Daikin D-BACS, Design Manual

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1.5 Explanations of Power Proportional Distribution 263
Power Proportional Distribution (P.P.D.)
2) Calculation of the proportional division value for a dairy power consumption
The proportional division value for a dairy power consumption is stored with factors of each indoor unit’s number and a
calendar date as a table shown below after adding the count result of hourly power consumption from 00:00 through
23:59. (with a graduation of 10 W)
3) Counting the electricity at the ceased condition of the unit
Even if an airconditioner is stopped or in the condition of thermostat -off (the condition that the compressors are
stopped as the temperature in the space where all the indoor units are installed falls down to the preset temperature),
the airconditioner consumes energy due to the energy consumption mainly by the crank-case heater in the outdoor
unit.
When the iPU is used, the rated power consumption of the crank-case heater is divided by the number of indoor units
in usual connection (for instance, two indoor units of 2.5 HP are connected to an outdoor unit of 5 HP etc.) and the
value is registered at the test run, adapting each indoor unit’s capacity.
(Example)
The iPU counts the indoor unit’s operating conditions every 20 seconds.
Since the indoor units send ON/OFF data of the crank-case heater to iPU, it adds one(+1) to the power counter inside
iPU at no operation of the airconditioner when the crank-case heater is ON.
When this counter reaches 180, it judges that the crank-case heater was on for one hour, and in case of the above
mentioned indoor unit, the counter goes back to zero after 25 Wh is added to the counting result.
This calculation process is conducted separately from the proportional division computation mentioned on this section,
and this input is got rid of from the pulse input of the watthour meter. Because of this procedure, the power
consumption in the space where the airconditioner is not used at all is counted constantly every month.
(However, as this airconditioning system is a multi-system, in case that one outdoor unit is shared to another tenant,
the count output can be seen in lower value rather than the crank-case heater’s power consumption registered,
because the crank-case heater doesn’t actuate when another tenant operates the airconditioner.)
Indoor unit No.
Date
001 002 003 004
April 1st
April 2nd
April 3rd
000150
002004
000313 000211
005202
001103 000741
009205
000086 004402
005902
008173
The set data in the dues control unit is not
deleted even if the electric power is turned
off, because the data is stored in the non-
volatile (flash) memory.
RXYQ5P
(Crank-case heater's output=50W)
FXFQ80M×2
(Power consumption at no operation=50/2=25W)