Lorentz PS1200 Solar Pumping Planning Guide

7
CAUTION People often forget to
make seasonal adjustments. Ideal
angles (from horizontal) are:
Summer optimum = latitude –15°
Winter optimum = latitude +15°
CAUTION: 0-25° latitudes: Apply a
minimum tilt angle of 10°, or dust and
debris will accumulate.
3.5 Setting the Solar Array Tilt Angle
Maximum performance is obtained from a solar
pump when its photovoltaic array is tilted (elevated)
to face the sun. The solar array racks that are supplied
with the pump systems are adjustable to the desired tilt
angle. It is the responsibility of the installer to perform
this adjustment.
Some systems include a solar tracker, and others with
a fixed (non-tracking) rack. Both types of array have a
manual tilt-angle adjustment. (The tracker follows the
daily path of the sun, but not the seasonal tilt variation.)
The optimum tilt angle is determined by the location
(latitude). It also varies with the time of the year. This
data is presented in the table below.
Should the tilt angle be adjusted periodically
through the year? This depends on the seasonal
water-use pattern, and also on human factors.
There are three options to chose from.
Select one of these options for seasonal management:
1. Year-round compromise (no seasonal adjust-
ment) Set the angle equal to the latitude of the
location and “forget it”. This is practical because
people often forget to adjust the array. The
performance displayed in the System Sizing Table
is based on this fixed compromise setting of the
tilt-angle.
2. Seasonal adjustment It is sufficient to perform
the adjustment only twice per year, at the spring
and autumn equinoxes, to the summer and winter
angles indicated below. For central USA, this will
increase the daily water production by about 8 %
in summer, 5 % in winter compared to option 1.
3. Seasonal use only If the pump is to be used
no more than half of the year, set the array to the
appropriate seasonal angle shown below, and
“forget it”.
If you use the pump all year but do not want seasonal adjustment to be required, set the angle to year-round
compromise (equal to latitude).
Table 1: Solar Array Tilt Angles by Latitude
Location
(example)
Latitude Summer Tilt Winter Tilt Year-round
Compromise Tilt
Southern Canada 50° 35° 65° 50°
Upper Third USA 45° 30° 60° 45°
Middle Third USA 40° 25° 55° 40°
Lower Third USA 35° 20° 50° 35°
Central Mexico 20° 5° 35° 20°

Lorentz PS1200 Specifications

General

Brand	Lorentz
Model	PS1200
Category	Water Pump
Language	English