Every design is shaped by constraints, from clothing to vehicles to solar arrays. While some designers get frustrated and push back against constraining factors, others embrace them to create effective, innovative designs. In the solar design industry, there are often many constraints - size, location, cost, and more - and many factors that designers must balance to achieve the best possible result.

A friend of mine, Paul Grana of Folsom Labs (creators of the design software HelioScope), recently wrote an article for SolarPro in which he examines common solar constraints and how smart designers effectively incorporate them into their design, planning, and execution. His exploration of the complexity of various design factors highlights the pitfalls of the “one-size-fits-all” canned design approach. Let’s take a deeper look:

Common Constraints in Solar Design

“Constraints might seem like an annoyance to avoid or minimize, but they are intrinsic to real-world activities,” Grana writes. “If that seems counterintuitive, keep in mind that a system without constraints would be infinitely large!” The most effective approach, he argues, is to acknowledge common constraints (and their hierarchy) and allow them to guide the design process. The most common constraints for solar array design are area, energy demand, and budget.

Maximizing the available area for a solar installation is often a designer’s primary concern. In order to make economic sense, the solar array must produce the greatest possible energy yield within the available area. Area may be determined by available space, ideal placement (such as south-facing rooftops), or financial constraints on how much surface area can be covered within the client’s budget. When making this calculation, Grana notes that designers “want to maximize power density... rather than specific yield.”

Another major constraint is meeting (but not greatly exceeding) the energy demand of the building. This constraint is most common in residential applications, where demand is limited. A smart designer will carefully review a client’s energy usage to determine demand and tailor their design to closely match it. “This type of optimization exercise is all about system capacity,” Grana writes. “When there is only so much demand for energy, the size of the array is critical.”

And, of course, there’s the budget. As Grana notes, “with a constrained cost, the financial return (revenue minus costs) for a system tracks closely with the total revenue.” Maximizing the specific yield is the foremost concern when designing an effective system within a constrained budget, as revenue is a result of the energy generated by the system.

Embracing a Holistic Approach

With so many (sometimes conflicting) factors to consider, smart solar designers must approach each project as an individual process, foregoing “canned” designs for those that are specifically tailored to meet a client’s unique needs. The holistic approach requires designers to consider all constraints and identify their hierarchy, in particular what Grana calls the “bottleneck” constraint - the primary constraint that will determine the system design.

For example, “the budget might constrain the system to be smaller than the rooftop would allow. In that case, the financial budget is the actual bottleneck, even though there is technically also a space constraint.” When a designer focuses on optimizing the primary constraint, they can create a holistic system designed to maximize efficiency and return on investment. This is why different constraints can lead to very different design results.

“Form Follows Function”

Most solar design projects today are about optimizing results around existing design constraints - superimposing a new function (solar energy) over an existing form (a rooftop, building, or land area designed without solar considerations in mind). This is in opposition to the common design maxim that form should follow function. As solar achieves greater dominance in energy production, new construction is beginning to reverse this equation by creating buildings that are themselves optimized for solar installations.

In an article for AutoDesk, architect Taz Loomans explores ways to improve building design by integrating solar installations into the initial approach. It’s an exciting glimpse into a future in which solar is a holistic part of building design rather than an afterthought. The vast majority of today’s designers, however, still need to embrace constraints as a primary concern in their designs and optimize function based on existing forms.

Our Design Expertise

The complexity of constraints in solar design reveals that there is no truly effective “one-size-fits-all” method of solar design. That’s why our approach at Solar Design Studio includes rigorous research and close consultation with our clients. Our depth of experience in both residential and commercial design, engineering, and installation gives us strong precedent to draw from as we optimize each design around the unique needs and constraints of the project and client.

If you have a complex solar problem in need of an optimized solution, we would love to hear from you! Contact us today to schedule a consultation and get started.

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