Craig DiLouie, LC, CLCP recently interviewed Michael Lunn, Director, Product Marketing, Eaton, on the topic of plug load control.
DiLouie: What are plug load controls? What are the benefits of automation of these loads in commercial buildings? (And why is plug load control being addressed by the lighting industry?)
Lunn: Plug load or receptacle control is now required in ASHRAE 90.1-2010 and California’s Title 24 2013. ASHRAE 90.1-2010 is the minimum building standard for the Department of Energy, several states currently have building codes that comply with or exceed ASHRAE 90.1-2010.
• ASHRAE 90.1-2010 requires automatic receptacle control of 50 percent of the 15 and 20 Amp receptacles, including those found in modular partitions, located in private offices, open offices and computer classrooms. Plug-in strips and devices can no longer be used for automatic receptacle control; the receptacle itself must be controlled.
• Title 24, 2013 requires controlled 120V receptacles in all buildings. Applicable areas include private offices, open office areas, conference rooms, kitchenettes and more. Plug-in strips and devices can no longer be used for automatic receptacle control; the receptacle itself must be controlled.
DiLouie: What are typical energy savings from plug load control?
Lunn: Plug load controls can provide 15-50 percent energy savings depending upon the space and application. If applied properly in a space and it’s controlled by occupancy sensors rather than scheduled, the potential energy savings increases. These savings potentials are calculated based on automatic controlled plug loads compared to appliances that are controlled manually with an On/Off switch. Actual energy savings may vary from installation to installation.
DiLouie: How would you characterize the size of this market? What are typical application?
Lunn: The plug load market is primarily driven by the commercial office and hospitality markets. Although many consumers are also putting in automatic plug loads in the residential market.
The retrofit market for commercial and public buildings in North America is growing from $18 billion in 2016 to $25 billion in 2025. This includes HVAC, lighting, controls and other products in these spaces. HVAC and controls will show the most growth over this time period.
Typical applications for plug load include office control of equipment such as personal printers, computer monitors and task lighting. Plug load controls are also widely used in hotel rooms and the control of vending machines and other large equipment.
DiLouie: What are prevailing commercial building energy code requirements relevant to plug load control?
Lunn:
• ASHRAE 90.1-2010 requires automatic receptacle control of 50 percent of the 15 and 20 Amp receptacles, including those found in modular partitions, located in private offices, open offices and computer classrooms. Plug-in strips and devices can no longer be used for automatic receptacle control; the receptacle itself must be controlled.
• Title 24, 2013 requires controlled 120V receptacles in all buildings. Applicable areas include private offices, open office areas, conference rooms, kitchenettes and more. Plug-in strips and devices can no longer be used for automatic receptacle control; the receptacle itself must be controlled.
DiLouie: What types of plug load controls are available, and how do they work?
Lunn: Several manufacturers currently offer a method to provide plug load control. The current prevailing method is to use a plug load control relay to control standard receptacles, although some manufacturers also use receptacles with integrated controls.
There are two strategies for providing automatic plug load or receptacle control.
• Occupancy based control: Occupancy or vacancy sensors constantly monitor if the space is occupied. When the space is vacant, the sensor will ensure the receptacles are automatically turned OFF either directly or by sending a signal to the lighting control system.
• Schedule based control: The lighting control system or some other time clock device ensures the receptacles are automatically turned OFF based on user defined time.
DiLouie: What are the pros and cons of standalone plug load control versus networking plug load controls into a larger system?
Lunn: Standalone systems can add plug load control rather simply at a low cost. This can be very effective on a space by space method, however this method does not scale easily to a larger network system.
For larger network systems, a building has more powerful and creative ways to reduce overall energy usage. The building manager can automate based on schedule or sensor to turn off plug load devices rather than rely on personnel to turn devices off manually.
DiLouie: What types of larger systems are available that provide room- or building/enterprise-based control?
Lunn: The standard for the last few years has been room based systems that control individual room lighting but also control room plug loads. Ideally the system would be able to control the plug load control independent of the lighting. Some systems will only turn on the plug load control if the lighting is also turned on/off. This poses issues for spaces that want to be controlled using a manual on/automatic off strategy.
The best systems control the plug load independent of the lighting, meaning the sensor turns on the plug load based on occupancy even though the lighting did not turn on. This is ideal for locations that require a manual on/automatic off control methodology.
DiLouie: What opportunities exist for electrical contractors in this market segment? What do they need to know to install and sell appropriate solutions to their customers?
Lunn: This is an opportunity for the electrical contractor to bring new value to his customers. Although plug load controls are required by some building codes, it is not widely understood. The electrical contractor that understands what spaces need plug load control and which spaces have exceptions will add value to the design and cost of the project.
The electrical contractor should also understand the types of plug load controls and systems available. Where the simple room-based relay solution may be a lower material cost, the installation of pipe and wire will increase. In order to use the relay solution, the receptacle would need a control wire from the relay as well as a constant hot connection for the bottom plug.
When looking at retrofit or renovations, the electrical contractor may want to install a wireless controlled receptacle. This allows the electrical contractor to use existing wiring, reducing labor and potential complications by not having to expose behind the wall.
DiLouie: What are common pitfalls in implementing plug load control, and how can electrical contractors and distributors mitigate them to get the best results for their customers?
Lunn: Common issues when implementing plug load control are to not use receptacles that have a constant hot and switched outlet. The switched outlet should be labelled using the approved NEMA standard and oriented on the top of the receptacle.
Electrical contractors should also look at the application to determine which solution relay or controlled receptacle is best for the application.
DiLouie: If you could tell the electrical industry just one thing about plug load controls, what would it be?
Lunn: Plug load controls is not required in all spaces and regions, however it is required for all projects that must meet ASHRAE 90.1 2016, which include government and LEED certified projects.
Although many people do not understand why plug load control is being required, it has been proven to be the next best energy reduction point in our buildings, especially office spaces. Since the mass adoption of LED lighting, we have continuously reduced the energy used by lighting in each space. The next potential energy reduction point is the plug load in those spaces.
DiLouie: Is there anything else you’d like to add about this topic?
Lunn: Remember plug load control can be achieved with a simple traditional occupancy sensor, room based control system, large enterprise systems, and wireless lighting control systems. Each method provides additional functionality and integration of controls and technology such as integrated power metering of plug loads that is now available on many wireless controlled receptacles.
Leave a Reply