Fundamental Chemistry and Hydraulics - Mathematics and Statistics for the Environment - page 376

■ EXAMPLE 14.35
Problem: A pump has a water horsepower requirement of 8.5 WHP. If the motor supplies the pump
with 12 HP, what is the efficiency of the pump?

Solution:

WHP output
BHPsuppl

85
12

.

Percent pumpefficiency = ×=×=×= 100 100 071 . 100 71 %

ied

■ EXAMPLE 14. 36
Problem: What is the efficiency if an electric power equivalent to 25 HP is supplied to the motor and
14 HP of work is accomplished by the pump?

Solution: Calculate the percent of overall efficiency:

WHP
MHP

14
25

Percent overall efficiency = × =× 100 100 =×= 056 . 100 56 %

■ EXAMPLE 14. 37
Problem: The motor is supplied with 12 kW of power. If the brake horsepower is 14 HP, what is the
efficiency of the motor?

Solution: First, convert the kilowatt power to horsepower. Based on the fact that 1 HP = 0.746 kW,
the equation becomes

12 kW
0.746 kW/HP

= 16.09 HP

Now calculate the percent efficiency of the motor:

BHP
MHP

14
16.09

Percentefficiency = × 100 = × 100 = 0. 87 ×= 100 87 %

REFERENCES AND RECOMMENDED READING
Davies, P. (2013). Types of Colloids . University of Bristol, http://www.chm.bris.ac.uk/webprojects2002/pda-
vies/types.html.
Irikura, K.K. and Johnson III, R.D. (2000). Predicting unexpected chemical reactions by isopotential searching.
Journal of Physical Chemistry A , 104(11), 2191-2194.
Missen, R.W., Mims, C.A., and Saville, B.A. (1999). Introduction to Chemical Reactions Engineering and
Kinetics. John Wiley & Sons, New York.
Morgan, G.T. and Drew, H.K. (1920). Researches on residual affinity and coordination. Part II. Acetylacetones
of selenium and tellurium. J. Chem. Soc. , 117, 1456.
Oxlade, C. (2002). Materials Changes and Reactions (Chemicals in Action). Heinemann, Portsmouth, NH.
Spellman, F.R. (2013). Handbook of Water and Wastewater Treatment Plant Operations , 3rd ed. CRC Press,
Boca Raton, FL.
Wahren, U. (1997). Practical Introduction to Pumping Technology. Gulf Publishing, Houston, TX.