Case studies

EMU Maintenance Depot

The EMU Maintenance Depot is a large maintenance and office building used as a main servicing hub for Auckland’s new electric trains.

The Challenge

The EMU Maintenance Depot is a large 7650m2 maintenance building constructed as the main servicing hub for Auckland’s new electric trains. It comprises of a main maintenance hall where train servicing takes place, ground floor offices, and a first floor depot control office. The sheer size and scope of this new facility meant that efficient air conditioning systems as well as variable fresh air tempering systems (to pre-heat the outdoor air over 18˚C minimum) were required to meet the diverse needs of all staff on-site.

The Solution

As specified by Opus, Mitsubishi Electric City Multi VRF equipment was selected to meet the cooling and heating, as well as the ventilation requirements in the EMU Depot.

In total, seven City Multi Heat Recovery Systems were chosen with 23 x concealed ducted indoor units and 1 x high wall indoor unit to provide the office sections of the building with efficient heating and cooling, and temperature control. These systems proved to be the most sensible solution as the ducted units are unobtrusively concealed in the ceiling out of sight, and the R2 Heat Recovery outdoor units allow for simultaneous heating and cooling of different indoor units operating off a common outdoor. This means the cooling/heating needs of each of the offices can be achieved simultaneously without compromise.

Variable tempered fresh air in this depot was also achieved using our range of “EP” High COP outdoor units connected to a DX coil located in an Energy Products AHU. This combination with the High COP outdoors enabled a COP in heating in excess of 4 to be achieved.

It was also very important to have the equipment centrally controlled and linked into the EMU’s Building Management System (BMS). By utilising a Mitsubishi Electric AG-150A-J central controller, both the VRF air conditioning systems and tempered fresh air systems can be controlled from a central point, which also allows for web access and a 365 day time schedule. In this case the Mitsubishi Electric BAC-HD150 was installed along with the central controller to provide high level control of all the available air conditioning functions through the BMS.