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DOE OSTI2025

Experimental investigation on heat transfer performance of drain water heat recovery heat exchangers

Water heating accounts for 18 % of residential energy consumption, and a substantial portion of this energy can be recovered through drain water heat recovery systems. Here, this paper investigates the heat transfer performance of drain water heat recovery heat exchangers. Two heat exchanger configurations were studied: vertical (gravity film exchanger) and horizontal. The heat recovery performance of the exchangers was quantified using sensible effectiveness and characteristic curves following the ε-NTU approach. Depending on the flow conditions, heat exchangers with a vertical configuration offered higher heat transfer effectiveness compared with the horizontal configuration under similar operating conditions. Furthermore, the results showed that properly designed and sized heat exchangers can effectively recover considerable amounts of waste heat from drains, depending on flow rates. Additionally, in the vertical heat exchanger configuration, low flow rates result in partially wet conditions, resulting in lower heat transfer effectiveness. Therefore, two distributor configurations are proposed to improve the heat transfer performance of vertically configured heat exchangers at low flow rates. The proposed distributor configurations and data presented in this paper will be useful in the design and development of drain water heat recovery systems in building applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2021

Flow condensation heat transfer performance of natural and emerging synthetic refrigerants

There is great interest in predicting flow condensation heat transfer for lower global warming potential (GWP) fluids. This paper analyzes the efficacy of common flow condensation correlations developed for particular fluids in order to identify their suitability to predict heat transfer performance of low GWP fluids. Condensation heat transfer data were extracted from the literature, including 19 papers and 1,473 data points for natural refrigerants [i.e., ammonia (R717), CO 2 (R744), propane (R290), isobutane (R600a)] and 35 papers and 5,030 data points for synthetic refrigerants [i.e., R12, R1234yf, R1234ze(E), R1234ze(Z), R22, R32, R41, R123, R125, R134a, R142b, R152a, R161, R404A, R410A, R448A, R449A, R450A, R452B, R454C, R455A, R513A] encompassing tube diameters of 0.1–11.5 mm, mass fluxes of 55–1200 kg/m2s, and saturation temperatures of -25°C–65°C. Correlations analyzed included Akers et al. (1959), Cavallini et al. (2006, 2011), Kim and Mudawar (2013), Macdonald and Garimella (2016), Shah (1979, 2009, 2013, 2016) and Traviss et al. (1973) for smooth tubes and Chamra et al. (2005) and Kedzierski and Goncalves (1999) for enhanced tubes. Since most studies did not report wall temperature, correlations which relied on wall temperature directly or indirectly were excluded from the analysis. For synthetic refrigerants, mean average error (MAE) ranged from 6%–257%, and Cavallini et al. (2011) and Kim and Mudawar (2013) were the best predictors for emerging synthetic refrigerants. Furthermore, the Kim and Mudawar (2013) correlation was found to best predict the heat transfer performance for propane and R600a data, but most correlations did not accurately predict ammonia and CO 2 flow condensation.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2022

Experimental and analytical study of the hydrodynamic and single and two-phase convective heat transfer performance of flexible PDMS microchannels with micropillar arrays

Various copper and silicon based thermal management systems are used in the cooling of electronics. However, the rigid nature of these materials along with their high thermal and electrical conductivity pose a difficulty in developing direct contact embedded flexible cooling systems that can offer robust cooling performance. The low density, thermal stability, chemical inertness, and electrical insulation of Polydimethylsiloxane (PDMS) make it an ideal material to develop lightweight direct contact thermal management systems for electronics. Its ease of fabrication with tunable flexibility provides the opportunity to go beyond traditional electronics and develop advanced active and passive thermal management systems for a wide–range of applications in foldable and wearable electronics, liquid cooling garments, microgravity, and electric motors. In this study, a flexible PDMS based microchannel with micropillar arrays, which enhance the thermal performance of the device through capillary-assisted flow, has been developed. The hydrodynamic and convection heat transfer performance of three PDMS wick pillar geometries, ranging from a porosity of 0.8–0.91, are investigated and compared under single-phase and two-phase conditions. Dielectric coolant FC-3283 is employed and permeability measurements are made for mass fluxes ranging from 53 kg/m 2 s to 369 kg/m 2 s. Given its conformability, the device demonstrates a deviation from Darcy’s Law, within the laminar regime, with an increasing permeability with mass flux at the rate of ~0.5–0.8 Darcy/(kg/m 2 s). A semi-analytical model has been developed and reported to quantify the conformability of the device. The heat transfer performance is experimentally evaluated using the same dielectric fluid for mass flux ranging from 105 kg/m 2 s to 420 kg/m 2 s with heat fluxes ranging from 1.5 W/cm 2 to 16 W/cm 2 . Heat transfer coefficients of up to 7000 W/m 2 K are observed, which are comparable to copper and silicon microchannels. The effect of porosity on the single phase thermal performance has been evaluated against the pumping power to provide a basis for thermal management system design. Finally, high-speed imaging is performed to study the two-phase flow characteristics to provide insight into the vapor formation and removal.

42 ENGINEERING↗

DOE OSTI2024

An Experimental Investigation of Sintered Particle Effect on Heat Transfer Performance in an “Annular Flow” Evaporation Tube

Wicking structures have been widely used within passive heat transfer devices with high heat fluxes, such as heat pipes, to enhance their thermal performance. While wicking structures promote capillary pumping of the working fluid and thin film evaporation, they can result in capillary evaporation and further enhance the evaporation heat transfer. In this study, a 0.5 mm thick layer of 105 µm sintered copper particles was added to the inner wall of a copper tube, aiming to form an “annular flow” and enhance the heat transfer characteristics by taking advantage of thin film and capillary evaporation. Acetone was chosen as the working fluid, and the performance of an evaporation tube was tested for power inputs of 10, 30, 50, and 70 W. For each power input, trials were run at inclination angles varying from -90 deg to 90 deg to investigate the capillary effects. The temperature measurements showed that the temperature distribution along the evaporation tube is always downward sloping, meaning the temperature at the fluid inlet is larger than the outlet. In conclusion, results show that an “annular flow” formed by a thin layer of sintered particles can promote thin film and capillary evaporation and, therefore, boost the evaporation heat transfer coefficient.

42 ENGINEERING↗

DOE OSTI2022

Three‐Tier Hierarchical Structures for Extreme Pool Boiling Heat Transfer Performance

Abstract Boiling is an effective energy‐transfer process with substantial utility in energy applications. Boiling performance is described mainly by the heat‐transfer coefficient (HTC) and critical heat flux (CHF). Recent efforts for the simultaneous enhancement of HTC and CHF have been limited by an intrinsic trade‐off between them—HTC enhancement requires high nucleation‐site density, which can increase bubble coalescence resulting in limited CHF enhancement. In this work, this trade‐off is overcome by designing three‐tier hierarchical structures. The bubble coalescence is minimized to enhance the CHF by defining nucleation sites with microcavities interspersed within hemi‐wicking structures. Meanwhile, the reduced nucleation‐site density is compensated for by incorporating nanostructures that promote evaporation for HTC enhancement. The hierarchical structures demonstrate the simultaneous enhancement of HTC and CHF up to 389% and 138%, respectively, compared to a smooth surface. This extreme boiling performance can lead to significant energy savings in a variety of boiling applications.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Dynamic condensation model of rolling droplets for high-performance heat transfer

Condensation is a critical process during vapor-liquid phase change in relation to heat transfer. To achieve a high heat transfer coefficient, the classical model for dropwise condensation requires a low contact angle and low contact angle hysteresis, failing to align with experimental observations on a hydrophobic and slippery quasi-liquid surface (QLS). Here, we report a dynamic condensation model that incorporates high-frequency condensate removal by emphasizing the role of timescale during droplet growth and shedding. Our model agrees well with the experimental result that a surface with high contact angle and low contact angle hysteresis promotes condensation, particularly during rolling-propelled condensate removal. Particle image velocimetry reveals that rolling droplets on a hydrophobic QLS exhibit 4-fold higher shedding speeds than the sliding droplets on a hydrophilic QLS, leading to significant heat transfer enhancement. This work deepens our theoretical understanding of condensation heat transfer and provides advanced physics-informed design rationales for water and energy systems.

42 ENGINEERING↗

DOE OSTI2024

Thermal and hydraulic performance of volumetrically heated triply periodic minimal surface heaters

Advanced heat transfer surfaces, mainly Triply Periodic Minimal Surfaces (TPMSs) have great potential to increase heat transfer performance over traditional heat transfer surfaces due to their tortuous flow path and higher surface area-volume ratio. The emergence of additive manufacturing of nuclear fuel motivates experimental investigation of such advanced geometries in the context of a nuclear reactor core. Here, this study employed a novel method to explore the performance of gyroid and diamond TPMS geometries. Volumetrically heated heaters were additively manufactured from conductive polymer filament, and airflow was used to simulate the convective heat transfer from the core within a nuclear reactor. The mass flow and volumetric generation rates were varied, local Nusselt number correlations were obtained using embedded thermocouples to measure the solid and fluid temperature, and friction factor correlations were developed using differential pressure measurements. The gyroid TPMS presented a friction factor 1.5 times higher than the diamond TPMS and 90 times that of the rod bundle. TPMS geometries showed Nusselt numbers 8–10 times higher than that of the rod bundle, also maintaining colder internal temperatures, which suggested that they could sustain 250–275 % higher power density than the rod bundle for a given centerline temperature. Hence, having the potential to greatly increase the safety margins and power output of a nuclear reactor core with similar volume.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2025

Local heat transfer measurement in a volumetrically heated TPMS lattice using distributed optical fiber thermal sensing

As additive manufacturing continues to reduce design constraints on heat exchange geometries, methods for high-fidelity local heat transfer measurements in nonconventional channel geometries are critical to their continued development. This study presents a novel method for measuring local heat transfer performance in volumetrically heated lattices using a distributed optical fiber temperature sensor. A diamond-type triply periodic minimal surface (TPMS) lattice, 3D-printed from a conductive polymer, was Joule heated while it was convectively cooled with air. Temperature measurements were taken at the solid–fluid interface across 14 internal locations using a single optical fiber over the Reynolds number range 800–2750. The TPMS lattice achieved up to 312% higher heat transfer coefficients compared to developing flow in a straight tube. A Nusselt number correlation was developed for the diamond TPMS, which showed good agreement with data collected for comparable geometries available in literature. In conclusion, this study presents a robust and new method for experimental measurement of the heat transfer coefficient in complex geometries and helps to understand and quantify the exceptional performance of TPMS heat transfer geometries.

TPMS↗

DOE OSTI2024

Thermal-hydraulic Performance of Emerging Low GWP Refrigerant Mixture under Flow Boiling in Brazed Plate Heat Exchangers

The hydrofluorocarbon (HFC) refrigerants used in the current refrigeration systems are facing a phase-down due to their higher greenhouse effect resulting in global warming, and thus HVAC&R industry has undergone a transition to low Global Warming Potential (GWP) refrigerants. Refrigerant mixtures are attractive alternatives since their composition can be tailored to comply with environmental regulations while preserving favorable thermophysical properties. However, the new low-GWP zeotropic mixture refrigerants have two or more components with different saturation temperatures at the same pressure level, known as temperature glide, which can cause the degradation of the overall heat transfer performance. The brazed plate heat exchangers (BPHX) provide excellent heat transfer performance due to a compact design and are used in several air-conditioning and refrigeration applications. In this study, flow boiling heat transfer and the associated pressure drop of the refrigerant mixture in a vertical BPHX were experimentally investigated. The single-phase water-to-water experiments were conducted in the tested heat exchanger with a counter-flow configuration. The flow boiling experiments charged with R-134a and R-454C were then performed in a pumped refrigerant loop to evaluate its thermal-hydraulic performance. Furthermore, parametric studies of various heat fluxes, mass fluxes, vapor qualities, and saturation temperatures were also conducted.

Yang, Cheng-Min↗

DOE OSTI2022

A Computational Fluid Dynamic Study on Polymer Heat Exchangers

Polymer heat exchangers have been developed for the applications involving weight restrictions or chemical compatibility and fouling issues owing to the low density, anticorrosive properties, and low thermal expansion of polymers. Recently development of additive manufacturing also brings new opportunities to make polymer heat exchangers with desired design that was hard to realize before. However, due to the lower thermal conductivity polymer composite, the overall heat transfer performance is still a challenge in the polymer heat exchanger technology. In present work, a computational fluid dynamic (CFD) model has been developed to study the overall heat transfer performance of additively manufactured polymer heat exchangers. The CFD results offer an insight of fluid flow and temperature distribution in the polymer heat exchangers. This study provides a guidance not only on the polymer material selection but also on the design of polymer heat exchangers. The conclusions will be helpful to design a polymer heat exchanger whose overall heat transfer performance is comparable to a metal heat exchanger.

Zhang, Mingkan↗

DOE OSTI2022

Wire-coil insert optimization for high-heat-load/flux synchrotron components

Many synchrotron components require high levels of internal-flow, forced-convection heat transfer to minimize surface temperatures, thermal gradients, and thermally induced stress on high-power beam-interacting surfaces. Wire-coil inserts, physically similar to a common spring, are mechanically fitted inside of component cooling passages to optimize heat transfer performance. They are routinely used in Advanced Photon Source (APS) front end and beamline high-heat-load/flux components to significantly enhance convection heat transfer-up to 400% compared to plain open passages. This has the additional benefit of greatly reducing coolant flow requirements for these components. Using several cooling passage sizes, five different wire sizes, and a range of pitch values, an experimental investigation conducted at the APS has determined the average heat transfer coefficient and resulting pressure loss as a function of water flow rate for 65 different wire-coil inserts. Data from this study have been non-dimensionalized and generalized to yield relationships that can be used to determine the heat transfer performance and resulting pressure loss for any given wire-coil insert that may be used at the APS. Through data reduction, the wire-coil insert characteristic dimensions have also been optimized to yield the highest heat transfer enhancement while minimizing the coolant flow requirements. These generalized expressions for wirecoil inserts will be presented, and they can be used by scientists and engineers during the component design process to evaluate achievable heat transfer performance and associated pressure loss, aiding in the establishment of optimized operating parameters and cooling passage flow distribution schemes.

43 PARTICLE ACCELERATORS↗

DOE OSTI2022

Robust silane self-assembled monolayer coatings on plasma-engineered copper surfaces promoting dropwise condensation

Dropwise condensation is well known to result in better heat transfer performance owing to efficient condensate/droplet removal, which can be harnessed in various industrial heat/mass transfer applications such as power generation and conversion, water harvesting/desalination, and electronics thermal management. The key to enhancing condensation via the dropwise mode is thin low surface energy coatings (<100 nm) with low contact angle hysteresis. Ultrathin (<5 nm) silane self-assembled monolayers (or SAMs) have been widely studied to promote dropwise condensation due to their minimal thermal resistance and scalable integration processes. Such thin coatings typically degrade within an hour during condensation of water vapor. After coating failure, water vapor condensation transitions to the inefficient filmwise mode with poor heat transfer performance. We enhance silane SAM quality and durability during water vapor condensation on copper compared to state-of-the-art silane coatings on metal surfaces. We achieve this via (i) surface polishing to sub-10 nm levels, (ii) pure oxygen plasma surface treatment, and (iii) silane coating integration with the copper substrate in an anhydrous/moisture-free environment. The resulting silane SAM has low contact angle hysteresis (≈20°) and promotes efficient dropwise condensation of water for >360 hours without any visible sign of coating failure/degradation in the absence of non-condensable gases. We further demonstrate enhanced heat transfer performance (≈5-7× increase over filmwise condensation) over an extended period of time. Surface characterization data post-condensation leads us to propose that in the absence of non-condensable gases in the vapor environment, the silane SAM degrades due to reduction and subsequent dissolution of copper oxide at the oligomer-substrate interface. The experiments also indicate that the magnitude of surface subcooling (or condensation rate) affects the rate of coating degradation. Finally, this work identifies a pathway to durable dropwise promoter coatings that will enable efficient heat transfer in industrial applications.

42 ENGINEERING↗

DOE OSTI2025

Steam generator model design parameter sensitivity study for small modular reactor system

Here, this study focuses on design parameter sensitivity studies pertaining to several Once-Through Steam Generator (OTSG) model cases both with and without a riser using python and advanced risk assessment and optimization tool, i.e. Risk Analysis Virtual Environment (RAVEN) developed at Idaho National Laboratory (INL), to support a Small Modular Reactor (SMR) system. The presented Steam Generator (SG) python-based model is a mathematical representation of a steam-generating unit for a Pressurized Water Reactor (PWR)-type SMR system, including fluid flow and heat transfer equations, models, and correlations. Design studies involve changing the model’s input design parameters (e.g., temperature, pressure, mass flow rate) to observe the resulting effects on the output of the system, such as the Heat Transfer Coefficient (HTC), Reynolds number, Nusselt number, and heat transfer performance. Sensitivity studies analyze the degree to which system output and/or desired parameters (e.g., HTC or heat transfer performance) are sensitive to changes in the input parameters. By using RAVEN, detailed design parametric sensitivity studies. Six input parameters—namely, the pressure, temperature, and mass flow rate for the inlet of the primary-side (hot fluid) and secondary-side (cold fluid) of the SG—were randomly perturbed via RAVEN’s Monte Carlo Sampler module, using uniform distributions (i.e., ±1%, ±5% and ±10 % relative changes) for 600 samples. The analysis results give valuable insights into SG system performance, and provide justification for further research and development such as optimized sensor placement, design verification, validation, and optimization.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2024

Steam Generator Model Design Parameter Sensitivity Study Using Advanced Optimization Tools

This study focuses on design parameter sensitivity studies pertaining to a steam generator (SG) model, using both Python and machine-learning tools. The SG model is a mathematical representation (including fluid flow and heat transfer equations/models/correlations) of a steam-generating unit in a pressurized water reactor (PWR)-type small modular reactor (SMR) system. Design studies involve changing the model’s input design parameters (e.g., temperature, pressure, mass flow rate) to observe the resulting effects on the output of the system (e.g., heat transfer coefficient [HTC], Nusselt number, heat transfer performance). Sensitivity studies analyze the degree to which system output and/or desired parameters (e.g., HTC or heat transfer performance) are sensitive to changes in input parameters. By using machine-learning tools such as the Risk Analysis Virtual Environment (RAVEN) developed at Idaho National Laboratory (INL), detailed design parametric sensitivity studies and model optimization were performed. Six input parameters—namely, the pressure, temperature, and mass flow rate for the inlet of the primary-side (hot fluid) and secondary-side (cold fluid) of the SG—were randomly perturbed via RAVEN’s Monte Carlo Sampler module, using uniform distributions (±1% relative changes). The analysis results give valuable insights into SG system performance and optimization, and provide justification for researching optimized sensor placement to effectively monitor and obtain experimental data.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2024

Steam Generator Model Design Parameter Sensitivity Study Using Advanced Optimization Tools

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2024

Performance Evaluation of Drain Water Heat Recovery Exchangers for Heat Pump Water Heaters

Water heating constitutes approximately 18% of energy consumption and is the second largest energy expenses in United States homes. Heat pump water heaters (HPWHs) are energy efficient technologies with lower carbon footprints as compared to conventional water heating technologies, such as gas and electrical resistance heaters. The performance of water-source HPWHs can be improved by recovering heat from blackwater using drain heat recovery heat exchangers. Depending on water draw patterns of single family and multifamily residences, the operation and heat transfer performance of these heat exchangers are highly transient. This paper examines the thermo-hydraulic performance of a drain heat recovery heat exchanger during its transient and steady-state operations. The heat recovery performance of the exchanger was evaluated at different inlet temperatures and flow rates ranging from 9°C to 36°C and 0.03 kg/s to 0.28 kg/s, respectively. The obtained effectiveness varies from 45%–85% depending on the operating conditions. The test facility, steady-state and transient experimental procedures are reported in detail. Further, the effect of operating conditions on the effectiveness is discussed. The experimental approach and results of the study will provide insights into the transient operation of drain recovery heat exchangers as well as, guide sizing for various steady state conditions.

Krishnan, Easwaran↗

DOE OSTI2023

Numerical Analysis of Novel Plate Type Heat Exchanger with Oval-Twisted Channels

The novel heat exchanger (HX) designs implementing geometrical and surface modification combinations are expected to perform better than traditional HX technologies. Applied enhancement techniques seek to achieve (1) higher overall heat transfer performance, (2) increased compactness, and (3) simplified or comparable manufacturability. One innovative enhancement technique is to generate swirling flow vortices induced by channel or tube twisting. The turbulence generated by the twisted cross-section greatly enhances the heat transfer rate with minimal increases in pressure drop. Plate-type HXs and Printed Circuit Heat Exchangers (PCHXs) are compact designs that achieve high heat transfer rates per unit volume by utilizing several small channels, which maximizes the heat transfer surface area between the hot and cold fluids. Currently, advanced manufacturing technologies enable the design and fabrication of compact-type units with complicated channel geometries to achieve the highest performance and meet the compactness criteria of innovative HX technology. The proposed HX design concept combines the compactness of plate-type HXs and twisted channels, which provide additional turbulence and flow swirl enhancement. The plate-type oval-twisted HX (PTOTHX) is a crossflow configuration, with 16 short channels on one side (for hot fluid) and 8 long channels on the perpendicular side (for cold fluid). The inlet plenums have flow guide vanes to redirect flow and produce uniformity across the various flow paths. The compact size and purportedly improved heat transfer performance of the PTOTHX investigated herein prove its viability in various applications. Some notable potential nuclear applications of the PTOTHX include reactor core, spent fuel cooling, and residual heat dissipation. To establish a reference case, circular channels (PTCHX) are also considered in the present study for comparison with (PTOTHX). This paper aims to outline the numerical analysis procedures for determining the viability of the PTOTHX by comparing its heat transfer performance with the PTCHX units. The computational study used STAR-CCM+, a commercial computational fluid dynamics (CFD) code. Sensitivity analysis and model selection studies are conducted to determine the appropriate mesh density and turbulence model to provide the reported results. Numerical analyses comparing the Nusselt number (Nu) of the PTOTHX design with a comparable HX unit, including a circular cross-section and no twisting (PTCHX), show an overall heat transfer performance increase of 29-55% for balanced flow and 29-59% for imbalanced flow. Oval-cross-sectional twisted channels induce swirling flow vortices, enhancing the working fluid's convective heat transfer capabilities.

25 ENERGY STORAGE↗

DOE OSTI2022

Design of a Compact Dry Cooler With an Aluminum Heat Exchanger Core for a Supercritical CO2 Power Cycle Is Evaluated for a Concentrating Solar Power Application

Abstract As the supercritical CO2 power cycle develops and the component technologies mature, there is still a need to reduce the associated capital and operating costs to maintain a competitive levelized cost of electricity (LCOE) in order to enter the market. When considering concentrating solar power (CSP) coupled with an sCO2 power block and sensible thermal storage, the technology presents a clean source for utility-scale power generation to support baseload or peak-load electrical demand. However, the LCOE of the technology is still considered higher than the competing technologies and should be reduced to better compete in the market; 2030 targets for dispatchable solar plants are 5¢/kWh for baseload CSP and 10¢/kWh for peaker plants, as set by the United States Department of Energy. In response to this need, this study is targeting improvements in the power cycle precooler to reduce power block contribution to LCOE. This study considers a dry cooler, as CSP plants are sensitive to water consumption because many installations are slated for remote or arid locations where solar irradiance is very high, but water is scarce. Furthermore, the power block footprint for an sCO2 system is quite compact, especially as compared to a steam cycle. Therefore, there is interest in installing a more compact dry cooler that is proportional to the reduced footprint sCO2 power block, while conventional dry coolers are an order of magnitude larger. The competing goals of size, performance, and cost were considered in this study to develop a compact dry cooler that can easily be packaged with the power block, significantly reducing the installation and transport cost compared to the current state of the art, while maintaining or improving upon the heat transfer performance and impact on plant LCOE. This paper details the high-level findings of a large dry cooler sensitivity study for design point selection, design of the compact dry cooler, expected year-round performance for the dry cooler and the power cycle, and the predicted LCOE for a 30-year plant life. It was found that an aluminum heat exchanger core can be suitably designed to meet the pressure and temperature requirements for a precooler in an sCO2 recompression Brayton cycle. The dry cooler assembly was found to have improved heat transfer performance, allowing for increased cycle efficiencies and a reduced plant LCOE. When coupled with a centrifugal blower and compact transition duct, the dry cooler assembly was able to reduce the installation footprint by over 50%.

14 SOLAR ENERGY↗