Today's performance and sustainability trends have increased interest in HVAC. HVAC systems alter the ambient conditions within buildings to maximize the comfort of occupants. Conventional HVAC systems focused mainly on temperature control, largely with mixed success based on the age-old problem of offices deemed too hot or too cold.
Poorly-commissioned HVAC systems can be blamed. Most facilities haven’t been incentivized properly to re-commission the HVAC units to prevent over-cooling spaces in the summer and over-heating spaces in the winter.
A new challenge has now arisen for HVAC systems, Indoor Air Quality (IAQ).
IAQ Places New Demands on HVAC Systems
The WELL building standard acknowledges the critical role that IAQ plays in individual health. New IAQ measures such as CO2, Particulate Matter (PM) and Volatile Organic Compounds (VOCs) have become important parts of any modern facility management plan.
There’s a problem, however. Very few buildings continuously monitor CO2; even fewer buildings have a single sensor that measures advanced IAQ metrics such as PM and VOC. The reason? The vast majority of buildings have HVAC systems that were originally commissioned without CO2, PM, or VOC included as part of the building specifications in the Owner’s Project Requirements (OPR). This would be true whether or not the building actually included a Building Automation System (BAS).
How to Add Wireless IAQ Sensors to a Building
Should the building’s existing infrastructure fail to include support for IAQ monitoring, then a retrofit scenario would exist. Retrofitting a BAS represents a costly option due to the installation of wired network connections and BAS software upgrades. The time required for project scoping, installation, and commissioning can also be prohibitive.
For buildings without a BAS or buildings having a functionally-obsolete BAS, wireless IAQ retrofits represent the way forward. The Internet of Things (IoT) delivers today’s answers. Wireless IAQ nodes take only minutes to install and connect wirelessly to an on-site gateway.
Not only does IoT drastically reduce the installation costs of adding new IAQ sensors to an existing building, but IoT also drastically reduces the time-to-data. Imagine a scenario where entire floors or buildings deliver real-time IAQ data to a cloud dashboard after same-day installation. IoT makes IAQ monitoring a visible reality to facility managers and building occupants without complex project management costs.
Wireless IAQ sensors break the box of conventional limitations. Each of these example implementation scenarios exist today:
- Expand temperature sensing throughout an entire HVAC zone. Install an array of wireless temperature/humidity sensors throughout a space, including every corner that has well-known deficiencies in HVAC airflow.
- Add CO2 sensors to shared workspaces, including every conference room on the floor or in the building. Track the range of CO2 levels in each conference room when occupied to determine proactive HVAC measures before complaints arise.
- Add PM and VOC sensors to air intake vents to regulate the amount of outdoor pollution entering a space. Outdoor pollution conditions vary and demand controlled ventilation systems should regulate the ventilation rate of outdoor air based on current conditions.
Real-Time IAQ Observation and Reporting
IoT facilitates the rapid addition of IAQ sensors to existing spaces and buildings. The job isn’t done. IAQ monitoring data has value, of course, but truly delivering on that value requires real-time visibility. A report of IAQ conditions at the end of the month provides minimal value.
Real-time IAQ monitoring data can be delivered to the cloud for visualization of real-time conditions. Any stakeholder having an interest in any room, floor or building can gain anytime, anywhere access to real-time IAQ data in a cloud dashboard. Simply seeing the data enables identification of obvious problems, and helps eliminate suspicions that a potential problem exists.
Real-time data enables real-time alerts and notifications. When given access to data, organizations are empowered to act for the benefit of all. Certainly, it would be easy to hide behind a veil of ignorance. The veil has been removed, however, because ready access to real-time IAQ data is here.
Access to historical trends and a history of alerts regarding potentially unhealthy conditions, provides the key to healthy buildings. Building occupants will gain the assurance they desire about the state of IAQ in the space in which the live, work and breathe. The stakes are highest for those occupying the space.
Integrating Real-Time IAQ Monitoring with an HVAC System
The "real time" factor in IAQ monitoring delivers value beyond assurance; take proactive action. It’s good to know, but even better to use.
How can you use real-time IAQ data? Naturally, adverse IAQ conditions within a space can be remedied through the HVAC system. In the same way that a freezing office condition can be corrected by increasing heating, high CO2 conditions can be corrected by increasing the flow of fresh air into the space.
Real-time IAQ data generated by wireless IoT sensors can control HVAC systems in a number of ways. Said another way, wireless IoT sensors can be fed back into the HVAC control loop to influence the automated actions executed by the HVAC system.
Integrating wireless IAQ sensors with a BAS
As noted, retrofitting a BAS to add IAQ sensors represents a costly option due to installation of wired network connections and BAS software upgrades. Wireless IAQ sensors that may not be native to the BAS can easily integrate with the BAS through standard communication protocols.
The figure below illustrates an IAQ Control Layer implemented in the cloud that receives real-time IAQ data generated via the IoT retrofits. The IAQ Control Layer treats the legacy BAS as a sub-system.
The IAQ Control Layer determines HVAC control actions based on the receipt of real-time IAQ data from the building. The determined IAQ control actions (e.g., setpoint adjustment) can then be transmitted to the BAS sub-system using an industry standard protocol such as BACnet. Upon receipt of the IAQ control action, the BAS would then execute the HVAC adjustment as determined by the IAQ Control Layer. The execution of the HVAC adjustment would address the deficient IAQ conditions in that particular area of the building.
Some buildings do not feature a BAS, but rely on stand-alone thermostats. For those buildings, the IAQ Control Layer can relay control commands directly to smart thermostats using standardized communication protocols such as Modbus or BACnet.
Regardless, the implementation of the IAQ Control Layer in the cloud enables a simple, cost-effective upgrade path as compared to conventional BAS retrofits.
The only obstacle standing in the way of real-time IAQ monitoring and control is commitment, not technology. The long-awaited revolution in the underlying structure of automated HVAC control is here.
IoT has delivered change to an industry in need. Poor IAQ is unacceptable. If real-time IAQ data was offered to every stakeholder in existing buildings, the offer would be readily accepted by those impacted. The price of healthy, sustainable buildings has been established with inexpensive IAQ retrofits.