CASE STUDY

Winter Gardens, Auckland – Glasshouse Heating

  • Carbon emissions reduction of 76 tonnes per year.
  • 192kW ÖkoFEN pellet boiler
  • Modulation range 19kW to 192kW – 10% to 100%
  • Fully automatic operation including online monitoring
  • 12 tonnes (58MWh) pellet fuel store on-site
  • Monthly pellet fuel deliveries by blower truck (no manual handling)

Glass house heating project which involved the replacement of a gas boiler as part of the Auckland Councils decarbonisation plan.

The Wintergardens at the Auckland Domain was designed in the early 1900s and opened in 1913. It is a treasure trove of rare and spectacular plants including the Amorphopallus titanum (corpse flower) and a large collection of chrysanthemums, in an ever-changing display that can be seen in two barrel-vaulted Victorian-style glass houses which face out onto an extensive courtyard and sunken pool. The main glasshouse is heated to house lush tropical and heat-loving plants. Maintaining the temperature at over 19 degrees Celsius during winter requires a lot of energy, around 350,000 kWh per year. This energy was provided by natural gas which is a fossil fuel and has a high environmental impact. To reduce this Apricus Eco and Tubman Heating have installed of state of the art, low emission ÖkoFEN wood pellet boiler system to heat the glasshouse.

The previous gas boiler was replaced by a fully automated 192kW OkoFEN pellet boiler. This boiler require minimal attention as they are self-refueling and deashing. This new system can be controlled easily online via a web browser or mobile phone app. All settings can be adjusted online and errors or alerts are automatically sent via email. The installation includes a 12 tonne wood pellet fuel store that only needs to be refilled once a month in winter. This is done by a blower truck with no manual handling of the fuel required at any time.

Located in close proximity to sites sensitive to air quality, such as Auckland Hospital, Grafton and Parnell, the OkoFEN pellet boiler was specified because it will cause no negative impacts on air quality. This is backed up with OkoFEN pellet boilers meeting the stringent Ultra Low Emissions Boiler requirements from Environment Canterbury. The installation of this heating system at the Wintergardens will reduce the site carbon emissions by 76 tonnes per year.

Wood pellets are the lowest carbon fuel for heating in NZ because they are made from waste products that would otherwise go to landfills (0.003 kgCO2e / kWh). Wood pellets in NZ are exclusively manufactured from waste wood, sawdust and wood shavings. Wood pellets are a 100% renewable fuel and a key part of the developing circular economy. In 2023, over 300,000 tonnes of wood pellets are manufactured in NZ, delivering 1,440,000 MWh of renewable energy. Bulk pellet deliveries with blower trucks are available throughout the country by a number of suppliers. 15kg bags of pellet fuel are available from Bunnings and Mitre10 for domestic use. All pellet fuel suppliers can be found via the NZ Bioenergy Association.