250 Room Hotel, Mascot – ENERMAX SMARTcube Gas Boosted system


11-storey 250 room leading International hotel adjacent to Sydney airport. Upgrading of hot water plant to deliver consistent and reliable heated water, energy reduction and durability.

Replacement of conventional gas boilers, feeding into large, pressurised storage tanks (now rendered obsolete and no longer part of system).

Essential that the system replacement be conducted with minimal disruption to hot water supply.

System Requirements:

Reliable hot water delivery over the full 11 storey building to accommodation rooms. Must be capable of consistently delivering 9,000L per hour at 65°C. Improved energy efficiency required together with system durability.

Original System:

  • 2 x conventional atmospheric gas tube bundled system boilers
  • 2 x 10,000L steel storage tanks

ENERMAX System Solution:

  • 6 x ENERMAX SMARTcube 500L tanks SC500, comprising dual stainless steel coils for hygienic hot water and high flow rate capability to the full 11-stories

  • 6 x Noritz 50L/min condensing Commercial Continuous Flow gas boosters, 330MJ/Hr at 95% thermal efficiency
  • 4 x Grundfos primary pumps for the system primary loop function

System is spilt over 2 plant locations – Level 1 and Level 8 – for consistent pressure delivery across all floors.

System Performance:

  • Footprint – total footprint (combined both plant levels) required – 7.2 sq mtrs, significantly less than the combined original system.

  • Installation changeover/retrofit disruption – Tfull hot water flow and temperature disruption was limited to less than 4 hours.

  • Delivery – is delivering consistently up to 9,300L at 65°C per hour (combined performance across both plant levels), servicing 250 rooms.
  • Energy Reduction – reduced energy usage, as system thermal efficiency has been improved from 81% (original system) to 95%.

  • Durability – the primary loop within the ENERMAX system is unpressurised, reducing load and wear on the Commercial Continuous Flow gas units.

  • Low NOx burner provides improved emissions and air quality.

  • Control system cascades the operation of the Commercial Continuous Flow gas units and enables connection to Building Management System to monitor operation.


This ENERMAX solution is a fit-for-purpose system. It provides hygienic heated water across 11 levels meeting client requirements for high volume consistent water heating delivery. Impact on heated water supply at changeover was minimal. Condensing gas burners deliver improved energy efficiency for energy savings over the system’s life. System durability and service costs, particularly of the Continuous Flow gas units, will be reduced due to the unique ENERMAX SMARTcube non-pressurised heat exchange system design.