Thermal Desalination Systems Research Articles

Thermal seawater desalination for irrigation purposes in a water-stressed region: Emerging value tensions in full-scale implementation

Water scarcity in arid regions has driven the spread of desalination. These systems contribute to water access but come at an intensive energy cost, and lead to brine discharge and associated environmental impacts. This work aims to investigate emerging societal issues and tensions when developing and implementing a thermal desalination system to produce irrigation water in the South of Spain. This has been done in a demonstration system for solar desalination able to recover water and salts from desalination brine. For this purpose, a context-sensitive design exercise has been implemented. First, tensions between social values expressed by diverse stakeholders have been identified. Then, a set of technical scenarios for the full-scale implementation of the system were designed and evaluated, comparing them to conventional membrane desalination. The analysis indicates high economic and energy costs to avoid the environmental impacts of increasing water production.

Development and comprehensive analyses of a hybrid solar–geothermal driven polygeneration system: Thermodynamic, exergoeconomic, and emergoenvironmental aspects

The present research proposed an innovative polygeneration system that uses solar, geothermal, and natural gas energy to produce power, heat, steam, and freshwater. The system consists of a proton exchange membrane fuel cell, an organic Rankine cycle, and a multi-effect thermal desalination system. The study included thermodynamic, exergy, exergoeconomic, exergoenvironmental, emergy-based exergoeconomic, and emergy-based exergoenvironmental factors in its comprehensive evaluation of the system. Results underscored the financial aspect of the organic Rankine cycle and cogeneration system, incurring costs of 0.4518 $/s and 1.054 $/s respectively, while also highlighting the system's capability to produce 6 kg/s of freshwater. The environmental impact rates were quantified for the organic Rankine cycle and cogeneration system at 0.1417 and 0.4814 pts/s respectively, situating the system within its ecological context. Further, the study detailed the total efficiency and net power output of the organic Rankine cycle and cogeneration system, ranging between 32.45–33.51% and 43.25–45.83% for efficiency, and 56956–56322 kW and 50174–51898 kW for net power output r espectively, showcasing the system's operational capacity. A parametric analysis was also integral to the study, examining the impact of key parameters on the functionality of the proposed system, thereby providing a nuanced understanding of the system's performance under varying operational scenarios.

Experimental investigation of tailoring functionalized carbon-based nano additives infused phase change material for enhanced thermal energy storage

The advancement of phase change materials (PCMs) as potential thermal energy storage (TES) materials for building envelopes holds promise for efficient energy utilization. However, the PCMs have a major drawback during energy storage, which is lower thermal conductivity, leading to inadequate heat transfer performance and energy storage density. The foremost objective is to formulate a nanocomposite by dispersing functionalized multi-walled carbon nanotubes in salt hydrate PCM with the presence of surfactant. A two-step technique is employed to formulate the nanocomposites with different weight concentrations (0.2, 0.4, 0.6 and 0.8 %) of carbon-based nanoparticles and these nanocomposites are thoroughly characterized to explore the thermophysical properties. Resulting the nanocomposite demonstrates a significant improvement in thermal conductivity, increasing by 91.45 %, which can be attributed to the well-developed thermal networks with the PCM matrix. The nanocomposite samples exhibit extreme thermal stability up to 477 °C with a slight enhancement of 4.6 %. Optical investigations further confirmed that the transmissibility of PCM decreased to 8.3 % from 62.8 %, indicating an enhanced absorption capability due to the dark color nature of the nanoparticles. Moreover, the formulated nanocomposite demonstrated both chemical and thermal stability, with negligible changes in melting enthalpy even after 300 cycles of heating and cooling operations. Additionally, a numerical simulation analysis of 2D heat transfer was performed using Energy 2D software to demonstrate the efficacy of thermal conductivity in heat transfer. The thermally energized nanocomposite is suitable for medium-temperature TES applications such as photovoltaic thermal systems, building applications, textiles, electronic cooling, and desalination systems.

Eco‐friendly approach to thermal energy storage: Assessing the thermal and chemical properties of coconut biochar‐enhanced phase change material

AbstractPhase change materials (PCMs) can absorb, store, and release substantial latent heat within a specific temperature range during phase transition and have gained huge attention due to environmental concerns and energy crises. However, PCMs have a significant downside in energy storage due to their relatively lower thermal conductivity, leading to inadequate heat transfer (HT) performance. The foremost aim of the research is to synthesize an eco‐friendly coconut shell biochar (CSB) dispersed with organic A46 PCM in the temperature range of 44°C to 46°C to form a green nanocomposite. A two‐step approach is adopted to formulate the nanocomposites with different weight concentrations (0.2% and 0.8%) of green CSB particles. The developed nanocomposite's thermal conductivity and chemical stability were examined using a thermal properties analyzer and a Fourier transforms infrared spectrometer. The developed biochar composites have excellent thermal conductivity (0.39 W/m K) compared with base PCM (0.22 W/m K). Also, the developed nanocomposites were physically mixed together; there were no additional functional groups formed compared to pristine PCM, and the prepared materials were composite. Furthermore, a numerical analysis was performed using two‐dimensional energy modeling software to ascertain the HT rate of A46 composites. These thermally energized green nanocomposites show great promise for thermal energy storage and thermal management applications like battery thermal management, photovoltaic thermal systems, desalination systems, electronic cooling, building applications, and textiles.

Solar-Driven Thermal and Mechanical Vapor Compressor Integrated Desalination System: Zero Emission, High Yield, and Cost Reduction

Solar-Driven Thermal and Mechanical Vapor Compressor Integrated Desalination System: Zero Emission, High Yield, and Cost Reduction

Definition of Exergetic Efficiency in the Main and Emerging Thermal Desalination Technologies: A Proposal

Increasing attention is being given to reduce the specific energy consumption in desalination processes, which translates into greater use of exergy analysis. An exergetic analysis provides relevant information related to the influence of the efficiency of a single component in the global plant performance and in the exergy cost of the product. Therefore, an exergy analysis identifies the main improvement potentials in a productive thermodynamic process. Related to desalination technologies, many previous papers deal with the calculation of the parameters involved in the exergy analysis, the exergetic efficiency of different processes, plants, and technologies among them. However, different approaches for formulating the exergetic efficiency have been suggested in the literature, often without sufficient understanding and consistency. In this work, these formulations, applied to the main desalination components and processes, are compared and critically reviewed. Two definitions of exergy efficiency are applied to the desalination components of the three main thermal desalination processes (multieffect distillation–thermal vapour compression, multistage flash distillation, and direct-contact membrane distillation). The results obtained for the exergy efficiency of the MED-TVC, MSF, and DCMD processes for the input–output approach are 21.35%, 17.08%, and 1.28%, respectively, compared to the consumed–produced approach that presented 3.1%, 1.58%, and 0.37%, respectively. The consumed–produced approach seems to better fit the thermodynamic behaviour of thermal desalination systems.

Applications of different types of heat pipes in solar desalinations: A comprehensive review.

Desalination processes are energy consuming and it is required to apply clean energy sources for supplying them to prevent environmental issues. Solar energy is one of the attractive clean energy sources for desalination. In solar thermal desalination systems, different thermal components could be used for heat transfer purpose. In solar desalination technologies, heat pipe as efficient heat transfer mediums could be employed to transfer absorbed and/or stored thermal energy. The objective of this study is to review applications of heat pipes in solar energy desalination systems. Regarding the performance dependency of these thermal systems on the variety of factors, scholars have investigated these systems by consideration of the effect of different influential factors. Based on the results, it is concluded that use of heat pipes could lead to proper performance of solar desalination systems. Aside from direct transfer of absorbed heat from solar radiation, heat pipes can be applied in the storage units of solar desalination systems to keep the systems active in night-hours or low solar irradiation conditions. The overall performance of the solar desalinations systems with heat pipes can be influenced by some factors such as filling ratio and operating fluid that affect the performance of heat pipes.

Enhancing solar distillation through beeswax-infused tubular solar still with a heat exchanger using parabolic trough collector

This scholarly investigation elucidates the imperative for advancing solar thermal desalination systems, an exigency compounded by the twin global challenges of burgeoning solar implementational proliferation alongside intensifying non-potable water scarcity. The primary research objective underlines manifesting the latent productivity within passive tubular solar still (TSS) configurations via an amalgamated active system through the integration of metallic thermal transfer constituents (heat exchanger) alongside parabolic trough collector (PTC). Additionally, accelerated vapor condensation kinetics are catalyzed by the inclusion of beeswax phase change material (PCM) within the tubular metallurgies. A thorough empirical analysis of said system scrutinizes the synergistic fusion of concentrated solar thermal capacities using concentrated solar power (CSP) paradigms in tubular solar photo-thermal frameworks with beeswax constituting the auxiliary PCM thermal sink. A bifurcated data set provides experimental controls lacking PCM alongside PCM incorporation with repeating data gathering phases assessing comparative solar distillation system performance. The culminating system productivity and efficiency results exhibit a 66.18 % and 54.04 % respectively enhancement. Thus, the amalgamation of PTC-augmented TSS with metallic thermal exchangers & PCM beeswax integration introduces pragmatic pathways for advancing intensive solar-powered desalination output. Further academic interrogation of enabling thermal and optical phenomena driving said performance optimization remains imperative.

Multi-dimensional low-carbon assessments of wind-driven seawater desalination system via hybrid life cycle modeling

Wind-driven desalination is a representative technology of renewable energy that not only alleviates water shortages but also reduces greenhouse gas (GHG) emissions generated by the utilization of fossil fuels. This study examined the GHG emissions from a wind-driven seawater desalination system by using the hybrid input-output life-cycle analysis (IO-LCA) to undertake a comprehensive low-carbon assessment by comparing with traditional thermal seawater desalination systems over the whole life cycle. The findings indicate that the GHG emissions of the wind-driven seawater desalination system are 96.14% lower than those of the traditional system. According to estimations, if reverse osmosis (RO) desalination is driven by wind power technologies at a larger scale, the annual GHG emissions can be reduced by an amount between 7.54E+05 and 3.71E+06 t CO2-eq. Although the construction stage increases the emissions to 55.41% over the whole life cycle, the payback period (Ypp) is about 2.69 years, which means that the level of GHG emissions could be reduced by 25.42% of the level of the traditional systems. Based on the multi-dimensional low-carbon assessment, this study is expected to provide quantitative assessments and policy implications to integrate low-carbon technologies with seawater desalination and promote sustainable development of seawater desalination industries.

Seasonal dynamic modeling and simulation of solar thermal membrane desalination system for sustainable freshwater production: a case study of Tanta, Egypt

AbstractMembrane distillation (MD) is an effective process for desalinating seawater, combining the merits of both thermal and membrane distillation. In this context, the sizing methodologies and optimization strategies are developed from the balance of the system’s energy demand. Therefore, accurate numerical modeling of the heat transfer and thermodynamic behavior of the MD systems is crucial for the optimal design of solar-based MD systems. The interest in utilizing solar thermal heating techniques for feed water heating in MD systems is increasing worldwide for sustainable freshwater production and lowering energy consumption. Hence, in this research, a coupled analytical modeling based on heat transfer, mass transport, and thermodynamic analysis is created to dynamically simulate a solar direct contact membrane distillation system (SDCMDS) driven by vacuumed tubes solar collectors (VTSCs) to analyze its performance, under real weather of Tanta, Egypt. The influences of the solar collecting area on the performances of the proposed SDCMDS for augmenting the freshwater production of the SDCMDS are studied. Four cases of the proposed SDCMDS are investigated: two identical VTSCs of 1.80 m2 each unit in summer (Case I), two identical VTSCs in winter (Case II), four identical VTSCs in summer (Case III), and four identical VTSCs in winter (Case IV). The results show that the utilization of four VTSCs connected in series significantly improved the feed seawater temperature range from 30.0 to 70.5 °C compared to a feed temperature range of 30.0–49.5 was achievable by utilizing only two VTSCs. Moreover, the daily averaged permeate flux were 2.21, 1.29, 3.41, and 2.07 L/day per m2 of solar harvesting area with daily cumulative distilled water yield of 7.48, 4.60, 23.04, and 14.78 L/day for Cases I, II, III, and IV, respectively, at a saline flowrate of 0.20 kg/s. The daily average total efficiency of the SDCMDS was obtained to be 14.70%, 12.50%, 24.95%, and 22.50% for Cases I, II, III, and IV, respectively.

Development, 4E-analysis, and optimization of a seawater thermal energy-driven desalination system based on seawater source heat pump, multi-effect desalination, and pressure retarded osmosis with reduced effluent concentration

Development, 4E-analysis, and optimization of a seawater thermal energy-driven desalination system based on seawater source heat pump, multi-effect desalination, and pressure retarded osmosis with reduced effluent concentration

HIGHLY EFFECTIVE DIRECT CONTACT HUMIDIFIER FOR THERMAL DESALINATION SYSTEM

The aim of the work is to increase the efficiency of thermal desalination systems with a humidification-dehumidification air cycle due to the reduction of electricity consumption. The most common designs of heat exchangers for air humidification have significant aerodynamic and hydraulic drops. To eliminate this disadvantage, it is proposed to use the internal volume of the vertical tube as an active heat and mass transfer zone during moisture evaporation from salt water to air. The operation of such desalination system has been mathematically modeled and its energy characteristics were determined. A special feature of the mathematical model is the consideration of heat and mass transfer equations for the humidifier and dehumidifier. The effective air velocity in the tube is 3 m/s. Effective operation of thermal unit with a film humidifier is possible then air mass flow is equal to the salt water flow. In this case, the geometric dimensions of the tube must be within the following limits: diameter 20...30 mm, height 2...2.5 m. The conducted mathematical modeling and obtained results give reasons to assert, that for the same rate of evaporation, the film heat exchanger has the lowest aerodynamic and hydrodynamic drops compared to other types of humidifiers. The use of such direct contact device will lead to a decrease in the electricity consumption necessary for salt water and air circulation in the humidification-dehumidification thermal installation.

Solar driven desalination system for power and desalination water production by concentrated PVT and MED system

Abstract In this paper, a thermodynamic study of the combination of Concentrated Photovoltaic Thermal (CPVT) and Multi Effect Desalination (MED) system was conducted. CPVT produces electricity, and the heat produced in CPVT is used for the MED system. Engineering Equation Software (EES) was utilized to simulate this system. The effect of CPVT parameters (area, concentration ratio, and average solar radiation) and MED parameters (effect number and temperature of heating steam) were investigated on the produced heat, produced power, exergy destruction, total mass flow rate (FR) of desalinated water, total FR of feed water, heating steam FR and total brine FR. The range of changes for CPVT surface, concentration ratio, and average solar radiation was considered from 2000 m2 to 20000 m2, from 5 to 15 and from 400 W/m2 to 1100 W/m2, respectively. Based on obtained results, as the surface area of the solar panel, the ratio of concentration, and average solar radiation increase, the heat produced increases. Transferring this heat to the MED unit increases the total FR of desalinated water. But it has no significant effect on the Gain ratio (GOR). As the surface area of the solar panel increases from 10000 m2 to 12000 m2, the average radiation intensity increases from 800 W/m2 to 1000 W/m2, and the concentration ratio increases from 10 to 12 in effect the number of 4 and steam temperature of 70 °C, the total mass FR of desalinated water increases by 29 %, 23 %, and 20 %, respectively.

Design and Simulation of a Low‐Temperature Thermal Desalination System

AbstractThe prototype of a low‐temperature thermal desalination system treating 2500 L day−1 of saline water was designed thermally and geometrically, to be integrated with a vacuum spray flash drum and spray nozzles, a plate heat exchanger‐type condenser, and a thermosyphon solar water heater to produce potable water for a small community. The design bases were the feed flow rate, the feed temperature from 45 to 65 °C, the salinity of 0.035 kg kg−1, and the vacuum drum pressure from 2 to 6 kPa absolute. The estimated yield of potable water based on the simulated droplet dynamics was in the range of 68.91–75.80 %. The plate heat exchanger and the thermosyphon solar water heater were designed for effective condensation and passive heating, respectively.

Hydrodynamic and thermal model for gravity-driven smooth laminar film flow undergoing flash evaporation cooling: Case study and correlation development

Hydrodynamic and thermal analyses have been carried out for gravity-driven smooth laminar film flow, undergoing flash evaporation at the free surface. A classical one-dimensional semi-analytical approach has been adopted to address a unique problem where hydrodynamic and thermal boundary layers (TBLs) approach from opposite directions and eventually intersect each other. This occurs due to the rapid evaporation cooling at the film-free surface exposed to the low-pressure ambiance, leading to the growth of a TBL from the free surface. In contrast, the hydrodynamic boundary layer (HBL) grows from the solid wall over which the film flow occurs. The intersections between the TBL and HBL edges, HBL edge and the free surface, and TBL edge and the wall, in conjunction with the attainment of a fully developed hydrodynamic condition, result in the division of the overall film domain into three distinct hydrodynamic and five distinct thermal sub-zones requiring zone-specific formulations. The model is successfully validated for hydrodynamic formulations with the existing experimental data. However, the lack of available experimental studies limits the validation of the proposed thermal model. Correlations for relevant thermal and hydrodynamic parameters, such as local Nusselt number, local free surface temperature, local bulk mean temperature, and local film thickness, are developed based on the model predictions. The proposed model and the correlations derived from its predictions are anticipated to serve as crucial benchmarks for optimizing the design of thermal management and desalination systems that are fundamentally driven by the film evaporation process.

Techno-economic feasibility and environmental impact evaluation of a hybrid solar thermal membrane-based power desalination system

The present study investigates the performance of a hybrid solar thermal membrane-based multigeneration system for generating power, cooling, heating, and water. The integrated arrangement consists of organic Rankine cycle (ORC), Kalina cycle (KC), ammonia-water refrigeration, Pressure retarded osmosis (PRO) and forward osmosis (FO). A comprehensive multicriteria assessment of energy, exergy, economic, environmental, and emergy (5 E) is conducted to ensure a systematic examination. The results indicate that the allocation of R113 in the ORC yielded the highest exergetic efficiency and energy cost of 46.61% and 0.08109 $/kWh, respectively. Additionally, the system achieved the lowest environmental impact of 1694 mPts.h−1 when employing R718. The utilization of rejected water–ammonia in the PRO and FO modules achieves a reasonable power density and water flux of 17.5 W m−2 and 67.94 l m−2h−1, respectively. Finally, emergy-based sustainability analysis revealed that the proposed system obtains a sustainability index of 0.73, which is greater than that of the fossil fuel-based power generation systems. Comparison of three considered scenarios based on emergy and economic analysis demonstrated that fossil fuel driven system is not providing sustainable products even with a 72.3% decrease in initial capital cost. For further improvements, we highlight several areas for additional research and provide recommendations for existing solar- and membrane-driven systems.

Geothermal energy integrated multi-effect evaporator (MEE) and multi-effect distillation (MED)-based desalination systems: an ecofriendly and sustainable solutions.

Desalination is a tried-and-true method for obtaining clean water from the ocean's brackish waters and recycling and reusing water. It requires a fair amount of energy, so it is necessary to create sustainable energy systems to lessen energy use and environmental impact. For thermal desalination procedures, thermal sources can be great heat sources. This paper's research focuses on thermoeconomically optimized multi-effect distillation and geothermal desalination systems. Collecting hot water from subsurface reservoirs is a well-established method of generating electricity through geothermal sources. Low-temperature geothermal sources, which have a temperature of less than 130°C, can be utilized for thermal desalination systems, for example, multi-effect distillation (MED). Geothermal desalination is affordable, and it is possible to produce power simultaneously. Because it only uses clean, renewable energy and produces no greenhouse gasses or other pollutants, it is also safe for the environment. The viability of any geothermal desalination plant will be influenced by the location of the geothermal resource, feed water supply, cooling water source, water market, and concentrate disposal site. Geothermal energy can directly supply heat for a thermal desalination system or indirectly give electrical power to reverse the osmosis (RO) membrane-based desalination plant.

A comprehensive review on solar thermal desalination systems based on humidification-dehumidification approach

A comprehensive review on solar thermal desalination systems based on humidification-dehumidification approach

Multistage interfacial thermal desalination system with metallic evaporators

Small scale and passive solar-thermal desalination system hold promise to be employed in decentralized and off-grid areas to address scarcity of potable water. Here, we present a compact multistage thermal desalination system based on interfacial evaporation and latent heat recovery. We develop a textured metallic evaporator substrate that serves as a wick and reduces the thermal resistance for interfacial evaporation. We demonstrate that the rate of evaporation can be increased by tuning the wettability of the condenser surface. Patterned wettability-contrast surfaces are shown to enhance the rate of condensation compared to an unpatterned substrate with spatially uniform wettability. In a single stage desalination system, with patterned condenser surfaces, the evaporation rate increases by ~11 % and the water collection increases by ~21 % compared to that using an unpatterned condenser substrate. The thermal to vapor efficiency of ~56 % in a single stage increases to ~185 % with the use of multistage system. We achieve a water collection of ~2.17 Lm−2 h−1 using a 5-stage system. A theoretical model based on heat and mass transport analysis is used to determine the influence of the system geometry and ambient conditions on the overall efficiency of the desalination system.

High-performance desalination systems from natural luffa vine: A simple, efficient and environmentally friendly solution for bio-based solar evaporators

In this study, agricultural waste luffa vines (LVs) were used to develop solar evaporators by surface carbonization and KOH treatment combined with freeze-drying method. Scanning electron microscopy (SEM), solar absorption, solar thermal management and salt dissolution tests showed that the water vapor generation rate of a single column of LV-based solar evaporator after surface carbonization was as high as 3.26 kg m−2 h−1 under 1 sun, and its evaporation efficiency (118%) even exceeded the theoretical valve. After 36 h of continuous use, there was almost no salt deposition. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle, thermal conductivity, evaporation enthalpy, and low field nuclear magnetic resonance (LF-NMR) analyses indicated that the high evaporation efficiency of LV-based solar evaporators after surface carbonization was mainly due to high water transport capacity, low water evaporation enthalpy, and high light absorption rate (91%) of LV. The excellent salt-deposition resistance benefitted from the natural multilayered gradient porous structures of LV, forming spontaneous salt backflowing systems. The desalinization rate of LV-based solar evaporators exceeded 99.9%, which was even higher than those of many membrane elements and thermal desalination systems. They also had excellent removal effects on dyes and oily wastewater. After 30 d of continuous soaking, the compressive strength of 2–cm LVs was still 9.4 MPa. KOH-freeze-drying treatment further improved the salt-deposition resistance of LV-based solar evaporators, but reduced their evaporation efficiency and mechanical performance. This work suggests that LVs with carbonized surface have significant potential for development of environmentally friendly biomass solar evaporators with efficient evaporation, excellent resistance to salt deposition, and good durability.