Mark Vender
District heating and cooling (DHC) was the focus of a full-day event held recently in Melbourne, which explored the potential of this technology. DHC systems are local energy networks provide heating and cooling to buildings in a district. They do this by supplying hot water or steam for heating systems, and chilled water for air conditioning.
Organised by energy company Engie and the Asia Pacific Urban Energy Association (APUEA), the event looked at the opportunities DHC presents for decarbonisation, particularly for universities. Accordingly, many stakeholders from that sector were present.
Potential benefits
Also in attendance was APUEA Executive Director Peter Lundberg. Lundberg believes that DHC has a major role to play in decarbonising the built environment.
“DHC may result in up to 50 per cent reduction in energy consumption, 50 per cent reduction in CO2 emissions and refrigerant fluid leaks,” he says.
“It may combine various end-users of different activities (office, residences, shopping centres, supermarkets, universities) in one system. This diversity reduces the peak heating and cooling demand, as not all buildings have their peak at the same time, and results in smaller plant. It is possible to reduce the installed capacity by up to 30 per cent.”
The sessions also highlighted the complementary role thermal storage systems could play. Lundberg says that these can further reduce the peak mechanical capacity of DHC systems, and can help increase the use of renewable energy by storing chilled water produced with intermittent renewable electricity.
The sessions noted other benefits of centralised systems, including lower operation and maintenance costs, more space in individual buildings, and reduction of urban heat island effects. They can also facilitate multiple production plants. Another feature is that it’s possible to use natural cold and hot sources including, rivers, lakes, geothermal, and also waste energy where available.
Ideal settings
Presenters at the event explained that DHC is best suited to developments with a mix of usage types or with constant heating and cooling demands.
“This is where the systems have greater benefits and relatively quick paybacks,” says Muhammad Ali, M.AIRAH, Technical Director DHC at Engie Net Zero Energy Solutions.
“Heating and cooling load density (kWth/km2) also plays an important role in the feasibility of DHC systems. You can find district heating and cooling plants in universities, airports, hospitals, CBD, and transit-oriented development (TOD) areas, industrial zones, municipalities and cities.”
In Australia, DHC has been successfully implemented in some universities – including Monash in Victoria and the University of Queensland – but has struggled to gain traction in other settings. Ali agrees there are challenges for wider uptake.
“DHC technology is more than 100 years old and it has proven itself as technically and commercially viable,” he says. “Yet its penetration in different market and regions has met different challenges.
“Factors that decide the success of a district heating and cooling system include load density, ramp-up (periodic addition of new end-users), initial cost of piping network, permits and licences, and interfaces with building systems.”
Ali also notes that there is a cultural barrier to overcome in some places.
“In some geographies, there is not a great penetration of DHC because it is still considered a foreign idea and its benefits are not properly realised,” he says. “With the recent net zero ambitions, DHC is being realised as a potential solution to decarbonise heating and cooling networks, and is being considered an important lever in the journey to reach net zero.
“This will surely increase the penetration of technology in new geographies. After all, DHC systems can be seen as a utility similar to electricity, water, and sewage, as they provide many benefits to our cities and communities.
A technology to watch
Lundberg says the event was a valuable temperature check for DHC systems in Australia.
“Universities have ambitious net zero targets in Australia, and it was encouraging to see that several universities attended the event and shared their stories,” he says. “They are exploring DHC as a technology that can be implemented in brownfield campuses to provide energy-efficient heating and cooling, reduce energy use, and integrate with the renewable technologies. Developers of greenfield campuses also talked about the opportunities of integrating DHC in their campus masterplans.
“This was a first event on this topic, and with the positive feedback, we believe that more similar events should be held in the future to capture the potential of DHC systems at universities in Australia.”
Image, courtesy of Engie, shows a panel session from the event featuring (from right) Muhammad Ali; Melbourne Energy Institute Energy Systems Program Leader Pierluigi Mancarella; ClimateWorks Centre Cities System Lead Margot Delafoulhouze; Engie Impact Decarbonisation Lead Niels Leemput; and AIRAH Chief Executive Tony Gleeson, M.AIRAH.
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