Thermal Module Research Articles

Kohonen’s algorithm in problems of classification of defects in printed circuit assemblies

The article presents a new method for diagnosing the technical condition of radio-electronic components, combining the methods of thermal diagnostics with the technologies of artificial neural networks. The structure of the method is shown, and the composition of the functional blocks is determined. The implementation of the method is a symbiosis of technologies for mathematical and simulation modeling of the technical state of a radio-electronic device with its physical tests and research of characteristics. When developing the method, specialized software tools for design and circuit design were actively used, such as Altium Designer CAD, SolidWorks, NI Multisim, the FloTHERM PCB thermal analysis module, as well as the MATLAB mathematical modeling and calculation package. With the help of these tools, a number of studies were carried out, including sets of numerical values of the power of circuit elements and temperature indicators of the printing unit, both for the correct state of the device and in states with artificially introduced defects. They, in turn, became the basis of the database of electronic node failures. To implement diagnostic procedures and identify the technical condition, an artificial neural network based on selforganizing Kohonen maps was created, its structure, parameters and algorithms of functioning were determined. The diagnostic procedure is based on the analysis of information from the fault database and its comparison with experimental data obtained as a result of a physical experiment. The results of the study showed that the network automatically classifies the characteristic defects of electronic components using the algorithms embedded in it. The list of characteristic defects in the proposed diagnostic method is limited to a discrete set of the most common faults, because, as their number increases, the use of the self-organizing Kohonen network for automatic classification becomes much more complicated and ineffective in terms of performance and reliability of identification. Among the advantages of this technology, it should be noted that the Kohonen network has the ability to convert largedimensional input data into a two-dimensional array. So, the results are easy to visualize and convenient to use when generating reports and recommendations for subsequent decision-making about the possibility of using an electronic device.

Evaluation of nominal operating cell temperature (NOCT) of glazed photovoltaic thermal module

Nominal operating cell temperature (NOCT) was commonly used to evaluate photovoltaic (PV) module temperature and this term is provided by the manufacturer but in case of photovoltaic thermal module, the NOCT was not fixed and varied with the circulating fluid mass flow rate and its temperature. In this study, a novel approach on NOCT evaluation of glazed photovoltaic thermal (PVTg) module for combined heat and power generation was presented by modifying the method of solar collector testing for water heating. The thermal characteristics in terms of optical and heat loss performances and finally the NOCT at various water flow rates and inlet temperatures could be evaluated. Experimental tests were performed with a PVTg module under Chiang Mai climate, and it could be founded that the calculated module temperature, the outlet hot water temperature and the generated electrical power agreed well with the experimental results. Monthly performance of this module was also evaluated and compared with unglazed PVT and conventional PV modules each having the same solar photovoltaic cell type. The average generated electrical outputs were 28.07, 31.89, and 30.38 kWh/month, respectively, while the glazed and the unglazed PVT modules could generate average thermal energy of 119.19 and 101.40 kWh/month, respectively.

Progress on the regeneration unit of a reverse electrodialysis heat engine

The reverse electrodialysis heat engine (REDHE) has emerged as a promising technique in the waste heat harvest field due to its ability to convert very low-grade waste heat (below 100°C) into power. A REDHE consists of a regeneration unit and a reverse electrodialysis (RED) cell unit, which are in charge of heat to the salinity gradient energy-conversion process and salinity gradient to the power conversion process, respectively. Despite the fact that a regeneration unit accounts for 60% to 70% of the energy destruction of the overall system, most of the research conducted on RED units has barely reviewed the regeneration units. Therefore, the evaluation of regeneration units is necessary. This work provides a review of the research progress made on regeneration units. In this paper, a systematic review of the operating fluids and regeneration methods employed in a regeneration unit is provided. Also, the effects of solvent and solute characteristics on the performance of a regeneration unit and the overall system and the working fluid selection principle are investigated. Additionally, the disadvantages of the methods employed in existing and future development directions are analyzed. Finally, other applications of the heat engine (apart from power production) are presented. Since the RED technology has been primarily used to recover blue energy, its operating fluid is the NaCl aqueous solution. However, the NaCl solution is not suitable for the REDHE technology. Specifically, it is not suitable for the regeneration process of a regeneration unit because the latent heat of water vaporization is huge, which leads to huge energy consumption in the regeneration module. Also, the power generation performance of the NaCl solution is poor, and the maximum power density is only 1/8 of that of the LiBr solution, resulting in the low efficiency of the overall system. Since the REDHE technology is used to recover low-grade heat energy, its regeneration unit adopts a low-temperature separation technology. The main regeneration methods used are distillation separation and membrane distillation separation. The distillation separation technology is the most mature, but it consumes more energy and has a high maintenance cost. On the other hand, the regeneration temperature of the membrane distillation technology is low, but the required technology is difficult to apply, and the cost of the membrane is high. It should be noted that the biggest difference between the REDHE and traditional separation technologies is that the former aims to build an optimal concentration gradient for the battery cells, rather than to perform the complete separation of components. For example, the seawater desalination process assumes that the separated water is pure water. For an RED cell, if the diluted solution is pure water, the battery performance will decline rapidly due to the decrease in the solution conductivity. Currently, more research work has been conducted on various separation technologies and less on the coupling of regeneration technology with power generation technology. Future research should focus on the coupling of the thermal separation module with the power generation module. Although the objective of the REDHE technology is to utilize the industrial waste heat, the heat-source temperature can be very low (down to 40°C), which means that the technology can also be used for low-grade heat recovery such as geothermal and solar energy. At the same time, although the technical efficiency of the REDHE is low, its power generation process is accompanied by electrode reaction and temperature change. This means that during power generation, the REDHE can also be used for sewage treatment, organic matter degradation as well as waste acid and alkali recovery.

Honeycomb-inspired design of a thermal management module and its mitigation effect on thermal runaway propagation

The mitigation of battery thermal runaway propagation remains challenging in the application of lithium-ion batteries, and safety enhancement remains a popular topic for battery thermal management. In this study, an aluminum honeycomb (AH) design module is proposed for a battery thermal management module, and its effects on thermal management (TM) and thermal runaway (TR) propagation are experimentally studied using an infrared imager. The results showed that AH contributed to an improved heat dissipation effect and thus mitigated thermal runaway propagation. In addition, the coupling effects of AH as well as forced convection and the phase change material (PCM) were investigated. The results indicated that the coupling effects of the AH and forced air along with the PCM both exhibited superior performance as compared to the AH alone. In a forced convection environment, the maximum temperature of the AH cell could be reduced by 17.1% under a moderate charging rate. In addition, under extreme conditions, AH was shown to mitigate TR propagation. We anticipate that the outcomes of this study can provide a new basis for the structural design of battery modules to achieve better performance and fire safety.

An improved process-oriented hydro-biogeochemical model for simulating dynamic fluxes of methane and nitrous oxide in alpine ecosystems with seasonally frozen soils

Abstract. The hydro-biogeochemical model Catchment Nutrient Management Model – DeNitrification-DeComposition (CNMM-DNDC) was established to simultaneously quantify ecosystem productivity and losses of nitrogen and carbon at the site or catchment scale. As a process-oriented model, this model is expected to be universally applied to different climate zones, soils, land uses and field management practices. This study is one of many efforts to fulfill such an expectation, which was performed to improve the CNMM-DNDC by incorporating a physically based soil thermal module to simulate the soil thermal regime in the presence of freeze–thaw cycles. The modified model was validated with simultaneous field observations in three typical alpine ecosystems (wetlands, meadows and forests) within a catchment located in seasonally frozen regions of the eastern Tibetan Plateau, including observations of soil profile temperature, topsoil moisture, and fluxes of methane (CH4) and nitrous oxide (N2O). The validation showed that the modified CNMM-DNDC was able to simulate the observed seasonal dynamics and magnitudes of the variables in the three typical alpine ecosystems, with index-of-agreement values of 0.91–1.00, 0.49–0.83, 0.57–0.88 and 0.26–0.47, respectively. Consistent with the emissions determined from the field observations, the simulated aggregate emissions of CH4 and N2O were highest for the wetland among three alpine ecosystems, which were dominated by the CH4 emissions. This study indicates the possibility for utilizing the process-oriented model CNMM-DNDC to predict hydro-biogeochemical processes, as well as related gas emissions, in seasonally frozen regions. As the original CNMM-DNDC was previously validated in some unfrozen regions, the modified CNMM-DNDC could be potentially applied to estimate the emissions of CH4 and N2O from various ecosystems under different climate zones at the site or catchment scale.

Portable Molecular Diagnostics Device for Identification of Asini Corii Colla by Loop-Mediated Isothermal Amplification

Asini Corii Colla (ACC; donkey-hide glue) is one of the most valuable tonic traditional Chinese medicines. Because of the large demand for gelatinous Chinese medicines, bovine or swine skin was sometimes used to make adulterated gelatine in recent decades. Food chemicals can greatly harm people’s health, and detecting chemicals in foods is extremely important. A loop-mediated isothermal amplification (LAMP) device with smartphone detection is demonstrated in this study for detecting the DNA of Asini Corii Colla. The complete system is composed of a hand-held box equipped with a smartphone, a cartridge heater, an ultraviolet LED, a disposable reaction tube, and a homemade thermal module. All the processes are powered by a set of rechargeable batteries. Comprehensive experiments of measuring temperature profiles are presented, which showed the accuracy of temperature under thermal control is less than 0.5 °C. By implementing one heating module with an ATmega328p-au microcontroller in the device, the DNA mixture is heated directly up to the reaction temperature within 5 min. Next, a DNA segment of Asini Corii Colla is utilized to evaluate the sensitivity of the DNA amplification in the portable device. A limit of detection to a concentration of 10−4 ng/μL is achieved. Real-time detection of Asini Corii Colla by a smartphone camera can be achieved using this portable device. The unique architecture utilized in this device is ideal for a low-cost DNA analysis system.

Influence of phase change material dosage on the heat dissipation performance of the battery thermal management system

The dosage of phase change material (PCM) used is a core parameter of the PCM-based thermal management module. In this paper, a PCM-based thermal management module is built, then its numerical model is established and validated by experimental data. To accurately evaluate the influence of PCM dosage on battery temperature, a parameter called “heat ratio” is proposed. The detailed parametric study of the PCM dosage and its effect coupled with the phase transition temperature, the thermal conductivity of PCM, and the heat transfer coefficient are systematically conducted under a single discharge process and discharge-charge cycle conditions. The results indicate that the “heat ratio” between 0.75 and 1 is relatively suitable for controlling the battery temperature in a single discharge process. Higher thermal conductivity of PCM is beneficial for improving the performance of cooling system as well as the utilization of PCM, and increasing the heat ratio of PCM can further reduce the temperature of the battery once the thermal conductivity reaches a threshold. The “heat ratio” bigger than 0.75 can guarantee the PCM with lower phase transition temperature exerts its advantage in controlling the operating temperature of battery in the case of short-term operation. On the other hand, under extreme working conditions or long-term operating cycles, a higher phase transition temperature will bring a better cooling performance. However, merely increasing the dosage of PCM is not feasible. To achieve a more stable and low power cooling effect, it is more effective to combine the passive and positive cooling strategy which has a reasonable convective heat transfer coefficient.

A new ultra-thin vapor chamber with composite wick for thin electronic products

The ever-increasing performance of thin portable electronic products has made their heat dissipation issues more and more severe, or even become failure. A novel 0.5 mm thick ultra-thin vapor chamber (UTVC) with six spiral woven meshes and single-layer mesh acting as the wick is developed for cooling portable electronic products. The heat load capacity of the UTVC could be improved through the mixed effect of the spaced structure and composite wick by both decreasing the pressure drop of vapor flow and the fluid flow. The UTVC is tested in five typical positions, and the results show that it can withstand heating power of 10.5 W, 10 W, 10 W, 10 W, and 9.5 W in gravity, horizontal, side, inverted and antigravity positions, respectively, implying that the influence of position on the heat transfer performance of the proposed UTVC is not significant. The effective thermal conductivity of the vapor chamber in the gravity position reaches about 18,000 W/m·K. Compared to the thermal module without UTVC, the one with UTVC has effectively improved the cooling effect of thin electronics and eliminated the hot spots.

A numerical study on effects of heat transfer fluids, copper mesh in packed bed and porosity, on charging time of paraffin based packed bed thermal energy storage

AbstractIn this study, a novel configuration of the latent heat thermal energy storage module based on the packed bed of encapsulated phase change material is investigated. The module is modeled and simulated using a Multiphysics tool COMSOL. The simulation results are validated with the experimental data. Using the validated model, initially, water was used as heat transfer fluid, and then refrigerant R‐134 and R‐22 were also used as heat transfer fluid (HTF) to predict the impact on the charging time. The comparison in terms of their thermo‐physical properties is also carried out. The results indicated that by using refrigerants (R‐134 and R‐22) as HTF, decreased the charging time. When the water was used as HTF, it took 11 hours to completely charge the system. Whereas, the charging time for R‐134 and R‐22 was 8.75 and 8.4 hours, respectively. It was also observed that edges of packed bed were melting much slower than the remaining bed. Therefore, to increase the transfer of heat near the edges, geometry of the module is modified and their impact is investigated.

Precooling of fresh air in façade mounted photovoltaic thermal panels by refrigeration

The integration of the photovoltaic thermal system on the building assists in supplying and reducing the building energy demand. The system integrates photovoltaic thermal modules and generates both electrical power and heat for the buildings. The current study focuses on the utilization of waste cooling energy from the photovoltaic thermal evaporator side as novelty in this research area. This will not only add up energy to the building system but also would be thermally efficient, if addressed properly. In this endeavor, we have investigated the performance of fresh air intake precooling in façade mounted photovoltaic thermal panels cooled by a refrigeration system. The structure of the photovoltaic thermal system, its design on the façade and the whole setup is presented for the first time ever, followed by the experimental construction platform. Finally, the ambient fresh air cooling characteristic and electrical power generation is analyzed through performance evaluation indices under natural weather conditions. The experimental results indicated the pre-cooled fresh air temperature difference of 10.27 °C. The maximum electrical efficiency of photovoltaic was 10.16% during testing period. The results can provide a valuable reference for the utilization of photovoltaic thermal panels assisted by heat pump system in supplying fresh air to indoor environment.

Design of an anti-interference multi parameter sensor

Aiming at the shortcomings of single function, easy to be affected by underground background gas and weak anti-interference of current mining environment parameter sensor, an environment multi parameter sensor is designed, which can simultaneously detect three parameters of methane, carbon monoxide and temperature in the environment. The interference of background gas is eliminated by optical identification method, and the reliability of temperature detection is realized by thermal resistance isolation module. At the same time, the filter circuit of the sensor is optimized, the interference suppression frequency band of the filter is expanded, the anti electromagnetic interference ability of the sensor is improved, and the problem of false alarm caused by the interference of large-scale frequency conversion equipment on the sensor is solved. The experimental results show that the sensor has strong anti-interference and high reliability.

Optical approaches for passive thermal management in c-Si photovoltaic modules

Elevated operating temperatures of solar cells encapsulated in modules lead to reduced efficiency and module lifetime. Here, we provide a comprehensive overview of the challenges and opportunities for passive optical thermal management of PV modules based on the rejection of sub-band-gap light by idealized reflectors and scatterers applied at different interfaces within crystalline Si modules and discuss the limitations to performance at each interface. We find that the annual power-weighted average operating temperature is most readily reduced via sub-band-gap reflection from the module glass, by 3.3 K for Al-BSF modules and 2.9 K for PERC modules with 100% sub-band-gap reflection. Sub-band-gap reflection at the cell interface offers up to 2.2 K (1.8 K) temperature reduction for Al-BSF (PERC) modules, increased cell rear reflection offers up to 1.2 K temperature reduction, and directional scattering offers up to 1.5 K reduction. Guide for passive optical methods of cooling photovoltaic modules Outdoor simulation of PV modules with integrated sub-band-gap reflective mirrors Mirrors at outer glass or cell rear interface are most promising Calculation of effects of backscattering of sub-band-gap light within the module Slauch et al. provide an overview of opportunities for photovoltaic thermal management focused on the rejection of incident sub-band-gap light. They calculate reductions in waste heat generated and operating temperature via combined optical, electrical, and thermal module simulation under 1 year of realistic outdoor conditions. This method allows the determination of the limits of passive optical cooling as a function of the sub-band-gap reflectivity and the reflective interface.

Experimental study of a novel strategy to construct the battery thermal management module by using tubular phase change material units

For the thermal management of cylindrical power battery module, the classical cuboid-like phase change material (PCM) module still remains problematic, because the bulky structure remarkably decreases the energy density and secondary heat-dissipation capability of the battery module. Here a novel strategy to construct the PCM module was proposed by substituting the bulky cuboid PCM module with tubular PCM units. Compared to the classical cuboid module, the assembled tubular PCM module confers numerous naturally-formed channels for air flow, an enlarged outer surface area for secondary heat dissipation, and a greatly reduced module weight. As a result, the tubular PCM module demonstrates a superior heat-dissipation performance for cylindrical power batteries. For example, with forced air convection, the temperature and temperature difference can be controlled below 47.2 and 1.0 °C respectively under an extreme working environment, i.e., 10 charge and discharge cycles at a high environment temperature of 40 °C. More importantly, this novel strategy also benefits the flexible assembling and maintenance of the modules, and saves 54% of the PCM amount, thus increasing the energy density of the battery module from 75.5 to 94.4 Wh kg−1.

РАСЧЕТ ЖЕЛЕЗОБЕТОННОЙ ПЛИТЫ ПЕРЕКРЫТИЯ ПРИ ВОЗДЕЙСТВИИ ПОВЫШЕННЫХ ТЕМПЕРАТУР ПОЖАРА

Розроблено методику чисельного дослідження напружено-деформованого стану залізобетонних конструкцій плит перекриттів з урахуванням нестаціонарних полів температур в арматурі і бетоні за стандартним температурним режимом і температурному режимі реальної пожежі. В рамках методики використовуються характеристики материлов, наведені в ДСТУ-Н Б EN 1992-1-2, а також вихідні дані, необхідні для застосування уточненого методу розрахунку. Ці дані встановлюються шляхом аналізу наявних в літературі експериментальних даних і характеристик матеріалів, наведених в Єврокодах. При оцінці вогнестійкості конструкцій уточненим методом розрахунку враховуються всі фактори, які справляють істотний вплив на напружено-деформований стан конструкції при пожежі. Визначають підвищення і поширення температури в конструкції в заданий момент часу (теплотехнічний розрахунок) і механічну поведінку конструкції (статичний розрахунок), при цьому враховується відповідний сценарій пожежі. Методика ілюструється на прикладі розрахунку на вогнестійкість залізобетонної плити перекриття. Проведено розрахунки з реалізацією пов'язаних термопрочностних завдань в програмному комплексі ANSYS. Проектування залізобетонної плити перекриття виконувалося в модулі Design Modeller програми ANSYS. Потім здійснювалися послідовно розрахунки в модулях TRANSIENT THERMAL і STATIC STRUCTURAL. Бетон і арматура моделюються об'ємними елементами. Підхід не вимагає прив'язки сітки кінцевих елементів до кроку арматури, що дозволяє застосовувати його до завдань з реальними розмірами. У прийнятій моделі бетону поверхня плинності складається з двох пересічних конічних поверхонь Друкера-Прагера. Результати розрахунків добре узгоджуються з представленими літературними експериментальними даними. Використання запропонованої методики дозволяє досить точно оцінити вогнестійкість залізобетонних конструкцій і прогнозувати їх напружено-деформований стан при пожежі.

Bond graph modeling of a water-based photovoltaic thermal (PV/T) collector

This paper deals with photovoltaic-thermal (PV/T) collectors that combine photovoltaic (PV) module and solar thermal (ST) modules to provide heat and electricity simultaneously. The use of a PV/T system not only enhances PV efficiency but also allows to use solar thermal energy for various heating applications. The performance evaluation of the PV/T collectors had been investigated both theoretically and experimentally for the past few years. In this work, we consider a new water-based PV/T configuration by incorporating a tedlar layer and parallel tubes and further investigate its modeling. The aim is to develop a non-linear dynamic model which gives a realistic and reasonable performance of the system. The fundamental equations are determined for the thermal part using a bond graph approach which is a generic and general tool to represent thermal transfers. Simulations are given to highlight the usefulness of the proposed design and its modeling, considering the influence of some external factors (e.g. wind action) and internal geometrical parameters (e.g. insulator thickness). The results indicate that the rise in wind speed can reduce thermal efficiency from 70% to approximately 40%. The results also show that with an increase in insulator thickness, there is a sudden change in outlet temperature but thicknesses of more than 0.14 m is not required as the energy losses become constant. The assessment of the electrical and thermal performance of a PV/T collector is taken into consideration for a sample weather condition of southern France. Further, our results are compared to existing experimental and numerical ones from the literature on alternative PV/Ts design to validate and demonstrate the viability and consistency of our model.

Design and performance evaluation of a dual-circuit thermal energy storage module for air conditioners

We present experimental results and a validated numerical model of a dual-circuit phase-change thermal energy storage module for air conditioners. The module incorporates a phase-change material encapsulated in compressed expanded natural graphite foam. We used n-tetradecane as the PCM with a transition temperature (~4.5 °C) suitable for air-conditioning applications. Heat exchange to and from the module is accomplished through two fluid loops operating as a heat source and sink embedded inside multiple slabs of the composite material. This dual-circuit design enables easier integration with air-conditioning equipment and provides enhanced flexibility in system operation as compared to the state-of-the-art thermal storage systems. When integrated with an air-conditioner, this design will enable peak-load shaving and enhances operational efficiency. The thermal storage device was designed for a nominal storage capacity of ~ 3.5 kWh. We evaluated the heat transfer and energy storage performance of this device using standalone heat transfer experiments to estimate key thermal resistances and identify design improvements before integration with an air conditioner. The numerical model of the heat exchanger uses a combination of discretized and lumped parameter approaches to maintain a balance between accuracy and computational expense. Our analyses show that the geometric features and integration of fluid tubes are key contributors to the thermal contact resistance between the fluid and the thermal storage material, and consequently, to the overall performance of the thermal storage module. Our standalone experiments also identified important operating scenarios in which this thermal storage module can be used for air-conditioning in buildings.

Photovoltaic Thermal Module With Paraboloid Type Solar Concentrators

The article presents the results of the development and research of the solar photovoltaic thermal module with paraboloid type solar radiation concentrators. The structure of the solar module includes a composite concentrator, which provides uniform illumination by concentrated solar radiation on the surface of the cylindrical photovoltaic thermal photoreceiver in the form of the aluminum radiator with photovoltaic converters. When exposed in concentrated solar radiation, the electrical efficiency of specially designed matrix photovoltaic converters increases, and the heat taken by the heat carrier increases the overall efficiency of the solar module. Uniform illumination of photovoltaic converters with concentrated solar radiation provides an optimal mode of operation. The consumer can use the received electric and thermal energy in an autonomous or parallel power supply with the existing power grid.

Performance analysis of a novel bifacial solar photothermic and radiative cooling module

Solar energy and universe coldness are two renewable and clean energy constantly sent from outer space to the earth. Solar thermal collectors and radiative coolers respectively harvest heat and cooling energy in this context. However, their static and monofunctional spectral properties mismatch energy demands in regions with large air temperature fluctuations throughout the whole year. In this work, a rotatable bifacial solar photothermic and radiative cooling (PT-RC) module capable of flexibly switch between solar heating and radiative cooling modes is proposed to realize smart thermal management. In the solar heating mode with solar irradiance of 1000 W/m2, the PT-RC module shows 83.3% solar thermal efficiency, which is even slightly higher than that of a typical solar thermal module. In the radiative cooling mode, the PT-RC module reaches up to 69.9 W/m2 net radiative cooling power and 11.7 °C temperature reduction. The heat and cooling energy of the PT-RC module throughout a typical day in Hefei city totals 17.7 MJ. This bifacial PT-RC module provides an alternative solution for integrating solar energy and universe coldness and shows potential in flexibly providing heat and cooling energy in different seasons.

Mapping design trade-offs

Widespread adoption of thermal storage systems is limited by their complex transient response, which is dependent on material properties, module geometry and thermal load. Now, an approach to evaluate energy and power density adapted from electrochemical storage reveals design trade-offs in thermal storage modules.

CTF and FLOCAL Thermal Hydraulics Validations and Verifications within a Multiscale and Multiphysics Software Development

Simulation codes allow one to reduce the high conservativism in nuclear reactor design improving the reliability and sustainability associated with nuclear power. Full-core coupled reactor physics at the rod level are not provided by most simulation codes. This has led in the UK to the development of a multiscale and multiphysics software development focused on LWRS. In terms of the thermal hydraulics, simulation codes suitable for this multiscale and multiphysics software development include the subchannel code CTF and the thermal hydraulics module FLOCAL of the nodal code DYN3D. In this journal article, CTF and FLOCAL thermal hydraulics validations and verifications within the multiscale and multiphysics software development have been performed to evaluate the accuracy and methodology available to obtain thermal hydraulics at the rod level in both simulation codes. These validations and verifications have proved that CTF is a highly accurate subchannel code for thermal hydraulics. In addition, these verifications have proved that CTF provides a wide range of crossflow and turbulent mixing methods, while FLOCAL in general provides the simplified no-crossflow method as the rest of the methods were only tested during its implementation into DYN3D.