HES PV Solar Design Series: 4. Solar Systems for Large Residential and Agricultural Rooftops - 2018 Innovations

One of the most active sectors of the solar market are the rural residential and agricultural customers. With larger roofs, the generating capacity often allows the buyer to offset 100% of their power needs with solar on an annual basis. These owners are thinking in the long term, whether retirees or generational land owners – That makes them good customers for solar.

In the fast moving solar technology world, there are new products which allow solar companies to install systems competitively and profitably. This article addresses some ideas about the  options to take to these customers.

If we think about solar installations from the top down, lets first talk about the solar modules. In 2018, for projects from 10-30kW on sloped roofs, we would recommend using the 330-340W, 72 cell modules. The larger panel size offers more watts with fewer mounts and inverters. The same racking accommodates 60 or 72 cell modules, so lower cost per watt is achieved with 72 cell panels. The 330/340W size is a compromise from the lower efficiency (305-320W poly) and the super efficiency Perc modules (+350W), and provides good overall value. HES stocks HSQ-330W and HS-340W in all its warehouses, see the product links.

Next, racking for sloped roofs. Fast-Rack rails offer two profiles HD & Ultra. The HD version allows spans up to 64 inches, which may fit the alternate trusses in barns perfectly.  The Ultra rail has 48" spans, and matches residential roof construction. For steel roofs, use the E-Jots, a self sealing hanger bolt to attach to the trusses. For residential roofs the Fast-Rack Talon has become the most popular and quickest way to secure rails to a shingle roof.  To help installers, we have an online Fast-Rack Bill of Materials Generator that tells you what parts to order based on the rows and columns of modules that you can fit on the project roof.

72 Cell Modules saves install time and costs with Fast-Rack and APs Inverters.

For inverters, the most popular answer here are the APS dual micro-inverters.  With 550W total output, and 2 MPPT channels at 275W each, they are ideally matched to the 340W modules. With simple and fast installation, the inverters mount behind the panels, and satisfy all the electrical code requirements for rapid shutdown, arc fault, and offer the bonus of panel level monitoring and total flexibility of system design.

Almost all system owners love to show off their solar system. With full, panel level monitoring the APS systems have a web page showing the owners whats happening on their roof. They can watch on their smart phone, tablet or computer.

Although we have a large selection of modules and inverters, the choices listed above may offer the lowest installed costs for systems on these types of roofs.  However,  installers should contact their HES sales rep to review your project, and let them use their experience to provide you an equipment proposal that meets your exact needs.

Stay tuned for more HES PV Solar Design Series articles.  Next:  HES PV Solar Design Series: 5. Solar Options for Space Constrained Residential Rooftops - 2018 Innovations.

 

 

 

 

 

Leave a Reply