Building retrofit – smart sensors are the key
Issue 01-2019:
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The J G O’Donoghue Building in Edmonton is an enormous, three story, 262,500 square foot office building operated by the Province of Alberta. A $32 m retrofit project of the building was completed in 2018 to meet the Alberta Go-Green program that incentivizes buildings to rely on renewable energy. The project was a full renovation that included the addition of solar power, tenant improvements and installation of new HVAC, electrical and plumbing systems to meet sustainability objectives.
The retrofit included the installation of 117 AirTest TR9277-EO wireless, zero energy, CO2, temperature and humidity transmitters that are powered solely by an on-board photovoltaic panel that harvests indoor ambient light. If desired, a button battery can also be used to provide 5 years of power.
These devices were installed in all meeting rooms in the building and are used to provide energy efficient Demand Controlled Ventilation (DCV) that allows the modulation of delivery of fresh outside air to the space based on the number of people in the space exhaling CO2. Wireless technology is often preferred in retrofit applications like this to avoid the cost of running wires.
The CON-ENOC wireless gateway is an important component if the Delta Controls system.
Installation details
The building control system selected for the project is made by Delta Controls and installed by ESC Automation in Edmonton. A key component offered as part of the Delta system is an inexpensive, add-on wireless gateway called the CON-ENOC which supports a wide range of devices that communicates using the low-energy, EnOcean wireless protocol, including the AirTest TR9277-EO.
The gateway can receive signals from up to 32 actual EnOcean communicating devices which then translates the information via an RS485 connection to the widely used BACnet wired communication protocol. Many other HVAC manufactures offer similar EnOcean gateways.
One important feature of the TR9277-EO is a test mode that allows for measurement of radio signal strength between the gateway and transmitter. In this installation, there were a number of metal interior walls in the building that potentially can be a barrier for radio communication. To meet this challenge, the CON-ENOC gateways were strategically placed within 15 meters (50 feet) of the EnOcean devices in such a way that the radio signal did not have to go through more than two walls.
In the test mode of the TR9277-EO, you can measure the radio signal strength between gateway and transmitter.
At a glance
The TR9277-EO offered a simple, fast and reliable way of integrating CO2, temperature and humidity measurement into the Delta Controls system using their CON-ENOC, EnOcean-to-BACnet gateway. This approach reduces total cost of installation in new and retrofit applications by drastically reducing wiring and labor costs. In spaces with high or variable occupancy, CO2 DCV can start saving energy immediately.
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