| “We were getting locked out because we couldn’t just
supply an equivalent control,” says Kenny Owen, engineering manager,
Master-Bilt. “We had customers, and this other competitor came in
and sold them on the benefit of electronic control and solid-state circuitry.”
Master-Bilt had used these types of controls before, but on a limited basis.
That is when Master-Bilt engineers realized that no one else had developed
this kind of control for walk-in freezers, so they decided to develop one.
From this decision was born the company’s new Mater Controller Demand
System with Reverse Cycle Technology, which was patent-pending at press
time. The new control system was officially unveiled at this year’s
National Restaurant Association Show, held in May at McCormick Place in
Chicago, IL, U.S. The Master Controller itself has been on the market for
nearly a year and a half, but the reverse version of the control was released
on Master-Bilt appliances in June, Mr. Owen reveals.
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| Master-Bilt
has just launched its patent-pending Reverse Cycle technology
for its commercial, walk-in freezers and coolers. The
technology, which is used in conjunction with its Master
Controller system, involves a reverse-cycle valve that
is added to the condensing unit. The valve’s primary
function is to reverse the direction of refrigerant flow
during defrost, reportedly reducing defrost energy usage
by 80 percent. |
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Defrosting a New Idea
The company’s new reverse-cycle defrosting involves a reverse-cycle
valve that is added to the condensing unit. The valve reverses the direction
of refrigerant flow during defrosts, which is automatically activated by
the Master Controller. The reverse-cycle valve is activated when the Master
Controller demand system determines that defrosting is necessary, and high-temperature
refrigerant flow is reversed through a multi-step process. Once the process
is triggered, refrigerant flows backward through the evaporator coil, heating
it along its entire length, which eliminates the buildup of frost.
To develop the new control and ensure it was different from competitive
offerings, Master-Bilt engineers analyzed the new solid-state electronic
control that its competitor had developed and decided to simplify it. “It
had a lot of drawbacks,” Mr. Owen says. “Just like most electronics,
the first generation doesn’t go nearly where you want it to.” Master-Bilt
saw this as an opportunity and decided to take advantage of it. “We
took theirs, we looked at it, and looked at all the benefits,” he
said. “We took out a lot of the unnecessary parts, kept the good
parts, and added a whole lot of other things to it.”
Typically, a walk-in freezer or cooler is supplied with several components
that are installed and wired in the field. In the new solution, an electric
expansion valve and an integrated circuit board have been put in place
and all of the wiring is done at the factory. “The electric expansion
valve and integrated circuit board do the work of the separate components,” Mr.
Owen says. “We added more reliability, but the biggest benefit we
added was simplicity.”
However, the research and development of the controller did not come without
obstacles. Although the controller was simplified in terms of components—which
left less of a chance for something to go wrong—the technology was
more advanced. A typical reverse-control system has been mechanically controlled
and uses more expansion valves, Mr. Owen explains. “This means more
parts, so there are more problems,” he says. “The beauty of
our system is that the plumbing is identical. Our electric expansion valve
works the same way in defrost and in cooling—it modulates the flow
of the system. It’s very simple; it’s all pre-wired. There
are no check valves. And it’s something no one else has done.”
But it did take some time to perfect, Mr. Owen admits. Master-Bilt did
all of the program debugging and has gone through hundreds of iterations
of programs in doing so, he says. “It took us about a year to get
it working the way we wanted and then about a year of field testing before
we started selling it,” Mr. Owen says. “We have been selling
the control on our freezer for about a year now, but the Reverse Cycle
part of it we’re just starting to sell on our appliances.”
The decision for Master-Bilt to be its own supplier—to design its
own control—was based on myriad reasons. A key factor is that no
other company will have this technology integrated into its controller. “It
could be used on other walk-in coolers or freezers, but we’re not
gong to sell it to others,” he discloses.
And the results look promising. With the new design, the reverse cycle
in the controller also results in an 80-percent reduction in defrost energy
usage because defrost time has been lessened, and there are no defrost
heaters, he says. This will prove to be beneficial, he says. “People
are looking for energy efficiency,” Mr. Owen contends. “Now,
I hope our challenge becomes how to build enough units to keep everyone
up and running.” But that, he says, still remains to be seen.
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