Australians have always loved their beer. Increasingly they are loving craft beers from smaller, independent brewers, with more than 600 independent brewers now operating across the country. Despite their popularity, many of these smaller operations face an uncertain future due to the pressure of rising energy costs and the energy intensive nature of brewing. However, Melbourne’s 3 Ravens Brewery is demonstrating how highly efficient heat pumps and some careful planning can allow you to produce a lot more beer for your energy dollar.
What started out as a small brewing exercise to produce a custom beer for a wedding, has now seen 3 Ravens become a leading independent Australian beer name. The 3 Ravens team are focused on continued growth, but, true to their values, want to ensure that as they increase production, they are also reducing their impact and giving back to their local Thornbury community. Thus, the brewery sought a better solution than upgrading the business-as-usual (BAU) equipment to cope with the planned larger volumes.
For 3 Ravens General Manager, Nathan Liascos, sustainability has always been really high on the brewery’s business agenda. “We see sustainable brewing as not just vital for the future of our business, but the wider industry. In planning for growth we wanted to go beyond the basic green measures and explore sustainable practices to maximise efficiency and lead the way in renewable energy innovation in our industry,” Mr Liascos said.
To do this, 3 Ravens engaged energy consultancy, Regenerate Engineering, to analyse the existing facility and processing equipment to better understand where and how the energy was being used and how it could be used better. Director at Regenerate Engineering, Jon Fettes, said, “Brewing beer is extremely energy intensive, using a lot of energy for cooling and heating processes.
“Like at many other breweries, 3 Ravens had a fairly balanced mix of heating and cooling being provided by different pieces of equipment. But the waste heat from one machine would make other equipment work harder to deliver their services as well as making the workspace uncomfortable,” Mr Fettes said.
A more efficient approach
Although 3 Ravens has always been an electric-only brewery, its electric processes have not been very efficient. Before the recent upgrade, a 15kW resistive element was used to preheat filtered water (hot liquor) and then 55kW elements were used to further heat then boil the wort produced from that hot liquor and the mash ingredients.
Two chillers were operating independently to produce chilled glycol treated water and chilled filtered water (cold liquor) to operate all process and ingredient cooling services. Also, the site had several ageing electric reverse cycle R22 HVAC split systems to provide space cooling and a cold storage facility.
Sticking with the existing equipment while ramping up production would have seen the brewery’s energy costs skyrocket and required a costly upgrade to the site’s electrical capacity. Continuing with the BAU equipment would also have created a significant liability with the HVAC equipment as the phase-out of harmful R22 refrigerants continues.
Regenerate Engineering and 3 Ravens approached the expansion and energy upgrade in a holistic and integrative way to maximise benefits to the business and the environment. With its focus on renewable energy and sustainability, planning for the energy project was aided by pre feasibility and feasibility studies managed by the Australian Alliance for Energy Productivity (A2EP) and funded by the Australian Renewable Energy Agency (ARENA) through its Advancing Renewables Program.
The feasibility studies included a detailed mass/energy balance of the process, applying pinch analysis principles to the analysis and development of options. The analytical work detailed how the proposed equipment could be integrated into the current plant and the extensive upgrades that would be required. An expansion of the initial proposal into space heating and cooling (HVAC) services for public spaces at the site was recommended due to further thermodynamic and cost efficiencies, which were identified in the process.
In the feasibility studies, a CO2 chiller heat pump was identified as a key piece of equipment. The chiller heat pump – a single cycle, flexible CO2 refrigerant chiller with advanced heat extraction – would largely replace the inefficient and separate heating and cooling processes.
Before the equipment changeover in the brewing hall, there were a number of other important, complementary measures that were needed to address space heating and cooling issues and maximise the benefits of the wider project.
First, 3 Ravens installed a “cool roof” to reduce thermal impacts from outside climate on the internal climate to increase comfort and reduce the work required by air conditioners. Then 74kW of solar photovoltaic panels were installed on the roof of the facility to supply clean, green electricity and reduce the amount of energy needed to be bought from the grid.
The challenges of using heat from chillers as process heat
All breweries use chillers that have a glycol tank as storage. Every chiller, by virtue of the laws of physics, makes more heat than cold, but traditionally the heat is airborne and a nuisance rather than a resource. Heating processes have rarely been integrated with cooling in brewing operations before.
Typically, heat pump systems work best operating in a constant state (optimised with variable speed systems), however, brewing is by nature a batch process. Where the heating and cooling services come from the same machine it is a challenge to ensure that the system can produce both thermal streams where they are not required at the same time.
While the brewing is still a batch process, the key to success in making this work is system flexibility, redundancy, increased storage and better use of heat exchangers in the process. This can ensure that the chiller heat pump can run for quite long periods. All these aspects will be driven and managed at 3 Ravens through advanced programmable logic controller (PLC) from Fermecraft, which utilises Industry 4.0 technology to automate the brewing to maximise energy efficiency.
Applications and reduction of resistive heating duty
Using the thermal model with scenario modelling, operational range was analysed according to the worst-case usage profiles of different brew recipes and schedules – including sour beers, which require cooling and steeping after inoculation and then re-boiling after an initial short boil. Seasonal performance of the CO2 chiller heat pump system was accounted for, as efficiency – or coefficient of performance (COP) – varies according to ambient conditions.
Further, when HVAC is added, the system needs to be robust enough to withstand the seasonal extremes and the demand that this adds.
It is worth noting that the cool roof installed at the facility is expected to increase the more efficient “cool weather” CO2 season by helping the roof-mounted adiabatic gas cooler run more efficiently.
Current state of play and expected benefits
As of June 2023, the new system has been installed. It will be closely monitored and further tweaks and adjustments will be made as 3 Ravens adds brewing automation features and commissions the space heating and cooling. It is anticipated that the impact of the system will be a huge improvement in energy productivity, with 3 Ravens looking to quadruple its production over the next few years without a corresponding increase in energy consumption. This will mean greater financial sustainability for the business and less emissions per beer for their climate-conscious customers.
“These energy focused upgrades have enabled us to ramp up production, control our costs and significantly reduce the emissions associated with each beer we brew. Something that’s really important to both us and our customers,” Mr Liascos said. “We hope that our actions inspire and motivate other breweries to take the same path and reinforce the importance of safeguarding our environment for generations to come.”
“What’s exciting about this project is that it is highly scalable and replicable – although modelling and plant choice will need to be adjusted to suit electrifying gas-powered process heat,” Mr Fettes said. “Rolled out across the brewing industry, the energy and emissions savings would be substantial.
Read the full detailed case study for this project on the FutureHeat website: www.futureheat.info/post/3-ravens-brewery-melbourne-heat-pumps-for-beer-production