Grocery stores use fans—lots and lots of fans—in their refrigerated display cases to keep food cool and safe. And while small, these fans use lots and lots of electricity—upward of 7.2 billion kilowatt-hours annually, according to an estimate from DOE’s Oak Ridge National Laboratory.
But there is a promising new option, developed by QM Power, a privately held Kansas City, Missouri-based firm, which could slash electricity consumption from these fans by more than two-thirds, cutting electricity demand by 4.9 billion kwh and saving grocery stores more than $516 million annually.
The option in question is a drop-in replacement fan whose motor is vastly more efficient than the standard units now used across the industry. The most commonly used option today, what is known as a shaded-pole motor (first developed in the 1880s), accounts for about 65 percent of the commercial refrigeration fan market; it is the simplest and least expensive type of small horsepower motor, but it is notoriously inefficient, only converting about 20 percent of the incoming electricity into usable mechanical energy. In addition, much of the wasted energy is dissipated as heat, adding to the existing refrigeration load. The other existing fan technology, electronically commutated or brushless motors (developed in the 1960s), accounts for the remaining 35 percent of the market. EC or brushless motors are more efficient than their shaded-pole competitors, but still top out at about 60 percent efficiency because of the need to constantly convert the grid-supplied alternating current to direct current for use in the motor.
In contrast, QM Power’s replacement, which it has dubbed the Q-Sync motor (see picture below), uses 30 percent less energy than existing brushless motors and as much as 80 percent less energy than the dominant shaded-pole motors. The trick? Using what ORNL dubs a “permanent magnet synchronous AC motor that can directly use grid supplied AC current.” The technology has been around for some time, but has always been far too expensive, because of the cost of the control circuit, to use in these small refrigeration units. QM Power has developed (and has a patent pending for) a less expensive controller and the rest, as they say, could be history.
While the initial target for the technology is the grocery store refrigeration market, ORNL estimates that similar savings could be achieved in other markets, such as evaporator and condenser fans in domestic refrigerators/freezers; walk-in coolers/freezers; and commercial and residential heating, ventilating, and air conditioning systems. Given the vastly larger size of these markets, numbering in the hundreds of millions of units, the total potential savings from QM Power’s novel technology would be significant, perhaps on the order of 1 quad (about 293 billion kilowatt-hours) per year in foregone source energy consumption. (DOE defines source energy as “the sum of the energy consumed at the site (site energy) plus the energy required to extract, convert and transmit that energy to the site” and estimates that there are 3.6 units of source energy per unit of site energy.)
While the estimates are admittedly loosely derived, it is clear that there are plenty of savings, and related environmental benefits through lower emissions, to be had.
[Additional information about QM Power and its new technology can be found here.]