Retrofit air-con to tackle climate change, researchers say


A simple tech fix could prompt radical environmental and economic overhaul. Andrew Masterson reports.


Air-conditioning units fitted in a block of flats in China represent considerable untapped fuel potential.

VCG/Getty Images

Domestic and commercial air-conditioning units could be retrofitted using existing technology and turned into “personalised, localised and distributed, synthetic oil wells”, according to researchers writing in the journal Nature Communications.

A team led by Roland Dittmeyer of Germany’s Karlsruhe Institute of Technology suggest that household air-conditioners could be easily upgraded to capture airborne carbon dioxide and water, as well as warm and cool built spaces.

The captured material could then be converted into renewable hydrocarbon fuels. These, say Dittmeyer and colleagues, could be “tapped, shared and stored” within and between communities in a way that obliquely signals a solution to climate change that is as much a matter of economic reform as technological change.

The researchers call the result “crowd oil”, a concept that redefines the humble air-conditioning unit as a critical component within a distributed “solar refinery” – roughly analogous to the already existing array of rooftop solar panels which, in economies that allow owners to sell personal surplus into the grid, already gives rise to the idea of “crowd electricity”.

“This could have a significant impact on the carbon dioxide load emitted into the atmosphere while safely storing available renewable electrical energy and heat in the form of high-energy-density chemical fuel, rather than in pressurised underground carbon dioxide reservoirs with a chance of leakage,” the authors write.

The approach, they note, would also represent an end-run around public distrust of large-scale carbon capture and storage (CCS) projects, which are not only disturbingly industrial in size, but also produce no useful end product.

The crowd-oil approach is much more human-scaled, and allows a sense of self-empowerment because the decision to retrofit existing air-con units is one that can in many instances be made on an individual level. It also generates a product – fuel oil – that can be used, stowed away or traded.

“The products generated in these decentralised synthetic oil wells could be used to replace conventional fossil fuels or stored for later use,” Dittmeyer and colleagues write.

They note that having a handy on-site store of tappable hydrocarbon fuel could be useful to plug any gaps in continuity for renewable fuel supply – in the same way that household battery technology operates.

Even better, it represents a doubling-down on green technology in the growing number of cases whether the electricity that powers the air-conditioner is generated via rooftop solar.

As proof of concept, the researchers present modelling for the system based on three examples: the massive Fair Tower in the city of Frankfurt, a supermarket, and a set of low-energy houses.

In each case, they report, the analysis “impressively demonstrates that air conditioning systems in place if equipped with the appropriate technology could indeed capture a very significant amount of carbon dioxide”.

“The environmental, economic and social consequences of such a distributed renewable oil well technology should contribute to the practical realisation of chemical fuels from carbon dioxide as feedstock in a circular sustainable economy of the future,” the authors conclude.

  1. https://www.nature.com/articles/s41467-019-09685-x
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