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SYSTEM DESCRIPTION
The following system description section provides a brief overview of the Reclaim Energy/
Panasonic Heat Pump components and functionality.
1.1
MAIN COMPONENTS
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The system components of the air sourced heat pump that
customers will receive include the following:
Heat Pump Unit, Storage Tank with PTRV, Controller,
Heat Pump mounting legs.
1.2
SYSTEM OPERATION
The CO2 heat pump unit receives cold water from the
bottom of the tank. Using heat from the ambient air the
heat pump heats the CO2 refrigerant to generate hot
water. The hot water returning from the heat pump unit
(fixed at 63°C) is injected into the top of the tank to provide
fast hot water recovery and excellent hot water
stratification. As this system delivers hot water exceeding
50°C, a tempering valve must be installed for delivery of
hot water to bathrooms. Un-tempered water may be
delivered to the kitchen and laundry according to AU/NZS
AS 3500 plumbing code.
The heat pump operation is controlled by an external
controller. The controller operates based on a sensor
connected to the tank at 55% – 69% level depending on the
tank model ID. The heat pump will be turned on if the
temperature at the sensor level on the tank drops below
59°C for the first cycle, or 37°C for the second cycle in a
day, and it will run until the tank temperature at sensor
level reaches 59°C. The system controls are designed to
ensure that it meets the legionella requirements, as
specified in the Australian standards. In the subsequent
heating cycles of every 24-hour period, the heat pump
"turn off" logic is adjustable by built-in timer settings.
The default timer setting is programmed to run on
continuous operation, this can be adjusted by the installer
based on the homeowners' requirements to suit their
needs. More details regarding the controller operation and
settings are outlined in Section 2.
At ambient temperatures below 5°C, frost may occur, if
this happens the heat pump will go into defrost mode in
order to protect the unit (i.e. the defrost functionality will
turn the heat pump on and will normally run for no more
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Reclaim Energy |
Quick Start/Install Manual – v1.0
than 15 minutes in duration). When the unit is in the
defrost function mode, the pump and fan will stop, and the
refrigerant heat will defrost the evaporator. As defrost
advances, the evaporator temperature will increase.
When a set temperature (pre-programmed) is achieved,
the defrost operation stops and the heat pump will operate
in line with its normal settings. More details regarding the
controller operation and settings are outlined in Section 6.
The "operational window" refers to heat pump "hot water
production" mode which can be set by using one of the
options on the controller. From time to time, especially
during the winter and in very cold climates, the heat pump
operation may be disrupted or extended by a built-in
anti-freeze or defrost operational mode. The defrost cycle
can occur ONLY during the operational window to defrost
the ice build-up on the evaporator at the back of the unit
which is an air-CO2 heat exchanger. The defrost cycle
occurs when the ambient temperature is less than about 5
°C. During the defrost operation, the fan and pump stop,
and the high- temperature refrigerant which is originally
used for hot water production is supplied to the evaporator
(=air-CO2 heat exchanger).
The frost cycle can take about 5 minutes, and this can
happen multiple times depending on the ambient
temperature, so in total, up to 20 minutes can be expected
for the entire defrost cycle. The heat pump also comes
with a built-in freeze protection cycle. Anti-freeze
operation can ONLY occur outside the operational window
of the heat pump and the purpose of the cycle is to protect
the water circuit (i.e. piping between tank and heat pump)
from freezing. If the ambient and water pipe temperatures
drop below 3°C, the heat pump will activate the anti-freeze
operation. During the anti-freeze operation, the heat pump
works as a normal heating cycle so the fan and pump
should be running. The anti-freeze operation stops when
the water inlet temperature reaches 53°C or ambient
temperature reaches 6°C.
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