Case study: reflecting on energy efficiency

Case study: reflecting on energy efficiency

Energy Savings
Published on 28 October 2019

DHL applied a solar reflective coating to the roof and reduced their energy use by 25% (reduced HVAC), saving $40,000 a year! 

"The savings achieved exceeded our expectations and we have already started installing the solar reflective coating on other buildings." - Kim Pilosio, GoGreen Lead APAC, DHL Supply Chain.

DHL is a global market leader in contract logistics. Our services include warehouse design, implementation and operations along with transport services for the aerospace, automotive, retail, technology, consumer and healthcare sectors. We have over 3200 employees working at over 47 sites across Australia.

The temperature controlled warehouse at Arndell Park is 15,850 square metres and is divided into two operational zones, with a wall separating them. Warehouse A, which is twice the area of warehouse B, is cooled by six air conditioning units, and warehouse B by four units. We have an annual energy bill of about $300,000, of which the major proportion is for operation of the air conditioning system (HVAC). We wanted to find ways to reduce this energy use and, of course, to save money. 

Our project involved applying a specialised heat reflective coating to the external roof area of warehouse A. We
expected the coating to significantly reduce the heat absorption of the building and reduce the heating load that
the air conditioning units have to manage. We hoped to see a reduction in the amount of energy used by the air conditioners of at least 10%.

At the beginning of the project we engaged an Accredited Certified Provider (ACP) and three months after applying the coating they provided a measurement and verification (M&V) report with the objective of assessing the impact of the reflective coating as well as providing base data for the calculation of energy saving certificates (ESCs) associated with this project.

Immediately after the coating was applied to warehouse A, we saw a significant fall in the total power at the meter servicing it, with no such fall occurring at warehouse B’s meter. Based on the M&V quantified savings over the six months of the project, we estimate an annual energy reduction of at least 25%, saving us more than $40,000 a year for warehouse A. The capital cost of the project was reduced by the 3700 energy efficiency certificates (ESCs) generated by the project.

Implementation costs: approximately $180,000 (less discount for ESCs)
Cost savings: approximately $40,000 per year
Energy savings for warehouse A: 390MWh per year – more than 25% reduction in HVAC electricity use
Simple payback: 3 years (allowing for ESC discount for 3700 ESCs)

Solar reflective coating
The solar reflective coating used in this project was developed in Australia and has been applied to many large roof surfaces such as warehouses and shopping centres. 

It works by reflecting a large percentage of the sun’s heat from the roof, as well as radiating heat reaching the roof from within the building – effectively ‘drawing heat out’. It has been shown to dramatically reduce the heat load in buildings.

Measurement and verification (M&V)
M&V provides a tool for businesses to independently monitor the impact of energy conservation measures (ECMs), and when designed and executed correctly, it can accurately quantify and allocate savings to ECMs. Savings are determined by comparing post-retrofit performance against a ‘business as usual’ forecast.

This article originally appeared here and is republished with permission.

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