Maintaining healthy and comfortable indoor environments currently comes with a hefty price tag: according to the World Economic Forum, CO2 emissions between now and 2050 from room air conditioners alone are set to account for 20-40% of the world’s remaining “carbon budget”.
Adding to this issue is the new focus on carbon dioxide's impact on indoor air quality. With a growing body of research linking it to reduced cognitive ability, CO2 is now being recognised as a real problem for indoor environments such as classrooms and offices.
So, what can we do to provide the indoor air quality that people deserve without it costing the earth? MOFs could be the answer.
What are MOFs?
MOFs are a new class of crystalline super-adsorbent composed of metal ions and organic linkers. Their highly porous nature often sees them likened to sponges, though unlike that material MOFs can be designed to capture, store and release specific gases. This is done through a careful selection of metals and linkers during the first stages of synthesis.
It is this bespoke quality along with a high storage capacity that gives MOFs so much promise. Other adsorbents, like activated carbon and silica gel, cannot hold anywhere near as much medium and are unable to be used in such a selective way. MOFs, on the other hand, offer record-breaking porosities (up to 10,000m2/g) and can be developed to target everything from ethylene and ammonia to carbon dioxide and methane from complex gas mixtures.
MOFs could easily be integrated into HVAC systems in the form of a CO2 scrubber. Interested in this technology? Find out more
Metal Organic Frameworks have:
The highest CO2 adsorption capacity known to man.
Engineerable structures for target CO2 capture.
The ability to capture CO2 even in the presence of humidity.
Half the energy requirements of the state-of-the-art amine solutions.
Boosting HVAC Energy Efficiency
One of the biggest benefits of using MOFs for indoor air quality is the ability to reduce the amount of energy used for temperature control during hotter months. A typical office building in the summer will use air conditioning to cool a room yet also have to introduce warmer outdoor air to ensure CO2 is kept within an acceptable range. With MOFs, though, more of the already-cooled air could be recycled back into the system without the need to worry about pollutants, in turn lowering the cooling duty and energy penalty incurred. This approach would prove especially effective in countries that experience longer periods of warm weather and rely heavily on HVAC (Heating, Ventilation, Air Conditioning) systems.
Using MOF Technologies' CO2 scrubbing technology within HVAC systems could cut a user’s energy footprint and operating costs by up to 67%. In environmental terms, this could add up to a carbon emission saving of 2.5 tonnes per month for a medium-sized office (400sqm). Want to find out more?
Transforming HVAC Systems
DCV Energy Efficiency
Using MOFs to improve air quality also has some added benefits for buildings with demand-control ventilation (DCV). These systems optimise indoor air quality through sensor-based airflow management, providing rooms with the right amount of fresh air when it is needed. In an ideal world, DCVs would recycle 100% of the air they use but the CO2 that naturally builds up over time means more has to be introduced at certain times.
Introducing a MOF-based material into an existing DCV offers a route out of this problem. The unique properties of MOFs allow them to be easily regenerated and reused, continuously removing CO2 and maintaining ideal conditions. The same principle also applies for air travel when air is recycled back into the passenger cabin during a flight.