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Heat Pumps both heat and cool but some heat much more effectively and efficiently than others.
All Heat Pumps imported into New Zealand are rated at +7degrees. This is the measurement used for most
standards including Energy Standards. When the ambient (outdoor) temperature gets cold all Heat
Pumps will suffer some reduction in performance and will be required to go into defrost
for a period of time. There are no exceptions here, but there is a very big difference in
cold temperature performance between brands which are designed to cool first and heat second
and those brands which start with heating in mind! Mitsubishi Electric Heat Pumps have a
reputation amongst all quality installers as the heat pump that really performs when things get cold.
Here are the technical reasons:
Larger Outdoor Unit Heat Exchanger Coil
Large Coil Effective Surface Area:
On viewing a Mitsubishi Electric outdoor unit you will notice that, model for model, we
are significantly bigger than most of our competition. This is because Mitsubishi Electric
give priority to heating - and to ensure efficient heating a unit must be able to move a
significant amount of air!
The larger the outdoor coil surface area, the more heat that can be absorbed from a
fixed amount of outdoor air, in any given period of time. In other words the physical
size of the outdoor unit allows for more coil surface area to be incorporated in the
design of the unit and a bigger fan to be fitted. This results in the heat pump
operating more effectively and efficient in low ambient conditions
Less Time spent in Defrost
Intuitive Defrost Cycle:
Basic physics dictate that all heat pumps will need to spend some time in a defrost cycle.
The most common complaint from a home owner is the length of time their heat pump spends in
a defrost cycle or the frequency in which it goes into a defrost cycle.
With a Mitsubishi Electric Heat Pump “Learning logic” or fuzzy logic is used to
optimise the frequency of the defrost cycle. By only defrosting when it’s absolutely
necessary, the Mitsubishi Electric Heat Pump spends more time in the heating cycle
and less time in the defrost cycle. This means that our heat pumps are pumping heat
when others are frequently stopping and starting or spending a prolonged amount of
time in defrost mode. Simply put; Mitsubishi Electric Heat Pumps are heating while
others are defrosting.
Maximum Compressor Speed:
Maximum compressor speed is used during the defrost cycle to ensure the defrost
cycle is completed in as short a time as possible. By running the compressor at
maximum frequency during the defrost cycle, heat from the indoor coil is
transferred quickly to the outdoor coil, which reduces the overall defrost
time period. Once again the unit is not required to spend long periods in
defrost mode unlike a unit which may have been specifically designed to cool.
Dry Coil Cycle:
On the completion of the defrost cycle, the Mitsubishi Electric Heat Pump accelerates
the outdoor fan to maximum fan speed for a short period of time. This clears the coil
of excess moisture and dries the coil fins completely prior to resumption of the heating
cycle. The result is an optimised coil performance that maximises the heat pump
performance in low ambient conditions.
Large Compressor Capacities
Mitsubishi Electric manufacture their own compressors. By incorporating larger and more
efficient compressors, Mitsubishi Electric compressors can perform better at lower
frequencies and this results in longevity of compressor life. These compressors
also require lower energy inputs, in low ambient conditions and are therefore more efficient.
H2 Performance Curve Low Ambient Efficiencies
In New Zealand we refer to H1 and H2 ratings. These are simply the level at which the performance
and efficiency of a heat pump is measured. H1 being at 7°C and H2 being at 2°C. The
H2 rating is the superior measurement for heating and as such we endeavour to provide our H2
rating where competitors may not be as confident to do so...
Energy Efficient Low Ambient Performance Efficiencies
Mitsubishi Electric have designed all heat pumps to produce “real world” actual low ambient temperature performance, at high efficiency, due to a combination of technologies. These include:
- Large outdoor coil surface area
- Superior Defrost Logic
- Large Compressor Capacities
- Generous Indoor Coil Capacities
- Superior operating software designed for a heating appliance
Although the H1 rating are accepted for MEPS we must remember that this is the Australian rating and
although possibly suitable for their climate a measurement at 2 degrees (H2 rating) is far more relevant to
New Zealand conditions. Mitsubishi Electric is one of the few companies that provide H2 ratings. NB: A unit
purchased at a 7 degree rating might be 30% less effective at 0 degrees and without either seeing the
performance curve data or having a H2 rating some such units are able to be sold into colder areas.
Superior low ambient degradation performance curves at “rated capacity” not maximum capacity are
the only true measure of low temperature COP and heating performance - when it really matters.
BE ASSURED THAT MITSUBISHI ELECTRIC HEAT PUMPS REALLY PERFORM WHEN IT GETS COLD!
HyperCore® Inverter
When conditions are extremely cold or ultimate performance is required - 99% of the time - Hyper-Heating
technology is used to gain maximum performance and efficiency. Mitsubishi Electric has now proven this
technology in the harsh winters of Scandinavia and Japan and has now introduced the HyperCore® Inverter
Heat Pump range into New Zealand.
Essentially, HyperCore® Inverter is a combination of superior heating software performance
enhanced by additional hardware improvements. The enhance cold weather performance is
due to a combination of the following:
Increased Air Off Temperature
HyperCore® Inverter produces an air-off condition 1.3 times higher than normal than a standard
heat pump at 68 degrees C. This enhanced air-off performance allows a given space to
heat up faster in low ambient conditions and for the inverter to ramp back faster. It
also allows the HyperCore® Inverter heat pump to reach target conditions prior to an initial
defrost cycle.
Extended Compressor Frequency
In HyperCore® Inverter mode the heat pump runs at a higher frequency limits. These faster
compressor frequencies combined with large coil surface areas gives HyperCore® Inverter the
ability to deliver high heat outputs when required at low ambient conditions. These
extended compressor frequencies are still well below many other brands of standard
heat pumps and as such will not stress or extend the compressors. The Mitsubishi
Electric compressor is designed for this performance.
Loading Logic HyperCore® Inverter
The fuzzy logic technology means that a number of key variables are controlled
electronically and combined for ultimate performance. These variables include;
large outdoor coils, higher compressor frequencies, high air off temperatures,
superior defrost cycle, and large coil area to produce H1 rated capacity down to
–15°C if required. The difference, of course. Is that Mitsubishi Electric HyperCore® Inverter
Heat Pumps will produce their full rated capacity at minus 15 degrees, the
ONLY Heat Pumps in the New Zealand market to guarantee this!
Large Outdoor Coil
HyperCore® Inverter outdoor units have a larger surface area to enable more heat to be absorbed at low ambient conditions
Tray Base Heater HyperCore® Inverter
All HyperCore® Inverter outdoor units have a 120 watt heater that is pulsed during low ambient operating
conditions. This is to prevent ice build up after defrost cycles in the unit base tray during
prolonged sub zero operating conditions. This build up is the reason some Heat Pumps go into
constant defrost and in extreme conditions without such a small heater it is impossible to
prevent an untimely defrost cycle. By using a 120 watt heater, similar to our dehumidifier
technology, Mitsubishi electric HyperCore® Inverter is in heating mode longer and is therefore
ultimately more efficient and effective than a unit that is constantly going in and
out of defrost!
Extended Heating Range
The operating range of HyperCore® Inverter has been extended to –25°C for those that really require it.
The HyperCore® Inverter unit guarantees full rated capacity to minus 15 degrees but will still perform,
with a reduced performance drop-off, to minus 25 degrees.
HyperCore® Inverter Indoor Coil
HyperCore® Inverter indoor units utilise the FB high efficiency indoor units that incorporate
bigger indoor coils and other deluxe performance features. This means that the
FB indoor unit is more efficient and that when combined with a HyperCore® Inverter Outdoor unit
the result is both, extraordinary high low ambient performance - and efficiency.
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