Page 284 - HVAC Pump Handbook

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Basics of Pump Application for HVAC Systems

Basics of Pump Application for HVAC Systems 281

88
87

86
Pump efficiency—% 85

84

83
82

81

80
800 900 1000 1100 1200
Pump speed—RPM
Figure 10.5 Pump effiency during constant flow, variable
head process.

possible efficiencies. Multispeed head-flow curves should be secured
from the pump manufacturer, and the actual proposed operation
should be drawn on them. Another example of a proposed variable
flow, variable head operation is shown in Fig. 10.6 which is an exam-
ple of mapping the variable-speed pump performance.

80 1180 RPM
70% 75% 80% 83%

60 1000 RPM 86% 87% Bep curve
Pump head—ft. 40 800 RPM 83%
86%

Individual
efficiency
20 lines of

0
0 400 800 1200 1600 2000 2400 2800 3200
U.S. Gallons per minute
Figure 10.6 Variable flow, variable head process.

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