Jeffrey Gingras, President, Systems LMP INC.
With the phase-out of HCFC refrigerants well underway and continued uncertainty about the eventual fate of HFCs, natural CO2 refrigerants are a great option for retailers who want to upgrade their current refrigeration systems, boost their sustainability, and avoid headaches associated with yet another synthetic refrigerant phase-out somewhere down the road. CO2 refrigerants are not only cost-effective and compliant with current restrictions but also exempt from future environmental regulations.
Natural refrigerants have steadily gained acceptance in new construction installations, but there’s been a lingering misperception that it’s too difficult to make the switch from synthetic to natural refrigerants in a store renovation. To be sure, renovations introduce some challenges that don’t exist with new construction, since the goal of a renovation—aside from the driving objective of complying with regulations or improving energy efficiency—is to ensure that there’s no downtime. You’ll need to have the new compression systems in place while still running the old systems to make sure any glitches are worked out before the switchover. But phasing in new, sustainable CO2 technology doesn’t need to be any more difficult than any other renovation project.
Just as you would with a renovation involving synthetic refrigerants, start by taking stock of your current systems and evaluating your existing equipment. What do you need to change? What can you reuse? What systems can you keep? With some careful planning and forethought, these questions will have you well on your way to a seamless transition from HCFCs to all-natural CO2.
How old are the evaporators and cases?
Is it time to replace everything, or does it make more sense just to switch out the evaporators? As long as cases are relatively new and in good condition, retailers can save thousands of dollars by keeping their existing cases and switching just the evaporators to a natural refrigerant system. On the other hand, if the cases are 15 20 years old and showing their age, a complete change as part of the renovation may be the way to go.
Is the HVAC system outdated?
After the renovation, if you’re saving on refrigerant costs but still losing energy with an inefficient HVAC system, you may find that your savings and sustainability picture has not improved as much as you would have hoped. To maximize the return on your renovation efforts, consider changing over to a new, more efficient heating and air conditioning system as another step toward increasing overall efficiency.
Where will the new CO2 rack go?
Typically when converting from a synthetic to a natural refrigerant, the new equipment is smaller than the old system it’s replacing. Gas coolers are about half the size of compressors, and cooler racks are smaller because the low and medium temperature are all on the same unit, so you only have one unit instead of two. The tricky part is often just fitting the new system into place while the old equipment is still in operation.
Work with your contractor to determine the best plan for both indoor and rooftop space and decide whether you will fit the new equipment into an existing compressor room, custom-build a new rack house, or build a whole new compressor room. The time for this conversation is before the renovation begins.
Do we have sufficient power?
To eliminate downtime, you’ll be running two racks (the old and the new) for a short time, gradually reducing the load on the synthetic system while bringing up the new, until the old equipment is taken out of operation altogether. Clear communication between contractors, suppliers, and electricians is necessary to ensure that the building’s maximum power is sufficient to handle both systems at once—and to avoid any unpleasant surprises.
Are the controls compatible?
The electronic controls for CO2 systems are extremely adaptable, allowing operators to optimize system performance like never before. In most situations, the new case controllers are compatible with existing building controllers, requiring just a software upgrade to the existing system, but as with the other steps in the renovation process, advance planning and testing are essential to a smooth transition from the old system to the new.
What happens next?
Coordination and communication at every stage of the renovation are the keys to keeping all the players—retailer, supplier, contractors, electricians, and controls technicians—on the same page so that everything is planned out and the switch goes off without a hitch.