Mitsubishi Heavy Industries Technical Review Vol. 56 No. 4 (December 2019)1

Remote Monitoring and Energy Saving of Air Conditioners
M-ACCESS Air Conditioner IoT Remote Monitoring SystemM i ts u b i s h i H e a v y I n d u s t r i e s T h e r m a l
S ystems, Ltd.

Recently, there has been a growing need to connect home appliances to the internet, andthere is a similar trend in commercial air conditioners installed in office buildings. If there were asystem that can monitor and control the operating status of air conditioners at remote locations, itwould be possible to pre-cool and pre-warm by the air conditioners when users return from outside,
also making it possible to turn off air conditioners remotely. Furthermore, the power consumptionof air conditioners is said to account for 20% to 40% of the annual power consumption ofbuildings, and by optimally controlling air conditioners, it is possible to reduce this amount.
M-ACCESS is a system that automatically controls the power consumption of air conditioners
using cloud-based servers, and this system realizes energy saving without spontaneous operation byusers. This system also contributes to the control of global warming through development on aglobal scale.

|1. System overview
Figure 1 shows an overview of the entire M-ACCESS system. An application server and astorage server are built on the cloud, and the application server performs functions such as
information visualization, energy saving control, and e-mail notification, while the storage server
has the function of storing the operational data of the air conditioner.

Figure 1 Overview of entire M-ACCESS system

An exclusive gateway (CGW) is also installed in the building to be monitored, and thebuilding is connected to the internet by ethernet communication (separate wireless module). Our
company's multi-package air conditioner and gateway can collect data on air conditioner operationby connecting to our exclusive communication line (Superlink communication line). Even forexisting air conditioners, M-ACCESS can be installed simply by connecting this “SuperlinkMitsubishi Heavy Industries Technical Review 56 No. 4 (December 2019)2communication line,” and the installation cost is very low.
Room air conditioners, commercial packaged air conditioners, heaters, and air conditionersof other companies can be also connected, although their functions are limited through theinterface.

|2. Functionality
Table 1 lists the functions of M-ACCESS. This paper introduces energy saving control andsignage display, which are two characteristic functions.
Table 1
Item
Indication ofoperation status
Operation of the airconditioner
Power consumption
trend display
Operation status
trend display
Signage display

Demand control
Energy savingcontrol
Schedule operation
Failure detection
Abnormal report
Report Output

2.1

Function list of M-ACCESS

Contents
Displays the operation/stop status, operation mode, air flow, set temperature, indoor
temperature, and error status of each air conditioner.
Change settings for operation/stop, operation mode, air flow, and set temperature ofeach air conditioner.
Displays the power consumption of the air conditioner for the past 13 months in
1-minute increments.
Displays the change of set temperature, indoor temperature and outdoor temperature
for the past 7 days.
Displays the daily power consumption of air conditioners in real time using a bargraph. When energy saving control (control of annual power consumption target) isset, the degree of energy saving achieved is clearly indicated by a change in thebackground color.
The operating target of the air conditioning system is set in advance, and the set
temperature, air flow, and operating conditions are controlled collectively to reduce
power consumption, such as peak cutting. Two control methods are available.
Sets an annual power consumption target and implements automatic control of air
conditioning while maintaining comfort to achieve the power consumption target.
The outdoor air temperature is monitored, and registered air conditioners arecontrolled (e.g., shifting of preset temperature and reduction of air flow).
The calendar is registered and the air conditioner operates according to the setschedule.
Detects signs of a specific fault before it becomes an abnormality, and sends
information via email.
Sends information via email if there is an error in the air conditioner.
Reports total operating hours, total power consumption, temperature, top 10 operating
hours, and abnormality history in PDF format.

Energy saving control (control of annual power consumption target)

M-ACCESS automatically calculates the monthly, daily, and hourly electric energy target for
the user's setting for annual electric energy target, taking into account the information on theexpected maximum and minimum temperature and the user's air conditioner usage. The air
conditioner achieves energy savings, which the electric power consumption target is specified by
M-ACCESS, by adjusting the compressor speed. However, if the M-ACCESS determines that thedifference between the set temperature and the room temperature will increase due to the limited
capacity, and that there is a possibility of compromising comfort, energy saving control istemporarily stopped. Thereafter, the difference between the set temperature and the room
temperature is checked again every hour on the hour, and if the difference is less than a certain
value, the energy saving operation is resumed. There is a difference between the target value andthe actual value of the electric energy, but this difference is checked every hour, every day andevery month, and the target values for the next hour, the next day, and the following month arereviewed to control the electric energy target set by the user throughout the year.
Figure 2 presents the results of energy saving control at a building in Osaka City. We
measured and compared the electric energy consumption for 10 days with and without the energy
saving target of 20%. The average maximum temperature and average minimum temperatureduring the 10-day test period were within ± 0.3°C, respectively, with and without control, therefore
the test environments can be evaluated as almost the same. As a result of the test, the average daily
power consumption was 400.1 kWh without control and 312.2 kWh with control. The power
consumption was reduced by about 22% as seen in Table 2. The difference between the set
temperature and the room temperature (mean deviation) was increased by about 0.28°C through theimplementation of energy saving control, but none of the building residents felt uncomfortableaccording to our interviews.

Mitsubishi Heavy Industries Technical Review 56 No. 4 (December 2019)3

Figure 2

Energy saving effect through control of annual electric energy target
Table 2

EnergyMeasurementsavingperiodcontrol

Averagemaximum
airtemperature[°C]

Energy saving control results
Averageminimum
airtemperature[°C]

ThiaTsMeandeviation

Averagepower
consumption[°C] [°C][°C][kWh/day]
7/30 to 8/3,
None
34.7
26.6
25.8 24.9
0.86
400.1
8/6 to 10
8/20 to 24,
Yes
34.8
26.3
26.6 25.5
1.14
312.2
8/27 to 31* Maximum and minimum temperatures are quoted from Japan Meteorological Agency data(Osaka)Thia is the average indoor temperature during the operation of the air conditioner.
Ts is the average set temperature during operation of the air conditioner.

2.2

Energysavings ofabout 22%

Signage display

Signage display is a function of visually displaying information on the air conditioner’s
current power consumption to the user by changing the background color of the screen. Figure 3
illustrates how the background color of the screen changes. In the energy saving control as
mentioned in paragraph 2.1, the calculated electric energy consumption target per day is comparedwith the actual electric energy consumption, and the background color changes from blue to red
according to the ratio. Users can see the air conditioner’s situation immediately on the screen, andthis system is expected to enhance user awareness of energy saving.

Figure 3

Signage display

Mitsubishi Heavy Industries Technical Review 56 No. 4 (December 2019)4|3. Future Development
Effective energy use has become important worldwide, and energy saving through remotecontrol is attracting attention, as are efforts to improve the efficiency of equipment. As mentioned
at the beginning of this paper, we will further improve performance and functions, expand therange of interconnectable equipment, and develop our business overseas. We will also develop
environmentally-friendly products and services on a global scale through an integrated system ofcooling and heating equipment.