Many people beat the summer heat by cranking the air conditioning. However, air conditioners guzzle power and spew out millions of tons of carbon dioxide daily. They’re also not always good for your health—constant exposure to central A/C can increase risks of recirculating germs and causing breathing problems.
There’s a better alternative, say a team of researchers from the University of British Columbia, Princeton University, the University of California, Berkeley and the Singapore-ETH Centre.
They call it the Cold Tube, and they have shown it works.
Air conditioners work by cooling down and dehumidifying the air around us—an expensive and not particularly environmentally friendly proposition.
The Cold Tube works by absorbing the heat directly emitted by radiation from a person without having to cool the air passing over their skin. This achieves a significant amount of energy savings.
The Cold Tube is a system of rectangular wall or ceiling panels that are kept cold by chilled water circulating within them. Since heat naturally moves by radiation from a hotter surface to a colder surface, when a person stands beside or under the panel, their body heat radiates towards the colder panel. This creates a sensation of cooling like cold air flowing over the body even if the air temperature is quite high.
Although these types of cooling panels have been used in the building industry for several decades, what makes the Cold Tube unique is that it does not need to be combined with a dehumidification system. Just as a cold glass of lemonade would condense water on a hot summer day, cooling down walls and ceilings in buildings would also condense water without first drying out the air around the panels. The researchers behind the Cold Tube conceived of an airtight, humidity-repelling membrane to encase the chilled panels to prevent condensation from forming while still allowing radiation to travel through.
The team built an outdoor demonstration unit last year in Singapore, inviting 55 members of the public to visit and provide feedback. When the system was running, most participants reported feeling “cool” or “comfortable,” despite an average air temperature of 30 degrees Celsius (86 degrees Fahrenheit). The panels also stayed dry, because of the special membrane.
Because the Cold Tube can make people feel cool without dehumidifying the air around them, the researchers say that we can look towards shaving off up to 50 per cent of typical air conditioning energy consumption in applicable space.
The researchers say that this design is ready. It can obviously be used in many outdoor spaces—think open-air summer fairs, concerts, bus stops and public markets. But the mission is to adapt the design for indoor spaces that would typically use central air conditioning.
Because the Cold Tube works independently of indoor air temperature and humidity, keeping windows open in our increasingly hot summers while still feeling comfortable becomes possible.
There’s another aspect of the Cold Tube that is particularly relevant in 2020, as the COVID-19 pandemic has brought to the public’s awareness how sensitive our health is to the quality of the air we breathe indoors. The idea of staying cool with the windows open feels a lot more valuable today than it did six months ago.
News Source: University of British Columbia
