Mitsubishi Heavy Industries Technical Review Vol. 51 No. 2 (June 2014)38

Room Air-conditioners conforming to
the Australian Standard for DRED
(Demand Response Enabling Devices)S a l e s d e pa r t m e n t
Air-Conditioning & Refrigeration
DivisionM a c h i n e r y, E q u i p m e n t & I n f r a s t r u c t u r eWith the world’s growing awareness of environmental conservation, especially the necessityof measures against global warming, demand response is becoming widely adopted to reduce peakpower demand. In Australia, in particular, the demand response standard known as demandresponse enabling devices (DRED) has been established, introducing this standard to some selected
appliances including air conditioners. There is already a rebate system in effect for the purchase ofproducts conforming to the DRED standards.
Mitsubishi Heavy Industries, Ltd. (MHI) has developed DRED standard-compliant
wall-mounted room air conditioners for the Australian market with brand-new remote controls withadditional functions: the ZMA series (8 models) and the ZMXA series (5 models). Their features
are introduced in this report.

|1. Features
1.1(1)

DRED-compliant control
Attaching importance to how a user feels
Our DRED control enables operation attaching importance to how the user “feels” while
controlling the power consumed in a certain time period, even during periods when demand
response is requested by electric power companies, by allocating sufficient power whennecessary (e.g., at the time of starting the air conditioner, during which expected performance
should be fulfilled) (Figure 1).

Figure 1 Schematic diagrams of air conditioner operation during the DRED
control period(2)

All power restriction modes are available
Highly accurate calculation of the total amount of power consumed during air conditioner
operation enables not only power restriction mode 1 (stopping the compressor), which ismandatory under the DRED standard, but also mode 2 (50% operation) and mode 3 (75%operation), which are optional. Figure 2 gives an example of a DRED connection
configuration.

Mitsubishi Heavy Industries Technical Review Vol. 51 No. 2 (June 2014)39

Figure 2 DRED connection configuration(3)

Compact design that fits the sizes of the current outdoor units
The development of a compact DRED controller has enabled its installation inside thecurrent outdoor units for the Australian market, thus realizing the DRED compliant function
without increasing the size of outdoor units (Figure 3).

Figure 3

1.2

DRED circuit board

Multifunctional remote control with excellent usability

The new remote controller can set a silent mode for the indoor or outdoor unit or both, aweekly timer for a weekly operation schedule, and a night setback to prevent the overcooling ofrooms during long-term absences (weak heating operation). In spite of these additional functions,the less frequently used buttons can be stored under a cover on the remote controller, allowing for alarger liquid crystal display with improved usability.

|2. Specifications
Table 1 shows the major specifications of the SRK-ZMA-S and SRK-ZMXA-S series.

External dimensions(Height × Width × Depth)

Limit electrical energy by
DRM3 (for 30 min.)*2Limit electrical energy by
DRM2 (for 30 min.)*1

Rated power consumption

Rated capacity

VoltageClass

External dimensions(Height × Width × Depth)

Limit electrical energy by
DRM3 (for 30 min.)*2Limit electrical energy by
DRM2 (for 30 min.)*1

Rated power consumption

Rated capacity

VoltageClass

Outdoor unit

Indoor unit

Heating

CoolingHeating

CoolingHeating

CoolingHeating

Cooling

Outdoor unit

Indoor unit

Heating

CoolingHeating

CoolingHeating

CoolingHeating

Cooling

mm

Wh

Wh

W

kWmm

Wh

Wh

W

kW
3.2

168

131

112

87

450

350

2.5

2.0

20

540×780×290

232

358

326

238

217

955

870

4.0

3.3

35

309×890×220

360

316

240

211

960

845

4.3

3.5

63596

581

397

387

1590

1550

5.8

5.0

510

487

340

325

6.8

6.0

60

626

697

417

465

1670

8.0

7.1

71

9.0

8.0

80

963

8816425872570

2350

1300×970×370

1065952710

63528402540

10.09.292*2: The amount of power consumed during DRED
Mode 3 (75%) operation*1: The amount of power consumed during DRED
Mode 2 (50%) operation

845×970×370

318×1098×248

802

810

535

540

2140

2160

750×880×340

1860

640×800×290

1360

1300

6.0

5.0

50

671

660

4474401790

1760

7.1

6.3

Single-phase 220-240 V

50

640×800×290

Single-phase 220-240 V35

SRK-ZMXA-S series

595×780×290

294×798×22

595×780×290

223

183

148

122595490

3.13

2.5525262215

175

155
165

143700110620

575

2.7
440

2.5

25

2.020

SRK-ZMA-S series

Table 1 Specifications list

Mitsubishi Heavy Industries Technical Review Vol. 51 No. 2 (June 2014)40