How to design on existing system (Retrofit)

Summary:

When a customer already has a solar system and wants to add new hardware (e.g., more panels or a battery), OpenSolar allows you to model retrofits and upgrades with accuracy and ease. This guide walks you through creating the existing system, designing the upgrades, and ensuring the proposal reflects only the new components.

Step 1: Mark the project as a retrofit

Once you have created a project, navigate to the Energy tab. From there, activate the retrofit settings by toggling on the Existing system/Retrofit switch.

Note: This can also be done by toggling the same switch in the Design tab.

Step 2: Input system production 

To accurately model your retrofit project, you must first input information about the existing system. You have three options for providing this data:

• Estimate based on system size (default): Choose this option if you want OpenSolar to build a virtual system and calculate its annual generation.
• Actual generation (kWh): Choose this option if you have historical generation data from a monitoring app or similar source. You will be prompted to input values and select a frequency.

Once you have chosen an option, proceed to the Design tab. The next steps will vary depending on the option you selected.

If you chose “Estimate based on system size”

You'll need to model the existing system by drawing panels on the roof and confirming key details like panel size, age, and tilt.

If you chose “Actual Generation (kWh)”

The existing system will be represented by the generation data you entered in the Energy tab. You can begin adding your new systems immediately.

Step 3: Add your new system/s

Start building one or more systems that you would like to offer your customer, just like you normally would when using OpenSolar. 

OpenSolar will calculate the total combined production, but will only factor in the new system for costs, pricing, and incentives. 

Step 4: Finalise the proposal

To finalise your proposal, navigate to the Online Proposal tab.

The proposal will automatically adjust to a retrofit template and will look very similar to a standard OpenSolar proposal. The key difference is that it includes the improved combined production from both the existing and new systems.

Here are the key features you'll see in a retrofit proposal:

• Existing system details: The proposal will include information on the existing system's size and production calculations, such as annual generation and self-consumption.

• Pricing & components: Only the new system is used for calculating the total price and the list of components included in the proposal.
• Combined production display: If the new system includes additional PV, the proposal will show the combined solar production from both the existing and new systems, providing a complete picture of the home's energy production.

Advanced: Model complete system

If you have chosen to use an estimate for the existing system but want more granular control, you can choose to model the complete system instead. This is particularly useful for complex retrofits where you need to add specific components or ensure electrical compatibility between the new and existing systems (e.g. adding a DC-coupled battery to a hybrid inverter).

To do this, navigate to the Panels tab, click Advanced, and select Model Complete System

Once you have designed the full existing system, you will have a choice when adding your new system:

• Show new system only: The design will start empty, and you will add only the new components you wish to design.
• Show combined system: The design will include all components from the existing system. This is useful for modifying existing hardware or checking electrical compatibility between old and new components.

Note: The final proposal will only show and price the new components. However, all total production calculations, such as annual generation and self-consumption, will be based on the combined output of both the new and existing systems.