Greensborough plaza management employes CarbonetiX Pty. Ltd. through the mechanical services contractor TCM Solutions from November 2010 to 2014. Our brief was to deliver cost and energy savings by optimising the Building Management System (BMS) and Heating Ventilation and Air Conditioning (HVAC). CarbonetiX visited the facility once a month to improve the control and automation of HVAC plant equipment.

Objectives

• Understand the entire HVAC plant operation and controlling strategies
• Improve control strategies to maximize the utility cost savings and reduce greenhouse gas emissions
• HVAC reviews for energy efficiency increasing upgrades
• Improve thermal comfort inside the building

Opportunities

A range of opportunities were identified during the on-site assessments, enabling the following key benefits:

Inefficient chiller staging logic

Due to incorrect placement of a pressure sensing device all chillers in one of the chiller plants were short cycling. This operation over stressed the power supply and reduced the economic life of the chillers significantly.

Solution

CarbonetiX proposed to change the control strategy, in two steps:

• Chang the time delays between chiller staging and relocate pressure sensor – this resulted in a significant reduction of short cycling of the chillers
• Provide an advanced control strategy for chiller staging

High variability in t emperature settings across facility & narrow temperature dead-band (comfort zone)

Temperature settings between the Air Handling Units (AHU) were greater than 2C to 3C. This resulted in some of the AHU’s fighting against each other to maintain the zone temperatures. There were also very narrow dead bands within the zones which made the AHU cycle between heating and cooling modes too frequently.

Solution

CarbonetiX changed the temperature settings across all AHU’s to operate with a minimum 2.5C temperature dead-band at a pre-agreed threshold.
Outcomes and client benefits

• Improved occupant thermal comfort
• Reduced chiller maintenance costs
  Reduction in energy utility bills

• Improved environmental credentials