As the global decarbonization trend gains momentum and stricter regulations on greenhouse gas emissions come into effect, the HVAC industry finds itself at the forefront of innovation. Indeed, the need to reduce carbon footprints -- combined with unprecedented levels of public and private funding -- has spurred the development of new cooling equipment technologies that often use humidity control to increase efficiency and reduce emissions.
For example, using technology developed by the Pacific Northwest National Laboratory (PNNL), Montana Technologies created the AirJoule™, which is a renewable energy and cooling technology that consumes as much as 75% less electricity than any other HVAC or water generating system.
According to PNNL, the new dehumidification technology “eliminates condensation on the evaporators in traditional A/C systems by harvesting energy generated spontaneously from adsorbing the water vapor in the air. The system uses a twin-chamber design, in which both chambers contain a novel desiccant material that has exceptional adsorption properties. Each chamber takes turns either removing moisture from air or regenerating the desiccant for reuse.
“In one chamber, outside air is passed over the paper-thin film of desiccant, pulling water vapor into the material’s nano-sized pores. The heat that is generated from adsorbing water vapor is then transferred to the other chamber to help release water previously captured in the pores. A light vacuum pressure helps regenerate the desiccant.”
The inventor of the technology, Pete McGrail, a Laboratory Fellow at PNNL, noted that “once the high-capacity desiccant is regenerated, the twin chambers reverse their functions and the cycle repeats, avoiding the need to add heat or cooling to the process. By balancing the heat transfer between chambers, we minimize energy consumption and allow the AirJoule system to continuously operate at ambient temperature, adding no extra load on an A/C unit.”
Another interesting technology comes from Transaera, which is developing a new class of affordable, energy-efficient, sustainable cooling systems. The company was recently added to the Carrier Ventures investment portfolio of companies selected for their next-generation technology, high-growth potential, and sustainability focus.
According to Carrier, current air conditioners consume more energy in humid conditions, and the majority of future cooling demand is expected to come from people living in hot and humid climates. “Transaera's novel desiccant technology uses a unique sponge-like material that grabs moisture from the atmosphere to enable its air conditioner to cool air more efficiently. The heat generated by the air conditioner is then used – instead of being wasted – to dry the material for the next cycle. Transaera intends to use this technology in partnership with Carrier to develop ultra-efficient climate systems.”
A new technology designed by researchers from Wyss Institute for Biologically Inspired Engineering at Harvard and Harvard’s Center for Green Buildings and Cities (CGBC) at the Graduate School of Design is called coldSNAP (cold Superhydrophobic Nano-Architectured Process). The proprietary technology uses a specialized coating that isolates incoming hot air from outgoing wet air, allowing the hot air to be cooled by circulating water without adding humidity to the inside of the building.
Inspired by the water repellency of duck feathers, this evaporative cooling technology consists of 3D-printed ceramic coated with a novel, nanoscale hydrophobic material, according to Wyss Institute’s website. “The coating effectively isolates water vapor from the air that is released into a building, preventing it from becoming humid while promoting heat transfer to maximize cooling.”
Wyss Institute adds that coldSNAP is a “durable, low-cost, low-energy evaporative cooling system that can work efficiently in hot and hot-humid climates, and could one day replace vapor-compression coolers with a much more environmentally friendly option. It could even be manufactured into the façades of buildings, which would allow them to effectively cool the space within while only using energy to pump water through the system.”
The same Harvard team is also working on a new dehumidification technology called Dryscreen, which is a water-selective membrane vacuum system that has been designed and fabricated with support from the U.S. Department of Energy. According to an article in Harvard magazine, Dryscreen is “a series of plates, each with a 20-micron-thick membrane sandwiched on either side. The membrane rejects oxygen and nitrogen molecules but permits the diffusion of water molecules.”
The article adds that Dryscreen allows air to come inside while pulling out moisture. The proprietary vacuum technology then sucks away the moisture on the membrane, removing humidity from the air. The technology could work well in humid climates like Miami, where the hot outside air would often feel comfortable if it weren’t for the humidity. Dryscreen could deliver that dehumidified comfort at a fraction of the environmental cost of a traditional air conditioning unit, according to the Harvard team.
These are just some of the recent innovations brought about by the decarbonization trend (and lots of cash from public and private entities). The HVAC industry is smart to capitalize on the trend, which is leading to the development of new technologies that could revolutionize the way buildings are cooled. I’m sure we’ll see even more HVAC innovations in the coming years.
