Water & Energy Production
o’deep desalination, through its process, combines two technologies namely desalination through MED (Multi-Effect-Distillation) or MED-TVC (Multi-Effect-Distillation – Thermal Vapour Compression) and the use of geothermal energy, a RenE (Renewable Energy), as the operating energy vector. Furthermore, with the possibility of cogeneration (production of electricity which is by using the process of o’deep desalination for free), we can considerably increase the production capacity of water while reducing the production costs through the use of SWRO desalination systems (Sea Water Reverse Osmosis).
For its applications o’deep desalination uses a heat exchanger whose model and process were designed and patented by the managers of the engineering company O’DEEP Innovactiv’ Development.
The process used is a system in which thermal energy is transferred using the difference of temperature between two environments, a fluid, seawater, and thermal flow from a solid body, a rock. This thermal transfer is done by convection between the seawater going through the heat exchanger and the geothermal flow of the host rock in situ.
Simplified model of heat exchanger
The local thermal regime is controlled by the surface temperature and the deep crustal heat flow. The thermal properties of the rock and water, just as the speed of the fluid, characterize the heat transfer process between the rock and the circulating water. In the diagram above, “L” stands for the length of the heat exchanger whose dimensions vary as a function of the data and in situ parameters of the thermal exchange between the seawater and the host rock.
The different possible desalination systems share the common trait of functioning of being generally highly intensive in non-renewable fossil energy, thus making the alternative solution proposed by o’deep desalination much more interesting, which, based on geothermal energy, reduces by a significant manner the production costs.
The access to the resource is done in two different ways, depending on the temperature of gradient in situ:
- for high enthalpy by installation of the heat exchanger type o’deep desalination – TBM (Tunnel Boring Machine) (see first schema below)
- and for medium and low (under certain conditions) enthalpy by drilling (rotary drilling) (see second schema below).
In the second case, combined with MED or MED-TVC technologies for desalination (see third schema below), the desalination process has been successfully demonstrated by a pilot research project in Greece. Today, in particular concerning high enthalpy, we can increase the production tenfold at large scale, which is going from 100 000 m3 to 1 000 000 m3/day or more, while generating by cogeneration energy of hundreds of MW, according to the production capacity of the plant.
On these facts, o’deep desalination with high enthalpy opens more important perspectives of applications. As the capital expenditure (Capex) and operational expenditure (Opex) of each plant differs depending on the chosen criteria, consequently the cost prices of one m3 of water or one kW/h of electricity will depend on them. Especially in the case of mega-plants, they will be always lower than the production costs of the most modern nuclear or other facilities.
o'deep solution high enthalpy
o'deep solution middle / low enthalpy
desalination system MED-TVC