Low Energy Performance Research Articles

Analysis of aerodynamic characteristics of missile with different sweep angle under supersonic condition

The increasing complexity of the modern battlefield requires that the aircraft can achieve multi-mission and low energy operation. In this paper, the dynamic characteristics of the missile are analyzed by building a 3D model of the missile and CFD simulation, in order to study the dynamic characteristics of the missile at different swept back angles. The lift force and drag force of the missile under different sweeps are studied, and the influence of the variable sweep angle on the aerodynamic characteristics of the whole body is revealed.

Achieving near Zero Energy Building in Albania: An Approach for the Retrofit of a Public-School Building

Since its introduction in 2010, the nearly Zero Energy Building (nZEB) concept has known a large diffusion in European countries. Albania, an aspiring candidate country to join the European Union EU, is paving the way towards its introduction by transposing EU directives in the fields of energy efficiency into the national legislation. Most of the national building stock includes buildings with low thermal and energy performance but with high refurbishment potential, too. The country can become an important contributor in the EU decarbonization strategy due to the high percentage of electricity produced by hydropower stations, making it one of the least carbon-intensity countries in the electricity production point of view. The article focuses on the evaluation of the energy performance of an existing school located in Tirana and the potentialities to reach the nZEB target, analysing both the suitable technological solutions and the energy market situation. The Primary Energy Factors PEF for the local electricity market are estimated referring to statistical data and in comparison, with neighbouring countries, Italy and Greece, in order to investigate the potential of the achievement of the nZEB target in Albania.

An Evaluation of the Environmental Payback Times and Economic Convenience in an Energy Requalification of a School

The majority of Italian schools (70%) were built in the absence of any legislation related to energy efficiency, and therefore have very low energy performance due to aging or poor quality of construction. An energy retrofit of this building stock is needed to meet the current European goals on greenhouse gas emission reduction. The retrofit is also needed in order to guarantee adequate comfort levels in indoor spaces and good conditions for learning and educational activities, that are often not reached in poor quality constructions. This work presents the results of an interdisciplinary study related to the energy requalification of a school located in Ostia, near Rome in Italy, built in the 1960s with a steel structure and Eternit infill. The scope of the analysis is to verify the economic and environmental effectiveness of four proposed retrofit interventions concerning the replacement of fixtures and the installation of an insulating coat. The current thermal transmittance of the walls was evaluated through thermofluximetric measurements conducted in situ; dynamic simulations were performed to determine the current energy performance and the energy performances following the four proposed retrofit scenarios. Energy and carbon payback times were evaluated (by means of the life cycle analysis (LCA) approach) and the economic value was determined for each of the four proposed retrofits, using a probabilistic approach. The results show that the replacement of windows is the most convenient intervention from all points of view. The study provides evidence that an assessment of schools’ energy retrofits should include both economic and life cycle aspects.

Life Cycle GHG Emissions of Residential Buildings in Humid Subtropical and Tropical Climates: Systematic Review and Analysis

Improving the environmental life cycle performance of buildings by focusing on the reduction of greenhouse gas (GHG) emissions along the building life cycle is considered a crucial step in achieving global climate targets. This paper provides a systematic review and analysis of 75 residential case studies in humid subtropical and tropical climates. The study investigates GHG emissions across the building life cycle, i.e., it analyses both embodied and operational GHG emissions. Furthermore, the influence of various parameters, such as building location, typology, construction materials and energy performance, as well as methodological aspects are investigated. Through comparative analysis, the study identifies promising design strategies for reducing life cycle-related GHG emissions of buildings operating in subtropical and tropical climate zones. The results show that life cycle GHG emissions in the analysed studies are mostly dominated by operational emissions and are the highest for energy-intensive multi-family buildings. Buildings following low or net-zero energy performance targets show potential reductions of 50–80% for total life cycle GHG emissions, compared to buildings with conventional energy performance. Implementation of on-site photovoltaic (PV) systems provides the highest reduction potential for both operational and total life cycle GHG emissions, with potential reductions of 92% to 100% and 48% to 66%, respectively. Strategies related to increased use of timber and other bio-based materials present the highest potential for reduction of embodied GHG emissions, with reductions of 9% to 73%.

Silicon photomultiplier (Si-PM) comparisons for low-energy gamma ray readouts with BGO and CsI (Tl) scintillators

We studied herein the low-energy performances of three multi-pixel photon counters (MPPCs, silicon photomultipliers, Si-PMs), namely, S13360-6050VE, S13360-6050CS, and S14160-6050HS, provided by Hamamatsu K.K. to read 1 cm3 BGO and CsI (Tl) scintillators. S13360s had 1/4 lower dark currents, while S14160-6050HS had 25% higher quantum efficiency and 1.5× higher gain with a lower operational voltage. S13360-6050VE and S14160-6050HS were used for surface mounting, while S13360-6050CS was in a black ceramic case. We changed the overvoltage and found that the best performances are achieved at overvoltages of +4 V and +2.5 V for S13360s and S14160-6050HS, respectively. In the case of the BGO scintillator, S13360-6050VE obtained a lower threshold of 6 keV compared to 9 keV of S14160-6050HS. Both surface-mounting Si-PMs achieved an energy resolution of ∼35% at 59.5 keV of the 241Am source. The threshold and the energy resolution of S13360-6050CS were the worst, because the black case absorbed approximately half of the scintillation photons. The CsI (Tl) scintillator yielded a number of scintillation photons that was 6× higher than the BGO. The same trends were measured for the three MPPCs. This result is attributable to the lower threshold determined by the dark current, and the energy resolution mainly dominated by the statistical fluctuation of the scintillation photons.

(Invited) Ion Tunable Electronic Materials Systems for Neuromorphic Computing

Tuning electronic conductance through solid state electrochemical ion insertion has emerged as a promising technology to enable next-generation, ultralow energy computing architectures1-3. Unlike two-terminal non-volatile memory elements, the three-terminal redox transistor decouples the ‘write’ and ‘read’ operations using a ‘gate’ electrode to tune the conductance state through charge transfer reactions involving ion injection into the channel electrode through a solid-state electrolyte. The insertion of ions into the bulk of the channel acts to dope the material through a gradual composition modulation that leads up to thousands of finely spaced conductance levels (synaptic weights) with near-ideal analog behavior. These properties enable low-energy operation without compromising analog performance and non-volatility. However, the strong coupling of ionic and electronic processes sharply challenges our current understanding of solid-state electrochemical systems, particularly at decreasing dimensions and timescales relevant to computing technology. In my talk I will discuss the rich portfolio of challenging, exciting fundamental science questions about ion tunable electronic materials systems and how we can harness these to realize a new paradigm for low power neuromorphic computing. Fuller, E. J.; El Gabaly, F.; Leonard, F.; Agarwal, S.; Plimpton, S. J.; Jacobs-Gedrim, R. B.; James, C. D.; Marinella, M. J.; Talin, A. A., Li-Ion Synaptic Transistor for Low Power Analog Computing. Advanced Materials 2017, 29.Fuller, E. J.; Keene, S. T.; Melianas, A.; Wang, Z. R.; Agarwal, S.; Li, Y. Y.; Tuchman, Y.; James, C. D.; Marinella, M. J.; Yang, J. J.; Salleo, A.; Talin, A. A., Parallel programming of an ionic floating-gate memory array for scalable neuromorphic computing. Science 2019, 364 (6440), 570.Li, Y. Y.; Fuller, E. J.; Asapu, S.; Agarwal, S.; Kurita, T.; Yang, J. J.; Talin, A. A., Low-Voltage, CMOS-Free Synaptic Memory Based on LixTiO2 Redox Transistors. Acs Applied Materials & Interfaces 2019, 11 , 38982.

Metallic states beyond the Tomonaga-Luttinger liquid in one dimension

In this paper, we propose some new strongly correlated gapless states (or critical states) of spin-1/2 electrons in 1+1-dimensions, such as doped anti-ferromagnetic spin-1/2 Ising chain. We find doped anti-ferromagnetic Ising chain to be a different metallic phase from the doped ferromagnetic Ising chain, despite the two have identical symmetry. The doped anti-ferromagnetic Ising chain has a finite energy gap for all charge-1 fermionic excitations even without pairing caused by attractive interactions, resembling the pseudo-gap phase of underdoped high Tc superconductors. Applying a transverse field to the ferromagnetic and anti-ferromagnetic metallic phases can restore the $Z_2$ symmetry, which gives rise to two distinct critical points despite that the two transitions have exactly the same symmetry breaking pattern. We also propose new chiral metallic states. All those new gapless states are strongly correlated in the sense that they do not belong to the usual Tomonaga-Luttinger phase of fermions, i.e., they cannot be smoothly deformed into the non-interacting fermion systems of the same symmetry. Our non-perturbative results are obtained by noticing that gapless quantum systems have emergent categorical symmetries, i.e., non-invertible gravitational anomalies), which are described by multi-component partition functions that are modular covariant. This allows us to calculate the scaling dimensions and quantum numbers of all the low energy operators for those strongly correlated gapless states. This demonstrates an application of emergent categorical symmetries in determining low energy properties of strongly correlated gapless states, which are hard to obtain otherwise.

Energy inequality as a risk in socio-technical energy transitions: The Swedish case of individual metering and billing of energy for heating

Improved energy efficiency in the housing stock is an important undertaking in the energy transition but is associated with both opportunities and risks. While there are possibilities to reduce energy inequalities in the housing stock, inequalities also risk being aggravated as actions for energy efficiency usually aim at the least energy efficient—and thus sometimes the least privileged—parts of the housing stock. In this paper, we use two different energy performance metrics (kWh/m2 and kWh/capita) to investigate the energy inequality in the Swedish multifamily building stock and explore the effects of these inequalities in the energy transition. More specifically, we investigate the implementation of individual metering and billing of energy for heating, which was recently implemented in the least energy efficient part of the housing stock. It was found that low-income households were overrepresented in the affected buildings. The consequence of this implementation is thus that the strongest protection against energy poverty in Sweden (collective billing for heating) is removed in a part of the housing stock where two of the predictors for energy poverty—low income and low energy performance—are overrepresented. It was concluded that acknowledging inequalities is crucial to avoid risks associated with the energy transition.

A matter of metrics? How analysing per capita energy use changes the face of energy efficient housing in Sweden and reveals injustices in the energy transition

Improving energy performance of the housing stock continues to be an important undertaking in the energy transition of many EU member states. However, tendencies of low-income households generally living in buildings with low energy performance pose a challenge for this transition, and cases of ‘renoviction’ and ‘green gentrification’ are becoming more and more noticed in the scientific community. More so, questions regarding the distributive justice of costs and burdens in the energy transition of the housing stock have been raised. In this paper, we approach this problem from a perspective of energy performance metrics. Although energy performance (kWh/m2, year) is generally lower in buildings inhabited by low-income households, residential density—and thus building utilisation—tends to be higher. By measuring per capita energy use instead of area-normalised energy use, we investigate if a high residential density can offset a low energy performance and change the perception of which buildings are considered energy inefficient and which are not. Results showed that by measuring per capita energy use instead of area-normalised energy use, energy inefficient buildings were found in high-income city centres instead of in low-income suburbs of Swedish cities. Moreover, there has been an unjust distribution of the imposition of the energy transition over the past decade where the residents with the initially lowest per capita energy use have carried a disproportionately high share of the energy savings. This suggests that a change of energy performance metrics could offer an approach for a more socially just and sustainable energy transition of the housing stock.

A Critical Review of Façade Retrofit Measures for Minimizing Heating and Cooling Demand in Existing Buildings

The building industry is currently experiencing a myriad of challenges, including low energy performance in existing buildings. Since the façade considerably contributes to heating and cooling in buildings, façade retrofit is presumed as an effective solution to minimize cooling and heating demand in existing buildings.In-depth scrutiny in façade retrofit actions reveals different Façade Retrofit Measures (FRMs) that aim to minimize cooling and heating demand in existing buildings. They include Energy Conservation Measures (ECMs), which prevent excessive heat transmittance, and Energy Modulation Measures (EMMs), which modulate energy consumption through passive heating and cooling strategies. A Combination of Measures (CoMs) is also the state-of-the-art in the face of retrofit actions.In this paper, a further analysis elaborates on the effectiveness of each measure in Cooling-Dominated (CD) and Heating-Dominated (HD) climates. This analysis showed that façade retrofit could reduce energy consumption for heating and cooling by up to 50% through architectural interventions.The study findings also revealed that ECMs effectively minimize energy consumption in a heating-dominated climate by lowering conductive and convective heat transfer. However, EMMs are more crucial in reducing energy consumption in a cooling-dominated climate by controlling radiative heat transfer.

Experimental comparison of R404A and R452A in refrigeration systems

In this study, R404A and R452A refrigerants used in refrigeration systems were compared experimentally. The energy performance of the system was investigated for widely used evaporation temperatures (−5, 0, +5 °C) and condenser temperatures (25, 35, 45 °C). It was seen that the coefficient of performance (COP) was higher but the power consumption of the system was lower when using R452A as a substitute for R404A. When R452A was used, the COP was improved by about 3% to 8% compared to R404A. Furthermore, the cooling capacity decreased by about 2% for condenser temperatures of 25 and 35 °C, while it increased at a condenser temperature of 45 °C. The power consumption of the system was also reduced by nearly 5%. The mass flow rate of the refrigerant was lower when the system was operated with R452A. In the middle term, R452A could be a suitable alternative refrigerant for commercial refrigeration applications due to its low global warming potential (GWP) value and better energy performance compared to R404A.

Optimal energy retrofit plan for conservation and sustainable use of historic campus building: Case of cultural property building

In the past several decades, global population growth and rapid economic development have resulted in significant increases in building energy consumption. To reduce green house gas emissions and building energy consumption, building materials and energy technologies must be optimized. Building retrofitting is a more efficient method than reconstruction to improve building energy performance. Because historical buildings are typically characterized by relatively low-performance construction and energy systems as compared to modern buildings, retrofits are essential for older historical buildings. Furthermore, energy retrofitting of historical buildings is becoming increasingly common. This study presents an energy-saving retrofitting methodology for historical buildings that have low energy performance to facilitate the continued use and conservation of cultural buildings. The building energy retrofit (BER) package combines passive, active, and renewable-energy technologies for each of four targets. Based on an energy-consumption analysis, the BER3 package of target 2 for preserving the historical value and building usability and improving energy savings reduced the total energy consumption by 61.2% and the heating and cooling loads by 45%. This study demonstrates that BER3 is the optimal solution for realizing energy-saving retrofits of historical buildings while preserving their historical value and usability. The application of BER3 reduced the average energy consumption of Underwood Hall by 54.2% in winter and 42.6% in summer. The application of BER3 also reduced the annual energy costs of Underwood Hall by 47.9%.

Parasitic Magnetism in Magnetoelectric Antiferromagnet.

Parasitic magnetism plays an important role in magnetoelectric spin switching of antiferromagnetic oxides, but its mechanism has not been clearly investigated. Unlike the widely obtained surface boundary magnetization in magnetoelectric Cr2O3 antiferromagnet, we previously reported that Al doping could produce volume-dependent parasitic magnetism (Mpara) in Cr2O3 with the remaining magnetoelectric effect and antiferromagnetic properties. In this work, we systematically investigated the magnetic properties of Mpara in Cr2O3 through its different exchange coupling characteristics with the ferromagnet at various conditions. The columnar grain boundaries cause an antiferromagnetic sublattice breaking to produce uncompensated spins and thus are considered to be responsible for Mpara in both undoped and Al-doped Cr2O3. Finally, a model was proposed for the formation mechanism of the parasitic magnetism in Cr2O3, which explains the reported magnetic characteristics of Cr2O3, and some current topics such as the domain formation and motion in Cr2O3 during magnetoelectric spin switching. This work contributes to a deep understanding of antiferromagnetic spintronics and provides a method to realize the low-energy operation of antiferromagnetic-based magnetic random access memory.

Synergistic effect of ZnO/ZIF8 heterostructure material in photodegradation of methylene blue and volatile organic compounds with sensor operating at room temperature

To improve the performance of ZnO in photocatalytic processes and gas sensing, ZnO was modified by coating the surface with a zeolitic-imidazolate framework-8 (ZIF-8). Partially dissolved Zn2+ ions from ZnO interacted with 2-methylimidazole (MeIM) to achieve a ZIF-8 coating on the ZnO surface as a ZnO@ZIF8 heterostructure. The ZnO@ZIF8 was further used as a photocatalyst for methylene blue degradation and the performance was compared with that of pure ZnO and pure ZIF-8. The result showed that the photocatalytic efficiency of ZnO@ZIF8 is better than that of pure ZnO. Furthermore, ZnO@ZIF8 was also used as a gas-sensing material for volatile organic compound (VOC) detection. The results indicated that ZnO@ZIF8 could respond to VOCs at room temperature (26 ​± ​2 ​°C) and was selective to ammonia while pure ZnO was unable to respond to all of the VOCs. The higher efficiency of ZnO@ZIF8 results from the synergistic effect between ZIF-8 and ZnO. Moreover, the combination of ZIF-8 and ZnO could be decreased by the electron-hole recombination process and also reduce the energy band gap which led to low energy operation.

Frequency Performance Distribution Index for Short-Term System Frequency Reliability Forecast Considering Renewable Energy Integration

Risk in a power system’s ability to survive imminent disturbances without recourse to low operational cost and non-interruptive energy delivery remains the responsibility of every grid operator. Intermittencies in renewable energy and dynamic load variations influence the quality of power supply. The sudden changes affect the system frequency, compromising the reliability of the system grid; generation response to frequency regulation is momentous in such an incident. Slower response or smaller reserve capacity may cause a power shortage. This paper proposes a novel predictive scheme for a short-term operational reliability evaluation for system operations planning. The proposed method evaluates the operational reliability of system frequency whiles considering high renewable power penetration and energy storage system incorporation. Required energy generations, and other grid parameters, are modelled as stochastic inputs to the framework. We formulate a reliability index as a frequency distribution considering system frequency control dynamics and processes. The IEEE Reliability Test System (RTS) is used to prove the efficacy of the proposed model.

Programming Pulse Width Assessment for Reliable and Low-Energy Endurance Performance in Al:HfO2-Based RRAM Arrays

A crucial step in order to achieve fast and low-energy switching operations in resistive random access memory (RRAM) memories is the reduction of the programming pulse width. In this study, the incremental step pulse with verify algorithm (ISPVA) was implemented by using different pulse widths between 10 μ s and 50 ns and assessed on Al-doped HfO 2 4 kbit RRAM memory arrays. The switching stability was assessed by means of an endurance test of 1k cycles. Both conductive levels and voltages needed for switching showed a remarkable good behavior along 1k reset/set cycles regardless the programming pulse width implemented. Nevertheless, the distributions of voltages as well as the amount of energy required to carry out the switching operations were definitely affected by the value of the pulse width. In addition, the data retention was evaluated after the endurance analysis by annealing the RRAM devices at 150 °C along 100 h. Just an almost negligible increase on the rate of degradation of about 1 μ A at the end of the 100 h of annealing was reported between those samples programmed by employing a pulse width of 10 μ s and those employing 50 ns. Finally, an endurance performance of 200k cycles without any degradation was achieved on 128 RRAM devices by using programming pulses of 100 ns width.

The effect of different parameters of the excess heat source on the levelized cost of excess heat

In areas with higher heat demand densities, district heating is the most logical way of achieving heat sector decarbonisation aims, especially when renewable energy or highly efficient cogeneration is used. However, excess heat from industry is also recognized as a valuable source with the high potential for utilization. It increases the economic and environmental viability of the system due to the low operation, investment and conventional energy costs. The main goal of this work was to define the effect of the main factors influencing the levelized cost of excess heat. The paper provided the feasibility of excess heat utilization in different district heating configurations, including solar collectors, cogeneration, peak load boilers, heat pumps and heat storages, showing that its overall utilization can be much lower than the expected 100% of the overall availability depending on the configuration. Furthermore, temperature levels of the excess heat source have been considered in the analysis to show changes in levelized cost of excess heat with different temperatures and the necessary preconditions for its utilization. It has been concluded that it is necessary to reduce the supply temperature of district heating in order to make the low temperature excess heat sources feasible.

Methods to improve UAV performance using hybrid-electric architectures

PurposeWhen comparing and contrasting different types of fixed-wing military aircraft on the basis of an energetic efficiency figure-of-merit, unmanned aerial vehicles (UAVs) dedicated to tactical medium-altitude long-endurance (MALE) operations appear to have significant potential when hybrid-electric propulsion and power systems (HEPPS) are implemented. Beginning with a baseline Eulair drone, this paper aims to examine the feasibility of retro-fitting with an Autarkic-Parallel-HEPPS architecture to enhance performance of the original single diesel engine.Design/methodology/approachIn view of the low gravimetric specific energy performance attributes of batteries in the foreseeable future, the best approach was found to be one in which the Parallel-HEPPS architecture has the thermal engine augmented by an organic rankine cycle (ORC). For this study, with the outer mould lines fixed, the goal was to increase endurance without increasing the Eulair drone maximum take-off weight beyond an upper limit of +10%. The intent was to also retain take-off distance and climb performance or, where possible, improve upon these aspects. Therefore, as the focus of the work was on power scheduling, two primary control variables were identified as degree-of-hybridisation for useful power and cut-off altitude during the en route climb phase. Quasi-static methods were used for technical sub-space modelling, and these modules were linked into a constrained optimisation algorithm.FindingsResults showed that an Autarkic-Parallel-HEPPS architecture comprising an ORC thermal energy recovery apparatus and high-end year-2020 battery, the endurance of the considered aircraft could be increased by 11%, i.e. a total of around 28 h, including de-icing system, in-flight recharge and emergency aircraft recovery capabilities. The same aircraft with the de-icing functionality removed resulted in a 20% increase in maximum endurance to 30 h.Practical implicationsAlthough the adoption of Series/Parallel-HEPPS only solutions do tend to generate questionable improvements in UAV operational performance, combinations of HEPPS with energy recovery machines that use, for example, an ORC, were found to have merit. Furthermore, such architectural solutions could also offer opportunity to facilitate additional functions like de-icing and emergency aircraft recovery during engine failure, which is either not available for UAVs today or prove to be prohibitive in terms of operational performance attributes when implemented using a conventional PPS approach.Originality/valueThis technical paper highlights a new degree of freedom in terms of power scheduling during climbing transversal flight operations. A control parameter of cut-off altitude for all types of HEPPS-based aircraft should be introduced into the technical decision-making/optimisation/analysis scheme and is seen to be a fundamental aspect when conducting trade-studies with respect to degree-of-hybridisation for useful power.

A modelling framework for the diffusion of low carbon energy performance contracts

The building sector contributes significantly to global energy consumption and CO2 emissions. It is urgent to reduce them through the retrofit of the current building stock and improvements in new building designs. The energy performance contracts that can deliver energy consumption savings must have an attractive rate of return to make financial sense for public and private sector buildings. These contracts must also have a wide uptake in the market to improve significantly the energy performance of the building stock. This paper develops a hybrid bottom up and system dynamics modelling framework to: (1) explore the diffusion of energy performance contracts and its effect on operational building energy consumption and (2) facilitate integration into policy making. The bottom up modelling component is used to provide estimates of potential operational building energy use savings. The estimates are the input to the system dynamics diffusion model which is used to explore diffusion pathways of energy performance contracts. The framework will facilitate scenario and policy analysis for the diffusion of the contracts on the building stock and their potential impact on energy consumption and associated CO2 emissions.

Exploring the Operation Factors that Influence Performance of a Spiral-Wound Forward Osmosis Membrane Process for Scale-up Design.

Forward osmosis (FO) technology has increasingly attracted attention owing to its low operational energy and low fouling propensity. Despite extensive investigations on FO, very few module-scale FO studies on the operation and design of the FO process have been conducted. In this paper, a simple and practical FO process design parameter called normalized membrane area is suggested based on a performance analysis of spiral-wound FO elements. The influence of operation factors on operating pressures and water recovery was investigated using 8-inch spiral wound elements in the continuous operation mode. The membrane area was adjusted by series connection of FO elements to a maximum value of 46 m2 (three elements). The feed and draw flow rates were varied between 5 and 15 LPM under various feed (10, 20, and 30 g/L) and draw (58.4 and 233.8 g/L) concentration combinations. The analysis of flow rates (feed, draw, and permeate flow rates) indicated not only high flow channel resistance on the draw side but also high permeate flow rates can induce higher operating pressures owing to strong mutual interaction of the feed and the draw streams. Feed water recovery was focused on as a key performance index, and the experimental recovery (RExp) and theoretical maximum recovery (RTh) values were compared. The results revealed the significance of the feed flow rate and the membrane area in terms of enhancing the water recovery performance. In addition, a clear relationship was observed between the membrane area normalized by the initial feed flow rates and the water recovery ratio (RExp/RTh), even though the applied operation conditions were different. Finally, an empirical equation to estimate the required membrane area of spiral-wound FO was proposed for the FO process design. The equation can be used to predict water recovery of FO systems as well, for example, if an FO system is operated at 0.08 m2L−1h of the normalized membrane area, the system is expected to offer 78% of the RTh value.