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EOC Series selection

SIZING To properly size a DC fan drive air-cooled oil cooler for mobile equipment, you should first determine some basic parameters associated with the system. HEAT LOAD There are some system parameters that will be required to properly accomplish the sizing calculations. Without system parameters, it is difficult to determine the optimal heat exchanger size. Normally many of the system parameters can be found on hydraulic schematics or on tags located on the actual equipment. Following are some basic param-eters that you should try to acquire before attempting the sizing calculations. However, it is not necessary to have every parameter listed below. • Main system flow rate (gpm) & working pressure (psi). • Electric motor HP driving hydraulic pump (if more than • Desired fan drive (hydraulic, electric, 12-24V DC, etc...). • BTU’s or HP to be cooled (normally given for lubrication systems). • Maximum pressure drop allowed through the heat exchanger. • Space available for heat exchanger (LxWxH). • External air condition (dirty, papers,etc…). In many instances the heat load must be determined by using a “total potential” method. This total potential or horse power method is the most common method, and is the sim- plest way to determine basic heat rejection requirements for mobile hydraulic systems. The total potential is equal to the maximum operating flow and pressure that are generated by the system under full load. To determine the total potential one add up the HP for all). • Desired temperature (°F). • Fluid type (SAE 10, 20, 30, etc....). • Ambient air temperature (warmest day).

Btu/ hr x Cv ____________ T - t ambient 44,538 Btu/hr x 1.13 Cv ________________ 140 o F - 100 o F ambient For most open loop systems with a vane or gear type fixed de - livery pumps. To calculate the Fs value required when applying the air/oil cooler into a return line use the formula. Fs = = 1258 Fs (HP) use the following formula. HP = [ System Pressure (PSI) x System flow (GPM) ] / 1714 Example: HP = (3000 PSI x 40 GPM) / 1714 = 70 HP or the total input potential To determine the system heat load in BTU / HR we must use a percentage (v) of the systempotential HP. The factor (v) can be calculated by adding up the actual inefficiencies of a system; however, for most applications a (v) value of 25% - 30% can be used. Example: 70 HP x .25 = 17.5 HP heat To convert the horsepower of heat into BTU/HR use the for- mula below: HP x 2542 = BTU/HR Example: 17.5 HP x 2545 = 44,538 BTU/HR Applying into a return line T = Desired system oil temperature leaving the cooler °F t ambient = Ambient air temperature entering the cooler °F Cv = Correction factor for oil viscosity. Example: ISO68 oil @ 150°F = 1.13 (see chart below)

Cp PRESSURE DROP CORRECTION FACTORS

Average Liquid Temperature

100 110 120 130 140 150 200 250

2.00 1.70 1.50 1.40 1.30 1.20 0.93 0.81

2.40 2.10 1.80 1.60 1.50 1.30 0.96 0.82

4.40 3.60 3.00 2.60 2.23 1.90 1.20 0.92

6.40 5.10 4.20 3.40 2.90 2.50 1.40 0.97

8.80 6.70 5.60 4.50 3.70 3.10 1.60 1.05

1.07 1.04 1.02 0.99 0.97 0.95 0.89 0.85

1.53 1.45 1.38 1.30 1.23 1.17 0.99 0.93

1.82 1.72 1.60 1.49 1.38 1.30 1.08 0.96

2.54 2.35 2.15 1.94 1.75 1.61 1.18 1.03

4.19 3.73 3.26 2.80 2.38 2.04 1.33 1.11

6.44 5.70 4.91 4.14 3.47 2.90 1.59 1.21

9.38 8.33 7.23 6.19 5.20 4.35 1.74 1.22

13.56 11.63

1.26 1.20 1.14 1.08 1.03 0.98 0.90 0.83

3.00 2.40 2.10 1.90 1.90 1.70 1.20 1.00

3.50 2.90 2.50 2.20 2.00 1.90 1.30 1.05

0.730 0.720 0.709 0.698 0.686 0.676 0.635 0.556

9.73 7.80 6.11 4.77 1.95 1.23

Cv VISCOSITY CORRECTION FACTORS

Average Liquid Temperature

100 110 120 130 140 150 200 250

1.11 1.09 1.06 1.04 1.03 1.01 0.98 0.95

1.15 1.12 1.10 1.08 1.05 1.04 0.99 0.96

1.25 1.20 1.17 1.13 1.11 1.09 1.01 0.97

1.38 1.32 1.27 1.24 1.19 1.16 1.04 0.98

1.45 1.40 1.35 1.29 1.25 1.22 1.07 0.99

1.08 1.06 1.04 1.03 1.02 1.02 0.98 0.95

1.14 1.13 1.11 1.09 1.08 1.06 0.99 0.96

1.18 1.16 1.14 1.13 1.10 1.09 1.00 0.96

1.26 1.25 1.20 1.17 1.16 1.13 1.01 0.96

1.37 1.31 1.27 1.24 1.20 1.17 1.02 0.97

1.43 1.39 1.35 1.30 1.26 1.22 1.08 0.99

1.56 1.48 1.40 1.34 1.30 1.27 1.09 1.01

1.84 1.67 1.53 1.44 1.39 1.33 1.14 1.02

1.19 1.14 1.09 1.05 1.03 1.01 0.98 0.97

0.92 0.89 0.88 0.85 0.84 0.83 0.79 0.76

0.83 0.80 0.79 0.77 0.76 0.74 0.71 0.69

0.85 0.84 0.84 0.83 0.82 0.82 0.80 0.79

note: AIHTI reserves the right to make reasonable design changes without notice.

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tel: 434-757-1800 355 American Industrial Drive LaCrosse, VA 23950

email: sales@aihti.com fax: 434-757-1810

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