Heat Through Air Conditioning? Students Develop Cool Idea

Heat Through Air Conditioning? Students Develop Cool IdeaAir conditioning installs in northern climates are useful—and certainly welcome—during the few months of summer, but aren’t quite a necessity.

In hot and humid areas such as Singapore, meanwhile, lack of reliable HVAC can pose serious problems for residents. But running systems day-and-night during patches of sweltering weather both costs money and wastes heat; now, a team of students has developed a way to reclaim air con waste and reduce spending.

Hot Stuff

According to Today Online, three students from Ngee Ann Poly Technical School in Singapore developed an idea for a heat recovery system which ties into air conditioning units and other appliances in a home or business, such as hot water tanks.

It works like this: The Domestic Waste Heat Recovery System uses a heat exchanger to absorb wasted air con heat and send it along to hot water tanks. The result? Running an air conditioner for eight hours generates enough captured and re-purposed heat to warm 110 liters of water to 40 degrees Celsius, enough for a family of four.

In Singapore, that means $20 saved monthly or $240 per year—and in a city-state critically dependent on air conditioning, every bit helps. It’s also worth noting that these numbers come from a prototype design, suggesting that actual heat transfer may vary.

What’s the Big Deal? 

Along with wasted money, wasted heat from air conditioning units can also impact the environment. That’s the finding of a 2007 study in Tokyo, which discovered that on a typical weekday the use of HVAC in the city’s downtown core caused a temperature increase of 1-2 degrees Celsius. While other environmental factors certainly played a role, the contribution of HVAC systems was significant and suggests a need for greater efficiency.

In Australia, publications like Sourceable suggest that the 53 million HVAC installations in the country could be made more efficient by making even small adjustments to heat load management, such as retrofit double glazed windows, window shielding, reflective roofs along with better HVAC maintenance to ensure that air flow is maximized while heat leakage is kept to a minimum.

Peak Performance

Ideas like the one from Singapore suggest the next step forward for HVAC efficiency: Recapturing waste heat and then re-purposing it in the same facility. But achieving maximum performance—especially in a commercial setting—requires dedicated maintenance of the technology needed to make this transfer possible. In this case, a heat exchanger.

In effect, this system adds another layer of complexity to HVAC by acting as a transfer mechanism between the cooling system and hot water tank. As a result, it’s essential to regularly descale these exchanges since interior build-up could compromise effectiveness and send waste heat back out into the environment. While the system is elegant and essential, simple steps like maintenance cannot be ignored if long-term gains are the goal.

With the HVAC industry increasingly focused on reclaiming waste heat and giving units dual-purpose in commercial and residential settings, ideas like the one from Ngee Ann are critical. But just as essential are the everyday and every-month tasks of regular cleaning and maintenance which mark the difference between marginal gains and true innovation.

Next Steps:

One comment


  • Interesting read, thank you.

    March 16, 2015

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