Airflow…it’s one of the unique factors that sets laboratories apart from other rooms. Labs must exhaust an exorbitant amount of air in order to stay in compliance and ensure the safety of their users. Because there is so much air leaving the space, new air is constantly being pulled from outside and conditioned (heated or cooled) to make up the difference. This heating and cooling of outside air consumes massive amounts of energy and makes labs costly spaces to operate. This however, also allows for small tweaks in your system to result in huge payoffs. In this article we discuss how changes to airflow can slash energy costs.
Check Airflow Levels
Start by examining how much air is actually being exchanged. Depending on the classification of your lab, you may be required to have 8 air changes per hour or higher. Because many labs don’t perform regular checks on airflow, we commonly see that they are actually over ventilating the space. By pulling the number back to the designated number of air changes you will see an immediate reduction in energy costs.
Install A Heat Recovery Unit
As you know labs exhaust a significant amount of air in order to stay compliant with safety standards. This air is required to be ventilated outside but that doesn’t mean we can’t use it to help lower energy costs. Heat Recovery Units work by taking the air that is being exhausted outside (which is conditioned) and running it in close proximity to air that is being brought inside. The goal is to allow the conditioned air to heat or cool the outside air, which allows your HVAC system to work more efficiently.
Consider This Example:
It’s the dead of winter and a mere 10-degrees outside. As air is pulled into your lab it is heated from 10-degrees up to 68-degrees (a 58-degree change!) so users of the lab remain comfortable. In a relatively short amount of time that heated air is then exhausted out of the building to comply with lab safety standards. With a heat exchanger, while that air is being exhausted out, it is run in close proximity to the fresh air being brough into the building (with a barrier between it of course to ensure the two don’t come in direct contact). Radiant heat from the air that 68-degrees leaving the building is transferred to the 10 degree air being pulled from outside. This heats the 10-degree air up to 25-degrees. Now the air only needs to be heated 43-degrees instead of 58-degrees.
This process can be done in the summer months as well to cool air coming into the building. This small change can have huge impacts because of how frequently air change rates occur in labs. By using some of the energy from the exhausted air you are able to reduce energy costs drastically.
Demand Control Ventilation/Air Monitoring System
This is a process of using sensors to monitor the air and adjust air flow rates based on the results. As chemicals or gases are detected in the air, sensors relay to the system to increase air change rates. This allows labs to reduce ventilation rates based on the real-time monitoring of lab pollutants and occupancy.
While this is great from a safety standpoint it is also great from a financial standpoint. In a standard lab you are not able to go below 6 air changes per hour and many are set even higher. However, with an air monitoring system you can lower rates to 4 air changes per hour when occupied and down to 2 air changes per hour when the lab is unoccupied. This is possible because of the system’s ability to ramp up quickly if needed and the constant monitoring of air quality by sensors. This reduction in air change rates results in significant savings! In fact, the reduced energy use will generally pay for the cost of retrofitting an air monitoring system within 2-5 years.