The Ultimate Guide:Solar Desalination Unit

Solar-powered desalination continues to gather momentum, especially in off-grid locations. Present-day solar-powered desalination unit primarily relies on solar energy absorbed directly or indirectly from sunlight. This makes solar-powered desalination quite cheaper and more environmentally sound in comparison to conventional desalination.

However, to get the absolute best from your solar desalination machine, you must follow, to the letter, the user instructions provided by the manufacturer. Beneath, our esteemed experts will walk you through the varying practices that will help you to optimally capitalize on your solar-powered desalination unit.

Solar Energy for brackish water treatment

1. Can Desalination be Powered by Solar?

The answer is yes. Globally, the current share of renewable energy for desalination is about 1 percent, including solar energy. Renewable energy options for water desalination: Fresh-Water-Desalination
In theory, desalination can be powered by wind, wave, geothermal or solar energy. Each method has advantages and disadvantages, as described below.

Fresh-Water-Advantages

2. What is Solar Desalination and How Does Solar-Powered Desalination Unit Work?

There are two common types of solar desalination: concentrated solar power (CSP) and photovoltaic (PV):

-CSP generates direct thermal energy, often used to evaporate water during thermal desalination processes.
-PV uses solar panels to generate electricity to power reverse osmosis pumps.

The entire desalination process does not require electricity, and drinking water can be obtained anytime and anywhere. It can be an alternative to traditional electricity-powered desalination system.

Figure 4. Thermal Solar Desalination

2.1 How it works.

Presently, the most commonly utilized solar desalination systems employ two varying desalination technologies; reverse osmosis and thermal distillation.

-Reverse osmosis.

Reverse osmosis is a distinguished and power-driven desalination process that alienates dissolved salts from water using partially permeable membranes. Portable solar-powered reverse osmosis systems primarily utilize solar energy indirectly. They consist of solar collectors, photovoltaics, and high-power batteries, which absorb solar power from the sun and convert it into electrical power.

-Thermal distillation.

Thermal distillation is commonly referred to as thermal desalination and it greatly resembles the organic hydrological cycle. This process simply involves evaporation and condensation. The salty water is essentially heated using a solar-powered heating source until evaporation occurs.

Freshwater turns into vapor leaving behind a residue of dissolved salts referred to as brine. The vapor is then funneled into the condenser, where it is chilled, consequently turning into liquid water, devoid of objectionable impurities.

2.2 Its primary components.

To utilize your solar water cleaning system optimally, you must comprehensively understand its chief components and the distinct roles played by each. Generally, there are two types of solar desalination unit; direct solar desalinators and indirect solar desalinators. Here is a brief breakdown of the main components of a solar-powered RO desalination unit.

-Standalone solar unit.

Solar-powered RO water makers utilize solar energy indirectly. As such, they consist of a standalone solar unit connected to the RO device. The solar unit consists of a solar collector that absorbs sun rays, photovoltaics that turn the solar energy into electrical energy, and high-capacity batteries, which reserve the generated power.

-Pretreatment filters.

Typically, most solar RO systems have an integrated pretreatment unit consisting of sediment filters and carbon filters. These filters are mainly tasked with eradicating harmful and aggressive pollutants capable of damaging the semi-permeable RO membranes. Common pretreatment systems fitted onto solar desalination systems include;

-High-pressure pump.

High-pressure pumps are mandatory in reverse osmosis desalination. The high-pressure pumps used in solar RO systems are powered by solar energy and they elevate the pressure levels on the feed water. This reverses the natural osmotic pressure, consequently forcing water to flow from the highly concentrated region (salty water side) to the lowly concentrated region (freshwater side).

-Reverse osmosis membrane filters.

The reverse osmosis membrane filter is the primary filtration medium in solar RO desalinators. It is a partially porous membrane that selectively grants passage to water molecules while blocking the passage of objectionable constituents. Typical RO membranes have an average pore size of 0.0001 microns. Other essential components include:

  • Membrane cleaning systems.
  • Post-treatment filters.
  • Storage tanks.

3. How Effective is Solar Desalination?

Compared with traditional power and heat sources, solar energy desalination unit can operate independently of steam, electricity, and other conditions. Solar energy has the advantages of safety, environmental protection, etc. The combination of two systems, solar energy collection and desalination process, is a sustainable desalination technology.

Solar energy is both a primary energy source and a renewable energy source. It is rich in resources, which can be used free of charge and does not need to be transported, without any pollution to the environment. No need to consume oil, natural gas, coal, and other conventional energy. Low energy consumption, very friendly to areas with energy shortage and high environmental requirements.

In addition, the investment cost is relatively low and therefore the cost of water production is low, making it suitable for sunny arid areas where water desalination is required.

Figure 14 Large solar RO system.

4. Why Should I Have a Solar Desalination Unit?

If your primary source of water is ocean water, well water, or salty lake water, and you live in an off-grid region, then you probably need a customized solar desalination system. Consuming water with excessive amounts of dissolved salts can cause acute health problems hence the World Health Organization (WHO) recommends that quality drinking water should have a maximum salinity of 600 mg/L.

Additionally, salty water corrodes metallic surfaces, kills plants, and scales electrical appliances. Having a top-notch solar desalination system guarantees an unlimited supply of desalinated fresh water, which is ideal for human consumption among other potable water applications. Here are a few reasons depicting the significance of solar desalination machine.

Unlimited access to fresh water.

Fresh water is a day-to-day necessity in virtually all homes, businesses, and industries. Solar desalination machines effectively convert salty water into potable water by shrinking salinity levels to below 1000 ppm. They utilize solar energy to drive the desalination process, either using semi-permeable membranes or evaporators. Effective solar-powered desalinators also eradicate other objectionable impurities including toxins, organic chemicals, suspended solids, and microbes among others.

Environmentally-sound.

Unlike conventional saltwater desalination units which rely on fossil fuels, solar-powered desalination machines are non-polluting and environmentally friendly. They utilize solar energy drawn from the sun, which is safe and does not contribute to global warming. By using a solar-powered desalinator, you are essentially helping the world mitigate adverse climatic changes.

Cost-efficiency.

If your residence’s water supply exhibits high salinity levels, you might be forced to buy bottled drinking water, which can be pretty expensive. However, with a high-level solar-powered water filter, you can easily and economically generate high-quality potable water. The Business Insider estimates that a gallon of bottled water costs approximately $1.22 and this is way more expensive than a gallon of filtered water, whose price ranges from $ 0.10-$0.20.

Solar Powered Reverse Osmosis Water Purifier

• Prevents premature damage to appliances, metallic surfaces, and plumbing fixtures.

Highly saline water consists of dissociated ions that catalyze the corrosion process. As a matter of fact, saline water eats up metallic surfaces 5 times more than potable water. It also destroys household appliances and plumbing fixtures by initiating rusting and scaling.

Installing a fully functional solar water cleaning system guarantees an unconstrained supply of fresh water, which is friendly to electrical appliances, plumbing fixtures, and metals. This prevents the pre-mature breakdown of valuable fixtures and ultimately extends their respective lifespans.

5. How to Maintenance Your Solar Desalination Machine?

Solar-powered desalination units are like typical machinery; they necessitate periodic maintenance to function smoothly, optimally, and perennially. Each unit comes with a detailed and easily comprehendible user manual, which elaborates all the necessary maintenance practices.

Ideally, there are two approaches synonymous with water treatment systems maintenance;

  • Proactive approach.
  • Reactive approach.

Proactive approach.

A proactive approach simply calls upon one to undertake the necessary maintenance practices before system glitches are realized. Our technicians recommend this type of approach as it;

  • Mitigates serious malfunctions, which can be expensive and laborious to repair.
  • Saves time.
  • Guarantees a consistent supply of high-grade potable water.

Reactive approach.

Maintenance undertaken reactively is initiated once system glitches are detected and there is a tangible effect on the quality of the output. For instance, once a dip in desalinated water quality is detected. This approach can be costly and it is highly discouraged by experts.

Mobile Solar-Powered Distillation System Workflow

6. Key Maintenance Practices For Your Solar Desalination Unit.

Installing a befitting pre-treatment system.

Having an effective, feasible, and comprehensive pre-treatment unit is a proactive way of looking after your solar desalination unit. Pretreatment filters typically eliminate aggressive pollutants such as sand and debris, which can clog membrane pores and ultimately tear down the RO membrane filters.

Backwashing the membranes and filters.

Over time, pollutants accumulate on the surfaces of your RO membrane and pre-treatment filters. This can lead to clogged filters and membrane pores, which consequently leads to lower desalination rates and lower service flow rates. Thoroughly cleaning the membranes chucks out the seized pollutants thereby maintaining the optimal functioning of your solar-powered water filter.

Replacing worn-out membranes and filters on time.

Even the most premium membranes and filters are prone to burnout. High-quality RO membranes have a projected lifespan of 3-7 years depending on the quality of the inlet water.  Replacing the membranes once burnout is detected ensures that your solar desalination unit retains its optimum performance levels. You can easily access first-grade parts and components at a pocket-friendly rate by visiting NEWater.com.

7. Tips and Tricks for Maintaining Solar Desalination Kit.

  1. Ardently follow the maintenance practices outlined by your manufacturer in the user guidebook.
  2. Do not clean or undertake periodic maintenance routines while your solar desalination system is powered on.
  3. If you are not well acquainted with the technicalities of the equipment, do not attempt to service or open the equipment. Warranty privileges can be lost if the unit is opened by unauthorized parties.
  4. Sanitize the solar desalination machine to eliminate microbial pollutants.
  5. Keep a close eye on pressure fluctuations, service flow rates, potable water quality, color, and odor.

8. Conclusion.

NEWater has specialized in the fields of marine desalination, household desalination, and solar desalination for 20 years. Our products can be found in various industries and fields. We provide you with boat water makers, desalination systems for home, portable solar desalination units, desalination skids, portable solar desalination equipment, etc.

For details, further information, or professional advice please contact our desalination experts. info@newater.com.
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