North American hydronics mechanical rooms. These new
circulators are ECM pumps. ECM stands for electronically
commutated motor and they are very different from the
PSC (permanent split capacitor) motors we are accustomed
to with wet rotor pumps. The rotor in this ECM motor
has permanent magnets instead of wire windings that are
separated from the system fluid. The magnets are located
inside a stainless steel rotor can and react to the magnetic
forces created by electromagnetic poles in the stator.
A microprocessor, which “sits on-board” the pump, reverses
the polarity of the stator poles rapidly (within milliseconds),
forcing the rotor to be rotated in the proper direction.
The faster these poles reverse their polarity, the faster
the rotor spins, meaning the faster the impeller spins.
ECM circulators can provide four times more starting
torque compared to a PSC wet rotor pump and incorporate
a microprocessor that has software on-board, allowing
the pump to perform many functions.
For example, one application may call for a constant
pressure differential where the building is zoned with
zone valves. Normally as valves close, the pump would
develop additional head pressure across the remaining
open zones, causing an increase in flow rate through
these zones. This wastes energy as well as creates potential
noise problems due to increased velocity. With this
constant differential in pressure capability, as valves
close, the pump momentary senses an increase in differential
pressure and quickly slows down the pump’s speed
to eliminate the change in pressure. The result is no
change in flow rate through the remaining open zones, no
wasted energy and no velocity noise problems.
Another application that the microprocessor can control
is called proportional differential pressure. The circulator
control is set for a specific design head loss for a
system. When the zone valve (or valves) then closes, once
the pressure differential starts to climb, the circulator
reduces its motor speed. The difference here is proportional
control instead of maintaining a set differential.
It will lower the speed and thus pressure differential
proportionally to the reduction in flow rate. The result is
an increased reduction in energy consumption.
The efficiency of these Greener circulators is designed
to meet the ever-increasing efficiency standards that
have made their way to North America. Their “wire to
water” efficiency is higher than the current PSC wet rotor
circulators. In addition, their multiple application capabilities
with on-board microprocessors, and their reduction
in wattage use, make them a compelling alternative
to current offerings. Contact me at gcarey@fiainc.com or
1-800-423-7187. ICM
A New Use for Oilheat
Oilheat technology has found a new application in the
battle against COVID-19. The pandemic has put a
strain on the supply of personal protective equipment
and shortages created problems for health care institutions.
Matt Hayes, the Director of “Southern Maryland Loves
You” (a non-profit), discovered thru a think tank with “Tech-
Port”, which is a group of local engineers who volunteered
their time in an attempt to contribute to the COVID-19
Pandemic needs, that N95 masks could be re-used, easing
the burden of tight supply, if they were heated long enough
and high enough.
How to do this? Enter Burch Oil a retail heating oil
marketer, Carlin Combustion/Hydrolevel, Thermo Products
and Triton Defense. They worked with Hayes to design
and fabricate a portable N95 mask disinfectant chamber.
The “Hot Box” had requirements that made an oilfired
heat source the perfect solution to maintain temperatures
high enough and long enough to disinfect up to 24,000 N95
masks per day while offering portability, safe fuel storage,
ample fuel supply and minimal electric needs.
The team agreed to fabricate the box from the ground up
to ensure sanitary conditions and decided to fabricate the
walls with an air gap to insulate between the box interior
and the exterior conditions. They added 4 feet to the rear of
the space to house the Thermo Pride oil furnace and Roth
oil tank and installed a Metal Fab prefabricated chimney
thru the roof to vent the furnace. A modified version of the
Carlin EZ Temp control was selected to operate the furnace
to maintain these high temperatures, and a Carlin aquastat
was used as a high limit control.
Four Hot Boxes are currently in use in Maryland.
Hot Box "Power Plant" Masks disinfecting
ICM/March/April 2021 21