 108 106 68 4718 Note: Ratings are based on 85 F - 115 F entering air temperature and 0 F sub-cooling. The temperature difference is between the saturated condensing temp. and the entering air temp. to the condenser. Units compliant with Title 24 are programmed to run their motors at a lessened top speed, significantly reducing their energy usage with a minimal impact on capacity. At full speed, each motor consumes 1169 watts. However, as these motors are continuously variable speed they will use significantly less energy during standard operation. See Corrections Factor Table on page 4. See Electrical Motor Amp Data Table on page 9. 5
Dimensional Data - Standard Model 6
Dimensional Data - Receiver Model (If Applicable) 7
Receiver Data Microchannel is available with a mounted receiver for applications where a remote receiver is desired. Included in the option are extended legs, receiver, 3-way valve, relief valve, rotalocks, ball valves, and ORI/ORD valves. Optional heated and insulated receivers are available. MODEL SIZE 10-3/4 x 48 10-3/4 x 60 12-3/4 x 72 14-3/4 x 96 RECEIVER CAPACITIES @ 80% FULL R-404A (LBS) 114 144 245 395 R-407A (LBS) 126 159 270 435 ADDITIONAL UNIT WEIGHT CONNECTION SIZES NUMBER OF RECEIVERS NUMBER OF FANS 1 2 NUMBER OF FANS INLET OUTLET 02 220-2 1-3/8 1-3/8 04 290-4 1-3/8 1-3/8 06 360 550 6 2-1/8 2-1/8 08 440 620 8 2-1/8 2-1/8 10 600 900 10 2-5/8 2-5/8 12 680 980 12 3-1/8 3-1/8 14 750 1,050 14 3-1/8 3-1/8 Control System Piping Schematic for Winter Control Head pressure control for systems with air cooled condenser is accomplished with two pressure regulating valves designed specifically for this type of application. When low ambient conditions are encountered during winter operation on air cooled systems with a resultant drop in condensing pressure, the Head pressure control s purpose is to hold back enough of the condenser liquid refrigerant so that some of the condenser surface is rendered inactive. This reduction of active condensing surface results in a rise in the condensing pressure and sufficient liquid line pressure for normal system operation. Eternal Equalizer Evaporator Distributor Condenser Gas Check Valve Compressor TEV HM Valve Receiver Solenoid Valve LL Drier 8
Electrical Data Variable speed EC motors provide vast energy savings compared to standard fan cycling arrangements. MX MODEL FAN MOTOR TOTAL FULL LOAD AMPS 208-230/3/60 460/3/60 380/3/50 MXH-02 19.6 9.8 MXH-04 39.2 19.6 MXH-06 58.8 29.4 MXH-08 78.4 39.2 MXH-10 98.0 49.0 MXH-12 117.6 58.8 MXH-14 137.2 68.6 Minimum Unit Circuit Ampacity = 1.25 x FLA of one motor + FLA of remaining motors. Maximum Unit Overload Protection = 4.0 x FLA of one motor + FLA of remaining motors. Power Consumption Compared to Requested Unit Airflow % Power Consumption % Requested Airflow 9
Control Panel Nomenclature CPC EC B 3 1 1 N RELAY BOARD (Optional) If supplied with condenser - specify: Danfoss, Novar, Others CONTROL OPTIONS: NC = No Controls EC = Pressure Controls TF = Temperature Controls CONTROL VOLTAGE: A= 208/230V B= 115V C= No Control Voltage D= 24V E = 208/230V w/o Transformer F = 115V w/o Transformer H = 24V w/o Transformer CONTROL TYPE: 3 = Johnson Electronic 4 = No Controls AMBIENT AIR SENSOR: T = Sensor Provided N = Sensor Not Required TYPE OF APPLICATION: 1= Standard 4 = No Control Operation (Terminal Blocks Only) 5= Winter Reduction (4 fans or more) FUSES AND BREAKERS: 1=Individual Fuses per Fan 2=Individual Circuit Breakers per Fan 4 = Terminal Blocks Only Note: Without Transformer - Control Voltage from Source Outside of Condenser Control Panel 10
Condenser Control Panel Standard Fan Control Panel Arrangement n Standard Johnson Controls adjust fan speed according to pressure. n Control setpoints are adjustable according to the needs of the system. n All fans will continuously vary their speed according to the control signal, providing precise capacity control and energy cost savings. n Internal motor programming allows fans to cycle off individually as system demand decreases. n Relay boards with analog outputs are also offered to allow speed control of these motors. n For full customer control, a no controls option provides individual control connections for each motor. Control Panel n Standard weather resistant enclosure is mounted on the right side of the unit when looking at the headers. n Control power is 24, 115 or 230 volts. A transformer is factory installed when required. n Each motor protected by fuses. n Disconnect not included, but may be required to meet local codes. Optional Arrangements n Winter reduction available on models with 4 or more fans. 11
Condenser Control Panel - Standard Johnson Controls 12
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