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Replacing a 15 year old R22 chiller with an ammonia one has been the first major step towards producing Australia’s first carbon neutral wine. Aiming at achieving a stable supply temperature in the most cost effective manner, a chiller system featuring ammonia screw compressors, variable speed drives and heat recovery was selected. 

Committed to reducing their carbon footprint and producing the first carbon neutral wine in Australia, Sirromet, one of Queensland’s largest wineries, worked with Bitzer Australia and Gordon Brothers for the installation of an ammonia chiller system at a winery set up for a 2,000 ton crush with 97 stainless steel tanks ranging from 3,000 litres through to 120,000 litres.

Energy and CO₂ savings

Based on Sirromet’s average medium load run time, the new ammonia chiller system enables estimated cost savings of up to 32% per annum, corresponding to energy cost savings of up to $20,000 per annum. Moreover, gas cost savings of up to $22,000 per annum can be realised thanks to the heat recovery system.

In terms of CO₂ emissions, the company estimates that the replacement of the R22 chiller with the ammonia one will allow for a reduction by 0.35kg of CO₂ per every 750ml wine bottle. Assuming an annual average production of 1,000,000 bottles, this translates to a reduction of 350tons of annual CO₂ emissions.

The installation features

The ammonia chiller system features:

• Two Bitzer screw compressors OSKA8561, offering a total turn down ratio of 8:1 and representing a minimum capacity of 60 kWR when one base load compressor is operating.
• Variable speed drives: A variable speed drive on the base load compressor provides control accuracy with efficiency gains. Moreover, a variable speed drive for the condenser fan enables motor speed regulation to maintain adequate condenser pressure, producing stable pressure at the least running cost.
• An Aqua Cool evaporative condenser for heat rejection, allowing a lower compressor compression ratio with reduced energy cost per kW of refrigeration.
• Alan Bradley PLC controller and HMI interface panel: The controller manages all functions including supply temperature, auxiliary controls, safety and alarms.
• Complete heat recovery system: the system prioritises the heat rejection to an ammonia de-superheater and an oil cooler recovery unit. The recovered heat is used for pre-heating water for the gas-fired boilers.

High reliability of the ammonia system

Chief wine maker Adam Chapman said that during vintage the new plant runs like a dream. “It is quiet, efficient, very powerful and, yes, smart too! When needed the power is there within three minutes, fully loaded on two compressors. The glycol went from a test point of +14°C down to -4°C within 30 minutes for a total storage of 33000 litres”.