A rhythmic pumping method inspired by the human heart could slash the energy used to move fluids through domestic and industrial pipes.
Forcing fluids through such systems – be it moving oil and gas from drilling rigs to refineries or circulating water in our home heating systems – is estimated to use between 10 and 15 per cent of the world’s electricity supply.
Turbulence inside pipes causes friction, which vastly inflates the energy needed to pump liquids. Previous attempts to reduce turbulence have included complex coatings on the inside of pipes, which would be costly to roll out on a wide scale.
Björn Hof at the Institute of Science and Technology Austria says copying the human heart is a natural starting point to address this problem because it has the benefit of millions of years of evolution. He and his colleagues discovered that pumping liquids through a pipe in pulses – much like the human heart moves blood – can reduce the friction in the pipe and therefore also the energy consumed.
To find out more, the researchers laced water with reflective particles and pumped it through transparent pipes while shining a laser into them, allowing them to visualise the swirls and eddies in the liquid.
They tried numerous rhythmic pulsing patterns, most of which actually increased the energy required to pump the water. But when they introduced a short resting phase between pulses – like that between heartbeats – they found that turbulence in the water diminished. The best experiments yielded a 25 per cent decrease in friction and a 9 per cent overall reduction in energy demand.
To capitalise on this in the real world, pumps would have to be modified to pulsate, which would have a cost, but would be much cheaper than upgrading the lining of often lengthy and awkwardly placed pipes, says Hof. However, as a scientist he says the practical applications are best left to engineers.
“What I don’t know at all is how happy my central heating pump would be if it was permanently switched on and off, so to speak. Then it may not last winter – I have no idea,” says Hof.