Power/Performance Bits: Nov. 11

Storing solar energy
Engineers at Stanford have designed a catalyst that could help produce vast quantities of pure hydrogen through electrolysis – the process of passing electricity through water to break hydrogen loose from oxygen in H2O.

Pure hydrogen (H2) is a major commodity chemical that is generally derived from natural gas. Tens of millions of tons of hydrogen are produced each year. Industrial hydrogen is used in petroleum refining and fertilizer production. The researchers want to use electrolysis to do things such as producing H2 from water and using the process to store solar energy. But to industrialize water-splitting they must find a more cost-effective process.

Electrolysis in classroom experiments is simple but to make electrolysis an industrial process a cheaper electrode must be found. As such, the researchers are trying to make H2 in the most efficient way possible without using precious metals — platinum is currently used.

The researchers have developed a cheap, durable and efficient catalyst that could take the place of platinum and could ultimately be used to store solar energy. They believe electrolysis could turn tanks of water into batteries for storing solar energy. During the day, electricity from solar cells could be used to break apart water into hydrogen and oxygen. Recombining these gases would generate electricity for use at night.

Graphic shows how electrolysis could produce hydrogen as a way to store renewable energy. During the day, solar panels supply surplus electricity for electrolysis, producing hydrogen. At night, hydrogen would be combined with oxygen from the air to generate electricity. (Source: Stanford University)

The team is now working to improve the catalyst they developed, and are engineering the material at nano-scale dimensions to catalyze the reaction more effectively. Other research initiatives include incorporating this catalyst into bench-top prototypes of future energy storage systems. The idea would be to use water electrolysis to store solar energy by day in the form of H2 and then, at night, to recombine hydrogen and oxygen into water, generating electricity in the process.

Diagnostic exhalations
Researchers from MIT’s Research Laboratory of Electronics, working with physicians from Harvard Medical School and the Einstein Medical Center in Philadelphia, believe that repurposing a piece of medical equipment standard in all ambulances in the United States and Europe could help paramedics make field diagnosis of shortness of breath easier.

The team has developed a new algorithm that can determine with high accuracy whether a patient is suffering from emphysema or heart failure based on readings from a capnograph — a machine used in every emergency department and operating room that measures the concentration of carbon dioxide in a patient’s exhalations.

Physicians knew that the capnograms of patients with congestive heart failure and emphysema were subtly but consistently different both from each other and from those of healthy subjects, and one of them believed the capnographic signal could be a source of diagnostically useful information, particularly for paramedics. A blood test performed in a hospital lab can accurately distinguish emphysema and heart failure, but it takes about an hour from the time a sample is received.

The system uses the capnograph and a minimally invasive sensor to collect the data, that the algorithm then analyzes.