Multi-stage parallel desalination system with integrated thermal management for waste heat recovery and method thereof

Abstract

ABSTRACT: Title: Multi-stage Parallel Desalination System with Integrated Thermal Management for Waste Heat Recovery and Method Thereof The present disclosure proposes a multi-stage parallel desalination system (100) with phase-change material-based thermal management that continuously produces fresh water by evaporating saline water using thermal gases. The multi-stage parallel desalination system (100) comprises a heater transfer unit (102), a coolant unit (108), and a desalination assembly (112) that is coupled to the heater transfer unit 102 via an intermediate evaporator surface (110). The multi-stage parallel desalination system (100) utilises varying thermal energy from steam and flue gases, commonly available in thermal power plants, mining, and allied industries, thereby reducing thermal pollution and provides an ecological benefit by repurposing energy. The multi-stage parallel desalination system (100) operates on thermal energy from waste heat recovery systems, significantly lowering input energy costs and improving overall energy efficiency.

Description

Field of the invention:

[0001] The present disclosure generally relates to the technical field of a desalinationtechnology, and in specific relates to a multi-stage parallel desalination system with phasechange material-based thermal management that continuously produces fresh water byevaporating saline water using thermal gases.Background of the invention:

[0002] One of the greatest threats affecting the developing world is a lack of fresh water. Inmany dry regions of the world, there is a severe problem with the lack of potable water.Water covers 71% of the earth's surface, of which 97% is salt water in the oceans. Humanscan acquire fresh water from only 0.5% of the available water. Reverse osmosis (RO), multistage flash (MSF), and other commercially available desalination methods are not costeffective in developing countries. Due to India's close proximity to a tropical area withabundant solar potential, water scarcity can be effectively alleviated by solar-powereddesalination techniques.

[0003] Generally, as a technology for distilling sea water, solar evaporation, whichevaporates water from bulk water source and membrane filtration are commonly used. Thetechnology for distilling sea water mainly uses a large-capacity plant of 10,000 tons or morea day, which mainly rely on fossil fuels as main energy source and consumes huge amount ofenergy. To solve the problem of depletion of fossil fuel and environmental pollution, seawater distillation technologies also takes into great consideration the use of renewableenergies such as solar thermal energy.

[0004] Meanwhile, there are many islands and remote areas and developing countries thatuse a technology for distilling sea water using renewable energy sources such as solarthermal energy is urgently required. Solar-thermal water evaporation is a process in whichliquid water changes from the liquid phase to the gas phase under the excitation of solarphotons, and the high temperature generated accelerates the evaporation of water severaltimes. In the natural environment, liquid water evaporates automatically because the wateralways has a partial pressure in air that is lower than the saturation vapour pressure.

[0005] Besides requiring a lot of energy, large-scale desalination is expensive, complex, andcomes with salty by-products that are hard to dispose of. Further, solar energy as input isunreliable and intermittent. Solar energy availability is highly dependent on weatherconditions and geographic location. Cloudy days, seasonal variations, and nighttime periodslimit the continuous availability of solar energy. The intermittent nature of solar energynecessitates the integration of energy storage systems or supplemental energy sources toensure a consistent and reliable water purification process.

[0006] Seawater desalination is an important way to augment freshwater supply, anddiverse techniques, including reverse osmosis and multistage flash, have been developed todesalinate seawater into fresh water. However, most of the technologies in use requireconsiderable energy input and large-footprint investments in installation and operation.

[0007] By addressing all the above-mentioned problems, there is a need for a highefficiency desalination system that produces fresh water by evaporating saline water usingthermal gases. There is a need for a multi-stage parallel desalination system with phasechange material-based thermal management for a waste heat recovery of industrial plants.There is a need for a multi-stage parallel desalination system that arrests thermal pollutionassociated with industrial plants for producing fresh water continuously. There is a need fora high-efficiency desalination system that operates on a wide variety of different PCMavailable in the market.Objectives of the invention:

[0008] The primary objective of the invention is to provide a multi-stage paralleldesalination system with phase-change material-based thermal management thatcontinuously produces fresh water by evaporating saline water using thermal gases.

[0009] Another objective of the invention is to provide a system that utilises waste heatfrom steam and flue gases, commonly available in thermal power plants, mining, and alliedindustries, thereby reducing thermal pollution and provides an ecological benefit byrepurposing energy.

[0010] The other objective of the invention is to provide a system that operates on thermalenergy from waste heat recovery systems, significantly lowering input energy costs andimproving overall energy efficiency.

[0011] Another objective of the invention is to provide a system that adjusts to varyingenergy content of incoming steam or flue gases, by varying quantity of PCM in proportion tothe energy content of the feed, ensuring optimal temperature regulation.

[0012] Another objective of the invention is to provide a system that integrates interfacialevaporation and vapor enthalpy recycling to achieve high productivity rates for desalinatedwater.

[0013] The other objective of the invention is to provide a system that moderates andregulates the temperature across the evaporator surface, preventing spot drying andoverheating of wicking structures.

[0014] The other objective of the invention is to provide a system that utilisesheterogeneous wettability surfaces on condenser surfaces to improve condensation rates,thereby increasing overall productivity

[0015] Yet another objective of the invention is to provide a system that utilises multiplethermally localized multistage stills (TLMS) units that run in parallel for enhancingproductivity and offering scalability. This parallel operation is thermodynamicallyadvantageous, providing input energy at higher temperatures.

[0016] Another objective of the invention is to provide a system that capture the enthalpyof vaporization during condensation and uses it to drive subsequent evaporation, enhancingenergy efficiency.

[0017] Another objective of the invention is to provide a system with adaptability todifferent energy content feeds eliminates the need for multiple devices, each optimized forspecific energy levels, simplifying the overall design and operation.Summary of the invention:

[0018] The present disclosure proposes a multi-stage parallel desalination system withintegrated thermal management for waste heat recovery and method thereof. Thefollowing presents a simplified summary in order to provide a basic understanding of someaspects of the claimed subject matter. This summary is not an extensive overview. It is notintended to identify key / critical elements or to delineate the scope of the claimed subjectmatter. Its sole purpose is to present some concepts in a simplified form as a prelude to themore detailed description that is presented later.

[0019] In order to overcome the above deficiencies of the prior art, the present disclosure isto solve the technical problem to provide a multi-stage parallel desalination system withphase-change material-based thermal management that continuously produces fresh waterby evaporating saline water using thermal gases.

[0020] According to an aspect, the invention provides a multi-stage parallel desalinationsystem. The multi-stage parallel desalination system comprises a heater transfer unit, acoolant unit, and a desalination assembly that is coupled to the heater transfer unit via anintermediate evaporator surface.

[0021] The heater transfer unit is configured to move from a first position to a secondposition, and vice versa, in response to varying thermal energy received from thermal gases.The heater transfer unit comprises an enclosure, and piping systems (pipes carrying thermalgases and pipes carrying coolant water) that are passing through the enclosure. Theenclosure has a telescopic assembly, configured to store a phase change material (PCM).The PCM enclosure is adapted to expand and contract in response to the varying thermalenergy from the thermal gases, thereby facilitating a reciprocating movement for the heatertransfer unit. The expansion and contraction of the PCM enclosure allows it to hold more orless quantity (mass) of the PCM. Thermal gases with higher energy input flux requires morequantity of PCM for thermal management and vice versa.

[0022] The piping systems comprise plurality of heating pipes. The heating pipes areconfigured allow the thermal gases to flow within the enclosure for facilitating uniform andvolumetric heating of the PCM. The expansion of the enclosure adjusts volume and therebythe mass quantity of the PCM based on the varying thermal energy, allowing thedesalination system to function with variable heat input sources. The PCM is solid-solidphase change material (SSPCM).

[0023] The coolant unit is positioned within the enclosure. The coolant unit is configured toregulate and maintain temperature of the PCM and prevent sensible heating of the PCMsubsequent to its complete phase transition. This aids in managing the varying thermalenergy from the thermal gases by keeping the PCM at a constant temperature by arrestingthe complete phase transition.

[0024] The desalination assembly comprises plurality of thermally localized multistage stills(TLMS) units. The TLMS units are configured to receive the varying thermal energy at theconstant temperature from the heater transfer unit through the intermediate evaporatorsurface. The TLMS units are configured to convert saline water into desalinated water usingthe received the varying thermal energy. The TLMS units are arranged in a parallelconfiguration as a single integrated desalination assembly.

[0025] In one embodiment, the intermediate evaporator surface is attached to anintermediate wicking structure.

[0026] Each TLMS unit comprises plurality of evaporation-condensation units that isconfigured to convert the saline water into the desalinated water. Each evaporationcondensation unit is a plate having a condenser surface on one side of the plate, and anevaporator surface on the opposite side, with a wicking structure draped over theevaporator surface. The wicking structure is configured to be partially submerged in thesaline water stored in a saline water reservoir, thereby absorbing the saline water andenabling faster water transport. The wicking structure is configured to receive the varyingthermal energy at the constant temperature from the evaporator surface and theintermediate evaporator surface, thereby evaporating the saline water absorbed by thewicking structure.

[0027] The condenser surface is disposed adjacent to the evaporator surface. Thecondenser surface is configured to condense vapor received during the evaporation of thesaline water through the wicking structure via enthalpy recycling, thereby obtainingdesalinated water, which is collected through a distillate channel. Further, each TLMS unitcomprises an end condenser plate that is adapted to be dipped in the saline water reservoir.

[0028] In one embodiment, the wicking structure is made of polyvinyl alcohol (PVA) clothwith high hydrophilicity, which is used to enable faster water transport with high capillarityand osmotic swelling. The condenser surface is configured with heterogeneous wettabilityfor enhanced condensation. The evaporator surface cum condenser surfaces are made withaluminium.

[0029] According to another aspect, the invention provides a method for desalinating salinewater using varying thermal energy input flux. The method comprises, heating, the heatertransfer unit, a phase change material (PCM) within a heater transfer unit using thermalenergy from thermal gases.

[0030] The method comprises, regulating and maintaining, by the coolant unit, temperatureof the PCM at a constant temperature, thereby managing varying thermal energy keepingthe PCM at the constant temperature. The method comprises, transferring the varyingthermal energy at the constant temperature from the heater transfer unit to the TLMS unitsof the desalination assembly via the intermediate evaporator surface.

[0031] The method comprises, evaporating saline water on plurality of evaporator surfacesof each TLMS unit using the transferred varying thermal energy at the constanttemperature. The method comprises, condensing the evaporated water on plurality ofcondenser surfaces of each TLMS unit. The method comprises, collecting, by the distillatechannel, the condensed water as desalinated water.

[0032] Further, objects and advantages of the present invention will be apparent from astudy of the following portion of the specification, the claims, and the attached drawings.Detailed description of drawings:

[0033] The accompanying drawings, which are incorporated in and constitute a part of thespecification, illustrate an embodiment of the invention, and, together with the description,explain the principles of the invention.

[0034] FIG. 1A illustrates a sectional side view of a multi-stage parallel desalination systemwith at least one thermally localized multistage stills (TLMS) unit, in accordance to anexemplary embodiment of the invention.

[0035] FIG. 1B illustrates a schematic view of the multi-stage parallel desalination systemwith at least one TLMS unit, in accordance to an exemplary embodiment of the invention.

[0036] FIG. 1C illustrates a sectional plan of the multi-stage parallel desalination systemwith a desalination assembly, in accordance to an exemplary embodiment of the invention.

[0037] FIG. 2 illustrates a flowchart of a method for desalinating saline water using varyingthermal energy input flux, in accordance to an exemplary embodiment of the invention.Detailed invention disclosure:

[0038] Various embodiments of the present invention will be described in reference to theaccompanying drawings. Wherever possible, same or similar reference numerals are used inthe drawings and the description to refer to the same or like parts or steps.

[0039] The present disclosure has been made with a view towards solving the problem withthe prior art described above, and it is an object of the present invention to provide a multistage parallel desalination system with phase-change material-based thermal managementthat continuously produces fresh water by evaporating saline water using thermal gases.

[0040] According to an exemplary embodiment of the invention, FIG. 1A refers to asectional side view of a multi-stage parallel desalination system 100 with at least onethermally localized multistage still (TLMS) unit 114. FIG. 1B refers to a schematic view of themulti-stage parallel desalination system 100 with at least one TLMS unit 114. FIG. 1C refersto a sectional plan of the multi-stage parallel desalination system 100 with a desalinationassembly 112 having plurality of TLMS units 114 attached to an intermediate evaporatorsurface 110.

[0041] The multi-stage parallel desalination system 100 comprises a heater transfer unit 102having thermal gas piping systems 106 and a coolant unit 108. The multi-stage paralleldesalination system 100 further comprises the desalination assembly 112 that is coupled tothe heater transfer unit 102 via the intermediate evaporator surface 110.

[0042] The heater transfer unit 102 is configured to move from a first position to a secondposition, and vice versa, in response to the varying thermal energy received from thermalgases. In one embodiment, the thermal gases comprise, but not limited to, steam or fluegases. The heater transfer unit 102 comprises an enclosure 104, the piping systems 106, andthe coolant unit 108.

[0043] The enclosure 104 has a telescopic assembly, configured to store a phase changematerial (PCM). The quantity of PCM, within the enclosure 104, is adapted to increase ordecrease in response to the varying thermal energy from the thermal gases, facilitated bythe reciprocating movement for the heater transfer unit 102. In one embodiment, the PCMmanages the varying thermal energy of the thermal gases by absorbing heat from thethermal energy of the thermal gases.

[0044] The piping systems 106 comprise plurality of heating pipes that is passing throughthe enclosure 104. The heating pipes are configured to allow the thermal gases to flowwithin the enclosure 104 for facilitating uniform and volumetric heating of the enclosedPCM. The unidirectional expansion of the enclosure 104 via the telescopic assembly enablesthe increase or decrease in the mass (quantity) of the PCM in response to the input energyflux and ensure optimum temperature control and thermal management. Further thiscontrol of the volume of the PCM enclosure also facilitates the volumetric thermalexpansion of PCM due to heating.

[0045] The expansion of the enclosure 104 adjusts volume of the PCM based on the varyingthermal energy, allowing the multi-stage parallel desalination system 100 to function withvariable heat sources. The enclosure 104 allows for variation of the PCM quantity based onthe incoming waste heat energy content (varying thermal energy). The PCM is solid-solidphase change material (SSPCM).

[0046] In one embodiment, the telescopic assembly comprises an outermost tube thathouses one or more inner tubes. The inner tubes are configured to slide in and out toextend or retract the length of the telescopic assembly. The telescopic assembly furthercomprises a locking unit that is configured to secure the inner tubes at the desired length.The locking unit can be a twist-lock, clamp, or pin system.

[0047] The coolant unit 108 is positioned within the enclosure 104. The coolant unit 108 isconfigured to regulate and maintain temperature of the PCM, thereby controlling thevarying thermal energy from the thermal gases at a constant temperature. The coolant unit108 prevents the sensible heating of the PCM subsequent to complete phase transition.

[0048] In one embodiment, the piping systems 106 are internally piped to ensure uniformbulk heating of the PCM, effectively overcoming the inherent low thermal conductivity (K) ofthe PCM. This design ensures that heat is distributed evenly throughout the PCM, facilitatingefficient energy transfer and storage.

[0049] To address variations in the energy content of incoming thermal gases, the length ofthe enclosure 104 is adjusted using the telescopic assembly. This telescopic feature allowsfor the expansion of the enclosure containing PCM 104, accommodating higher energyinputs from the thermal gases. By increasing the amount of PCM in response to the energycontent of the input feed, the multi-stage parallel desalination system 100 maintainsoptimum temperature control. This adaptability is crucial for the multi-stage paralleldesalination system 100, as it ensures that the PCM can absorb and store varying amountsof thermal energy, thereby stabilizing the operating temperature and enhancing the overallefficiency of the desalination process.

[0050] The desalination assembly 112 comprises plurality of thermally localized multistagestills (TLMS) units 114. The TLMS units 114 are configured to receive the varying thermalenergy at the constant temperature from the heater transfer unit 102 through theintermediate evaporator surface 110. The TLMS units 114 are configured to convert salinewater into desalinated water using the received the varying thermal energy. The TLMS units114 are arranged in a parallel configuration as a single integrated desalination assembly 112.The intermediate evaporator surface 110 is attached to an intermediate wicking structure110A.

[0051] In one embodiment, the heater transfer unit 102 is a heater and thermalmanagement unit (HTMU). The HTMU is configured to keep the temperature across theintermediate evaporator surface 110 at an optimum level and prevent spot drying of theintermediate wicking structure 110A.

[0052] Each TLMS unit 114 comprises plurality of evaporation-condensation units 116 that isconfigured to convert the saline water into the desalinated water. In one embodiment, eachevaporation-condensation unit 116 is an evaporation-condensation plate 116 having acondenser surface 116A, an evaporator surface 116B, and a wicking structure 116C. Theevaporator surface 116B is attached to the wicking structure 116C. The wicking structure116C is configured to be partially submerged in the saline water stored in a saline waterreservoir 118, thereby absorbing the saline water and enabling faster water transport. Thewicking structure 116C is configured to receive the varying thermal energy at the constanttemperature from the evaporator surface 116B and the intermediate evaporator surface110, thereby evaporating the saline water absorbed by the wicking structure 116C.

[0053] The condenser surface 116A is disposed adjacent to the evaporator surface 116B.The condenser surface 116A is configured to condense vapor received during theevaporation of the saline water through the wicking structure 116C via enthalpy recycling,thereby obtaining desalinated water, which is collected through a distillate channel 120.Further, each TLMS unit 114 comprises an end condenser plate 122 that is adapted to bedipped in the saline water reservoir 118.

[0054] In one embodiment, the wicking structure 116C is made of polyvinyl alcohol (PVA)cloth with high hydrophilicity, which is used to enable faster water transport with highcapillarity and osmotic swelling. The condenser surface 116A is configured withheterogeneous wettability for enhanced condensation. The evaporator surface 116B andthe condenser surface 116A are made with aluminium. In one embodiment, evaporatorsurface 116B is covered with a PVA cloth-based intermediate wicking structure 116C.

[0055] In one embodiment, the Poly Vinyl Alcohol (PVA) hydrogel-based wicking structures(110A, 116C) exhibit exceptional water absorptivity and capillarity, which are essential forensuring high rates of water transport. These properties make the wicking structures (110A,116C) highly efficient, contributing significantly to the overall performance of the multistage parallel desalination system 100.

[0056] Productivity rates exceeding 5 kg / m² / hr are anticipated using the desalinationassembly 112, the efficient operation of the wicking structures (110A, 116C) in conjunctionwith the heater transfer unit 102. The heater transfer unit 102 operates in parallel, utilizingenergy from steam or flue gases, and is seamlessly integrated with the enclosure 104. Thissetup allows for effective heat transfer, maintaining optimal conditions for desalination.

[0057] The enclosure 104, which contains phase change material (PCM), plays a critical rolein accommodating variations in the energy content of the input steam or flue gases. ThePCM's ability to absorb, store and uniformly spread thermal energy ensures that the systemcan handle fluctuations in input energy, making the multi-stage parallel desalination system100 versatile and capable of working with a wide variety of energy feeds. This adaptability,combined with the high-efficiency wicking structures and parallel operation of the heatertransfer unit, ensures maximum freshwater production and optimal performance of thesystem under diverse conditions.

[0058] In one embodiment, the multi-stage parallel desalination system 100 is capable ofeffectively harnessing the variable energy content of steam or flue gases. The multi-stageparallel desalination system 100 integrates interfacial evaporation and vapor enthalpyrecycling for ensuring high productivity in thermal desalination. In interfacial evaporationthe heating is restricted to the liquid vapor interface (thermally localized). Vapor enthalpyrecycling occurs when the enthalpy of vaporization extracted during the condensationprocess drives the subsequent evaporation. Each TLMS unit 114 integrates interfacialevaporation with vapor enthalpy recycling.

[0059] Referring to FIG. 1C of the multi-stage parallel desalination system 100, plurality ofTLMS units 114 operate in parallel as a single desalination assembly 112. Each TLMS unit 114is connected to the enclosure 104, and the TLMS units 114 function simultaneously toenhance overall productivity. By operating in parallel, the multi-stage parallel desalinationsystem 100 significantly increases freshwater production and efficiency.

[0060] The freshwater productivity and efficiency of the multi-stage parallel desalinationsystem 100 are optimized through the capability to manage variable heat inputs. This isachieved by controlling the incoming flow rates of steam, allowing the multi-stage paralleldesalination system 100 to adapt to different energy inputs and maintain optimalperformance. The inclusion of the heater transfer unit 102 is crucial in preventing localizedoverheating and drying of the wicking structure (110A, 116C), ensuring that it operates atthe ideal temperature.

[0061] The TLMS units 114 are meticulously integrated to form a cohesive singledesalination assembly 112, with the primary goal of maximizing fresh water production. Thisintegrated design ensures that the multi-stage parallel desalination system 100 operatesefficiently, leveraging the parallel operation of multiple TLMS units 114 to achieve thehighest possible freshwater yield.

[0062] In one embodiment herein, the multi-stage parallel desalination system 100comprises at least three TLMS units 114, each connected to one side of the heater transferunit 102. The TLMS units 114 operate in parallel, significantly boosting the system's overallproductivity. The side of the heater transfer unit 102 facing the TLMS units 114 functions asthe intermediate evaporator surface 110. This surface is covered with a PVA cloth-basedintermediate wicking structure 110A. The PVA cloth, known for its high-water absorptivityand capillarity, ensures efficient water transport and evaporation.

[0063] By positioning the TLMS units 114 in parallel and integrating them with the heatertransfer unit 102, the multi-stage parallel desalination system 100 effectively utilizes thethermal energy from steam or flue gases. The intermediate evaporator surface 110, with itshigh-efficiency wicking structure, plays a critical role in the evaporation process, enhancingthe desalination rate and overall efficiency of the system. This configuration ensures thatthe multi-stage parallel desalination system 100 can achieve maximum freshwaterproduction while maintaining optimal performance.

[0064] The PVA cloth is hydrophilic with excellent capillarity, enabling it to transport waterfrom the saline water reservoir 118 to the evaporator surface at a sufficient rate. Thisproperty ensures continuous and efficient water supply to the evaporator surface foreffective desalination.

[0065] The enthalpy of vapor, which condenses over the condenser surface 116A, isharnessed and used to drive evaporation on the opposite side. Each condenser surface 116Ais equipped with a channel 126 to collect the water that condenses on its surface. Thesechannels 126 are fixed to each condenser surface 116A and direct the desalinated water tothe distillate channel 120, which carries the desalinated water away to a storage container124.

[0066] The end condenser plate 122, immersed in the saline reservoir 118, is positioned atthe end of each TLMS unit 114. The end condenser plate 122 is crucial for maintaining thetemperature gradient along the length of each TLMS unit 114, facilitating the recycling ofvapor enthalpy through repeated condensation and evaporation processes. This mechanismnot only enhances the efficiency of the desalination process but also ensures consistentfreshwater production.

[0067] The saline reservoir 118 is designed to store the saline water that needs to bedesalinated. Each wicking structure 116C, which is draped over the evaporator surfaces116B, has one end submerged in the saline reservoir 118. The wicking structure 116C uses acombination of capillary action and osmotic swelling to transport water from the reservoirto the evaporation zone efficiently.

[0068] The end condenser plate 122 is extended and submerged in the saline water at oneend, maintaining it at a temperature close to room temperature. This setup creates asignificant temperature difference between the initial evaporator surface and the endcondenser plate 122. This temperature gradient is essential for driving the desalinationprocess, as it facilitates the continuous recycling of vapor enthalpy through successivecondensation and evaporation cycles. This mechanism ensures efficient desalination andmaximizes freshwater production from the system.

[0069] According to another exemplary embodiment of the invention, FIG. 2 refers to aflowchart 200 of a method for desalinating saline water using the varying thermal energy.The method comprises, heating, the heater transfer unit 102, a phase change material(PCM) within a heater transfer unit 102 using thermal energy from thermal gases, asdepicted in step 202.

[0070] The method comprises, regulating and maintaining, by the coolant unit 108,temperature of the PCM at a constant temperature, thereby maintaining the varyingthermal energy at the constant temperature, as depicted in step 204. The methodcomprises, transferring the varying thermal energy at the constant temperature from theheater transfer unit 102 to the TLMS units 114 of the desalination assembly 112 via theintermediate evaporator surface 110, as depicted in step 206.

[0071] The method comprises, evaporating saline water on plurality of evaporator surfaces116B of each TLMS unit 114 using the transferred varying thermal energy at the constanttemperature, as depicted in step 208. The method comprises, condensing the evaporatedwater on plurality of condenser surfaces 116A of each TLMS unit 114, as depicted in step210. The method comprises, collecting, by a distillate channel 120, the condensed water asdesalinated water, as depicted in step 212.

[0072] Numerous advantages of the present disclosure may be apparent from thediscussion above. In accordance with the present disclosure, a multi-stage paralleldesalination system is disclosed with phase-change material-based thermal managementthat continuously produces fresh water by evaporating saline water using thermal gases.

[0073] The multi-stage parallel desalination system 100 utilises waste heat (varying thermalenergy) from steam and flue gases, commonly available in thermal power plants, mining,and allied industries, thereby reducing thermal pollution and provides an ecological benefitby repurposing energy. The multi-stage parallel desalination system 100 operates onthermal energy from waste heat recovery systems, significantly lowering input energy costsand improving overall energy efficiency.

[0074] The multi-stage parallel desalination system 100 adjusts to varying energy content ofincoming steam or flue gases, by varying quantity of PCM in proportion to the energycontent of the feed, ensuring optimal temperature regulation. The multi-stage paralleldesalination system 100 integrates interfacial evaporation and vapor enthalpy recycling toachieve high productivity rates for desalinated water. The multi-stage parallel desalinationsystem 100 moderates and regulates the temperature across the evaporator surface,preventing spot drying and overheating of wicking structures.

[0075] The multi-stage parallel desalination system 100 utilises heterogeneous wettabilitysurfaces on condenser surfaces to improve condensation rates, thereby increasing overallproductivity. The multi-stage parallel desalination system 100 utilises multiple thermallylocalized multistage stills (TLMS) units 114 that run in parallel for enhancing productivity andoffering scalability. This parallel operation is thermodynamically advantageous, providinginput energy at higher temperatures. The multi-stage parallel desalination system 100captures the enthalpy of vaporization during condensation and uses it to drive subsequentevaporation, enhancing energy efficiency. The multi-stage parallel desalination system'sadaptability to different energy content feeds eliminates the need for multiple devices, eachoptimized for specific energy levels, simplifying the overall design and operation.

[0076] The multi-stage parallel desalination system 100 harnesses green steam derivedfrom waste heat recovery or flue gases, which reduces thermal pollution and enhancesecological sustainability. By utilizing thermal energy from waste heat that would otherwisebe lost, the multi-stage parallel desalination system 100 minimizes input energy costs andimproves economic viability. The multi-stage parallel desalination system 100 features atelescopic PCM enclosure arrangement that adapts to varying qualities and energy contentsof the recovered steam or flue gases, ensuring optimal temperature regulation. Thisinnovation eliminates the need for separate devices tailored to different energy contents,thereby streamlining system design and operation.

[0077] The multi-stage parallel desalination system 100 incorporates PCM-based thermalmanagement to effectively handle higher energy fluxes without causing overheating, thusensuring precise temperature control over the evaporator surface. By maintaining theevaporative structure's temperature below 70°C with PCM-based thermal management, thesystem prevents localized heating. Additionally, the multi-stage parallel desalination system100 enhances condensation efficiency and productivity through condenser plates withheterogeneous wettability surfaces. The multi-stage parallel desalination system 100addresses the low thermal conductivity of PCM materials by employing volumetric heatingvia integrated heating pipes, which ensures uniform heating of the PCM mass. The multistage parallel desalination system 100 manages high operating temperatures efficiently,reduces material degradation, and maintains performance by utilizing green steam.Furthermore, the multi-stage parallel desalination system 100 boosts overall productivity byoperating multiple units in parallel, optimizing energy use and improving energy efficiency.

[0078] It will readily be apparent that numerous modifications and alterations can be madeto the processes described in the foregoing examples without departing from the principlesunderlying the invention, and all such modifications and alterations are intended to beembraced by this application.

Claims

1. A multi-stage parallel desalination system (100), comprising: a heater transfer unit (102) configured to move from a first position to a second position, and vice versa, in response to varying thermal energy received from thermal gases, wherein the heater transfer unit (102) comprises: an enclosure (104) having a telescopic assembly configured to store a phase change material (PCM), which is adapted to expand and contract in response to the varying thermal energy from the thermal gases, thereby facilitating a reciprocating movement for the heater transfer unit (102); and one or more piping systems (106) having plurality of heating pipes configured to allow the thermal gases to flow within the enclosure (104) for facilitating uniform and volumetric heating of the PCM; a coolant unit (108) positioned adjacent to the enclosure (104), wherein the coolant unit (108) is configured to regulate and maintain temperature of the PCM, thereby controlling the varying thermal energy from the thermal gases at a constant temperature; and a desalination assembly (112) coupled to the heater transfer unit (102) via an intermediate evaporator surface (110), wherein the desalination assembly (112) comprises: plurality of thermally localized multistage stills (TLMS) units (114) configured to receive the varying thermal energy from the heater transfer unit (102) through the intermediate evaporator surface (110), wherein the plurality of TLMS units (114) is configured to convert saline water into desalinated water using the varying thermal energy at the constant temperature, wherein the plurality of TLMS units (114) is arranged in a parallel configuration as a single integrated desalination assembly (112).

2. The multi-stage parallel desalination system (100) as claimed in claim 1, wherein the PCM is solid-solid phase change material (SSPCM).

3. The multi-stage parallel desalination system (100) as claimed in claim 1, wherein each TLMS unit (114) comprises plurality of evaporation-condensation units (116) that is configured to convert the saline water into the desalinated water.

4. The multi-stage parallel desalination system (100) as claimed in claim 3, wherein each evaporation-condensation unit (116) comprises: an evaporator surface (116B) attached to a wicking structure (116C), wherein the wicking structure (116C) is configured to be partially submerged in the saline water stored in a saline water reservoir (118), thereby absorbing the saline water and enabling faster water transport, wherein the wicking structure (116C) is configured to receive the varying thermal energy at the constant temperature from the evaporator surface (116B) and the intermediate evaporator surface (110), thereby evaporating the saline water absorbed by the wicking structure (116C); a condenser surface (116A) disposed adjacent to the evaporator surface (116B), wherein the condenser surface (116A) is configured to condense vapor received during the evaporation of the saline water through the wicking structure (116C) via enthalpy recycling, thereby obtaining desalinated water, which is collected through a distillate channel (120); and an end condenser plate (122) adapted to be dipped in the saline water reservoir (118).

5. The multi-stage parallel desalination system (100) as claimed in claim 4, wherein the wicking structure (116C) is made of polyvinyl alcohol (PVA) cloth with high porosity, which is used to enable faster water transport with high capillarity and osmotic swelling.

6. The multi-stage parallel desalination system (100) as claimed in claim 4, wherein the condenser surface (116A) is configured with heterogeneous wettability for enhanced condensation.

7. The multi-stage parallel desalination system (100) as claimed in claim 4, wherein the evaporator surface (116B) and the condenser surface (116A) are made of aluminium.

8. The multi-stage parallel desalination system (100) as claimed in claim 1, wherein the intermediate evaporator surface (110) is attached to an intermediate wicking structure (110A).

9. A method for desalinating saline water using varying thermal energy, comprising: heating, a heater transfer unit (102), a phase change material (PCM) within a heater transfer unit (102) using varying thermal energy from thermal gases; regulating and maintaining, by a coolant unit (108), temperature of the PCM, thereby controlling the varying thermal energy from the thermal gases at a constant temperature; transferring the varying thermal energy at the constant temperature from the heater transfer unit (102) to plurality of thermally localized multistage stills (TLMS) units (114) of a desalination assembly (112) via an intermediate evaporator surface (110); evaporating saline water on plurality of evaporator surfaces (116B) of each TLMS unit (114) using the transferred varying thermal energy; condensing the evaporated water on plurality of condenser surfaces (116A) of each TLMS unit (114); and collecting, by a distillate channel (120), the condensed water as desalinated water.