Articles and interviews with James Trevelyan
Our Story
About Coolzy
Professor James Trevelyan, invented Coolzy.
He had become addicted to Pakistan mangos since his first visit in the early 1990s. That’s why he was there in June, the peak of summer when the best mangos come onto the market because they ripen in the 45°C heat.
One morning in June 2004, soon after midnight, James woke suddenly as his old window air conditioner thudded to a halt. The military government had imposed electricity load shedding because too many people had connected energy-hungry room air conditioners to the grid.
His bedroom was completely dark: there was no fan, no light, and no sound except for mosquitos. Sweat was running down his face in the 40°C heat (the walls retain their heat all through the night). He thought to himself “if only I had a gentle flow of cool air on my face and chest, I would be able to fall asleep again, and it has to run on a battery-powered UPS for two hours.”
That was the moment that the idea of Coolzy was born. Billions of people around the world need a sustainable, energy-efficient cooling solution, and so far Coolzy is the only technology that can meet that demand.
But it took more than a dozen prototypes and years of testing to get to the products you can buy today.
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With frequent power interruptions lasting an hour or longer, the conventional solution was a large 10 kVA generator to keep the house air conditioners running. In fact, diesel generators became the featured product in many air conditioner shops.
Being close to neighbours, a large enough generator was not an option for James’ family home. The noise and fumes would be unacceptable.
As a professor in the University of Western Australia, he took the challenge to his mechanical engineering students: design a tiny battery powered air conditioner running on no more than 350 Watts. He thought it would be an easy project for them, but the initial results were disappointing.
He realised that the real challenge was not the refrigeration: a small but otherwise conventional air conditioner was the easy part. The real difficulty was how to deliver the cool air to where it was needed without mixing with the 40°C room air.
Part of the solution was a bed tent, like a mosquito net but using special material to retain the denser cool dry air over the bed. The tent not only concentrated the cooling, but also kept out the mosquitos, another summer menace in Pakistan as they carry dengue and malaria.
He founded our company Close Comfort Pty Ltd in 2007 to conduct the research and development in Australia. Over the next 6 years, James worked with his students to gradually develop and realise his dream of energy-efficient, localised air conditioning technology.
In the summer of 2013, Professor Trevelyan arrived at the foot of the Himalayas, to conduct tests in some of the hottest areas of Pakistan. The results exceeded his expectations.
He showed the first prototype to locals who could not dream of affording the electricity cost and generator for conventional air conditioners. The first question they asked was “how much will it cost to buy them?” James had not even thought of making them for others: it was still just a curiosity project… would it work at all? So he asked them how much they would pay for one. They thought for a moment and suggested more than $350 US dollars in local currency. It was only later than James realised why they would pay so much: normal sleep is impossible without air conditioning. That is the price they were prepared to pay to be able to enjoy normal sleep.
After more years of market research and testing in different countries and climatic conditions, the first Coolzys went on sale to Pakistan customers in 2016 under the Close Comfort brand.
Customer education has been the main challenge, starting with James’ wife. When confronted with a bed tent, she immediately refused even to try sleeping in it. “You know I have claustrophobia… I am not sleeping in that thing,” she exclaimed. Eventually she was persuaded, with great reluctance.
The next morning, she awoke surprised: “that was the best sleep I have ever experienced with an air conditioner, and I heard the birds outside because the window was open.”
Our early customers were soon sold on the idea as their electricity bills were reduced by 90% or more.
We created the Coolzy brand in 2021, and Coolzy.com became our online store. We now sell in over 30 countries and have stores in Australia, Indonesia, Europe, USA and Pakistan.
Since then, our research and development at Close Comfort continues, developing patented technologies and improving the performance of our air conditioners and developing new product lines.
At Coolzy.com we are committed to providing sustainable solutions to cool a warming world.
Early Steps
Here we show some of the important steps on the way to Coolzy. This photo shows the very first packaged Coolzy being tested by one of James’ students in steamy tropical Queensland heat. At the time we only knew the basics of refrigeration and air conditioning. At the time, the aim was to provide cooling for sleeping through intense heat in the Pakistan summer with high humidity and indoor temperature around 40 °C. The fabric enclosure around the bed retained much of the dense, cool, dry air coming from the wooden box. At first we thought that a mosquito net would be sufficient, but we soon learned how easily cool air flowed off the bed through the net like a cascade of water.
The cooler had large automotive heat exchangers. Students searched car wrecking yards for inexpensive air conditioning components and fans, but fitting them all in a plywood box was quite a challenge.
A Stylish Bedroom
Here’s a concept drawing for the first Coolzy that James’ wife was prepared to accept in her home. He re-designed the air cooling machinery to fit in a blanket box at the foot end of the bed.
His wife arranged for Pakistan experts to make the decorative curtains enclosing the bed.
The cool air is much denser than the warm humid air outside the enclosure and stays just above the mattress.
Although physically quite large, the air cooler ran on only 250 Watts of power, low enough to run easily on a battery back up power supply. These power supplies are common in households across South Asia and many other countries experiencing regular power blackouts.
The air cooler
At first it seemed simple. All we had to do was to build a tiny air conditioner. Here’s an expert cabinet maker working on a very unusual piece of furniture.
Gradually James learned that the theories taught to students are only the beginning. There are so many practical considerations to factor into the design. Every cooling device will condense water from humid air and the water has to go somewhere, preferably lower down. Water won’t flow up hill without a pump, and a pump is an undesirable complication and uses electric power. It has to be avoided if possible. Furthermore, it’s essential to keep the water away from the electrical wiring!
The first real test
Summer in Perth, Western Australia can be very hot. Not quite as hot as Pakistan, but well over 40 °C during the day. Who better to try out this prototype than a young honeymoon couple. After six weeks in James’ guest bedroom, they pronounced this prototype a complete success. It kept them comfortable through the hottest days and nights.
Students came in later and patiently measured the air flow patterns to confirm James’ predictions. They discovered an unexpected flow pattern where the warmer air returned to the air cooler. An invisible swirling vortex formed, drawing in warm air from above.
Smaller, lighter, the first really portable mini air conditioner
The next challenge was to design a smaller, lighter machine that would be easily portable. This photograph shows another prototype, this time using components from a commercial portable room air conditioner.
Xia Jin, a research and development engineer, performed many tests to confirm that the technical performance would meet the demands of Pakistan summer heat. In this photograph she is using a thermal camera to visualise the distribution of heating and cooling coming from the copper pipes.
Islamabad, Pakistan, June 2014
This was the first real test for Coolzy. James travelled back to Pakistan where the first ideas emerged ten years earlier.
He unpacked the Coolzy prototype from its packing, hoping that it had survived the long journey by air. He connected it to the pop-up bed tent made in Lahore specially for the test. Last minute cardboard additions secured with masking tape directed the warm air to the ceiling.
He prepared a downstairs bedroom just in case, because the heat in the upstairs bedroom was several degrees higher than he had expected.
Exhausted, he fell asleep and woke, refreshed and comfortable, 9 hours later. The little Coolzy exceeded his expectations. Local people asked how much it would cost to buy. Until then, for James, it had just been a technical challenge. At that moment, when he realised how excited local people were about enjoying affordable air conditioned comfort, the commercial potential of Coolzy first became apparent.
Ongoing R&D
We continue our research and development to continually improve Coolzy.
Here we are testing air flow patterns that help to deliver Coolzy’s focused cooling, concentrating all the cooling power where it is needed, not sharing most of the cooling with the ceiling, walls, floor and furniture like typical room air conditioners.
The world needs sustainable cooling that deliver comfort for billions of people without cooking the climate with greenhouse emissions from power stations and refrigerant gases.
The new generation Coolzy models use 100 grams of natural R290 refrigerant, sealed in hermetically welded tubes for the life of the product. Even if released, this gas has a negligible carbon footprint. With higher thermal efficiency, the new Coolzy delivers more cooling for the equivalent power.
We will be releasing even more improvements in the coming seasons.
