Photovoltaic (PV) energy, also referred to as solar energy, is a clean, renewable source of power which converts sunlight into thermal or electrical energy.  The electrical energy produced through PV sources is then converted into electricity. There are three major types of solar energy:  passive, active, and thermal solar. Passive solar energy systems are built directly into a building’s blueprints (walls, windows, skylights) to improve heating and lighting efficiency. Active solar energy systems use a mechanism to collect and convert energy into a usable form. Active solar energy systems are most often seen as solar panels on roofs or in solar farms. Thermal solar energy is the process of using the sun’s radiation to heat water. This basic concept is used to reduce water heating bills or can be used in its simplest form for things such as heating a pool with a solar cover.

The most common photovoltaic source used to convert sunlight into electricity is the solar panel. Solar panels are made up of a series of individual PV cells. Typical solar modules consist of 32, 36, 48, 60, 72, or 96 cells. Modules are then grouped together to form a panel or a larger array. PV cells capture sunlight, more specifically photons, by using a semiconducting material which then converts the sunlight/photons into direct current (DC) electricity. In most cases, the semiconducting material is silicon. Solar panels can range from 100W to 415W, the highest wattage currently available from manufacturers. The amount of power in watts per panel increases as technology continues to improve. Currently, SunPower manufactures the highest power rated panel on the market.

solar diagrams















PK Electrical designs commercial PV systems, as opposed to residential. The key components of a commercial PV system are solar panels, junction box(es), a DC disconnect, inverter(s), an AC disconnect, a grid connection/main breaker tie, mounting infrastructure, and production meter(s). Additional components that may be included in a PV design are power optimizers, battery bank(s), a charge controller, an energy monitoring system (Wi-Fi), and customer submeter(s).

In order to design an efficient PV system, the tilt and azimuth angles must be properly calculated. Tilt angles range from 5° to 30° in increments of 5°. The azimuth angle refers to the sun’s position in the sky. 180° (south-facing) is the ideal azimuth for a PV system. Not all situations allow for a 180° azimuth however, which is why it is a critical element of the design calculations. There are multiple configurations to mount PV panels to ensure the designed PV system reaches its maximum energy production potential. Mounting is also referred to as module racking. One method of mounting a PV system is Slope Roof Mounting, which can include a rail or rail-less racking system. Another option is is Ballasted Mounting, which is utilized on flat roofs without penetrating the roof by using CMU blocks or other weighted devices to secure the unit. Finally, PV systems may be mounted on a Stand-alone rack. Stand-alone racking systems are considered when designing a solar farm in a field or parking lot where a structure might not be present.

solar panel







Every PV system design follows standard steps to guarantee the client receives the most efficient design. First, designers must determine the client’s power usage (kWh). During this stage, designers should also work with the architectural team and stakeholders to investigate and decide where the PV system will be located and the method in which it will be mounted. These factors will influence the required tilt and azimuth angle of the system. After verification of the client’s power usage, tilt, and azimuth, designers then utilize the National Renewable Energy Lab’s (NREL) PVWatts Calculator. This calculator allows designers to calculate the DC Size in kW required for the PV system. Once the DC system size is determined, designers can size the solar panels, establish panel quantities, and produce a layout. Designers then convert the designed DC system to AC and ascertain the type and quantities of components required to produce the necessary amount of power to meet the client’s needs.

A real-world example of a PV design completed by PK Electrical is at the Denver International Airport.  The Concourse B Expansion required 212 kWh in order to reach LEED Gold qualification status. It was known that the roof tilt angle was 10° and the azimuth angle of the building area where the solar panels would be placed was 180°. Using the NREL PVWatts Calculator, we concluded that the DC System size required from DEN’s power usage of 212 kWh was 143 kW. The PV panel that was specified during design was a 400W panel, which meant that 358 panels were required on the roof. With those calculations, PK Electrical’s designers were able to then calculate the necessary inverter size and quantities as well as the other components to complete the designed system. Additional equipment was detailed in the final design including power optimizers, DC and AC disconnects, an EPO push button, meters, and a zig-zag transformer.

While this overview of Photovoltaic (PV) or solar energy only scratches the surface, knowing the basics of the PV design process allows for a better appreciation of what goes into the planning and design for a renewable solar project and proves that sustainability is much more than a buzzword in our industry!


commercial solar panels

Photovoltaic (PV) energy, also referred to as solar energy, is a clean, renewable source of power which converts sunlight into thermal or electrical energy.  The electrical energy produced through PV sources is then converted into electricity. There are three major types of solar energy:  passive, active, and thermal solar. Passive solar energy systems are built… Read More

Each year the Nevada Women’s Fund hosts an event to recognize extraordinary women in the northern Nevada community.  The mission of the Nevada Women’s fund is to remain, “dedicated to strengthening our community by empowering women to improve their lives and those of their families”.  The organization is governed by a Board of Directors including… Read More

Founded in 1996 by Karen Purcell, P.E., PK Electrical has grown from a small local business to a nationally recognized electrical engineering firm. This would not have been possible without our thoughtful leadership and innovative designs. The firm has had the privilege of continuing to work with the clients that it began working with 25… Read More

What is Project NEON? Project NEON is an almost $1 billion project that is extremely important for Las Vegas. It “is the largest public works project in Nevada history” and has been in progress since December 2015 (NDOT). This project affects the “Spaghetti Bowl” and surrounding freeway areas, which are some of the most congested… Read More

What Is The Southeast Connector? The Southeast Connector is a two-phase electrical engineering project that connects Eastern Sparks, Nevada to Southern Reno, Nevada. It is a limited access roadway with major intersections at Greg Street in Sparks, Pembroke Drive, Mira Loma Drive and South Meadows Parkway in Reno. The roadway will terminate into Veterans Parkway… Read More

The PK office attended the 25th anniversary of the Nevada Women’s Fund Salute to Women of Achievement luncheon yesterday at the GSR.  This years theme was focused on STEM, specifically, women in STEM, so who better to be chair of the event, than PK’s very own Karen Purcell!  As principal of PK Electrical, a 28 person Electrical Engineering firm, with offices… Read More

Experienced Microstation/AutoCad Drafter Needed!! Here is a rare chance to join the region’s leading Electrical Engineering firm that is expanding! Do you take pride in the quality of work you produce? Do you enjoy and excel in a team environment? Do you want to grow yourself and your electrical engineering career to the next level? We are… Read More

Are you looking for a great career opportunity? Are you looking to join an innovative engineering firm? Experienced Electrical Engineer/Designers!! Do you want to work for a great company and live in a great place? Here is your chance to join the region’s leading Electrical Engineering firm! Some of our wins: Solid expansion through the… Read More

At PK Electrical we value creating a fun, positive, team-oriented environment.  At the end of 2014, a FUN committee was created to plan and organize activities for PK as a whole to participate in.  Since its inception, we have had an Ugly Christmas Sweater contest, Email BINGO, Valentine’s breakfast potluck, and a Bowling Night.  Some… Read More

Take a look at one of our latest and greatest completed projects!  It’s such a pleasure to see the end result of all the hard work and commitment that our great design and construction team invested into this CMAR project.  This is a facility that is truly appreciated and cherished by the community of Douglas… Read More

PK Electrical had an Ugly Christmas Sweater contest today in our Reno office….we are still waiting to tally the results.  Who do you think has the Ugliest/ Tackiest sweater? Merry Christmas and Happy New Year from everyone here at PK!… Read More

Today, Thursday, November 6th from 11 AM to 10 PM all 3 Chili’s in Reno/ Carson City are donating 15% of their sales to the Veterans Guest House. So the employees in the PK Reno office headed down the street to Chili’s for lunch! Please click this link for more details!  Give Back Event Flyer You can… Read More

Electrical Engineers Need to Express Themselves Too The Monday Morning Meeting Gathered around our big layout table is where you will find the employees of PK Electrical on a typical Monday morning; even the Denver office joins us via telephone. Our Monday Morning Meeting is a great way for us to stay connected to each… Read More

On Wednesday 7/29 I had the honor of attending the Patriot’s Luncheon at the Reno Air National Guard Base, put on by Barracuda Championship (formerly Reno-Tahoe Open), benefitting Veterans Guest House and featuring K9s For Warriors. PK Electrical bought a table, where I sat with Joey Ganser and Dugan Hadler (also with PK), Steve Ainsworth… Read More

Karen Purcell, P.E. has written an article that appears in PE Magazine. As a society, we learn about the world and advance our well-being through science and engineering. The United States may be known around the world for its higher education but compared to many other leading and steadily emerging countries we lack a strong focus… Read More