One of the most interesting conversations that I had at LightFair, this year, was discussing lighting-HVAC integration with Chris Wolgamott, Principal Product Manager, Technology & Product Management, at the Northwest Energy Efficiency Alliance (NEEA). Chris graciously agreed to do an interview about his pioneering LLLC-HVAC integration pilots.
SHILLER: You and NEEA are approaching lighting-HVAC integration a bit differently than DLC. Can you explain how DLC is targeting large buildings but NEEA is targeting small to midsized buildings. Why this is different and what it means in practice? BMS vs NLC software controlling HVAC?
WOLGAMOTT: The pilot project that NEEA is working on is based on small to medium sized commercial buildings that are using a
single zone rooftop unit (RTU) HVAC system. We choose this type of HVAC system because it is typically controlled by a single thermostat (per RTU), without any Building Management System (BMS) or Energy Management System (EMS). This is one of the simplest HVAC systems and used in a majority of small to medium commercial buildings. A DOE report says it is about 60% of the commercial square footage in the US. I want the Luminaire Level Lighting Controls (LLLC) to communicate directly with the thermostat, thus removing any additional equipment and if possible, simplifying the programming and installation.
SHILLER: Another example of the difference between DLC’s and NEEA’s approaches is DLC’s focus on broad NLCs, while NEEA is focused specifically on LLLC-NLCs. Can you explain the advantages of the LLLC network of luminaire-based sensors? Any other advantages to the LLLC approach over room-based sensor approaches?
WOLGAMOTT: LLLC is a subset of NLC. What that means is that that LLLC is always a network lighting control system, but not all network lighting control systems are LLLC. NEEA has been focused on LLLC for many years. With LLLC you get a sensor in every fixture. This gives you a granularity of sensors in the space that are not available with standard network lighting controls. This granularity can lead to many benefits including: better occupancy data and understanding what’s going on in the space. We’ve found that you also get better energy savings, and that the lighting operates better. One of the hardest parts with lighting controls is having them operate as programmed and having the ability to meet the needs of everyone in this space. With LLLC, we see the lighting controls operating as programmed more often, and we see that people have less issues with the lighting controls.
SHILLER: In your approach, can you explain how the LLLC-NLC controls the HVAC? How the LLLC-NLC and thermostat are integrated / communicate?
WOLGAMOTT: The goal of this pilot is to see if we can use the sensors in the LLLC to act as a proxy for people counting in the space. We can then use the occupancy data that we are getting from the LLLC sensors to tell the thermostat how to optimize the RTU, based on how occupied the HVAC zone is. We will do this by using 15 minute average occupancy data from the sensors, in each of the fixtures, to tell the thermostat how occupied the space is. For example, if the space has 10 LLLC fixtures and 8-10 of the fixtures show occupancy, then the thermostat would operate as programed (72 degrees + 1 degree of deadband). However, if 4-7 of the LLLC fixtures show occupancy, then the thermostat would let the deadband expand by 1 degree (this means the thermostat would not turn on the RTU until the temperature reached 70 or 74 degrees). Next, if 1-3 LLLC fixtures showed occupancy, then the thermostat would let the deadband expand 1 more degree (triggered at 69 or 75 degrees) before the system would react. The final stage is if no LLLC fixture shows occupancy then the thermostat would go to full setback mode.
We are currently using Bluetooth NLC as our communication protocol. In our current pilot, we have a router that the LLLC system sends a signal to that is then relayed to the thermostat. However in the next installation, we will not need this extra piece of equipment. We now have a thermostat that can communicate directly with the LLLC system.
SHILLER: With your approach, there really is no participation by the HVAC manufacturers, correct? But you do need participation from a thermostat manufacturer? Can you explain this and the advantages?
WOLGAMOTT: The hope is that we can simplify the installation process by not having to involve multiple contractors. We are currently working with a thermostat manufacturer that is providing us with a high quality thermostat that can communicate directly with the LLLC system. If we can simplify the install to just having the lighting installers be able to install the thermostat. Then, all of the “programming” is done in the LLLC system, so we think there will be less of a barrier to all parties involved.
SHILLER: I know one of your goals is to minimize comfort complaints by building occupants. Can you share things you’ve done to proactively avoid comfort complaints? Can you explain why this is so challenging as everyone wants a different set-point?
WOLGAMOTT: We will learn more as we continue to install these projects, but the hope is that we are only making small increases to the deadband, so there will be less comfort issues. I have said that HVAC is like a Goldilocks product, in that someone is always too cold, too hot, or just right. This is regardless of what the temperature is. Our hypothesis is that as the number of people in the space gets smaller, the less likely they will be to notice 1 degree changes in the temperature.
SHILLER: LightNOW has previously written about your project at the MWConnect facility, in Sacramento, CA. Can you share how that pilot project is going? When do you expect to have HVAC savings data to share publicly? Do you already have lighting savings data to share publicly? Even without the HVAC savings data, are there lessons that you’ve already learned from the MWConnect pilot project that you’ll be able to apply to future projects?
WOLGAMOTT: Things are going well. We expect to have the report on this first pilot by the end of this summer. I will wait until we have the final report before I share the findings.
SHILLER: At LightFair, you indicated that you’re getting inquiries from around the country into your approach, and requests to create pilot buildings in other regions of the US. Are you able to share what types of entities of making these requests, and what types of pilot projects you anticipate doing next?
WOLGAMOTT: I have been surprised by the amount of interest this project has been garnering. I have heard from utilities, controls manufacturers, and installers as well. I am hoping to have multiple sites in the Northwest before the end of the year.
SHILLER: How large do you see the energy saving potential of lighting-HVAC integration? DLC often mentions up to 20% of total building energy use, which is an enormous number.
WOLGAMOTT: In the preliminary projects, we are thinking the HVAC saving could be between 7%-15%, but I would be ecstatic with 5% HVAC savings. I think building type and location will play a big part in how much the savings will be. I think it’s possible that there could be bigger savings potential, but at this point, I am going to be conservative in my estimation.
SHILLER: What’s your opinion on how utility rebates will become available for lighting-HVAC integration? Do you see rebates becoming available soon or taking years? How much utility interest are you seeing for lighting-HVAC integration rebates?
WOLGAMOTT: I am not sure I am able to project when or if there will be utility rebates, but I will say that I have heard a lot of interest and excitement about the potential for small to medium commercial businesses. If the saving numbers come anywhere close to the estimates, I think that we would not have to wait too long to see programs in place, that customers will be able to take advantage of.
SHILLER: Chris, thank you for taking the time to share your expertise with LightNOW readers. Very appreciated.
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