April 27, 2017
Packaged Rooftop Unit Advanced Controls Retrofit
What does this incentivize?
This incentive provides funds for installing–yep–advanced controls on existing packaged rooftop units (RTUs). The affected RTUs must be between 7.5 and 25 tons and serve constant volume systems. To be eligible for it, you must implement the following three things:
- Variable speed controls on the RTU supply fan
- Demand control ventilation
- At least one of the three specified economizer control strategies
Also the RTU supply fan must have three-phase power, and the RTU has to have natural gas heat. No heat pumps allowed.
What doesn’t this incentivize?
You’re not eligible for this incentive if any of the following three things are true:
- You install advanced controls on a new packaged RTU
- Your existing RTU has a variable-air-volume (VAV) distribution system
- You install controls on a split DX system rather than a packaged RTU (e.g., an indoor air handling unit with a condensing unit on the roof).
You also can’t double dip on this measure with incentives for demand control ventilation, an EMS upgrade, variable speed drives on fans, or air side economizers.
Also if you have existing economizer controls or sensors, they can’t be reused as part of this measure. One more thing, the economizer must be locked out when the outside air dry bulb temperature exceeds 69°F.
What control strategies can I use, and how much can I get for adding them?
To be eligible for the incentive, you have to implement variable speed control on the supply fan, add demand control ventilation, and use advanced economizer controls with one of three methodologies specified by ComEd. You can add additional control strategies, but it won’t get you any more money. As long as those three strategies are implemented, you can receive $100 per ton of cooling. It could look like this:
So why is this incentive complicated?
The devil’s in the details on this one. There are lots of limiting factors, so be really careful making sure you’re eligible for this incentive before you go to the trouble of applying for it.
What’s the bottom line?
You need to have a very particular set of RTUs to take advantage of this incentive. The system improvements it encourages aren’t fancy, but they should save you a decent amount of money on using equipment that’s typically pretty inefficient (constant volume RTUs).
Who would this incentive be if it were a figure skater?
Tonya Harding. It’s for equipment that’s probably a little older at this point, not everyone will like it, and its strengths are pretty specialized, but it’s good at what it does.
Where does the worksheet for this incentive live?
Click here! It’s on page 5.