Using a dishwasher may beat donning a pair of marigolds and scrubbing your plates by hand — but they also have their drawbacks. They often do not kill all of the harmful microorganisms that can lurk on unwashed tableware, employ long cycles that use large quantities of electricity and release soap down the drain that can end up polluting the environment. A more efficient, environmentally friendly and faster solution may lie in dishwasher designs that use superheated steam to clean and kill bacteria.
A model of a prototype steam dishwasher was created by fluid mechanics expert Professor Natalie Germann of the Technical University of Dortmund and her colleagues.
The inside of the dishwasher sports a steam nozzle, above which a plate can be placed.
In simulations, the team found that, when the device was activated, the steam inactivated 99 percent of heat-resistant bacteria deposited on the plate in just 25 seconds.
Prof. Germann said: “Steam comes out of the nozzle at a very high velocity.
“We can see shocks, and the turbulent flow that is created has eddies and vortices.
“We also include heat transfer, which shows how the heat changes in the simulation box and the condensation on the solid surfaces.”
The shock waves created by the high velocity steam are reflected around by surfaces inside the dishwasher.
While the present study focussed on the steam’s ability to kill bacteria, the team said that the shockwaves have the potential to effectively dislodge food debris from plates and glassware.
Paper author Dr Laila Abu-Farah of the Technical University of Munich said: “Our study helps determine the strength of the shocks, the position of the shocks, and the vortices that are created inside the dishwasher.
“These things are very important for arranging the items or objects inside the dishwasher and the placement and orientation of the nozzles.”
READ MORE: Energy bills horror: Britons to pay £5 to cook Sunday roast as pric…
At present, the researchers have only modelled a simple steam dishwasher that cleans a single plate — whereas a commercial version would need to clean multiple items at once.
However, while this would take longer than just 25 seconds, the team have said that the concept should be much faster and more efficient than conventional, water-based machines.
The initial costs of a steam dishwasher would also be higher than their regular counterparts, but would pay off in the long run thanks to needing less water and electricity to run — not to mention eliminating the need to buy detergent.
The concept, the researchers said, would be ideal for use in hotels, hospitals and restaurants, where high standards of hygiene must be met.
Elon Musk in end of the world warning: ‘Just a matter of time’ [REPORT]
Royal Navy pulls rug from under Putin in Black Sea with undersea drone [INSIGHT]
EU sent horror warning as 10 ‘terrible’ winters loom [ANALYSIS]
Prof. Germann said: “We confirmed that the dishwasher application using superheated steam is promising.
“This is the first work combining fluid dynamics and heat transfer with phase change and bacterial inactivation.
“It thus lays the foundation for future computational research and further technical work.”
The full findings of the study were published in the journal Physics of Fluids.