Explanations Of Power Proportional Distribution - Daikin VRV III-S Technical Data Manual

10

Explanations of Power Proportional Distribution

10 - 1 What is the Power Proportional Distribution.
(System Ex.: Normal VRV)
Watthour meter
with oscillator
Power supply
3 phase
Power supply
single phase
HUB
PC iPU
To other iPU
• Previously the general way for requesting the electricity charge at rental buildings was that a management staff read a watthour meter and billed
the tenants by manual-account based on the operation time which were counted through time-counters.
However, this method takes a lot of time for the management staff. In addition, as airconditioning consumes much different electricity for either the
operation of airconditioning (thermostat-on) or the operation of fan only (thermostat-off), it might cause to give unfair sense to the tenants inhabited
in the spaces with different heat load, though "operation-time" itself is the same.
For instance, even if a certain higher preset temperature is applied in summer for energy saving, fee for airconditioning may equal to the fee without
preset temperature so far as it is counted based on the operation time.
• Electric energy distributing function of intelligent Manager carries out the proportional division computation in consideration of those thermostat-
on and thermostat-off operations and saves time for building management staffs to read watthour meters, and also supplies tenants printed data
useful for making the bills.
Namely, iPU is the products created by the concept to help the assignment of bill-issuing and offers users the reasonable price of the products.
• Yet, since iPU is persistently the system assuming each indoor unit's power consumption based on the data which is transferred from indoor units,
depending on the power consumption of the airconditioner in the standard installation conditions, it should be noticed that iPU is not the products
which complies with the Weight and Measure Act as shown in the catalogue.
The details of the cause to count error is described at chapter 2.
10 - 1 - 1Count method (for a conventional VRV system)
1) The following proportional division computation is carried out every one hour and assigns the power consumption of airconditioning system to each
indoor unit.
Heat load depending on the operation conditions of airconditioner
Thermo-step (*2)
a = (a1+a2¥T)
Thermo-step (*2)
b = (b1-b2¥T) ¥
a1, a2:correction factor for cooling
b1, b2:correction factor for heating
T:indoor unit's suction air temperature
Indoor units N's power consumption (kWh) = total pulse input from wattmeters x¥
38
•
Since this system detects power consumption as the base of the count,
specified watthour meters should be used by all means.
Power supply
single phase
10
Power consumption (kWh)
(Ttconstant)
10
• VRV Systems • Network Solution
Outdoor unit
Indoor units: a maximum of 64 units
= power consumption of indoor unit's fan
+ power consumption of optional heater
+ the rated power consumption in cooling (*1) × a
+ the rated power consumption in heating (*1) × b
*1:The value which is registered at the test run,
adapting the indoor unit's capacity
As shown in the left, heat load is calcuated
from an equation of the first degree which
approximates the correlation, among thermo-
step, indoor unit's suction air temperature and
power consumption, into the linear line under
the standard conditions of the unit.
*2:"Thermo-step" signifies that an airconditioning
capacity is expressed in a range of the values
0-5 mainly based on the opening grade of an
Thermo-step
electronic expansion valve in an indoor unit.
Heat load by one hour calculated through the
operating of airconditioner N
Total heat load by one hour caiculated through
the operating conditions of all the airconditioners