Air conditioning is one of the biggest energy hogs in a building, and it usually relies on refrigerants that are anything but eco-friendly. Under the TÜBİTAK SME R&D Start-up Support Funding Programme (1507), we at Innorma R&D, Solimpeks' R&D start-up, developed a solar-energy-supported indirect evaporative cooler (S-IEC) — and in testing it reached a maximum COP of 8.92, delivering 3.12 kW of cooling from about 350 W of electrical power.
Why an indirect evaporative cooler?
An indirect evaporative cooler chills air without adding extra humidity to the space — a genuine advantage, especially in humid climates. Where typical AC units run on chemical refrigerants such as R134a or R410a, which contribute to greenhouse gas emissions, our system uses just plain water and air — no refrigerant circuit at all, not even natural options like R290. Lower energy consumption than conventional systems is the other half of the promise.
How did we design the prototypes?
We started with fundamentals: conceptual design, sketches, and mathematical models — including psychrometric diagrams to understand how the humidification chamber would perform. Ansys Designmodeler, Ansys Meshing, and Ansys Fluent handled the detailed flow and thermal analyses, letting us experiment virtually with different configurations. One clear outcome: for our design, a counter-flow setup generally offered better heat-exchange performance.
Then came the build. Exploring two slightly different approaches produced two distinct versions — Prototype A and Prototype B — each requiring its own manufacturing techniques. This phase also covered sourcing components, setting up the humidification chamber, and carefully determining sensor placement for accurate data.
What did the tests show?
Both prototypes went through extensive tests in a climate-controlled room simulating a range of environmental conditions, including extreme ones. Prototype A generally showed greater efficiency, leading to a higher COP; Prototype B shone in higher-temperature conditions, achieving larger temperature differences. Each design has distinct strengths — useful for matching them to their best applications.
The headline finding: a maximum COP of 8.92, meaning roughly 3.12 kW of cooling capacity for about 350 W of electrical consumption.
Can it run entirely on solar power?
Yes — that was the point of our in-depth PV integration analysis, covering both performance and economics. Roughly 780 Wp of PV capacity, paired with an MPPT (Maximum Power Point Tracking) system and inverter, should be more than enough to cover the cooler's annual energy needs. That points to a high potential for commercialisation, especially in off-grid applications — and it means the project hit all the main goals we set.
Who is the S-IEC for?
The high-efficiency, solar-supported design suits sectors where cooling demand is high and energy independence matters: industrial settings such as factories, workshops, the automotive and metal industries, and shipbuilding; and public or commercial spaces including shopping centres, cinemas, restaurants, universities, cultural centres, places of worship, hospitals, and homes. Specialised environments — greenhouses, animal farms, and data storage centres — are a critical application area, where precise climate control with minimal humidity increase and low energy consumption is essential.
The strategic target regions are countries dominated by the Mediterranean climate, including Türkiye and European nations, plus the entire MENA region: high temperature and humidity, abundant solar resources ideal for PV-assisted operation, a nearly year-long cooling requirement, and active transitions toward renewable and clean energy technologies.
A cooler, greener tomorrow
Wrapping up testing feels like a major step forward. This project is not just about a cooler; it is about pushing the boundaries of energy efficiency and environmental responsibility — massive energy savings and high cooling capacity with zero chemical refrigerants.
