A solar powered
steam engine capable of transforming salt water into fresh drinking water has
been created by students at Aston University.
Saline groundwater occurs across vast areas in India,
Australia, United States, Middle East and other regions and desalination is
essential to provide freshwater in arid places remote from seawater, lakes and
rivers.Current methods of
desalination however, can use substantial energy and can discharge significant
amounts of concentrated saline water which pollutes surrounding areas.
Opubo Igobo and Clara Qiu have developed ‘DesaLink’, a new prototype which uses
sunlight and steam pressure for the desalination of groundwater. The
Engineering students have demonstrated that it can provide freshwater from
brackish wells, while operating entirely from solar energy while producing only
a minimal waste stream of concentrated brine.
Opubo Igobo said:
“As a shortage of freshwater tends to coincide with abundance of sunlight we
wanted to make use of existing solar energy to drive the desalination process. We
believe the ideal groundwater desalination system should operate using a
sustainable energy source and be capable of providing a high recovery of
freshwater from saline feedwater.”
system is cheap to run and highly effective and works by linking the solar
Rankine cycle to reverse osmosis (RO). Unlike conventional desalination
systems, which use electric motors to drive the desalination process, DesaLink
uses the pressure of steam evaporated in solar collectors. The linkage system
between the steam piston and the high-pressure pump, which is designed for
maximum efficiency, is the novelty of the design. DesaLink also uses a batch
rather than continuous process seen in many other desalination systems.
The prototype unit
has been designed entirely at Aston University and built in partnership with DuRose
Ltd, a company in the West Midlands. It is planned for the pilot scale system
to be tested in the Punjab region of India.