20 Hunter St, Sydney and 65 Berry St, North Sydney
This month we review the benefits of weather-adjusted measurement and verification (M&V), as highlighted by upgrade projects at two buildings that receive Buildings Alive services.
In commercial buildings, the overarching purpose of energy efficiency projects / upgrades is to achieve a reduction in energy use. Therefore, when upgrades are carried out, it is important to understand and compare the real-world results against theoretical estimates contained in the business case. Often this crucial evaluation step is missed and the success, or otherwise, of the upgrade is not measured. “Measurement and Verification” (M&V) is a process that uses actual measurements to reliably determine post-upgrade savings for energy, demand, cost and greenhouse gas emissions.
Buildings Alive’s M&V process uses actual measurements of electricity and weather, rather than estimates or theoretical engineering calculations based on previous studies, manufacturer specifications or any indirect data. Savings are determined by comparing post upgrade performance against pre-upgrade performance under similar operating conditions.
Building Bio – 20 Hunter St
- Type: A- Grade office tower
- NLA: 10,147 m²
- Built: 1998
- Location: Sydney CBD
- Owner: TIAA-CREF
- Facility manager: CBRE
- Commenced Buildings Alive’s REF Service: March 2014
20 Hunter Street, a TIAA-CREF owned commercial property, recently underwent a major HVAC plant upgrade with a new PowerPax chiller being installed. The CBRE building management team were very keen to understand the effect of the chiller upgrade on the building’s performance, and worked with Buildings Alive to quantify the value of the upgrade to the building owner.
A weather- and occupancy-normalised statistical model was generated using pre-upgrade data. This aligns with the International Performance Measurement and Verification Protocol’s (IPMVP) Method C, “Whole facility measurement”, where savings are determined by measuring energy use at the whole facility level. Short-term or continuous measurements are taken throughout the post-upgrade period. Such M&V techniques can also be used for the generation of carbon credits under the NSW government’s Energy Saving Scheme, a further incentive for funding energy efficiency upgrades.
The weather and occupancy normalised model identified the additional savings arising from the chiller upgrade as shown in the below image comparing Jan-April 2016 to Jan-April 2017. The additional savings were estimated to be 19% from January – April, contributing to a saving of 38MWh electricity and a reduction in greenhouse gas emissions of 31 tonnes CO2-eq. The owners were delighted with the savings and subsequently gave approval for the installation of a second PowerPax chiller in June / July 2017.
Building Bio – 65 Berry St
Type: A Grade office building
- NLA: 14,521 m²
- Built: 1986
- Location: North Sydney
- Owner: Charter Hall
- Facility Manager: Knight Frank
- Commenced Buildings Alive’s REF Service: Feb 2013
65 Berry St recently underwent a comprehensive HVAC system upgrade, which involved the replacement of the existing floor-by-floor package units in favour of a central chilled water system. Subsequently, Buildings Alive used our ‘Rapid M&V tool’ to provide feedback on the real-world savings that have been achieved. The weather adjusted energy model is built using historical electricity and weather data for the base building under pre-retrofit conditions, which forms a basis for comparison with subsequent changes in the building.
Buildings Alive’s weather-adjusted statistical model quantified the post-upgrade savings, as shown in the image below. The savings were estimated to be 31 % from Nov 2016 – April 2017, compared to the baseline period, which equates to electricity savings of 180 MWh and 150 tonnes of CO2-eq.