The Green Cooling Summit 2025, held virtually and jointly organized by the German Environment Agency (UBA) and GIZ Proklima on behalf of the German Federal Ministry for the Environment, Climate Action, Nature Conservation and Nuclear Safety (BMUKN), focused on sustainable cooling and heating in buildings. Over two days, international experts discussed natural refrigerants, energy efficiency, and passive strategies for climate control in residential and commercial settings.
In his keynote, Daniel Colboure (Re-Phridge) addressed the growing energy demand from indoor climate control, citing a 5% annual rise in cooling consumption and that air conditioning now accounts for 7% of global electricity use and 3% of CO2 emissions. He advocated for a hierarchy of sustainable technologies, favoring natural refrigerants and passive design, supported by regulation and behavioral adaptation.
The first session, led by David Behringer (Öko Recherche), compared chillers and condensing units using natural and halogenated refrigerants with GWPs below 750. Based on a TEWI (Total Equivalent Warming Impact) analysis for UBA, results showed similar energy efficiency between HFC/HFO blends and natural refrigerants. Best-performing units used HCFO R-1233zd and R-717 (Ammonia). The study also analyzed emissions of trifluoroacetic acid (TFA), noting high emission ratios per kW in condensing units.
Session two featured Cristina Mariaca Orozco (UNIDO), who presented Colombia’s district energy strategy, and Joseph Amankwa Baffoe (EPA Ghana), who highlighted Africa’s first climate-friendly air-conditioning chiller using R-290 at a Near Zero Energy Building in Accra. Dr. Andreas Koch (DENA) shared district heating case studies and decarbonisation strategies.
In session three, Miquel Pitarch (U4E) promoted an Integrated Policy Approach to boost energy efficiency and climate-friendly technologies, projecting potential annual savings of 915 TWh and CO2 reductions of 817 million tonnes by 2040 across 156 developing countries. IFC’s Ana Luiza Dutra and Denis Medvedev presented the Cooler Finance report, estimating that sustainable cooling could avoid up to USD 8 trillion in costs by 2050.
On the second day, session four examined passive strategies. Marco Schmidt (TU Berlin) introduced passive cooling and shading solutions. Dr. Yosr Allouche (IIR) showcased technologies for sustainable cooling access under extreme heat, and Prof. Mark Nieuwenhuijsen (Institute for Global Health) assessed the health benefits of urban green infrastructure.
Session five covered experiences with room cooling and heating using natural refrigerants. Ole Nielsen (Öko-Recherche) presented a global overview of R-290-based AC and heat pumps. Mustafa Abunofal (Cool Up) discussed strategies for scaling up sustainable cooling in hot climates.
Session six featured breakout discussions on sector challenges and opportunities. The event closed with reflections from Guntram Glasbrenner (GIZ Proklima) and Julika Schmitz, emphasizing the sector's momentum and the need for continued collaboration and policy support.
“We need continued collaboration, innovation and enabling policies to accelerate sustainable cooling and heating,” said Guntram Glasbrenner, Program Manager, GIZ Proklima.
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