With the rapidly decreasing cost of renewable electricity and potentially GHG-free hydrogen, the industrial sector could conceivably be decarbonized by using either resistive heaters or hydrogen combustors, according to the analysis. Significant science and engineering challenges, however, still remain. For intermittent renewable electricity, either cheap high-temperature storage or low capacity factor furnaces need to be developed.

A third grand challenge is on the opposite side of the thermal spectrum from heat: refrigeration. The goal is to invent refrigerants for both food and air conditioning without today’s leakage of hydrofluorocarbons, a set of extremely powerful greenhouse gases. Successful new refrigerants must be non-flammable, non-toxic and affordable, as well as preferably drop-in solutions to today’s systems, said Majumdar.

“With the rise of refrigeration and cooling in emerging economies, this is a major challenge,” Henry said.

In many developing economies the growing demand for air conditioning is about reducing humidity as much as temperature, so new refrigerants will have to accomplish this as well, said Prasher. Alternatively, new technologies could be developed to decouple dehumidification from cooling.

Buildings and heat transport

Space and water heating in both residential and commercial buildings are responsible for more than 6 percent of U.S. GHG emissions. New building materials that can both conduct heat and block it – on demand – are needed to reduce energy for heating and cooling. The ability to control thermal conductance in a building’s shell could save 10 percent to 40 percent of GHG emissions, so this represents another worthy challenge to tackle, the researchers say.

Lastly, a particularly large challenge is to develop the ability to transmit heat over long distances with little loss of energy. This is achieved with steam today, but that is not at the scale or distance needed. The goal here is to develop the heat equivalent of an electrical power line – an effective method for transporting large megawatt-scale heat using minimal equipment and materials. The discovery of a thermal superconductor could enable this, but the practicality of deploying one on a large scale is not clear. Another potential research avenue, according to the researchers, is to discover new pumpable fluids with reversible chemical reactions to transmit energy in chemical, rather than thermal, form.

“Deep decarbonization without breakthroughs in thermal science and engineering seems inconceivable, but attention from researchers and funders hasn’t reflected that,” said Majumdar. “We hope this analysis will be a call to action for the broader R&D community.”

Arun Majumdar is also a professor of photon science at SLAC National Accelerator Laboratory.

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