OPTIMIZING K-12 SCHOOL FACILITIES DURING HEAT WAVES
Canadian K-12 schools are typically occupied in the cooler months, but the start and finish of school years can bring warm and humid weather. As the heat of summer extends into the first few months of the school year, optimize your facilities to create a cool environment without a large spike in energy consumption.
Heat waves difficult to ignore in Western Canada
Over the course of a school year, Canadian schools can experience weather ranging from frigid to scorching. Weather extremes in Canada can result in a range of outdoor temperatures upwards of 60 degrees.
Most schools have no students during the hottest months, but it is normal for the heat of summer to flow into the first few months of the school year. School districts in Canada not only need to prepare for cold temperature extremes but also heat waves.
Heat waves have been difficult to ignore – Western Canada has experienced record-breaking heat waves over the past few years. In British Columbia, temperature records were broken in 2017 and in 2018. Alberta has also had a record-breaking summer, with new all-time heat records created throughout the province.
Spikes in consumption and emissions from heat waves
Cool facilities provide relief from hot outdoor temperatures, but it is not without a significant consumption of energy.
Looking beyond consumption, heat waves can also directly impact power generation by reducing the generation capacity due to warmer air or water. In extreme events, generation capacity is reduced around 2 per cent for every degree Celsius (1). When combined with increased demand, this risks large-scale failures and blackouts.
Hot weather also increases the greenhouse gas emissions related to energy generation. Increases in summer-average temperature from 1˚ Celsius to 5˚ Celsius has a corresponding increase in electricity demand of 7 percent. Under the existing power generation system, the increase in demand causes upwards of 16 per cent increase in sulfur dioxide and nitrous oxides (2).
The impacts of hot weather extend throughout the energy sector – from generation to demand. At the facility level, optimization of cooling systems can reduce the demand and ultimately utility expenses.
Leverage cooler nighttime air
The need for heating vastly exceeds the need for cooling in most K-12 facilities in British Columbia and Alberta. However, cooling facilities during warm weather can become a top priority to keep students, teachers and staff comfortable.
Cool is not always a simple process in school facilities due to their equipment – many facilities lack mechanical cooling systems.
As temperatures tend to drop at night, cooler outdoor air can be introduced into facilities in preparation for hot days. Free cooling (which still requires energy for ventilation but not for conditioning the air) purges a facility with cooler outdoor air, typically at night. If occupancy is low enough during the day (which tends to be the case in the summer when there are no students and teachers), air handlers can then be turned off after a facility is purged.
Default approaches to cooling not optimal
When a facility does not need to be heated (particularly in the summer), there are two default approaches. One tactic is turning off all equipment to minimize energy consumption if the facility has low occupancy and does not require extensive ventilation. Another is cooling the entire facility. Both approaches are not ideal – they lack a balance between comfort and energy efficiency.
“Cooling can be more occupancy dependent than heating,” says Marco Bieri, Energy Efficiency Engineer with Rede Energy. In the summer, occupancy tends to not follow a routine. Then during the school year, facilities are typically conditioned when students are in class and cooling systems can be turned off after the daytime heat subsides.
For efficient cooling that keeps students, teachers and staff comfortable, cooling should align with occupancy. This is where communication becomes essential.
Communication is vital for managing hot weather
In Canada, heating systems tend to take the priority over cooling.
“There has been less money that has gone into cooling systems compared to heating systems. You need to understand and communicate what the capability is for your facilities,” says Bieri. Communicating the capability of a facility’s cooling system will manage expectations.
For facilities with air conditioning systems, setpoints and schedules should align with the building’s occupancy during the heat wave. As weather changes, setpoints and schedules can be routinely adjusted to match the occupancy needs and outdoor temperature.
“Keep communication open to have occupants’ trust that the schedules can be adjusted for warmer weather and then can be changed back when the weather events are done,” says Bieri.
Calendar reminders and weather alerts can contribute to ongoing tracking and adjusting schedules in parallel to school occupancy.
Prepare for heat waves with audits and maintenance
Efficiency of equipment is improved when it is routinely serviced, cleaned and monitored.
When facilities are operating under normal or extreme weather events, data from a building automation system can indicate opportunities for mechanical or scheduling adjustments. Analytics of building data during routine weather will prepare the building to respond to extreme weather. Get started with building analytics.
- Añel, Juan A.; Fernández-González, Manuel; Labandeira, Xavier; López-Otero, Xiral; de la Torre, Laura. Impact of cold and heat waves on electricity generation. Economics for Energy, February 2017. (https://res.mdpi.com/atmosphere/atmosphere-08-00209/article_deploy/atmosphere-08-00209-v3.pdf)
- Meier, Paul; Holloway, Tracey; Patz, Jonathan; Harkey, Monica; Ahl, Doug; Abel, David; Schuetter, Scott; and Hackel, Scott. Impact of warmer weather on electricity sector emissions due to building energy use. Environmental Research Letters, December 2017. (http://iopscience.iop.org/article/10.1088/1748-9326/aa6f64)