30 | Health New Zealand Te Whatu Ora - Wairau Hospital T T Richard Loader Heat pumps to replace coal boiler The new heat pump system at Wairau Hospital is estimated to save energy costs by up to 10% annually, as well as deliver a cleaner, more efficient and sustainable energy source. REGIONAL DEVELOPMENT In August this year Wairau Hospital in Blenheim will officially transition from its existing coal boiler heating system, to a cleaner and greener heat pump system that will provide heating, and cooling throughout the 65-bed hospital, as well as domestic hot water. The $8 million plus Health New Zealand Te Whatu Ora project, is driven by the government’s initiatives to remove coal boilers from hospitals and schools by 2025. Wairau Hospital’s current coal boiler system has been in operation since the mid 1980s and consumes 800 – 900 tonnes of coal each year, providing heat to a 15000sqm footprint that includes the main hospital and outbuildings. The new heat pump system is estimated to save energy costs by up to 10% annually, as well as deliver a cleaner, more efficient and sustainable energy source. Philip Reardon the hospital’s Facilities Manager and Senior Responsible Officer (SRO) for the project, says the hospital and professional consultancy firm Beca had been investigating options to replace the coal boiler system since 2019. “We essentially had four main options to consider, including a methane gas system from local landfill, wood pellet and wood chip options, and the heat pump system. “In the end, the heat pump option was selected because of its resilience, cost to operate and efficiency. Once that decision was made, the detailed design work was passed over to design engineering consultancy WSP who were better placed resource wise to handle the project.” The key components of the new system include three large Black Diamond Technologies heat pump systems supplied by Mitsubishi Electric, that will deliver the hospital’s heating and cooling. “Two large heat pumps deliver 500kW output each, and provides either heating or cooling depending on the season and demand. A smaller 160kW unit can simultaneously heat and cool. Mitsubishi Electric also supplied a number of CO2 heat pumps for the hospital’s domestic hot water. “The new units will be housed outside where the existing chiller units currently sit until they are decommissioned. Two 1000kW emergency backup diesel generators were supplied by Dependable Power.” Philip says that following detailed design, the project went out to GETS (Government Electronic Tendering System) with Blenheim based Cuddon Engineering awarded the role of lead contractor. “They are a very broad-spectrum design and build company and do structural engineering and fabrication, freeze dryers and HVAC systems, so they brought a lot of experience and technical know-how to the project. “Procurement of the key components and equipment was all handled internally, with expert advice from WSP. Because of the long lead time required to procure some of the equipment we obtained exemptions within Health New Zealand to purchase them before the tender went out for the project. The installation contract was signed just before Christmas 2023 and installation is now well underway.” Duncan Jarvie, the client-side project manager explains that the hospital will continue to be heated by the coal burners until the heat pumps are operationalised. “We have just completed some pipework modifications to allow a ‘hot swap’, from coal to heat pump energy. Hotwater shut downs during the project, like the pipework alterations, have been a challenge as they impact on the hospital’s operation. “There was a lot of mitigation around time of day, the weather, the right time of year for temperature,” says Duncan. “The same thing applies for the back-up generators. So far, we’ve managed those shutdowns very well, with minimal impact to the hospital,” he says. “A key learning for me is that there is a lot more energy use around the circulating systems than there is from people actually running hotwater. “There will be a review of the pipes and lagging and in the future we may move more towards decentralised units that are closer to its use.”
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