Mitsubishi Electric City Multi R2 Series, Manual

Page: 172 / 248

Evaporating temperature control (during cooling)
Energy efficiency control
• Suitable situations
Lower compressor
frequency
Increase of target
evaporating temperature
Reduced power
consumption
Target evaporating temp. (
°C)
4 patterns for setting
target evaporating
temperature
Enthalpy
Pressure
Condenser
Evaporator
During normal
operation
During evaporating
temperature control
During
normal
operation
During evaporating
temperature control
The amount of compressor
work is reduced.
R2-Series EP
R2-Series P
WY-Series
WR2-Series
Y-Series EP
Y-Series P
During cooling, the temperature of the refrigerant is controlled according to the air conditioning load. This helps to ensure
energy-efficient operation.
Normal mode
The evaporating temperature is
kept constant regardless of the
load. Even at low loads, the normal
evaporating temperature does not
change, and energy loss is
generated during partial load
operation.
No.1
No.2
No.3
No.4
1
2
Smart evaporating temperature control mode
The evaporating temperature is increased and the compressor input is decreased
according to the load, resulting in increased operating efficiency.
There are two patterns for controlling the evaporating temperature, as follows.
The evaporating temperature is controlled to be constant regardless of the ΔT. It is
set to a value that is higher than the normal evaporating temperature.
The evaporating temperature is controlled in accordance with the ΔT. It can be
selected from 4 control patterns.
* The availability of and varies depending on the model. Refer to the function table.
* Changing the evaporating temperature reduces latent heat capacity. Select an appropriate pattern according to
the installation conditions.
* The fixed temperature control function and the automatic control shifting function cannot be used
simultaneously.
1 2
Largest ∆T (temp. difference) of
IU inlet/set temp. (°C)
*1 To change the evaporating temperature setting, the setting of the dip switch on the
outdoor/heat source unit needs to be changed.
*2 When the difference between the indoor unit air-intake temperature and the actual temperature
exceeds 1°C, the evaporating temperature based on this difference is constant.
- Spaces with constant high temperatures from heat sources such as OA equipment
- During low load times when air conditioners are used for cooling (such as during the morning)
Evaporating
temperature is
increased.
1 2
Image of evaporating temperature control
(Fixed temperature control)
Image of evaporating temperature control
(Automatic control in 4 patterns)
High sensible heat operation (during cooling)
R2-Series EP
R2-Series P
WY-Series
WR2-Series
Y-Series EP
Y-Series P
• Image of evaporating temperature control during high sensible heat operation in full cooling mode
• Temperature and humidity conditions
IC01 IC02
PAC-SC36NA-E
(Optional part)
CN3S
(Outdoor unit
control board)
IC03
Humidity
information
1
2
Humidity
sensor
Control board
Humidity
sensor
Humidity
sensor
Evaporating temperature is controlled according to room temperature and humidity.
• Image of installation of locally-procured humidity sensors
Comfortable
Humidity
Temperature
Comfortable zone
Humidity
Temperature
Comfortable zone
Humidity
Temperature
Comfortable zone
Comfortable
temperature and
humidity
Comfort level
in room
Status of
outdoor unit
Zone
Evaporating
temperature control
High humidity
High temperature
and humidity
High sensible
heat operation
A little
humid
Uncomfortable
Temperature of
indoor unit refrigerant
is kept high
Hi
Lo
High
Target evaporating
temperature
Low


Difference between indoor unit
inlet temperature and set temperature
High

Low

Hi
Lo
High
Target evaporating
temperature
Low


Difference between indoor unit
inlet temperature and set temperature
High

Low

Hi
Lo
High
Target evaporating
temperature
Low


Difference between indoor unit
inlet temperature and set temperature
High

Low

*Control board is to be
configured onsite.
**Humidity sensor → locally procured
Humidity information is sent to
the control board.
The control board judges the
humidity information and sends a
HIGH/LOW signal to the outdoor
unit through CN3S. The outdoor
unit shifts the evaporating
temperature depending on the
information from the control
board.
1
2
In high sensible heat operation mode, air conditioners consume
less energy, thereby realizing cost savings.
With the installation of a locally-procured humidity sensor, the
evaporating temperature of the outdoor/heat source unit can be
controlled optimally as shown below according to the difference
between the indoor unit inlet temperature and set temperature.
A wide range of temperature settings is available, from a low
evaporating temperature close to normal operation temperature to
a high evaporating temperature to realize energy savings.
Hi
(low humidity)
Lo
(high humidity)
High
Target evaporating
temperature
Low
Difference between indoor unit
inlet temperature and set temperature
High Low
Comfortable and
energy-saving
operation even at low
compressor rotating
speed
Compressor rotates at
medium speed to
reduce humidity
Compressor rotates at
high speed to reduce
temperature and
humidity
Temperature of
indoor unit refrigerant
is greatly reduced.
Temperature of
indoor unit refrigerant
is slightly reduced.
172
OUTDOOR UNIT FUNCTIONS