VCBO has always worked to provide the most energy efficient projects possible, within the project budget and performance expectations set forth by the Owner. With this approach, we have designed and constructed a number of LEED certified schools, as well as numerous high-performing schools across the State. |
 Odyssey Elementary School |  Canyon Creek Elementary School |  Kay's Creek Elementary School |
So, what is a net-zero building?
There have been several definitions of net-zero throughout the years, but the current standard for a net-zero building is a building that generates as much energy as it uses - on site, over the course of a year. For each of the Davis School District elementary schools, a large photovoltaic array on the roof of each building generates as much energy in kilowatts throughout the year, as the school uses over the course of the same year.
Why does designing a net- zero school matter?
From a school district perspective, operating a net-zero school reduces the potential volatility in energy costs. At the end of the day, this puts more money into the classroom. This money can be spent within the school for other resources and programs, and to better serve students and teachers.
A net-zero school also shows the District’s commitment to healthy air and a more sustainable future.
A net-zero building can also be used as a teaching tool – the students can track energy use, compare it to energy generation and see what happens to the power use and generation as the sun shines, it snows, and the temperatures fluctuate. This engagement and data review can be as basic or technical as the teachers would like it to be.
So how do you achieve net-zero?
The first step in achieving net-zero is to drive down energy use through smart design. A couple of ways to do this include:
-Determining the right orientation for the building – make sure there is not too much solar heat gain in the summer months, and enough solar access in the winter.
-Design an air-tight and thermally sound envelope.
- Select an efficient mechanical system, and make sure it is not over-sized or over-designed for the building. You can even consider letting the temperatures shift up a bit in the summer and down a bit in the winter to save energy.
-Use high-quality, LED lighting, and do not over-light the building.
Integrate effective controls to make sure your building management team can control the start-up and set points of the mechanical and lighting systems and manage energy use through the day, season and year.
Engaging the building users to help reduce energy consumption is imperative in achieving net-zero success. The more informed the building users are of the ways in which they can be more energy conscious in the classroom, the better.
Finally, you determine how renewable your energy system can be.
Considerations as you ponder the potential for net-zero on your next project:
Building and Site Size
In order to maintain renewable energy system on site, you have to balance the building size and energy use with the available area for renewable energy systems. Schools are often optimally sized, with relatively large roof areas and lower heights, typically one to two stories, providing an optimal spot for photovoltaic panels on the roof.
Smaller sites can consider alternative locations for renewable energy such as covered parking, or even off-site renewable energy systems.
Building Energy Use Profile
The amount of renewable energy required for the building is typically estimated through the use of an energy model. This model creates an assessment of how much energy is being used to heat and cool the building, power all the electronics and equipment, based on the orientation and building envelope design. This model estimates hours of operation, start-up and operational energy use profiles, and makes assumptions based on typical user behaviors.
As designers, we have a great deal of influence on the building envelope and how it impacts heating, cooling and lighting. Though we have knowledge of the number of occupants, we do not have much control over hours of operations, and how occupants use the building. It is vital for the Owner to be an interval member of the team and convey the vision of net-zero to all occupants.
While this energy model gets very close to the actual energy profile of the building, the best opportunity to right-size the renewable energy system is to track actual energy use for one year and size the system based on actual data.
Electrical Costs, Fees and Demand Charge Impacts
Even with a renewable energy system, if you tie it back to the electrical grid, you will need to continue to pay fees to the power provider and these fees increase as they realize the impact of PV on their grid. Additionally, demand charges may still apply as net-zero is assessed on an annual basis. There will likely be times, in the winter specifically, when more energy is used to heat the schools at peak times when the sun may not be out and the system not generating electricity. Managing these peak demands will help reduce operating costs and reduce the size of the PV array upfront.
Early Investments Enable Net Zero Success
A wide-range of investments are needed to ensure a successful net zero project. Starting from the beginning of the process, these investments include:
-Engage an energy modeler early in the process
-Invest in a high performing building envelope
-Select the right mechanical system
-Commission your building - make sure your energy impacting systems work properly from the beginning
-Plan for and install an effective building management system to control your energy use
Each of these early investments will result in ongoing cost savings, and ensure net zero is achievable.
Let’s Do It!
If you are ready to design a net zero building, give us a call and we’ll guide you through the process and help you achieve your goals!
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