WEG CFW11 Applications Manual page 14

Installation
To facilitate the understanding of sizing, we use the following system as an example:
Figure 3.1 – Example of a photovoltaic pumping system
For this example, based on desired flow a motor pump of 3 CV was selected as a reference, the sizing of the
system's number of modules follows the equations:
MOTORPUMP SIZING
CALCULATION OF DAILY HYDRAULIC ENERGY
��
��
���������� ������������������ ������������ ( �� ) = �� ∗ ��
∗
�� ��
3600
Where:
E : Daily hydraulic energy (Wh/day).
H
g : Acceleration due to gravity (9.81 m/s²) – has a constant value.
: Manometric height (20 m) – value varies according to project layout.
H
m
ρ : Water density (1,000 kg/m³) – has a constant value.
a
Q : Pumped volume (90 m³/day) - value varies according to pumped volume need
d
: Hours of Sun Peak (3.9 kWh/m²) – value varies according to location, use the lowest seasonal
(HSP)
β
irradiation value.
CALCULATION OF THE FINAL ENERGY REQUIRED
���������� ������������������ ������������
�� =
��
������������������
Where:
L : Final energy required (W/h).
: Pump Efficiency (0.3) – average of the pumps for this application.
n
motorpump
POWER CALCULATION
��
���������� (�� ) = 1,25 ∗
��
(������)
��
The power (W ) obtained results in 5.24 kW , and for the proposed example this power is enough for the 3 CV
p
p
pump selected. The equations presented are analogous for the other designs and their respective powers.
Solar Pump Drive | 14