Tamahere Eventide Home and Retirement Village

The Challenge

All Seasons Air Conditioning was engaged by the developer at Tamahere Eventide Home Trust, which is an outreach of the Methodist Church of New Zealand, to design the HVAC system for the new build complex. The property includes a 24 room hospital, 16 apartments, 36 units as well as sundry and communal spaces.

With the large number of small inhabited rooms and with many tenants that are restricted in their movement, all areas in this project are deemed occupancy class A by NZS 5149. Therefore, traditional VRF with its long refrigerant pipe runs was not a viable solution. As such, Mitsubishi Electric HVRF was chosen as it removed the requirement for two forms of mitigation throughout the whole project.

The Mitsubishi Electric Solution

Three Mitsubishi Electric City Multi HVRF Systems, which serve mostly ducted units, supply milder air off temperatures to each room by utilising water as the medium. Furthermore, every unit can be controlled independently to meet each area’s specific needs.

The HVRF units are supplied with tempered fresh air by two air handler units (AHU) coupled with four PEFY Full Fresh Air Ducted indoor units. Using the full fresh air, the ducted system’s minimum air changes per hour are able to be achieved while also controlling the temperature output of each unit.

A single traditional VRF solution serves the ducted, high walls and cassettes for the larger common areas.

A small number of single split systems serve the main reception, reception office, north-east offices, ground floor guest rooms, and apartments to overcome piping length or total refrigerant charge limitations.

All units are managed via local wall controllers with a touch screen central controller overseeing unit status and scheduling, which is accessible by the aged care staff.

Overall, the chosen solution met the budget requirements over a chilled water system for the Tamahere Eventide Home Trust.