“Pumping and Hydraulics’ Solutions for Irrigation and Water Supply”
DIESEL Pump Data Chart
This chart is suited to diesel driven pumps used for irrigation and enables the operator to quickly find pump operating costs in $/ML given operating head (metres), assumed pump efficiency  and diesel cost in $/Litre.

Interestingly, the flow rate pumped is not required for establishing $/ML.

This chart is based upon a new 75kW engine at 25 deg C with a Brake Specific Fuel Consumption (BSFC) of 215 gms/kWh (equivalent to 0.25 Litres/kWh**) but no attempt has been made to equate this performance to any particular engine.

Because of the widely varying performance of diesel (and other ICE) engines used in irrigation, due to such variables as naturally aspirated, turbo charged, twin turbo charged, varying cooling systems, etc, the actual BSFC of a new engine in the field may vary from 215 gms/kWh. In this case, all derived data in this chart should be re-rated accordingly.

CALCULATING ENGINE FUEL CONSUMPTION
Because BSFC varies with engine and fuel types and configurations, the formula to calculate fuel consumption needs to incorporate the BSFC.
Lets start with the kWh/ML for electric motors:

   kWh/ML = 2.724 x m(TDH)/OPE (refer to www.talle.biz/data)
     (where OPE is overall pump/motor/drive efficiency)

Select a diesel engine with, say, 215g/kWh BSFC
Diesel has a specific gravity (SG) of 0.86.
Therefore, the volume of 215g of diesel = 0.215/0.86 = 0.25 litre
Therefore, 1 kWh work requires 1/4 litre of diesel (@ 215g/kWh)
Now our formula for Litres/ML can be written as:

Litres/ML =  2.724 x m (TDH) (but only where BSFC = 215g/kWh)
                       4 x OPE
             =  0.681 x m (TDH) (but only where BSFC = 215g/kWh)
                          OPE
This can also be expressed as:

Litres/ML = 2.724 x (BSFC g/kWh) x m(TDH)
                             (SG)  x  OPE 
Formula for Litres/Megalitre

= 0.681* x metres (TDH)
   Derating x pump Eff%

Based on BSFC of
       215gm/kWh
       (0.25Litres/kWh)

*NOTE:
0.681 is derived from
2.724 (constant in kWh/ML formula) multiplied by 0.25 Litres/kWh (BSFC)

Ie, 2.724 x 0.25 = 0.681

**NOTE:
   Based upon
   Specific Gravity
   of diesel = 0.86

Ie, 0.215kg/kWh / 0.86    
     = 0.25 Litre/kWh
ABN 92 105 345 506
Last Update
June 16th 2020
Tallemenco Pty Ltd, Windsor Gardens, SOUTH AUSTRALIA, 5087.
ABN: 92 105 345 506
Mobile  0414 492 256
Intn'l:   Cell  +61 414 492 256
Skype:    robwelke

DERATING FACTORS FOR DIESEL ENGINES

Generally, diesel engines used for irrigation require numerous de-rating factors according to their individual application. 

DERATING factors used in AUSTRALIA;
  for biofuel, add 7% (0.93)
  for engine accessories, check with manufacturer
  for gear drive, add 5% (0.95)
  for belt drive, add 10% (0.90)
  for each 25kW below 75kW, add 5% (0.95/25kW)
  for altitude, add 1% per 200m above sea level (0.99/200m)
  for temperature, add 5% for each 10 deg C above 25 deg C (0.95)
  for humidity, add 3% for every 10% humidity over 65%
 
DERATING factors used in United States (ref USDA;NRCS Ch 8);
  for engine accessories, add up to 8% (0.92)
  for gear drive, add 5% (0.95)
  for belt drive, add 10% (0.90)
  for elevation, add 3% per 1000ft above sea level
  for temperature, add 1% for each 10 deg F above 60 deg F


DERATING FACTORS FOR other ICE ENGINES
  Consult engine manufacturer


Derating factors are accumulative.
Therefore, add all derating factors applying to each site.
Eg, operating at 45 degC (10% derate) plus belt drive (10% derate),
= [1-(0.1 + 0.1)] = 0.80

Download a full size PDF copy of the Diesel Pump Data Chart

DISCLAIMER
This chart is NOT intended for use as an engine selection tool.
No responsibility will be accepted for any application of this chart.
BSFC and SG of Common Fuels
This formula can then be applied to a range of fuels, including:
  # diesel engine     (SG = 0.86 @ 16oC/60oF) (ave BSFC = 230g/kWh)
  # gasoline engine  (SG = 0.75 @ 16oC/60oF) (ave BSFC = 300g/kWh)
  # LPG engine        (SG = 0.55 @ 16oC/60oF) (ave BSFC = 260g/kWh)
  # CNG engine       (SG = 0.32 @ 16oC/60oF) (ave BSFC = 250g/kWh)

  #these figures are rough averages and may vary widely
   - check with engine manufacturer.

  Appropriate BSFC and Specific Gravities need to be factored into the formula.

CALCULATING IN US UNITS
Adopting the following conversions:
   3.785 litres = 1 gallon US
   1 metre = 3.2808 ft
   BSFC [g/(kW·h)] = BSFC [lb/(hp·h)] × 608.277  
   BSFC [lb/(hp·h)] = BSFC [g/(kW·h)] × 0.001644
   1 Megalitre = 0.8107 ac-ft

Gallons (US)/ac-ft = 0.16457 x (BSFC lb/hp.hr) x ft (TDH)
                                          SG   x  OPE