Product Guide

Selection
SQFlex
3
13
3. Selection
Sizing of SQFlex system
Grundfos has developed a PC-based sizing tool
enabling the sizing of SQFlex systems.
The sizing tool is integrated in Grundfos WinCAPS and
covers both solar- and wind-powered systems. Visit
Grundfos.com to use WebCAPS, our online version of
WinCAPS.
The following three parameters must be known for the
sizing of the optimum SQFlex system:
• installation location
• maximum head required
• quantity of water required.
With a view to the sizing of a correct solar-powered
SQFlex system, the world has been divided into six
regions:
• North America
• South America
• Australia/New Zealand
• Asia/Pacific
• Southern Africa
• Europe/Middle East/Northern Africa.
Each region is divided into a number of zones
according to the solar radiation in kWh/m
2
per day.
Voltage effect on pump efficiency
The pump efficiency can vary quite a bit depending on
input voltage. This chart shows the dropoff in efficiency
as the voltage gets lower. For example, if you have two
systems with the exact same wattage rating, but
System A is running at 120V and System B is running
at 35V, System A will produce 20 % more water than
System B.
SQ Flex optimal efficiency
Panel output voltage (% loss in gallons/day)
120V - 300V - 0 %
90V - 5 %
60V - 10 %
35V - 20 %