Lowering the temperature of heating hot water to help facilitate heat pump implementation 

The Australian commercial building sector annually consumes more than 40 PJ of fossil gas, primarily for space heating. Such heating can be economically electrified with heat pumps to reduce energy costs and carbon emissions. However, currently only around 20 commercial buildings are being retrofitted with heat pumps each year. At that rate, it will take several decades for the current building stock of approximately 5,000 large commercial buildings to get off gas.

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A2EP has identified two vital steps for the economical electrification of commercial buildings via heat pump installations:

1. Data collection- which is widely recognised and accepted

2. Lowering the heating hot water (HHW) temperature- which is often overlooked or abandoned before being thoroughly pursued.

The case for HHW reduction: 

• For every 1 °C reduction in HHW, heat pump performance improves by 2% to 3% 

• Reducing HHW temperatures to below 70 °C removes the need for heat pumps to have dual stage compression, reducing capital cost by more than 25%. 

• Reducing the HHW temperature to below 60 °C increases the range of heat pumps applicable, therefore competitive options available.

Recently, A2EP published a guide called Retrofitting commercial buildings with heat pumps: a how-to guide (PDF), which includes guidelines for hot water temperature reduction testing. It was developed utilising work from various studies and by performing hot water temperature reduction testing at various commercial sites with the aim of maximising the overall system efficiency whilst also minimising the required size, cost and complexity of a proposed heat pump retrofit installation.