ASHRAE Journal - December 2022 - 104

frostshielD is coming
fros shielD is coming
DEFROST-FREE HEAT PUMPS
FrostShield is a revolutionary new
mechanical and unit control technology
for dedicated outdoor air systems that not
only extends the operating range of
air-source heat pumps, but also removes
the need for the unit to enter defrost
mode during heating operation.
SCAN TO SEE
FROSTSHIELD
IN ACTION
or visit FrostShieldHP.com
Brought to you by:
FrostShield Mechanical and Unit Control Technology
What is FrostShield?
FrostShield is a revolutionary new mechanical and unit control
technology that not only extends the operating range of
air-source heat pumps, but also removes the need for the unit
to enter defrost mode during heating operation. This feature
extends the life of HVAC equipment, but has the potential to
save a tremendous amount of electrical energy and improves
occupant comfort. First applied to dedicated outdoor air
systems (DOAS), FrostShield can be applied to any air-source
heat pump system including chillers, unitary equipment in both
the residential and commercial markets, and other systems such
as refrigeration and process control.
Why is FrostShield Valuable to the end user?
Defrost has long been a hurdle to the acceptance of air-source
heat pumps. The excessive energy usage, noise, lack of comfort,
and inability to easy apply in colder climates are the primary
factors to this. However, now that FrostShield removes all of
these obstacles, there is a tremendous opportunity with the
electrification and decarbonization movement to change
the way buildings use energy. As more and more municipalities
and countries push energy conservation and the removal of
fossil fuels, heat pumps equipped with FrostShield will be
perfectly positioned.
What Does This Mean for Lower Ambient Climates?
With FrostShield, the application range is extended by keeping
the outdoor coils clear and able to properly complete the
refrigeration cycle. While at a certain point, under -20°F, there's
just not enough there to work with and the unit would have to
revert to using an auxiliary heat source. However, for the vast
majority of applications, the unit can function just fine.
If Using Some of the Discharge Gas, Doesn't That Mean There's
Less Capacity?
FrostShield only utilizes a maximum of 10% of the available
discharge gas to keep outdoor coils clear. While that means a
slight reduction (between 2-4°F) in discharge air temperature,
it can be easily made up by increased compressor capacity via
VFD overclocking.
Will A Form of Auxiliary Heat Still be Needed?
This will all depend on the outdoor environment, and what
you're trying to accomplish. Even today, applications may require
auxiliary heat to reach the desired discharge air temperature.
The amount of heat needed by a unit with FrostShield is
only that small amount the unit cannot produce by itself, and not
the full amount that would be required by a unit requiring defrost.
Additionally, in the case of a mechanical failure, it's always
good practice to have a backup just in case.
Visit frostshieldhp.com to learn more.
http://www.FrostShieldHP.com http://www.frostshieldhp.com
ASHRAE Journal - December 2022

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