How to Overcome Demand Control Ventilation Challenges of COVID Safety Measures
Our engineers have laid out the most important considerations when disabling demand control ventilation.
Now as commercial real estate (CRE) owners and operators plan for reopenings — and the uncertainties around their occupants’ return — they must determine how best to build occupant confidence in the safety of their buildings.
Over the past few months, we’re learning more about the airborne spread of COVID. It’s now critical for owners and operators to take a closer look at how their buildings are being ventilated to determine if their HVAC systems are up for the task.
Buildings commonly circulate air by zone ventilation (air delivered room by room, floor by floor) and adjust fresh outdoor air intake through demand control ventilation. This method works through a series of logic sequences that dictate the amount of air that should be brought into a space based on its occupancy.
Lately, based on recommendations from industry leaders such as ASHRAE, the community has been toying with how best to mitigate the spread of COVID indoors, and what happens if we disable demand control ventilation?
Demand Control Ventilation: The Outside Air Challenge
Here’s how demand control ventilation could be problematic in helping prevent airborne spread: Typically, demand control ventilation matches outside air with the number of people in a building while using the least amount of energy possible, but COVID restrictions demand higher amounts of outdoor air be brought into the building regardless of occupancy levels.
By disabling demand control ventilation, building operators can ventilate spaces more manually by zone, ensuring that even when there is no demand, fresh air will circulate in, and reduce the likelihood that viral particles will recirculate to the space.
While turning off demand control ventilation addresses the health and safety concerns, it also means that more outdoor air will be brought into the building that will require cooling or heating — significantly impacting overall energy costs and overall equipment performance.
EXAMPLE: The compressor or boiler will have to work harder to deliver that 65- or 70-degree air we expect in an office space. Carbon Lighthouse data shows that if COVID HVAC measures are implemented without optimization, an average 115k sq. ft. office building in Los Angeles with an annual energy spend of $230,000 could see a 70% spike in costs, paying upwards of $370,000.
Finding Balance with Data-Backed BMS Optimizations
To prioritize the health and safety needs of occupants while continuing to work toward business goals, operators must carefully evaluate the impact that COVID safety measures like demand control ventilation will have on HVAC systems — resulting from working their equipment harder both from an operations and cost standpoint.
Those with a means of ingesting building management system (BMS) data have a headstart in maintaining energy efficiency while managing errant variables like fluctuating outdoor air.
EXAMPLE: Operators could use BMS data to help inform the proper damper directions and fan speeds that should be implemented, based on the amount of outdoor air being brought in.
This may seem daunting but aligning with a partner who can make these optimizations for you may be a smarter solution — and the return on investment can be justified by the potential extension of equipment life and energy savings at stake.
When occupants eventually return to the office — however they return to the office — buildings will likely be required to maintain a level of health and safety that is higher than what was ever expected prior to the pandemic.
Operators should take the opportunity now to strategically invest in technologies and solutions to help them efficiently deploy COVID-mitigation measures — and just as importantly ensure that these investments also serve as solid building blocks for their portfolio’s longevity and resilience against future disruptions.