Valve Concept Research Articles

Determination of the Flow Angle in Hydraulic Components

The paper presents a general analytical equation for the determination of the flow angel in hydraulic components like valves and pumps. Exemplary, the method is applied to two different valve concepts – a cartridge valve and a rotary slide valve.cos(εavg)=1/2(cos(αl)−cos(αr)) The huge advantage of this equation is the simple expression with no dependencies on operation conditions. Only the geometry is important. The underlying phenomenon is valid for turbulent flows. Thus it is useable for almost all hydraulic applications. It makes it possible to predict the flow force as well as to optimize the flow geometry. It describes the flow angle of the free jet behind a narrow section (e.g. a control edge of a valve). By a suitable choice of the angle of the free jet, the flow force can be reduced by changing the direction of the outgoing impulse. With regard to cavitation, the impact of the free jet can be shifted and thus the cavitation erosion can be shifted or weakened. This paper deals with the investigation of the flow angle of free jets as well as the prediction of the flow force in valves without CFD. For the illustration a cartridge and a rotary slide valve are used as technical applications. In the first section, geometric factors influencing the flow angle are discussed, as well as the transferability of the results under varying operating conditions (laminar and turbulent). Using a generic minimal model, the behaviour of the flow angle with respect to geometric influence factors and operating conditions is investigated by means of CFD. The results are adapted to real applications in the second section. The direct adjustment of the flow angle results in a significant improvement in the characteristic behaviour of the presented valves (such as flow force and resistance torque). It becomes clear how efficient the adjustment of the flow angle can be if the basis of the formation of the free jet is known. Due to the derivation of the relationship with the help of an abstracted minimal model, the knowledge gained can be used in many ways and can also be transferred to other applications in the field of fluid technology. Optimization processes are more efficiently without using elaborated simulation models e.g. driven by CFD.

Transcatheter bicuspid venous valve prostheses: fluid mechanical performance testing of artificial nonwoven leaflets

BackgroundChronic venous insufficiency (CVI) is a common disease with a high prevalence. Incompetent venous valves are considered as one of the main causes. Besides compression therapy, various surgical therapies are practiced, whereby the reconstruction of valves is of central importance. There is an unmet clinical need, no valve prosthesis is commercially available to date. This work introduces two versions of a patented prosthetic bicuspid valve design made of electrospun thermoplastic silicone polycarbonate polyurethane (TSPCU) nanofiber leaflets attached in a nitinol stent, and their performance in static and pulsatile operation.ResultsThe valves mainly fulfill the requirements widely accepted in literature. Valves of both versions were functional in the physiological pressure range up to 50 mmHg with design specific differences.ConclusionsThe here introduced design versions act as a platform technology and can be tailored for an intended implantation site. Evaluation of the original and modified valve concept demonstrated efficacy, with limitations at higher loads for original design. At the current state, the modification is preferable for fabrication, as one processing step is eliminated. Moreover, specific design recommendations could be drawn for valves of similar basic structure. Future work will focus on long-term performance and biocompatibility prior to the initiation of preclinical in vivo studies.

True pinch mode of magnetorheological fluids

Abstract Magnetorheological (MR) fluids are representatives of smart materials. They react to magnetic fields by developing a yield stress. The effect has been employed in real-world applications such as automotive chassis systems or optical finishing. By convention, MR devices can be operated in at least one of the fundamental modes: flow, shear, squeeze, gradient pinch of which the former has been the least studied and understood. In pinch mode, the material in the flow channel is exposed to non-uniform magnetic fields in the direction parallel to fluid flow. As a result, only the volume of MR fluid near the channel walls are energized to modify the particular material property (yield stress). The result is the channel’s effective diameter change. The behavior of the material in pinch mode is unique and unseen in the other controllable fluids. To study the material’s characteristics in the specific mode, the authors developed a novel circuit concept for energizing the material in an effort to achieve the ‘true-zero’ pinch mode magnetic behavior. Contrary to the existing pinch mode valve concepts, the concept valve allows to achieve zero magnetic flux density in the center of the flow channel regardless of the current level. To test the hypothesis a prototype valve was modeled, manufactured and tested across a range of external (flow rate, current/magnetic flux) stimuli. The obtained results yield sufficient evidence proven by results of magnetic simulations to support the underlying hypothesis. The experimental results illustrate the pinch mode type behaviour, i.e. the slope change in the pressure vs flow rate characteristics.

Early Feasibility Study of a Hybrid Tissue-Engineered Mitral Valve in an Ovine Model.

Tissue engineering aims to overcome the current limitations of heart valves by providing a viable alternative using living tissue. Nevertheless, the valves constructed from either decellularized xenogeneic or purely biologic scaffolds are unable to withstand the hemodynamic loads, particularly in the left ventricle. To address this, we have been developing a hybrid tissue-engineered heart valve (H-TEHV) concept consisting of a nondegradable elastomeric scaffold enclosed in a valve-like living tissue constructed from autologous cells. We developed a 21 mm mitral valve scaffold for implantation in an ovine model. Smooth muscle cells/fibroblasts and endothelial cells were extracted, isolated, and expanded from the animal's jugular vein. Next, the scaffold underwent a sequential coating with the sorted cells mixed with collagen type I. The resulting H-TEHV was then implanted into the mitral position of the same sheep through open-heart surgery. Echocardiography scans following the procedure revealed an acceptable valve performance, with no signs of regurgitation. The valve orifice area, measured by planimetry, was 2.9 cm2, the ejection fraction reached 67%, and the mean transmitral pressure gradient was measured at 8.39 mmHg. The animal successfully recovered from anesthesia and was transferred to the vivarium. Upon autopsy, the examination confirmed the integrity of the H-TEHV, with no evidence of tissue dehiscence. The preliminary results from the animal implantation suggest the feasibility of the H-TEHV.

Design, analysis, and validation of an orderly recruitment valve for bio-inspired fluidic artificial muscles

Biological musculature employs variable recruitment of muscle fibers from smaller to larger units as the load increases. This orderly recruitment strategy has certain physiological advantages like minimizing fatigue and providing finer motor control. Recently fluidic artificial muscles (FAM) are gaining popularity as actuators due to their increased efficiency by employing bio-inspired recruitment strategies such as active variable recruitment (AVR). AVR systems use a multi-valve system (MVS) configuration to selectively recruit individual FAMs depending on the load. However, when using an MVS configuration, an increase in the number of motor units in a bundle corresponds to an increase in the number of valves in the system. This introduces greater complexity and weight. The objective of this paper is to propose, analyze, and demonstrate an orderly recruitment valve (ORV) concept that enables orderly recruitment of multiple FAMs in the system using a single valve. A mathematical model of an ORV-controlled FAM bundle is presented and validated by experiments performed on a proof-of-concept ORV experiment. The modeling is extended to explore a case study of a 1-DOF robot arm system consisting of an electrohydraulic pressurization system, ORV, and a FAM-actuated rotating arm plant and its dynamics are simulated to further demonstrate the capabilities of an ORV-controlled closed-loop system. An orderly recruitment strategy was implemented through a model-based feed forward controller. To benchmark the performance of the ORV, a conventional MVS with equivalent dynamics and controller was also implemented. Trajectory tracking simulations on both the systems revealed lower tracking error for the ORV controlled system compared to the MVS controlled system due to the unique cross-flow effects present in the ORV. However, the MVS, due to its independent and multiple valve setup, proved to be more adaptable for performance. For example, modifications to the recruitment thresholds of the MVS demonstrated improvement in tracking error, albeit with a sacrifice in efficiency. In the ORV, tracking performance remained insensitive to any variation in recruitment threshold. The results show that compared to the MVS, the ORV offers a simpler and more compact valving architecture at the expense of moderate losses in control flexibility and performance.

Bistable Valves for MR Fluid-Based Soft Robotic Actuation Systems

Magnetorheological (MR) fluids have unique characteristics that make them well-suited for soft robotic actuation systems. Two particularly interesting applications are bistable valves and force-amplified grippers, which only require power to switch states. These design topologies can not only make MR fluid actuation systems more efficient, but can also allow them to be constructed from entirely compliant materials. In this work, we describe new bistable valve mechanism concepts; the first design is constructed using traditional rigid components while the second design is composed of entirely compliant materials. This includes liquid metal coils, compliant magnetic composites, and silicone flexures. The MR valve concept is modeled using magnetic field theory and scaling laws are determined from MR fluid holding pressure experiments. Then, experimental results are used to show that rough tubing surfaces can withhold an average of 5× more pressure than smooth tubing surfaces. Both rigid and compliant valve topologies are then constructed and tested, showing the ability to hold up to 88 kPa and 37 kPa of pressure, respectively. These valves are then implemented for controlling a soft multi-fingered PneuNet gripper and a new force-amplified MR fluid gripper, which has the ability to provide up to 324$\%$ higher load capacity than purely pressure-driven mechanisms (with the addition of a 25 mm diameter and 12.7 mm thick Nd-Fe-B magnet). Finally, we show how these bistable valves and grippers can be used for grasping and manipulation applications.

Splitting Ventilator Valve Concept Used In The COVID-19 Treatment Through Additive Manufacturing Technique

Due to COVID-19 outbreak, many sectors around the globe have been facing the most diverse crisis. Regarding the health system, hospitals all over the world have been going through, among so many challenges, shortage of resources that could, if available, help them on the fight against COVID-19, and even save the lives of their patients. This review paper aims to offer for both healthcare providers and patients, better conditions when fighting the disease, regarding the actual primary care shortage, and addressing a splitting valve concept coupled to the mechanical ventilators in the most severe cases. The automated valve development with a monitoring and analysis system for pulmonary mechanics will stablish the database parameters of patients with COVid-19 and SARS, in order to assist the medical team in the treatment of diseases and the average evolution of the clinical condition of patients at an early stage, contributing to a reduction in the time of hospitalization and treatment and mortality. These information is saved on a database shared with other hospitals, allowing a search for matching patients; with similar or same pulmonary compliance, gender, height, weight, respiratory frequency and, in most severe cases when the patient needs mechanical ventilation, the availability of the nearest treatment is verified viewing immediate care. Regarding the mechanical ventilator device usage, the automated valve views engaged to a human-machine interface from the systems hardware allows the treatment of multiple patients, under the same ventilator, in an individualized way. To achieve that, pressure transducers and controllers of flow and temperature will continuously monitor the adequate flow of air and pressure to each patient that are under the same ventilator. Moreover, when monitoring each patient among the health units and hospitals integrated to the system, the medical team is helped defining the best strategy to the treatment stage and, by these means, the use of mechanical ventilator by the CoVID-19 patient is amplified, allowing to attend more than one patient who will need mechanical ventilation with SARS an accuracy treatment and monitoring method.

Design and numerical simulation for the development of an expandable paediatric heart valve.

Current paediatric valve replacement options cannot compensate for somatic growth, leading to an obstruction of flow as the child outgrows the prosthesis. This often necessitates an increase in revision surgeries, leading to legacy issues into adulthood. An expandable valve concept was modelled with an inverse relationship between annulus size and height, to retain the leaflet geometry without requiring additional intervention. Parametric design modelling was used to define certain valve parameter aspect ratios in relation to the base radius, Rb, including commissural radius, Rc, valve height, H and coaptation height, x. Fluid-structure simulations were subsequently carried out using the Immersed Boundary method to radially compress down the fully expanded aortic valve whilst subjecting it to diastolic and systolic loading cycles. Leaflet radial displacements were analysed to determine if valve performance is likely to be compromised following compression. Work is ongoing to optimise valvular parameter design for the paediatric patient cohort.

Multi-Response optimization applied to a mechanically assisted reed valve of a hermetic reciprocating compressor

• novel valve concept to improve variable speed compressors. • simultaneous improvement of efficiency, cooling capacity and reliability. • significant reduction of the valve impact velocities. Reed valves are widely used in hermetic reciprocating compressors for domestic refrigeration. They are crucial components in terms of efficiency, cooling performance and reliability of the compressor. While reed valves already cause a significant proportion of the thermodynamic losses in fixed speed compressors, they cause even more challenges in variable speed compressors. Especially in variable speed compressors, a further improvement of the reed valve dynamics requires the consideration of a new valve concept. In this work, a new and cost-effective concept of a mechanically assisted suction reed valve is introduced. Simulation based response modelling and a multi-response optimization approach are applied to systematically optimize the design. Simulations between 1500 rpm and 5000 rpm indicate the strengths and weaknesses of individual optimized design variants over a wide compressor speed range. Calorimeter and valve dynamics measurements show considerable improvements of the COP and the valve impact velocity.

Hydrogel Microvalves as Control Elements for Parallelized Enzymatic Cascade Reactions in Microfluidics.

Compartmentalized microfluidic devices with immobilized catalysts are a valuable tool for overcoming the incompatibility challenge in (bio) catalytic cascade reactions and high-throughput screening of multiple reaction parameters. To achieve flow control in microfluidics, stimuli-responsive hydrogel microvalves were previously introduced. However, an application of this valve concept for the control of multistep reactions was not yet shown. To fill this gap, we show the integration of thermoresponsive poly(N-isopropylacrylamide) (PNiPAAm) microvalves (diameter: 500 and 600 µm) into PDMS-on-glass microfluidic devices for the control of parallelized enzyme-catalyzed cascade reactions. As a proof-of-principle, the biocatalysts glucose oxidase (GOx), horseradish peroxidase (HRP) and myoglobin (Myo) were immobilized in photopatterned hydrogel dot arrays (diameter of the dots: 350 µm, amount of enzymes: 0.13–2.3 µg) within three compartments of the device. Switching of the microvalves was achieved within 4 to 6 s and thereby the fluid pathway of the enzyme substrate solution (5 mmol/L) in the device was determined. Consequently, either the enzyme cascade reaction GOx-HRP or GOx-Myo was performed and continuously quantified by ultraviolet-visible (UV-Vis) spectroscopy. The functionality of the microvalves was shown in four hourly switching cycles and visualized by the path-dependent substrate conversion.

Finger-powered fluidic actuation and mixing via MultiJet 3D printing.

Additive manufacturing, or three-dimensional (3D) printing, has garnered significant interest in recent years towards the fabrication of sub-millimeter scale devices for an ever-widening array of chemical, biological and biomedical applications. Conventional 3D printed fluidic systems, however, still necessitate the use of non-portable, high-powered external off-chip sources of fluidic actuation, such as electro-mechanical pumps and complex pressure-driven controllers, thus limiting their scope towards point-of-need applications. This work proposes entirely 3D printed sources of human-powered fluidic actuation which can be directly incorporated into the design of any 3D printable sub-millifluidic or microfluidic system where electrical power-free operation is desired. Multiple modular, single-fluid finger-powered actuator (FPA) designs were fabricated and experimentally characterized. Furthermore, a new 3D fluidic one-way valve concept employing a dynamic bracing mechanism was developed, demonstrating a high diodicity of ∼1117.4 and significant reduction in back-flow from the state-of-the-art. As a result, fabricated FPA prototypes achieved tailorable experimental fluid flow rates from ∼100 to ∼3000 μL min-1 without the use of electricity. Moreover, a portable human-powered two-fluid pulsatile fluidic mixer, capable of generating fully-mixed fluids in 10 seconds, is presented, demonstrating the application of FPAs towards on-chip integration into more complex 3D printed fluidic networks.

Measurements of a Novel Digital Hydraulic Valve Comprising a Cushioning Feature

Abstract This article presents simulation data and measurements of a novel valve concept that features a soft landing concept. The purpose is to validate the design framework that has been applied to design the valve. The experimental results are obtained with a test rig manufactured specifically for this type of valve design. The validation includes studying the valves switching dynamics, cushion pressure dynamics, and movement-induced flow (MIF). The tests show that the tendencies are captured accurately although the exact magnitudes of forces do not match fully and a noticeable difference between simulated and measured plunger position is revealed. This amounts in a significant difference in the cushion pressure. Therefore, the pressure model is validated by using the measured lift and velocity derived hereof and this shows sufficient correspondence between the two pressures.

Modeling and Validation of Moving Coil Actuated Valve for Digital Displacement Machines

This paper concerns a novel moving coil actuator integrated with a high-performance seat valve for use in digital displacement machines (DDM), which is an emerging fluid power technology that sets strict actuator requirements in order to get a high energy conversion efficiency. Hence, the mechanical switching time must be in the millisecond range and the actuator power consumption must be in range of few tens of watts. The objectives are twofold: First, establish a proof-of-concept for the integrated actuator/valve that relies on several principles and mechanisms new or uncommon in fluid power applications. Second, formulate and validate a transient numerical model describing the actuator/valve. A coupled simulation model is established to predict the switching performance in which transient electromagnetic finite-element-analysis with dynamic remeshing is coupled to a set of ordinary differential equations describing the motion dynamics. In this way, the movement induced hydromechanical fluid forces caused by rapid acceleration of the valve plunger is coupled with the electromagnetic dynamics. The proposed model is compared rigorously against measurements obtained from a series of experiments based on a fully operational valve prototype. Comparisons of, e.g., transient flux density, current, and plunger position, show that the model describes both the actuator and the valve motion very well. Finally, results are presented when testing the prototype valve in fully operational DDM to establish proof-of-concept for the proposed valve concept. The actuator/valve is shown to be capable of rapid switching in less than 4 ms, while only consuming approximately 45 W corresponding to 0.7% of the machine output power.

TCT-5 Long-term Preclinical In Vivo Results with a Restorative Aortic Valve

Cross-linked animal tissues are being used in virtually all modern biological aortic replacement valves. Limitations in tissue durability, consistency and sourcing should be overcome by novel alternative materials. The restorative aortic valve concept is based on supramolecular polymer technology

Full simulation of a piezoelectric double nozzle flapper pilot valve coupled with a main stage spool valve

This paper develops a detailed simulation model, realized by the software Simscape, which can be a powerful tool to analyze the performance of a double nozzle flapper valve actuated by a piezoelectric ring bender. The particularity of this valve is that the use of the torque motor and flexure tube is avoided, thus reducing the complexity, manufacturing time and cost of the valve assembly. The model accounts for all the real phenomena present in the valve, such as fluid compressibility and fluid viscosity. The viability of the valve concept is validated by step tests simulated at different valve openings. It is shown that the response time obtained for a supply pressure of 210 bar and necessary to reach 90% of the maximum opening degree (corresponding to a maximum spool position of 1mm and maximum flow rate of 60 l/min) is only 6 ms, which is comparable with typical commercially available double nozzle flapper valves, but with the advantage of having removed critical components such as the torque motor and the flexure tube.

Cardiovascular tissue engineering: From basic science to clinical application.

Valvular heart disease is an increasing population health problem and, especially in the elderly, a significant cause of morbidity and mortality. The current treatment options, such as mechanical and bioprosthetic heart valve replacements, have significant restrictions and limitations. Considering the increased life expectancy of our aging population, there is an urgent need for novel heart valve concepts that remain functional throughout life to prevent the need for reoperation. Heart valve tissue engineering aims to overcome these constraints by creating regenerative, self-repairing valve substitutes with life-long durability. In this review, we give an overview of advances in the development of tissue engineered heart valves, and describe the steps required to design and validate a novel valve prosthesis before reaching first-in-men clinical trials. In-silico and in-vitro models are proposed as tools for the assessment of valve design, functionality and compatibility, while in-vivo preclinical models are required to confirm the remodeling and growth potential of the tissue engineered heart valves. An overview of the tissue engineered heart valve studies that have reached clinical translation is also presented. Final remarks highlight the possibilities as well as the obstacles to overcome in translating heart valve prostheses into clinical application.

3D Biofabrication of Thermoplastic Polyurethane (TPU)/Poly-l-lactic Acid (PLLA) Electrospun Nanofibers Containing Maghemite (γ-Fe₂O₃) for Tissue Engineering Aortic Heart Valve.

Valvular dysfunction as the prominent reason of heart failure may causes morbidity and mortality around the world. The inability of human body to regenerate the defected heart valves necessitates the development of the artificial prosthesis to be replaced. Besides, the lack of capacity to grow, repair or remodel of an artificial valves and biological difficulty such as infection or inflammation make the development of tissue engineering heart valve (TEHV) concept. This research presented the use of compound of poly-l-lactic acid (PLLA), thermoplastic polyurethane (TPU) and maghemite nanoparticle (γ-Fe2O3) as the potential biomaterials to develop three-dimensional (3D) aortic heart valve scaffold. Electrospinning was used for fabricating the 3D scaffold. The steepest ascent followed by the response surface methodology was used to optimize the electrospinning parameters involved in terms of elastic modulus. The structural and porosity properties of fabricated scaffold were characterized using FE-SEM and liquid displacement technique, respectively. The 3D scaffold was then seeded with aortic smooth muscle cells (AOSMCs) and biological behavior in terms of cell attachment and proliferation during 34 days of incubation was characterized using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and confocal laser microscopy. Furthermore, the mechanical properties in terms of elastic modulus and stiffness were investigated after cell seeding through macro-indentation test. The analysis indicated the formation of ultrafine quality of nanofibers with diameter distribution of 178 ± 45 nm and 90.72% porosity. In terms of cell proliferation, the results exhibited desirable proliferation (109.32 ± 3.22% compared to the control) of cells over the 3D scaffold in 34 days of incubation. The elastic modulus and stiffness index after cell seeding were founded to be 22.78 ± 2.12 MPa and 1490.9 ± 12 Nmm2, respectively. Overall, the fabricated 3D scaffold exhibits desirable structural, biological and mechanical properties and has the potential to be used in vivo.

Piezo-driven valve for disruption mitigation studies in tokamaks

Disruptions are a major issue for the safe operation of tokamaks. Hence the mitigation of disruptive effects is of high priority in view of ITER and DEMO. Previous experiments at ASDEX Upgrade have shown that the injections of massive amounts of gaseous impurities using in-vessel valves mitigate disruptions very efficiently, due to short time of flight of the gas towards the plasma edge and the applicability of pure noble gases. A new valve concept for in-vessel massive gas injection has been developed at ASDEX Upgrade to replace the old valves which suffered from reliability problems. This new valve is a normally closed valve since the valve plate is pressed into the main sealing by a stainless steel bellow (acting as a spring), sealing off the gas reservoir, which can hold 42cm3 of gas at a pressure of up to 5MPa. The valves actuator consists of 4 piezoelectric stacks which are mounted in two parallel pairs into a monolithic titanium frame. This frame is rigidly connected to the valve plate and it amplifies the stroke of the stacks to allow a total stroke of the valve plate of 2.2mm, which is reached after 5ms. The diameter of the straight valve nozzle is 14mm allowing a peak flow rate of 44kPam3/s after 1ms. The valve has a size of 173mm×88mm×70mm.

Proof-of-Concept Evaluation of the SailValve Self-Expanding Deep Venous Valve System in a Porcine Model

Purpose: To evaluate the SailValve, a new self-expanding deep venous valve concept based on a single polytetrafluoroethylene cusp floating up and down in the bloodstream like a sail, acting as a flow regulator and allowing minimal reflux to reduce thrombogenicity. Methods: Both iliac veins of 5 pigs were implanted with SailValve devices; the first animal was an acute pilot experiment to show the feasibility of accurately positioning the SailValve via a femoral access. The other 4 animals were followed for 2 weeks (n=2) or 4 weeks (n=2) under a chronic implantation protocol. Patency and valve function were evaluated directly in all animals using ascending and descending phlebography after device placement and at termination in the chronic implant animals. For reasons of clinical relevance, a regimen of clopidogrel and calcium carbasalate was administered. Histological analysis was performed according to a predefined protocol by an independent pathologist. Results: Deployment was technically feasible in all 10 iliac veins, and all were patent directly after placement. No perioperative or postoperative complications occurred. Ascending phlebograms in the follow-up animals confirmed the patency of all valves after 2 or 4 weeks. Descending phlebograms showed full function in 5 of 8 valves. Limited reflux was seen in 1 valve (4-week group), and the function in the remaining 2 valves (2-week group) was insufficient because of malpositioning. No macroscopic thrombosis was noted on histology. Histology in the follow-up groups revealed a progressive inflammatory reaction to the valves. Conclusion: This animal study shows the potential of the SailValve concept with sufficient valve function after adequate positioning and no (thrombogenic) occlusions after short-term follow-up. Future research is essential to optimize valve material and long-term patency.

Design of a thermosyphon-based thermal valve for controlled high-temperature heat extraction

Conventional concentrated solar power (CSP) is a reliable alternative energy source that uses the sun’s heat to drive a heat engine to produce electrical power. An advantage of CSP is its ability to store thermal energy for use during off-sun hours which is typically done by storing sensible heat in molten salts. Alternatively, thermal energy may be stored as latent heat in a phase-change material (PCM), which stores large quantities of thermal energy in an isothermal process. On-sun, the PCM melts, storing energy. Off-sun, the latent heat is extracted to produce dispatchable electrical power.This paper presents the design of a thermosyphon-based device with sodium working fluid that is able to extract heat from a source as demand requires. A prototype has been designed to transfer 37kW of thermal energy from a 600°C molten PCM tank to an array of 9% efficient thermoelectric generators (TEGs) to produce 3kW of usable electrical energy for 5h. This “thermal valve” design incorporates a funnel to collect condensate and a central shut-off valve to control condensate gravity return to the evaporator. Three circumferential tubes allow vapour transport up to the condenser.Pressure and a thermal resistance models were developed to predict the performance of the thermal valve. The pressure model predicts that the thermal valve will function as designed. The thermal resistance model predicts a 5500× difference in total thermal resistance between “on” and “off” states. The evaporator and condenser walls comprise 96% of the “on” thermal resistance, while the small parasitic heat transfer in the “off” state is primarily (77%) due to radiation losses.This simple and effective technology can have a strong impact on the feasibility, scalability, and dispatchability of CSP latent storage. In addition, other industrial and commercial applications can benefit from this thermal valve concept.