Fundamentals of Solar Design in Solar Installation

As of 2024, India is the 5^thlargest economy in the world, it is also the 3^rd largest energy-consuming country and ranks 4^th among the top GHG -emitting countries in the world.

India also stands 4^th globally in Renewable Energy Installed Capacity (including Large Hydro), 4th in Wind Power capacity & 5^th in Solar Power capacity. The country has set an enhanced target at the COP26 of 500 GW of non-fossil fuel-based energy by 2030.This is the world's largest expansion plan in renewable energy.

While the installations are growing, it is essential to ensure that not only the solar panels lasts for 25years but the entire installation lasts for the lifetime. Here, Design and Workmanship of the installation plays a critical role. Hence it is crucial for professionals to have a decent understanding of solar design.

Why understanding the fundamentals of solar design is crucial for professionals and businesses in the solar industry?

Like any other type of design, solar design involves a set of specific rules and practices that can be used to suit site conditions and consumer requirements. Despite the availability of standardized kits in the market, each solar plant is unique to its location—much like every house is distinct.

To draw a comparison, installing a solar plant is not as simple as installing an air conditioning unit in your home; it is more like installing a central air conditioning system. This process requires careful design based on the customer's needs, the number and size of rooms, and other factors. You can also think of it like interior designing, where the approach must reflect the customer's taste while considering space availability and specific site conditions.

Similarly, solar design is influenced by factors such as location, customer requirements, roof type, and shadow conditions.

Let us understand various aspects in solar design.

What Is Solar Design?

Solar design is a blueprint for solar installation, similar to how an architect provides a detailed plan to the engineer on-site. What does a solar design typically include?

1.     2Ddrawings showcasing

·      Plant layout – panel/module arrangement

·      Structure layout

·      String and Cable layout

·      Earthing layout

2.    Details i.e. Datasheets of all major equipment including but not limited to Solar panels, inverters, remote monitoring system.

3.    Generation report (PVsyst/any simulation software report) that includes the exact system configuration with system losses and estimated generation.

We recommend checking the Aerem’s partner app that facilitates your design processes with guidance from our experts to solve any complexities in your project.

Key Elements of Solar Design

1.     Site Assessment and Feasibility Studies

Site survey and feasibility is like the diagnosis for a patient, if the diagnosis is done rightly, the surgery or the course of treatment is also provided accordingly. Any mistake in the diagnosis and the patient is bound to suffer from the incorrect treatment.

Similarly, when information is misreported in a site survey form or things are missed out due to ignorance, then there are high chances of design flaws leading to either delay in installation, troubleshooting and even unexpected expenses.

We recommend checking out our blog on site assessment to know more on what exactly to record in site surveys.

2.     System Sizing and Configuration

Since every site is unique, there are no set rules even for system sizing, but one thing which is commonly seen is the lack of sufficient space to install a solar plant that will generate enough to suffice the customer’s electricity needs. Hence, when it comes to choosing the solar panel rating, we recommend going fora higher capacity of solar panel in order to increase the system size if space is an issue.

Moreover, it is also recommended to overload the inverter for its optimal functioning. Since the solar output is varies throughout the day and the rated peak capacity can be only be seen during peak periods, overloading the inverter helps to optimize the performance, also it can reduce the cost of the system too since you opt for a small inverter when overloading.

Also, a right design is not just about putting together the best of technology together it also means you balance the cost of the system while maintaining the performance. For example, a tracker system definitely performs better than a fixed tilt system, but it is way more expensive than fixed tilt, moreover space and maintenance required for the tracking systems is always higher. And the cost of the fixed tilt system can give a payback period of 4-5 years which is fairly acceptable while providing generation for around 25 years without major hassle of maintenance.

3.      3D and 2D Layouts

While 3D layouts are not mandatory for designing a solar plant, but they are super useful when it comes to:

·      Analyzing shadows and estimating losses due to shading.

·      Allows to try various permutations and combinations in case of different roof orientations, capacity can be calculated by trying and placing modules in the software and comparing generation to arrive at the optimum capacity

·      Help in converting leads as clients can fully visualize the look of the rooftop solar plant and comment on any changes that they need and especially for customers concerned about aesthetics.

·      Helps the installation team to work quicker as it becomes very easier to understand positioning of panels, cables, inverter and junction boxes quickly as compared to 2D layouts.

There are various software out there to create 3D models, check out our blog on Solar software hereto know more.

Also, 3D layout scan be more of an add-on and help in pre-sales, but when it comes to detailed designing especially for plants above 10kW, it is always recommended to get 2Ddesigns prepared along with the 3D layouts.

4.     Shading Analysis

More often, a rooftop site will have shadow casted by nearby buildings, water tanks, trees etc. that doesn’t mean the site is not suited for solar. We just need to understand the time and duration of the shadow to ensure that it has minimal effect on the generation.

While, it is possible to calculate the shadow length and time with formulas and apiece of paper, it is often cumbersome and exhaustive. In such cases, software like Helioscope and PVsyst make it easier to figure out the length and time of the shadows, this allows the designer to make customizations and more sophisticated designs to optimize capacity without any negative effect on the generation.

Also, it is not just the nearby buildings or water tanks that cast shadow, solar panels can also cast shadow on each other, if the distance between the rows is not maintained well. The distance will vary as per the location, direction of the solar panels, hence shading analysis can help figure out the exact distance required to be kept between the panel rows.

5.     PVsyst Reports

PVsyst reports or generation reports from any similar software help you to estimate generation as per your system configuration, location, orientation, tilt and system losses. While there is a general understanding about the average generation in specific location, PVsyst reports provides generation which is precise to the site conditions. You can also import 3D models into PVsyst for better accuracy of shading. Moreover, it provides monthly estimate of solar generation.

This estimate becomes important to calculate IRR and payback period. This helps the customer to understand the financial benefits and thereby helps you close the deal effectively.

Additionally, these software tools have extensive library of components include the latest solar panels, inverters etc. PVsyst Reports includes the efficiency and other performance details which helps you to showcase the additional generation through the components if you are using say a high efficiency inverter or a half cut monocrystalline solar panel.

Best Practices in Solar Design

While the list can be comprehensive, here are few pointers that you as an EPC company can swear by:

• Do not install solar panels in areas where the shadow is being casted in the afternoon hours. Shadows not only reduce  generation but also damage solar panels in long term.
• Always design as per safety standards and regulations, considering the weather conditions and to extend the life of the solar panels.
• Thoroughly check and follow the guidelines from solar panel and inverter manufacturers.
• Ensuring the engineers visiting the site are well trained to conduct a site survey. Make digitized site survey forms and SOPs.
• Explain and convey design details with the client before final design layouts in order to avoid any last-minute changes.
• Check well in advance the price and delivery schedule for components selected to avoid unnecessary costs and delays.
• Discuss the designs with the installation team, once the deal is closed, the installation engineer/team should visit the site along with the designs. This helps the team to acquainted to the site and also identify any potential issues with the installation process.

Conclusion

A good design is essential as it ensures that your system operates optimally, remains robust, and lasts for along time without significant maintenance issues. The better the design, the higher the energy generation and the more satisfied the customer will be. Additionally, installing solar panels is a major decision for customers, and word of mouth often plays a crucial role in selecting an EPC (Engineering, Procurement, and Construction) company. A well-designed solar plant strengthens your portfolio and keeps your clientele happy. Therefore, paying attention to design is certainly worth the time and effort.

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