Solar photovoltaics have penetrated the new construction industry, period. One outstanding example is the California mandate that all new homes must have solar installed starting January 1, 2020. The push for solar in new construction is exciting for the solar industry, and also presents new potential issues for architects and builders.
Architects bring a keen eye to the building function and aesthetics but they may be unaware of how solar systems can be designed to give the most value to their clients. Let’s call this blog “An Architect’s Guide to Designing PV.”
Understand your client’s motivation for including solar in their new building
Knowing what are your customer’s motivating factors and interest in solar in the early stages of your project will affect design considerations for best PV implementation and choices around sourcing.
Commercial customers, for example, may state that marketing the solar is very important to them. Making sure that their array is visible to the public will be an important consideration.
A business with new construction in certain communities may need a certain amount of PV or may need to generate a certain amount of energy using their PV to be accepted in the community or be issued a license to operate. If so, you may need to look at leveraging the website, like PVWatts to size the system correctly, or determine whether you should be entertaining a roof vs ground-mounted system.
Once you have an idea of why your client is interested in solar, your next step is to query local installers for their recommendations on solutions and what solutions they are able to provide. You may find some installers capable of some types of projects and not others, furthermore, some may have access to products, mounting styles, and integrations others are not. This will further your understanding of what is possible both material-wise and building/electrical code wise; for example, you may find PV must be mounted in certain ways to accommodate local wind speed code.
Rooftop solar design considerations
Now that you have an idea of “why” and “how” how you might integrate solar with your new construction project, you can get started on drafting designs for the system. In truth it is best to work with solar designers at a specific firm for this but as the project stands you may not be able to choose the final contractor, especially if the project is out for public bid. So in this section, we will discuss best practices for general roof mount designs.
1. Shading Impact: The first consideration for rooftop solar is the impact from shading, whether it is from an HVAC rooftop unit, a parapet wall, or other obstacles on the roof, PV is best kept at a distance from obstacles for optimal production. Specifically, PV should be 2 ft back from every vertical foot of height of a solid object so as not to shade at the December solstice.
2. Optimal Direction: Rooftop PV performs best when facing south, but it can still be made to work facing east and west. Do not use north-facing roof pitches.
3. Flat Roof Placement: When you have a flat roof panels are most likely to be placed in landscape orientation to achieve as much PV as possible
Ground and carport array considerations
If the rooftop is not a good option for the client or they need a bigger system than the roof will allow, ground mounting or carports can be good options. Note that ground mounts are significantly cheaper than carports so if this is a financially driven purchase you may be able to rule carports out quickly, however if the build already has a non solar carport it is not very expensive to upgrade it to a solar carport. Additional considerations are:
1. The further the system is from the main service the more expensive the project will be – whether it is trenching, wire, or wire pulling, these costs will add to the final cost.
2. Ground mounts should be tilted at 30 degrees for optimal year-round production and should be spaced (if you have rows) so as not to shade each other.
3. Carports can straddle multiple parking spaces and find their best economics in continuous systems – they also have a special synergy with EV chargers.
4. Carports can be designed to allow water to pass through or to not permeate water. This may be an important consideration to a client
5. Carports, although traditionally manufactured with galvanized steel, can be painted to match a customer’s business or offerings furthering the curb appeal.
What is BIPV? (Building-integrated PV)
Building-integrated PV is solar jargon for building materials that serve a dual purpose by performing their original function and also generate energy. The most common example we see today are solar shingles, a product really only offered by Tesla to their select residential markets. Michigan Solar Solutions, until the spring of 2020 offered shingles by a company called RGS who was licensed by DOW Chemical to sell the powerhouse shingle. They were unsuccessful in developing a large enough market and finally went out of business. As time goes on we will continue to see this market emerge. At the very forefront of BIPV are companies like Onyx and Lumos Solar that do make translucent PV glass for windows, skylights, awnings, and walkways. While BIPV is not yet cost-effective, it can send a powerful message to a business’s clients about their commitment to sustainably sourced electricity.
The advantage of a solar contractor strategic alliance
As solar PV becomes more relevant in new construction projects, architects will need to give thought to these solar design issues when working on a building project. You now have a basic guide to integrating solar with your next project. It may even be valuable to form a strategic alliance with a market-leading solar contractor so you can quickly line up expertise and available solutions with the needs of your client and project. We here at Michigan Solar Solutions welcome this type of strategic relationship; we hope you will reach out the next time you are looking to design a project that includes solar PV. We are happy to help!
If you or another business is interested in having an undeniable impact on your triple bottom line give us a call for a free consultation to see if solar is right for you! Call (248) 923-3456 or request a Free Online Solar Analysis for Your Business.
Michigan Solar Solutions is a commercial and residential solar installer and electrical contractor that has served the lower peninsula of Michigan since 2007. We have installed thousands of panels and have a happy customer near you, check out what our customers think of us on Guild Quality.