The case for better cooling

The real impacts and how to cut them

Cooling has been part of human ingenuity for millennia—from windcatchers and ice houses to today’s supermarket chillers, hospital pharmacies, data centres and comfortable homes. In 2025, cooling is everywhere and essential: it keeps food safe, medicines viable, people productive, and industrial processes within tight tolerances. Yet “more cooling” often triggers controversy. Heatwaves raise demand and strain grids; some argue air conditioning should be limited, others call it a public health necessity. Cooling is indispensable and it must be made radically cleaner. That’s the mindset behind HydroCool.

1. Understanding the real impacts of cooling

There’s no such thing as “making cold”. Cooling works by moving heat from one place to another—from your hot apartment (Space A) to the outdoors (Space B), or from a server rack to a cooling loop. That transfer takes work (energy) and usually relies on a refrigerant that absorbs and releases heat. In dense cities, air conditioners discharging heat can intensify local heat stress, but the main environmental footprint of cooling comes from a few clear and actionable hotspots:

Electricity use. Cooling is one of the fastest growing uses of electricity. Demand surges during hot spells and, in many regions, it already accounts for a significant share of building demand. The more efficient the system (higher COP/EER/SEER), the less energy we need per unit of cooling and the lower the indirect emissions when the grid isn’t fully renewable. That’s why cutting the energy needed for the same cooling output is the single biggest lever to reduce both climate impact and operating costs.
Refrigerants. Many legacy systems rely on HFCs, which are synthetic gases used as refrigerant with very high global warming potential (GWP). Leaks during operation and at endoflife translate into direct emissions. EU regulation is accelerating the shift toward natural refrigerants such as CO₂ (R744), ammonia (R717) and hydrocarbons (e.g., propane R290), alongside water based solutions. That’s why selecting low GWP refrigerants and engineering for ultralow leakage can eliminate a large slice of lifecycle emissions.
End of life & circularity. When equipment is retired, insufficient recovery of refrigerants and poor recycling of components turn into avoidable emissions and material loss. Designing for easy maintenance, repair and upgrade—and ensuring proper recovery at decommissioning—makes a major difference across a system’s lifetime. That’s why circular design and responsible end-of-life handling prevent refrigerant release while recovering valuable materials.

2. From impacts to solutions: introducing HydroCool

If cooling’s impacts come from energy use, refrigerants and end of life, then “better cooling” means delivering the same comfort with less electricity, climate-friendly working fluids, and equipment designed to be maintained, repaired and recycled. That’s exactly what HydroCool sets out to do. HydroCool is rethinking how cooling works with a new CO₂-based system that moves heat more efficiently and uses climate friendly fluids.

Instead of a metal compressor that gets very hot and wastes energy, we use a liquid piston that presses CO₂ (a natural refrigerant) more gently, keeping it at almost the same temperature. That means less friction, no oil, and less electricity to move the same amount of heat. We also re‑use energy that most systems throw away: a small expander acts like a tiny turbine, capturing part of that “lost” energy and feeding it back into the cycle. And because the system can switch smoothly between different operating modes, it stays efficient in both mild weather and heatwaves. We design for real life—fewer moving parts, no lubricants, and a modular layout make the unit easier to maintain, repair and recycle.

The result: the same comfort with less power, natural refrigerants by default, and a smaller footprint over the equipment’s lifetime.

3. From here onwards

HydroCool shows how refrigeration technology can move in a sustainable direction. It rethinks the compression process and recovers energy that conventional systems waste. This way, it delivers cooling with less electricity, natural refrigerants and equipment that is easier to maintain and reuse at the end of its life.

Cooling, however, is only one element of spatial planning. It interacts with other decisions about how buildings are designed and operated, how shade and vegetation are integrated, or how energy systems are organised at scale. When joined up with better building practices, renewable energy and planning that reduces urban heat stress, cooling becomes part of a coordinated approach. That is how we move from more cooling to better cooling, delivering what communities need while easing the climate burden.

Author: Guillem Figueras

Editorial: Lucía Salinas