Council explains waste heat issue at pool
Aimee Wilson
12 June 2025, 6:00 PM
IceInline chair Murray Miller helped install the 350m of piping infrastructure connected to the Alexandra Pool. The Molyneux Aquatic Centre would need to use additional power from a booster heat pump to raise the temperature of the waste heat coming from IceInline.
IceInline chairman Murray Miller said last week the waste heat initiative between the two community facilities had been a wasted opportunity, as nobody knew how to run it properly.
Waste heat from making ice over winter has been piped through to the Alexandra pool since 2018 when the ice rink upgraded its plant room - at a cost of $960,000.
The computer in the plant room at IceInline showed the waste heat leaving the facility at between 25 degC and 32 degC, but council said by the time it got to the Alexandra pool it was considerably lower than that.
Parks and recreation manager Gordon Bailey said the electricity savings envisaged from using the waste heat had not been achieved, and the plant had not performed as originally promoted.
“It was never designed to be the primary source of heating for the pool; supplementary only.”
He said a booster heat pump was required to extract the useful heat from the low-grade heat provided by the ice rink.
“This was not required in the original design and places a limit on the amount of heat that can be recovered. Therefore, the pool needs to lift the temperature up before it can be used in the pool. This requires additional electricity.”
Canadian company Accent Refrigeration Systems shipped the ice plant to New Zealand, and brought an expert installer to set up the 350m long and 400m diameter pipe between the two facilities.
Council said early indications of energy savings was $20,000, however the actual savings proved to be only between $11,000 and $13,000 (from the 2021 figures).
“More accurate energy measurements indicated there were minimal energy savings, and it depended on a number of factors such as pool hall humidity level, and the price council purchased electricity at."
The underground infrastructure was set up so that in the future it could be extended to Molyneux Estate, Molyneux Park and the two nearby schools, providing heat for the wider community.
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