Arrays and Mounting Configuration#

This page explains how collector arrays and their mounting configurations work in SunPeek, including fixed-tilt installations and single-axis tracking systems.

Overview#

In SunPeek, a collector array represents a group of solar thermal collectors that share the same orientation, collector type, and sensor connections. Arrays are the primary unit for Power Check analysis.

The mounting configuration defines how collectors are oriented relative to the sun:

Fixed mounting (MountingFixed): Collectors have a constant tilt and azimuth angle.
Single-axis tracking (MountingSingleAxis): Collectors rotate around one axis to follow the sun.

Note

Single-axis tracking support is available in the Python API. WebUI support for configuring tracking arrays is planned for a future release.

Mounting Types#

MountingFixed#

Use MountingFixed for fixed-tilt installations where collectors maintain a constant orientation.

Parameters:

MountingFixed Parameters#
Parameter	Description	Unit	Range
`surface_tilt`	Tilt angle from horizontal plane	degree	0-90
`surface_azimuth`	Compass direction the collectors face (North=0, East=90, South=180, West=270)	degree	0-360

Example:

from sunpeek.components import Array, MountingFixed
from sunpeek.common.unit_uncertainty import Q

# South-facing collectors tilted at 30 degrees
mounting = MountingFixed(
    surface_tilt=Q(30, 'deg'),
    surface_azimuth=Q(180, 'deg'),  # South
)

array = Array(
    name='Fixed array',
    plant=plant,
    collector=collector,
    mounting=mounting,
    area_gr=Q(500, 'm**2'),
    sensor_map={...},
)

MountingSingleAxis#

Use MountingSingleAxis for single-axis tracking installations where collectors rotate around a fixed axis to follow the sun. The surface orientation is calculated automatically based on sun position using pvlib.

Configuration Parameters:

MountingSingleAxis Parameters#
Parameter	Description	Unit	Range
`axis_tilt`	Tilt angle of the rotation axis from horizontal	degree	0-90
`axis_azimuth`	Compass direction of the rotation axis (North=0, East=90, South=180, West=270)	degree	0-360
`max_angle`	Maximum rotation angle from the horizontal position	degree	0-90

Common Configurations:

Horizontal N-S axis (tracks E-W): axis_tilt=0, axis_azimuth=180
Horizontal E-W axis (tracks N-S): axis_tilt=0, axis_azimuth=90
Tilted axis: Set axis_tilt to match latitude for optimal year-round performance

Example:

from sunpeek.components import Array, MountingSingleAxis
from sunpeek.common.unit_uncertainty import Q

# Horizontal N-S axis tracker (tracks east-to-west)
mounting = MountingSingleAxis(
    axis_tilt=Q(0, 'deg'),        # Horizontal rotation axis
    axis_azimuth=Q(180, 'deg'),   # N-S orientation
    max_angle=Q(60, 'deg'),       # Maximum rotation from horizontal
)

array = Array(
    name='Tracking array',
    plant=plant,
    collector=collector,
    mounting=mounting,
    area_gr=Q(500, 'm**2'),
    sensor_map={...},
)

Virtual Sensors for Tracking Arrays#

When using MountingSingleAxis, SunPeek automatically calculates time-varying surface orientation based on the sun position and tracker configuration. These values are available as virtual sensors:

Tracking Virtual Sensors#
Sensor	Description	Virtual
`surface_tilt`	Instantaneous tilt angle of collector surface	Always calculated
`surface_azimuth`	Instantaneous azimuth angle of collector surface	Always calculated
`ideal_rotation_angle`	Optimal tracker rotation angle based on sun position	Always calculated
`rotation_angle`	Actual measured rotation angle (if sensor available)	Optional (measured)

Accessing Virtual Sensors:

# After loading measurement data
use_csv(plant, csv_files=[...])

# Access time-varying surface orientation
tracking_array = plant.arrays[0]

# Get surface tilt as a time series (pint-pandas Series)
surface_tilt = tracking_array.mounting.surface_tilt.data
print(f"Surface tilt range: {surface_tilt.min():.1f} to {surface_tilt.max():.1f}")

# Get ideal rotation angle
ideal_rotation = tracking_array.mounting.ideal_rotation_angle.data

The virtual sensors are calculated using pvlib.tracking.singleaxis().

Array Properties#

Arrays provide convenient properties for accessing orientation, regardless of mounting type:

# For fixed mounting, tilt and azim are scalar Quantities
if array.has_orientation():
    print(f"Tilt: {array.tilt}")
    print(f"Azimuth: {array.azim}")

# For tracking mounting, tilt and azim are Sensor objects
# containing time-series data
if not array.has_orientation():
    print("Tracking array - orientation varies with time")
    print(f"Tilt data: {array.tilt.data.head()}")

# The orientation property returns tilt/azim in degrees
# Works for both fixed (scalar) and tracking (raises if time-varying)
if array.has_orientation():
    orient = array.orientation
    print(f"Orientation: tilt={orient['tilt']}°, azim={orient['azim']}°")

Backward Compatibility#

For backward compatibility, the legacy tilt and azim parameters on Array still work. They are automatically converted to MountingFixed internally:

# Legacy syntax (still works)
array = Array(
    name='Array',
    plant=plant,
    collector=collector,
    tilt=Q(30, 'deg'),
    azim=Q(180, 'deg'),
    area_gr=Q(500, 'm**2'),
    sensor_map={...},
)
# Internally creates: MountingFixed(surface_tilt=Q(30,'deg'), surface_azimuth=Q(180,'deg'))

# Recommended new syntax
array = Array(
    name='Array',
    plant=plant,
    collector=collector,
    mounting=MountingFixed(
        surface_tilt=Q(30, 'deg'),
        surface_azimuth=Q(180, 'deg'),
    ),
    area_gr=Q(500, 'm**2'),
    sensor_map={...},
)

Hint

While the legacy syntax is supported, we recommend using the explicit mounting parameter for new code to make the mounting configuration clear and enable future tracking support.

Additional Array Parameters#

Beyond mounting configuration, arrays have additional parameters for shading and layout calculations:

Array Parameters#
Parameter	Description	Unit	Required
`name`	Descriptive name for the array	—	Yes
`collector`	Collector type used in this array	—	Yes
`mounting`	Mounting configuration (`MountingFixed` or `MountingSingleAxis`)	—	Yes
`area_gr`	Total gross collector area	m²	Yes
`row_spacing`	Distance between collector rows (for shading calculations)	m	No
`ground_tilt`	Slope of the ground beneath collectors	degree	No
`sensor_map`	Mapping of sensor slots to sensor objects	—	Yes

For details on sensor mapping, see Sensor Mapping.