Solar Collector Model Data

Construction tab in model data under Solar Collector header


Once a solar collector surface has been placed you can define its properties on the Constructions tab under the Solar Collector header.

Solar collector type

You can change the type of solar collector using the drop list. Choose from:



Depending on the type of solar collector selected you will see different data below. For Solar hot water collectors the only data that can be edited here is the material used to represent the panel in rendered views on the Visualisation tab. All of the rest of the data is defined with the HVAC Solar collector component and its host loop.


When the 2-Photovoltaic option is selected further configuration and performance data for the PV panels can be entered as shown in the screenshot below.



You can define the cost of the collector per area. The units will be the unit of currency currently selected on the Program options dialog per area (e.g. GBP/m2 or USD/ft2).


Costs for the electric distribution can be included separately on the Load centre dialog.


This setting allows you to associate solar panels with either the building or the site, depending on whether they attached to the building or a fixed part of the site layout. Most of the time you won’t need to change it, but for some simulations it can be important to attach panels to the site rather than the building. For example if you are trying to optimise the orientation of the solar collector using the parametric or optimisation tools, or using the ASHRAE 90.1 automated baseline or UK DSM tools, you should leave panels that are attached to the building structures set to the default building level. However for panels that are fixed site objects, you should set these to be site level objects to ensure that they are not rotated with the building as part of any parametric variations.


Select whether the component block is considered to be part of the building or the site, choosing from:



This material is used only to define the texture to represent the Solar collector in rendered views on the Visualisation screen.

Flat surface position

Although solar panels are represented as special types of 3-D component blocks in DesignBuilder modeller, they are simulated as flat (based on the Maximum flat surface thickness threshold accessible on the Advanced tab of the Model options dialog). You can control how the single surface used to represent a flat solar panel in simulations is defined. Choose from:


Photovoltaic options

Performance type

Select from:



Depending on the selection you will be able to select from either a simple or equivalent one-diode definition of the panel.

Tip: PV panels are included in the electrical generation side of the model by specifying them on the Generator list tab of the Electric load centre dialog when one of the d.c. Buss types is selected.

Performance model

Choose the component to be used to define the performance of the collector. When the 1-Simple performance type is selected, select from the list of previously defined Simple Photovoltaic components, or when 2-Equivalent One-Diode is selected then choose from one of the Equivalent One-Diode components.

Heat transfer integration mode

The PV model allows for different ways of integrating with other EnergyPlus heat transfer surfaces and models and calculating cell temperature. Choose from:


Note: The above decoupled PV solar panels shade solar radiation from any other building surfaces below so they can be used to model PV shading, awning and the reduced solar gain on roofs where there is a ventilated cavity below the panel. They will be less accurate from the thermal point of view for building integrated PV panels where there is a significant thermal solar gain through the panel and into the building fabric.

Note: Building Integrated PV (BIPV) panels with closer thermal links with the building fabric can be modelled directly on the Construction and Glazing dialogs by selecting the appropriate categories. In this case further Heat transfer integration modes are allowed.

Modules in parallel

This field is the number of series-wired strings of PV modules that are in parallel to form the PV array. The product of this field and the next field should equal the total number of modules in the array.


The Modules in parallel and Modules in series data are only used for 2-Equivalent One-Diode PV arrays.

Modules in series

This field is the number of modules wired in series (on each string) to form the PV array. The product of this field and the previous field should equal the total number of modules in the array.