Freeze-thaw refers to the process of water freezing and thawing, often causing physical changes or damage

 Sponser by:

 "This Content Sponsored by Buymote Shopping app

BuyMote E-Shopping Application is One of the Online Shopping App

Now Available on Play Store & App Store (Buymote E-Shopping)

Click Below Link and Install Application: https://buymote.shop/links/0f5993744a9213079a6b53e8

Sponsor Content: #buymote #buymoteeshopping #buymoteonline #buymoteshopping #buymoteapplication"

Freeze-thaw

Freeze-thaw desalination (or freezing desalination) uses freezing to remove fresh water from salt water. Salt water is sprayed during freezing conditions into a pad where an ice-pile builds up. When seasonal conditions warm, naturally desalinated melt water is recovered. This technique relies on extended periods of natural sub-freezing conditions

A different freeze thaw method, not weather dependent and invented by Alexander Zarchin, freezes seawater in a vacuum. Under vacuum conditions the ice, desalinated, is melted and diverted for collection and the salt is collected.

Electrodialysis

Electrodialysis uses electric potential to move the salts through pairs of charged membranes, w trap salt in alternating channels. Several variances of electrodialysis exist such as conventio electrodialysis, electrodialysis reversal

Electrodialysis can simultaneously remove salt and carbonic acid from seawater, Preliminary estimates suggest that the cost of such carbon removal can be paid for in large part if not entirely from the sale of the desalinated water produced as a byproduct,

Microbial desalination

Microbial desalination cells are biological electrochemical systems that implements the use of electro-active bacteria to power desalination of water in situ, resourcing the natural anode and cathode gradient of the electro-active bacteria and thus creating an internal supercapacitor.

Wave-powered desalination

Wave powered desalination systems generally convert mechanical wave motion directly to hydraulic power for reverse osmosis. Such systems aim to maximize efficiency and reduce costs by avoiding conversion to electricity, minimizing excess pressurization above the osmotic pressure, and innovating on hydraulic and wave power components. One such approach is desalinating using submerged buoys, a wave power approach done by CETO and Oneka Wave-powered desalination plants began operating by CETO on Garden Island in Western Australia in 2013 and in Perth in 2015, and Oneka has installations in Chile, Florida, Califomia, and the Caribbean.

Wind-powered desalination

Wind energy can also be coupled to desalination. Similar to wave power, a direct conversion of mechanical energy to hydraulic power can reduce components and losses in powering reverse osmosis. Wind power has also been considered for coupling with thermal desalination technologies.

Desalination by thermophoresis

In April 2024, researchers from the Australian National University published experimental results of a novel technique for desalination. This technique, thermodiffusive desalination, passes saline water through a channel that is exposed to a temperature gradient. Due to thermophoresis, species migrate under this temperature gradient, orthogonal to the fluid flow. Researchers then separate the water into fractions. After multiple passes through the channel, the researchers were able to achieve a NaCl concentration drop of 25000 ppm with a recovery rate of 10% of the original water volume

Design aspects

Energy consumption

The desalination process's energy consumption depends on the water's salinity. Brackish water desalination requires less energy than seawater desalination.

The energy intensity of seawater desalination has improved: It is now about 3 kWh/m² (in 2018), down by a factor of 10 from 20-30 kWh/m² in 1970. This is similar to the energy consumption of other freshwater supplies transported over large distances, but much higher than local fresh water supplies that use 0.2 kWh/m² or less

A minimum energy consumption for seawater desalination of around 1 kWh/m² has been determined, excluding prefiltering and intake/outfall pumping. Under 2 kWh/m² has been achieved with reverse osmosis membrane technology, leaving limited scope for further energy reductions as the reverse osmosis energy consumption in the 1970s was 16 kWh/m²

Supplying all US domestic water by desalination would increase domestic energy consumption by around 10%, about the amount of energy used by domestic refrigerators Domestic consumption is a relatively small fraction of the total water usage.

Energy consumption of seawater desalination methods (kWh/m²)

Desalination Method

Multi-stage

4-6

Multi-Effect

"MED

Mechanical Vaper Compression MVC

7-12

none

7-12

3-5.5

Energy

1.5-2.5

Electrical energy

50-110

60-110

Thennal energy

0.5-19.5

5-8.5

Electrical equivalent of thermal energy

13.5-255

6.5-11

Total equivalent electrical energy

Note: "Electrical equivalent refers to the amount of electrical energy that could be generated using a given quantity of thermal energy and an appropriate turbine generator. These calculations do not include the energy required to coriatruct or refurbish items consumed

Given the energy intensive nature of desalination and the associated economic and environmental costs, desalination is generally considered a last resort after water conservation, But this is changing as prices continue to fall.

Cogeneration

Cogeneration is generating useful heat energy and electricity from a single process. Cogeneration can provide usable heat for desalination in an integrated, or "dual-purpose", facility where a power plant provides the energy for desalination. Alternatively, the facility's energy production may be dedicated to the production of potable water (a stand-alone facility), or excess energy may be produced and incorporated into the energy grid. Cogeneration takes various forms, and theoretically any form of energy production could be used. However, the majority of current and planned cogeneration desalination plants use either fossil fuels or nuclear power as their source of energy Most plants are located in the Middle East or North Africa, which use their petroleum resources to offset limited water resources. The advantage of dual-purpose facilities is they can be more efficient in energy consumption, thus making desalination more viable.

The current trend in dual-purpose facilities is hybrid configurations, in which the permeate from reverse osmosis desalination is mixed with distillate from thermal desalination. Basically, two or more desalination processes are combined along with power production. Such facilities have been implemented in Saudi Arabia at Jeddah and Yanbu bar

A typical supercarrier in the US military is capable of using nuclear power to desalinate 1,500,000 L (330,000 imp gal; 400,000 US gal) of water per day 11021