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DOE OSTI2025

A Modelica Implementation of an Organic Rankine Cycle

Organic Rankine cycle (ORC) systems generate power from low-grade heat sources, such as geothermal sources and industrial waste heat. A key feature is that a working fluid is selected to match the temperature of the source. With the vast pool of candidate working fluids comes the challenge of developing a large number of robust thermodynamic media models. We implemented a subcritical ORC model in Modelica that uses working fluid data records and interpolation schemes in lieu of thermodynamic medium evaluation for energy recovery estimation. This is a component model that can be integrated into a larger energy system model. It does not require detailed thermodynamic, heat transfer, or machine analysis. Our ORC model fills a gap where working fluids are ready to choose or easy to add, and at the same time can be integrated into an energy system.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

DOE OSTI2023

Characterization and Electrochemical Analysis of Acidic Condensate-Induced Corrosion on Aluminized Coating on Steel in Residential Heaters

Condensing furnace residential heaters are starting to replace outdated and less efficient non-condensing units in homes across the US. However, the burning of natural gas in these new units produces acidic gases, which can form acid droplets (H 2 SO 4 , HNO 3 , H 2 CO 3 , etc.) that are corrosive to low-grade heat exchanger metallic materials. Type-1 aluminized steel has been used in industrial applications, such as marine, heating, and automobile parts, due to its resistance to oxidation at elevated temperature. Many components of the condensing furnaces, including heat exchangers, are made from type-1 aluminized steel. We investigated the interaction of type-1 aluminized steel substrates with two acidic condensate liquids by 500 h corrosion exposures as well as short-term electrochemical impedance measurements. SEM plan and cross-sectional view images revealed damage to the Al-Si rich layer and exposure of the steel substrate. The non-uniform damage in the Al-Si rich layer was likely attributed to a pitting corrosion mechanism and induced by high acidity of the condensate liquid. Electrochemical impedance measurements in an acidic condensate revealed lower corrosion resistance of the aluminized steel surface with a weld line, identifying welded sections as preferential corrosion initiation sites.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Performance Validation of a Thermally Integrated 50 kW High Temperature Electrolyzer System

In the proposed project, INL and OxEon seek to improve the value proposition of hydrogen production by integrating reversible fuel cell operations at relatively small scale for distributed energy applications. This goal will be accomplished by converting a 50 kW solid oxide electrolysis cell or SOEC system into a reversible system that operates at 30 kW in electrolysis mode and approximately 10 kW in fuel cell mode. The reversible SOC system will be operated for over 3,000 hours using an improved catalyst in the fuel electrode. Steam for the electrolysis will come from an electric boiler Thermal Energy Distribution System that will be configured to mimic an industrial source of low-grade heat. Thermodynamic analysis will be performed to demonstrate the potential of the system to achieve >85% system efficiency in electrolysis mode. Finally, a technoeconomic analysis will be completed to show potential to produce hydrogen at a cost of $2/kg. The figure at the right indicates a target cost breakdown to achieve that goal.

08 HYDROGEN↗

DOE OSTI2024

ORNL Campus Sustainability and Decarbonization using Waste Heat Recovery from the Oak Ridge Leadership Computing Facility’s High-Performance Computing Data Center

Heat pumps are a clean and efficient technology that can be powered by renewable electricity to transfer heat using a refrigerant from one place to another by different heat sources, making buildings clean and environmentally friendly. With the support of the ORNL Laboratory Modernization Division, this project explored and evaluated an innovative solution that uses water-water cost-effective midtemperature heat pump (MTHP) technology to leverage the low-grade waste heat from ORNL Frontier and the data center to deliver 85°C hot water, which replaces hot steam generated using natural gas combustion boilers for water heating or space heating in the buildings of ORNL campus. Two scenarios were studied. In the first scenario, which considered the 5600-5700-5800 complex only, Carrier’s commercial 1,000 kW MTHP technology achieves more than 6,640 MWh/year energy savings, an emission reduction of 858 TCO2e/year CO2, and a payback time of 4.85 years. In the second scenario, which considered the 5600-5700-5800 complex and Buildings 5100, 5200, and 5300, the CO2 emission reduction is 1,483 TCO2e/year, the operating cost savings are $0.21 million annually, and the payback time is 3.74 years. Additionally, a comprehensive HP ShowCase Tool was developed for evaluating the optimal solution to improve sustainability and decarbonization of the buildings on the ORNL campus. The tool is an Excel-based tool integrated with VBA (Visual Basic for Applications) coding. The tool includes collected ORNL campus building information and an MTHP library, which comprises collected commercial and ORNL-defined MTHPs. The tool was used to evaluate the sustainability and decarbonization of the ORNL campus. The tool can be widely used or referenced for heat pump solutions and building decarbonization renovation strategies to modernize ORNL facilities and energy use–intensive equipment to enable efficient, sustainable, and resilient operations in the future.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2022

Power and energy capacity tradeoffs in an all-aqueous copper thermally regenerative ammonia battery

Thermally regenerative ammonia batteries (TRABs) can provide energy storage and produce electrical power from low-grade waste heat instead of electricity. The use of all-aqueous copper-based electrolytes has recently produced higher power densities than those achieved using previous TRAB approaches based on reversible metal deposition and dissolution processes, but further gains are possible in power and energy density. We investigated the limitations of power and energy density and how they are impacted by the electrolyte composition and discharge currents. By increasing the ammonia concentration from 1 to 5 M, the power density of the battery increased from 11.2 to 28.5 mW cm –2 , but the energy density decreased from 0.56 to 0.31 Wh L –1 . Increasing discharge current densities from 4 to 12.5 mA cm –2 increased the average power density during discharge from 2.4 to 5.9 mW cm –2 without appreciable losses in energy density. Increasing the copper concentration from 0.1 to 0.5 M increased both energy density to 2.15 Wh L –1 and energy efficiency to 2.2% but did not substantially impact the power density. Furthermore, these results represent the highest performance metrics achieved for a low-grade waste heat to electricity system.

25 ENERGY STORAGE↗

DOE OSTI2023

Experimental performance of ejector heat pump operating in the sub-critical mode

Ejector heat pump (EHP) is an efficient-energy technology with a promising potential to replace the vapor compression cycle in heating and cooling applications. It can be powered by low-grade waste heat and uses environmentally friendly working fluids. EHP has also become a viable solution in research seeking cooling applications. However, little attention has been paid to using EHP for heating purposes. In order to investigate this, a steam EHP for domestic water heating was designed and built. The coefficient of performance (COP) is evaluated at various operating and design conditions in sub-critical operational modes to achieve higher condensation temperatures. Two primary nozzles with a throat diameter of 1.5 mm and 2.0 mm were investigated. The primary nozzle is movable along the ejector’s axis, allowing investigation of its positional effects on the EHP’s COP. Further, experimental measurements revealed that using a smaller throat diameter results in a high COP and low back pressure. The EHP COP and back pressure increase when the LTE temperature increases. Using a throat diameter of 1.5 mm, the EHP COP increases as the nozzle exit position (NXP) becomes closer to the constant area section. A COP of 2.42 and a back pressure of 4.28 kPa are achieved at a high-temperature evaporator (HTE) temperature of 130 °C and a low-temperature evaporator (LTE) temperature of 30 °C using a primary nozzle with 1.5 mm.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2024

District heating utilizing waste heat of a data center: High-temperature heat pumps

Data centers are energy-intensive facilities with substantial low-grade waste heat. High-temperature heat pumps can be critical in boosting the data center’s waste heat for district heating, improving the system-level energy efficiency of data centers, and reducing CO 2 emissions in district heating. This study built thermodynamic models to assess high-temperature heat pumps with six configurations using low global warming potential refrigerants to supply heat up to 120 °C. The heat pump configurations include single-stage or two-stage cycles with advanced components, such as internal heat exchanger, economizer, flash tank, or parallel compressor. The refrigerants include R1234ze(Z), R1233ed(E), R1224yd(Z), R600, and R600a, and R245fa is used as a reference. A case study was carried out to recover the waste heat from the Frontier high-performance computing data center and provide hot water for district heating at the US Department of Energy’s Oak Ridge National Laboratory campus. The optimized performance of high-temperature heat pumps is characterized with various effectiveness of internal heat exchangers, and the operating parameters of economizer or flash tank, as well as their combination. The results show that the configurations of two-stage cycles with internal heat exchanger + flash tank and internal heat exchanger + economizer/parallel-compressor provide the highest coefficient of performance under scenarios of the maximum allowable value and a fixed value (0.3) of the internal heat exchangers’ effectiveness, respectively. R1234ze(Z) and R600a are the most promising refrigerants, considering trade-offs between the coefficient of performance and the volumetric heating capacity. The single-stage cycle with internal heat exchanger + economizer/parallel-compressor using R1234ze(Z) is recommended for utilizing Fronter’s waste heat in district heating. A one mega-watt high-temperature heat pump will reduce 33,100–33,200 metric tons of CO2 emission annually, corresponding to 85.4 %–85.6 % of equivalent CO2 emissions from natural gas boilers. Here, this study provides good guidelines for designing and deploying high-temperature heat pumps to support sustainable data centers and decarbonize district heating in the US.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2026

Application of Ibuprofen Sodium Dihydrate for Thermochemical Energy Storage

Thermochemical energy storage (TCES) offers a transformative approach to address grid instability by harnessing reversible chemical reactions for efficient heat storage and release. Here, we introduce pharmaceutical organic salt hydrates as a class of materials with exceptional performance for low-grade waste heat recovery. We demonstrate ibuprofen sodium dihydrate (ISD) as an example organic hydrate exhibiting a dehydration temperature range of 60-110 °C and a remarkable dehydration enthalpy of up to 59.5 kJ/mol of water, ideally suited for capturing industrial and residential waste heat. Using rigorous multimodal characterization, including thermogravimetric analysis, differential scanning calorimetry, in-situ FTIR, in-situ PXRD, and NMR, we demonstrate ISD's superior thermal, chemical, and structural stability over 150 hydration-dehydration cycles, achieving an unprecedented cycling efficiency of ~99.9%. Compared to conventional inorganic salt hydrates like strontium chloride hexahydrate and calcium oxalate monohydrate, ISD showcases enhanced durability without deliquescence or pulverization, even under high-humidity conditions. In-situ analyses confirm the transition from ISD to ibuprofen sodium anhydrous (ISA) proceeds with structural reorganization, thereby combining the dehydration mechanism with phase transitions, resulting in higher energy storage capacity. Microstructural analyses reveal that repeated water intercalation and structural transitions aid in creating significant porosity that enhances water transport kinetics, further improving the hydration/dehydration performance. By combining the phase change and chemical dehydration mechanisms, ISD paves the way for designing a new class of organic salt hydrates, offering tunable properties to meet diverse thermal energy storage demands and supporting sustainable grid resilience.

Thangaraj, Kavin C.↗

DOE OSTI2026

Case Study of Integrating High-Temperature Heat Pump with LiBr-H2O Absorption Chiller for Data Center Liquid Cooling

Data centers (DCs) are physical infrastructures that support artificial intelligence workloads. The rapid growth of artificial intelligence is putting substantial pressure on the US power grid. Most of electricity consumed by IT equipment, accounting for 50%-60% of total DC power, ultimately becomes waste heat. This heat is dissipated by DC’s cooling facilities, accounting for an additional 30%-40% of total DC power. Recovering and repurposing this waste heat offers a significant opportunity to enhance energy efficiency and reduce operating costs of DCs. One potential pathway is converting heat to cold using thermal-driven absorption chillers, therefore, reducing the power consumption in DC cooling facilities. Existing studies mainly demonstrate the technical and economic feasibility of repurposing DC’s waste heat for cooling applications but provide limited technical details on how to integrate the thermal-driven absorption chillers with DC cooling systems. In addition, the low-grade waste heat available from DCs must be upgraded to higher temperatures suitable for absorption chillers. This paper presents a case study on integrating high-temperature heat pumps with a LiBr-H2O absorption chiller to use DC waste heat for cooling. A thermodynamic model of single-effect, LiBr-H2O absorption chiller and an empirical model of high-temperature heat pumps were built. The case study considers ASHRAE W17 liquid-cooled DC, with facility service water supplied at 17.0℃ and returned at 25.3℃. The thermal behaviors of absorption chiller components were predicted for the generation temperature ranging from 75.0℃ to 115.0℃. Based on the available waste heat in the integrated system, two waste heat recovery strategies were evaluated: a facility service water-based strategy and cooling water-based strategy. Results indicated that the cooling water-based strategy achieves higher Coefficient of Performance (COPs) than the facility service water-based strategy. The relatively low cooling COPs of single-effect LiBr-H2O absorption chillers could be offset by high heating COP of high temperature heat pumps. The maximum cooling COP of absorption chiller and the overall COP of integrated systems occur at lower generation temperatures, but these conditions also yield lower cooling capacities. In practice, system operation should balance the trade-off between the COP and cooling capacity

Wang, Pengtao [ORNL] (ORCID:0000000214713429)↗

DOE OSTI2025

Thermomagnetic generators for ultra-low-grade marine thermal energy harvesting

Low-grade thermal gradients in marine environments represent an underexploited energy source for autonomous sensing and monitoring. Converting such small temperature differences into usable electrical power remains a key challenge for ocean-deployed systems. We present a deployable thermomagnetic generator thoroughly characterized for marine-relevant energy harvesting. The device powers an internet-connected sensor and harvests ultra-low temperature differences akin to those at the ocean surface. It draws heat from water and rejects it to ambient air, operating optimally at a temperature difference (ΔT) of ~7.5 °C. Laboratory prototypes generated up to 6.7 mW at ΔT ~ 10 °C with gentle airflow (~1 m s -1 ). A separate controlled wave-tank demonstration validated stable operation and sensor powering under marine-like boundary conditions. Given its voltage and power margins, the generator could sustain multiple sensor nodes. Scalability and material assessments identify modular deployment and non-rare-earth alternatives as pathways toward practical marine energy harvesting and low-grade waste-heat recovery.

16 TIDAL AND WAVE POWER↗

DOE OSTI2021

Energy Conversion from Heat to Electricity by Highly Reversible Phase-Transforming Ferroelectrics

The search for performant multiferroic materials has attracted general research interest in energy science as they have been increasingly exploited as the conversion media among thermal, electric, magnetic, and mechanical energies by using their temperature-dependent ferroic properties. Here we report a material development strategy that guides us to discover a reversible phase-transforming ferroelectric material exhibiting enduring energy harvesting from small temperature differences. The material satisfies the crystallographic compatibility condition between polar and nonpolar phases, which shows only 2.5°C thermal hysteresis and a high figure of merit. It stably generates 15μA of electricity in consecutive thermodynamic cycles in the absence of any bias fields. We demonstrate our device to consistently generate 6μA/cm 2 current density near 100°C over 540 complete phase transformation cycles without any electric and functional degradation. The energy-conversion device can light up an LED directly without attaching an external power source. Furthermore, this promising material candidate brings the low-grade waste-heat harvesting closer to a practical realization, e.g., small temperature fluctuations around the water boiling point can be considered as a clean energy source.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2021

Porous Covalent Organic Polymers for efficient Fluorocarbon-based Adsorption Cooling

Adsorption-based cooling is an energy-efficient renewable-energy technology that can be driven using low-grade industrial waste heat and/or solar heat. Here, we report the first exploration of fluorocarbon adsorption using porous covalent organic polymers (COPs) for this cooling application. High fluorocarbon R134a equilibrium capacities and unique overall linear-shaped isotherms are revealed for the materials, namely COP-2 and COP-3. The key role of mesoporous defects on this unusual adsorption behavior was demonstrated by molecular simulations based on atomistic defect-containing models built for both porous COPs. Analysis of simulated R134a adsorption isotherms for various defect-containing atomistic models of the COPs shows a direct correlation between higher fluorocarbon adsorption capacities and increasing pore volumes induced by defects. Combined with their high porosities, excellent reversibility, fast kinetics, and large operating window, these defect-containing porous COPs are promising for adsorption-based cooling applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2023

Lignetics CRADA closeout report

Lignetics is one of the leading domestic producers of wood pellet fuels used for domestic heating. The company also produces pellets for other applications including animal bedding. The primary feedstock used for the production of Lignetics products is woody biomass. To improve the economics of pellet production, Lignetics is evaluating advanced preprocessing technologies developed by researchers at INL. In the proposed project, INL and Lignetics will work collaboratively to assess the feasibility of integrating INL’s advanced preprocessing technologies (fractional milling, high moisture pelleting and low temperature drying) in Lignetics production facilities. The successful completion of the project relies on the integration of the fractional milling and high moisture pelleting (HMP) process and low temperature drying to improve the economics of woody biomass pellet production for use in biofuel and bioproduct applications. In the HMP process, the biomass loses some moisture during compression and extrusion through the pellet die due frictional heat developed. Also, as pellets have a definite size and shape, they can be further dried in low temperature grain or belt dryers. Belt dryers are better suited to take advantage of low-grade and waste heat because they operate at lower temperatures than rotary dryers (Tumuluru et al.) Rotary dryers, for example, typically require inlet temperatures of 260°C, but more optimally operate around 400°C. In contrast, the inlet temperature of a belt dryer, such as a commercially available vacuum dryer, can be as low as 10°C above the ambient temperature, although more typically they operate at higher temperatures, between 90°C and 200°C. Because of their lower temperature operation, fire hazards and emissions to the air are lower for belt dryers in addition to reducing drying and overall pelleting costs, INL’s technology also has potential to reduce emissions at Lignetics facilities.

09 BIOMASS FUELS↗

DOE OSTI2023

System efficiency and power assessment of the all-aqueous copper thermally regenerative ammonia battery

Thermally regenerative ammonia batteries (TRABs) use low-temperature (T < 100 °C) heat to provide stationary energy and power with higher power densities and efficiency relative to other waste heat devices. TRABs are an active area of research in waste heat devices, but currently there is little consensus on what aspect of the system is limiting TRAB performance and what maximum efficiencies are possible. Experiments and numerical models were used here to examine the sensitivity of the battery and distillation column in a TRAB system to key operating variables, thereby establishing practical limits and identifying focus areas for improving performance. Battery power was eight times more sensitive to ohmic losses than kinetic and mass transfer losses, regardless of the operating temperature, and the peak power density was simulated to be 18.8 mW cm –2 at 75 °C. Theoretical energy efficiency limits were defined for a series of ammonia concentrations and operating pressures, ranging from 5 – 12%, which is 2–3 times higher than previous experimental estimations. Atmospheric pressure column operation used a larger amount of waste heat compared to sub-atmospheric pressure. It is estimated that the volume of the battery would take up 9.2m 3 for every 1% of the power output of a natural gas turbine, but with realistic improvements to cell conductivity, the size would reduce to 2.5 m 3 . Finally, the results presented in this work will help streamline future development by focusing on minimizing ohmic losses and provide specific data for full system evaluation of future TRABs.

25 ENERGY STORAGE↗

DOE OSTI2022

Chapter 10 - Thermal Energy Harvesting Using Thermomagnetic Effect

Low-grade thermal energy, either in the form of waste heat or nature heat, is available abundantly around us. Since Carnot efficiency reduces with decrease in operating temperature difference, there are very limited practical options for low-grade thermal energy conversion. Thermomagnetic effect is the effect of heat on magnetic properties of a material. This phenomenon can be used to generate electricity using either direct thermal to electrical energy conversion or indirect thermal to mechanical energy conversion. This chapter provides a broad overview of various aspects of thermomagnetic energy conversion. We first explain the working principle behind the thermomagnetic energy harvesting. We then formulate mathematical equations needed to calculate the work output and energy conversion efficiency of a thermomagnetic cycle. Based on this formulation, we provide a list of working materials that can be employed in the thermomagnetic harvesters. At last, we describe various thermomagnetic harvesters proposed in the literature.

ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION↗

DOE OSTI2020

Chapter 3 - Harvesting Thermal Energy with Ferroelectric Materials

Thermal energy is considered the ubiquitous form of energy as all other forms of energy ultimately degrade to thermal energy. Thermal to electrical energy conversion is currently an important method for electricity generation. The traditional power cycles, however, become technically and economically unviable when heat source temperature reduces below 100 °C. Thermal energy harvesting has been proposed as a viable alternative for low-grade thermal to electrical energy conversion. Thermal energy harvesting is a method of generating electricity using temperature-induced variations in material properties. It is particularly useful when the heat sources are available free-of-cost, either in the form of natural heat or waste heat. While there are several thermal energy harvesting techniques, pyroelectricity is the most promising as it can be used in situations where spatial thermal gradients are difficult to establish or the temperature of the heat source is changing. Despite the fact that the pyroelectric effect in ferroelectric materials has been known for past several decades, thermal energy harvesting using ferroelectric materials has not been much explored in the literature. In this chapter, we would explore various aspects of thermal energy harvesting using ferroelectric materials. We have first established the physics behind ferroelectricity, then provided a detailed description on ferroelectric thermal energy harvesting, discussed various ferroelectric thermodynamic cycles and devices proposed in the literature, and finally described various other emerging applications of ferroelectricity.

DIRECT ENERGY CONVERSION,MATERIALS SCIENCE,OTHER I↗

DOE OSTI2023

Systems Biology-Based Optimization of Extremely Thermophilic Lignocellulose Conversion to Bioproducts

This was a collaborative project involving researchers at the University of Georgia, North Carolina State University, Sanford‐Burnham‐Prebys Med. Discovery Institute and the University of Rhode Island. The over-arching goal was to demonstrate that non-model microorganisms, specifically extreme thermophiles, can be a strategic metabolic engineering platform for industrial biotechnology. We engineered the most thermophilic lignocellulose-degrading organism known, Caldicellulosiruptor bescii (Cbes) , which grows optimally near 80°C, and the most thermophilic fermentative organism known, Pyrococcus furiosus (Pfu) , which grows optimally at 100°C, to produce several key industrial chemicals. This work leveraged recent breakthrough advances in the development of molecular genetic tools for these organisms, complemented by a deep understanding of its metabolism and physiology gained over the past decade of study in the PIs’ laboratories. We applied the latest metabolic reconstruction and modeling approaches to optimize biomass to product conversion. Bio-processing above 70°C can have important advantages over near-ambient operations. Highly genetically-modified microorganisms usually have a fitness disadvantage and can be easily overtaken in culture when contaminating microbes are present. The high growth temperature of extreme thermophiles precludes growth or survival of virtually any contaminating organism or phage. This reduces operating costs associated with reactor sterilization and maintaining a sterile facility. In addition, at industrial scales, heat production from microbial metabolic activity vastly outweighs heat loss through bioreactor walls such that cooling is required. Extreme thermophiles have the advantage that non-refrigerated cooling water can be used if needed, and heating requirements can be met with low-grade steam typically in excess capacity on plant sites. We assembled a highly interdisciplinary team that brought together all of the expertise for the project to have successful outcomes. This project also built upon and utilized extensive information already available in the PIs’ labs for both Cbes and Pfu to develop models that provide a comprehensive description of these organisms’ physiology and metabolism that were utilized to inform metabolic engineering strategies. The models were validated with experimental data and the results demonstrated that unpretreated lignocellulose has the potential to be converted into value-added industrial chemicals at high loading at bioreactor scale. The data generated from this research were published in twenty-one peer-reviewed papers in international journals with online access.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2024

Hawaii Solar Desalination Project

This project built the world’s largest Forward Osmosis (FO) solar thermal desalination plant at the NELHA Hawaii Ocean Science and Technology Park for a high visibility “on sun” demonstration of seawater desalination for agricultural applications. The project included re-commissioning an existing 2MW micro-dish solar thermal array and coupling it to a next-generation 500m3/day FO system. The purpose of the project was to validate FO at commercial scale; to verify that the water produced is safe for potential downstream agricultural users; to gather data on capital cost, energy consumption and operating expense for the technology; and to demonstrate that FO can be successfully coupled to low-grade thermal resources. The plant implemented advancements in FO component technology, including hot nano-filtration, polymeric heat exchangers, draw solutions, and improved FO membranes, and operated from June 2022 to September 2023 - producing 30gpm of permeate water. Thermal energy was below 30kWh/m 3 during operation, establishing a new benchmark in thermal desalination technology, with recovery rates at times exceeding 65%, well above what commercial RO systems can achieve. Combining the plant capital cost (CAPEX) and the operating expenses (OPEX) yields a Levelized Cost of Water (LCOW) that is competitive with existing carbon-intensive technologies such as RO. The ability of the plant to operate from a renewable resource paves the way toward a low-carbon desalination future using low-grade thermal resources.

14 SOLAR ENERGY↗