Heat Production Research Articles

Early quality control of stabilized dredged material by correlating heat production with strength

This study explores the use of isothermal calorimetry to assess heat release during the initial phases of dredged sediment stabilization with the primary goal of predicting the 28 days unconfined compressive strength (UCS) and enhancing the stabilization process' quality control (QC). The study was performed on dredged sediment (DS) samples collected from Göta river, Gothenburg, Sweden. The water content of the raw DS was set to 138%, 185%, and 291%, and mixing was performed with water-binder ratios 4, 5, 6, 7, and 8 using a binder consisting of 40% Portland limestone cement and 60% slag. The heat release measurements were conducted during the first seven days of hydration, non-destructive free-free resonance tests (FFR) were performed at 7, 14, and 28 days of hydration, and the 28 days UCS was done to assess the compressive strength of stabilized DS. For each water content, a statistical analysis was performed to determine the strength of the relationship, specifically using linear regression to assess how well early calorimetric data could predict the UCS and a correlation was found between the 28 days compressive strength and heat release of stabilized DS after a 48 h of hydration. By measuring water content and heat release in the early stages of stabilization, it is thus possible to assess the binder content and predict the ultimate compressive strength of a treated dredged sediment.

USING AMMONIA FUEL AS A MEASURE TO REDUCE GREENHOUSE GASES

The presented work highlights the possibilities of using ammonia as an alternative fuel in order to achieve low-carbon development of the state and strengthen the fight against greenhouse gases. Since the Industrial Revolution, combustion has been the primary method of energy conversion for human activities, including power generation and transportation. Today, these sectors continue to rely heavily on hydrocarbon fuels. As a result, the largest absolute increase in carbon dioxide emissions in 2022 was from electricity and heat production. With global electricity demand increasing by 2.7%, emissions in the energy sector increased by 1.8% (or 261 Mt), reaching an all-time high of 14.6 Gt. Thus, a large part of CO2 emissions is produced through these sectors, which is the main culprit of global warming, undermining the fight against climate change. The need for decarbonization is taken into account by program documents, including government strategies, which not only warn but also prohibit the excessive formation of pollutants and stimulate the promotion of carbon-free technologies in energy sectors. It is common knowledge that the innovative development of fuel combustion technologies is necessary to achieve the future goals of a carbon-neutral system. Despite the considerable efforts made to reduce greenhouse gas emissions during the combustion of hydrocarbons, for example, by increasing the combustion efficiency, these efforts are not enough to achieve low greenhouse gas emissions. The progress in this field is analyzed and it is found that ammonia is receiving increasing attention as one of the most attractive energy carriers due to its carbon-free nature. However, the use of ammonia in combustion is not without problems, including low flame speed, narrow flammability limits, and tendency to NOx formation. Therefore, the further introduction of ammonia as a fuel in energy and industry requires comprehensive studies of the combustion working process. Research should be based on determining the influence of the main technological factors, the possibility of using mixed fuels, as well as establishing the optimal geometric and mode parameters of the fuel combustion system.

A Critical Review of Overheating Risk Assessment Criteria in International and National Regulations—Gaps and Suggestions for Improvements

The escalating environmental threat of indoor overheating, exacerbated by global climate change, urbanisation, and population growth, poses a severe risk to public health worldwide, specifically to those regions which are exposed to extreme heat events, such as Australia. This study delves into the critical issue of overheating within residential buildings, examining the existing state of knowledge on overheating criteria and reviewing overheating guidelines embedded in (a) international standards and (b) national building codes. Each regulatory document is analysed based on its underlying thermal comfort model, metric, and indices. The advantages and limitations of each document are practically discussed and for each legislative document and standard, and the quantitative measures have been reviewed, analysed, and summarised. The findings illuminate a global reliance on simplistic indices, such as indoor air temperature and operative temperature, in the existing regulatory documents. However, other critical environmental parameters, such as relative humidity, indoor air velocity, and physiological parameters including metabolic heat production and clothing insulation, are often not included. The absence of mandatory regulations for overheating criteria in residential buildings in some countries, such as in Australian homes, prompts the call for a holistic approach based on a thermal index inclusive of relevant environmental and physiological parameters to quantify heat stress exposure based on human thermal regulation. Gaps and limitations within existing guidelines are identified, and recommendations are proposed to strengthen the regulatory framework for overheating risk assessment in residential buildings. The findings hold significance for policymakers, building energy assessors, architects, and public health professionals, providing direction for the improvement of existing, and development of new, guidelines that aim to enhance indoor thermal condition and population health while ensuring energy efficiency and sustainability in the building stock.

Economic Analysis of Renewable Energy Generation from a Multi-Energy Installation in a Single-Family House

The promotion of Renewable Energy Sources RES installations in single-family houses is an element of the broadly understood decarbonisation strategy. Investments in photovoltaic installations and pellet boilers have a direct effect on decreasing CO2 emissions, thereby contributing to the improvement in air quality and mitigation of climate change, but the question remains of whether they are economically viable. High energy consumption by households results in a significant burden on their budgets. The purpose of this study was to conduct an economic analysis of the renewable electricity (photovoltaic microinstallation—PV) and heat (a pellet boiler) produced in three consecutive years by a single family situated in North-Eastern Poland. The economic analysis was based on the determination of the electricity and heat production costs for renewable energy sources and selected fossil fuels. Profitability metrics such as net present value, internal rate of return and discounted payback period were used for the assessment. For the comparison of electricity costs, the costs of electricity from the power grid were confronted with the costs of electricity generation from a PV microinstallation. For the comparison of heat production costs, the following scenarios were analysed: (i) eco-pea coal vs. pellet, (ii) natural gas vs. pellet and (iii) heating oil vs. pellet. Next, comparisons were made and analysed for multi-energy systems. When comparing the PV microinstallation investment with the variant of using electricity from the power grid, a positive NPV equal to EUR 5959 was obtained for the former, which proved it was profitable. Among the heat generation variants, the lowest total costs were related to eco-pea coal (EUR 29,527), followed by pellet (EUR 33,151) and then natural gas (EUR 39,802), while the highest costs of heat generation were attributed to burning heating oil (EUR 63,445), being nearly twice as high as the cost of burning pellets. This analysis of multi-energy systems showed that the RES system composed of a PV microinstallation for electricity production and a pellet-fired boiler for heat generation was most advantageous because it yielded the lowest total costs (EUR 41,265) among all the analysed variants. A properly selected PV microinstallation and an automatic pellet-fired boiler can make a single-family house economical and provide it with sufficient amounts of renewable electric and heat power throughout the year.

Mitochondrial fission is required for thermogenesis in brown adipose tissue.

Brown adipose tissue (BAT) thermogenesis is pivotal for maintaining body temperature and energy balance. Mitochondrial morphology is dynamically controlled by a balance between fusion and fission, which is crucial for cell differentiation, response to metabolic insults, and heat production. Dynamin-related protein 1 (Drp1) is a key regulator of mitochondrial fission. This study investigates the role of Drp1 in BAT development and thermogenesis by generating Drp1-deficient mice. These mice were created by crossing Drp1 floxed mice with fatty acid-binding protein 4-Cre (aP2-Cre) transgenic mice, resulting in aP2-Cre+/-Drp1flox/flox (aP2-Drp1f/f) mice. The aP2-Drp1f/f mice exhibited severe BAT and brain hypoplasia, with the majority dying within 48 hours postnatally, highlighting Drp1's crucial role in neonatal survival. Impaired thermogenic responses were observed in aP2-Drp1f/f mice, characterized by significantly decreased expression of thermogenic and lipogenic genes in BAT. Ultrastructural analysis revealed disrupted mitochondrial morphology and reduced lipid droplet content in BAT. The few surviving adult aP2-Drp1f/f mice also showed impaired BAT and brain development, along with BAT thermogenesis dysfunction during cold exposure. Our findings underscore the essential role of Drp1-mediated mitochondrial fission in BAT thermogenesis and neonatal survival, providing insights into potential therapeutic approaches for metabolic disorders.

Radiogenic heat production provides a thermal threshold for Archean cratonization process

A striking feature of the Yilgarn craton at the current erosional level is an abundance of late K-rich granites with radiogenic heat production elevated far above global crustal averages. Extrapolated back in time, the total thickness and contribution to crustal heat production and heat flow from these granites were greater, implying that the deeper crustal sources must also have had elevated radiogenic heat production. Through back-calculated and time-integrated one-dimensional thermal modeling underpinned by geological and geochemical constraints for the model crustal columns, we find that elevated radiogenic heat production provided a significant internal driver for prolonged crustal melting and eventual cratonization of the Yilgarn craton. Our results show that elevated thermal gradients driven by high heat production thermally primed the mid- and deep crust at or above the threshold for large-volume partial melting over long periods of time, as evidenced in the magmatic rock record. This would have been amplified by any additional heat that may have been provided by the mantle melting processes that punctuated the geological history. Over time, advective movement of progressively more radiogenic heat production to the shallower crust would have resulted in two complementary outcomes: progressively refractory deep crust and long-term cooling. The widespread granite “bloom” at 2650−2600 Ma records the final time at which the crust was fertile enough to melt in large volumes and the thermal gradient was hot enough to intersect the solidus. The magnitude of radiogenic heat production in the Yilgarn craton has been underestimated in previous studies, resulting in an underappreciation of the importance of its contribution to internal drivers of magmatism and ultimately cratonization.

Feedstock Characterization for Enhanced Heat Recovery from Composting Processes: A Review

Compost Heat Recovery Systems (CHRS) sustainably capture heat from composting waste biomass, helping reduce greenhouse gas emissions and fossil fuel reliance. The choice of feedstock affects the performance of CHRSs as it controls the microbial activities and the amount of heat generated. This review evaluates plant-based, animal-derived, and non-agricultural feedstocks to optimize CHRS energy recovery. A systematic review of 244 studies, published from 1996 to 2023 and available on Scopus, Web of Science, and external databases, categorized feedstocks based on properties like carbon-nitrogen ratio (C/N), moisture content, bulk density, and heating value to assess their impact on energy recovery and compost quality. The review followed the PRISMA guidelines, excluding irrelevant documents and those that lacked quantitative data. Animal-based materials, which have high levels of moisture and nutrients, such as nitrogen (14.50–32.20 g/kg TS) and phosphorus (13.0–13.5 g/kg TS), promote rapid growth of microbes and consistent heat production supported by their stable carbon content (353.8–450.0 g/kg TS) and optimal C/N ratios (5.90–28.90). On the other hand, plant-based materials that are rich in volatile solids (327.2–960.0 g/kg TS) and lignin (36.7–290.0 g/kg TS) offer a steady and prolonged release of heat but decompose more slowly.

Fabrication of Novel Polyurethane matrix-based Functional Composites with Enhanced Mechanical Performance

Thermoplastic polyurethane (TPU) has gained significant interest in several fields, including automobile steering wheels, and the electronics sector due to their easier processability, abrasive resistance, and self-lubricating performances. However, their strong inherent flammability and significant smoke and heat production during burning limit their industrial applications. Therefore, its applicability can be enhanced with the addition of high-strength reinforcement and making them antibacterial and flame-retardant. This research is designed to examine the influence of zirconium phosphate (ZrP) and zinc oxide (ZnO) nanoparticles on the novel polyurethane/glass fiber reinforced composites for flame retardant and antibacterial applications with improved mechanical performance. Three different types of novel polyurethane (PU1, PU2, PU3) matrices were prepared using different recipes, and 7% ZrP and 5% ZnO nanoparticles were added to the polyurethane matrices separately, and their corresponding composite samples were fabricated using glass reinforcement. Mechanical i.e., Charpy impact, hardness and tensile, and functional i.e., flame retardancy (FR) and antibacterial tests were performed to compare their performance. Mechanical testing results showed that PU3-based composite samples showed the highest values of impact force, hardness, and tensile strength in both ZrP and ZnO nanoparticle-based composite samples. Furthermore, 7% ZrP-PU3 composite exhibited the best performance of flame retardancy due to the presence of hexamethylene diisocyanates (HDI) content. Likewise, the 5% ZnO-PU3-based composite exhibited the highest antibacterial activity along with enhanced mechanical performance.

Role of LED (Light Emitting Diode) Light Illumination on the Growth of Plants in Greenhouse Farming-Hydroponics: IOT Technology

This review paper of literature highlights role of Light Emitting Diode (LED) on the growth of plants under controlled conditions of greenhouse farming particularly hydroponics. “Internet of Things (IOT)” is a system of interconnected computing devices, sensors, objects, microcontrollers, and cloud servers that can transmit data across a network and control other devices remotely without human intervention. Light Emitting Diode (LED) is a more efficient, versatile, lasts longer, highly energy-efficient, directional, narrow light spectrum, low power consumption, and little heat production. Common LED colors include amber, red, green, and blue. Hydroponic grow lights are designed to mimic the natural light that plants need for photosynthesis. Plants can only use the spectrum of visible light to produce photosynthesis, and this narrow spectrum (400 to 700 nanometer) is recognized as the Photosynthetically Active Radiation (PAR). The development and growth of diverse plant species can be influenced differently by a variety of colored LED lights. LED illumination provides an efficient way to improve yield and modify plant properties. Therefore, LED systems plays an important role in controlling morphological, genetic, physiological, chemical properties, increasing the synthesis of a variety of beneficial secondary metabolites, and optobiological interactions of plants in greenhouse farming. In general, red and blue light is essential for maximizing the photosynthesis process due to their strong absorption by the plant chlorophyll molecules. LED illumination sources are increasingly being utilized to enhance the growth rate of vegetables and herbs cultivated in greenhouses worldwide. LED illumination spectrum manipulation could enable significant morphological adaptations, and identification of the wavelength ranges is required to increase the plant photosynthesis process.

Techno-economic analysis of a biogas power plant: Moving to sustainable energy supply and green environment through waste management

The feasibility of establishing an anaerobic digestion power plant for producing electricity, heat, and bio-fertilizer using a combined heat and power system using municipal solid waste in Sanandaj has been designed and simulated. The optimal condition for biogas production will be identified using an experimental design, and subsequently, modeling under optimal conditions was performed using Aspen Plus. The anaerobic digestion process was simulated under thermophilic conditions at a temperature of 55 °C, pressure of 1 atm, and retention time of 15 days. The daily biogas production amounted to 32,174 m3 from 380 tonnes of municipal solid waste. The daily production of electricity and heat was 2.9 MW and 3.3 MW, respectively. The daily production of bio-fertilizer was 48 tonnes. The electricity produced can meet approximately 3 % of Sanandaj's total demand. In addition to energy production from waste, the economic evaluation indicated that the project's net present value over a 20-year operational period was approximately 6333,333 €, demonstrating the project's economic viability. Furthermore, establishing this power plant will prevent 85,023 tonnes of CO2 annually. The results indicated the effectiveness of the designed plant in replacing power generation with fossil fuel and reducing greenhouse gas emissions.

Regulatory framework for the promotion of heat pumps in the European Union

Heat pumps (HPs) are viewed by the European Union (EU) as a decisive instrument for accomplishing the goals of net zero emissions by 2050. This technology has the potential to help reach this goal by allowing greater integration of renewable energy sources and the use of waste heat. With a particular focus on industry applications, this paper reviews the evolution of the regulatory frameworks and policy efforts for the promotion of HPs at the EU level and assesses the achievement of the set goals. The imperative decarbonization of the industrial sector stands as a critical milestone in realizing the ambitious 2050 targets, constituting nearly 26 % of the EU's total final energy demand. This manuscript delineates the industrial sectors and process applications where HPs could potentially increase energy efficiency, shedding light on the primary obstacles hindering their widespread deployment. Moreover, the study delves into the landscape of ongoing research and development (R&D) projects within the EU, showcasing tangible evidence of the feasibility of HP application. Comprehensive in scope, the paper provides a thorough examination of existing policies related to HPs at both the EU and Member States levels, emphasizing a glaring absence of a robust regulatory framework necessary to propel the widespread adoption of this technology in EU industries. Furthermore, the manuscript also provides indications on possible ways of promoting HTHPs in the industrial sector, with attention not to repeating the mistakes that occurred in the past with the promotion of renewable energy. It is expected that the conclusions extracted can be of interest to developers and policymakers as well as to practitioners of other emerging technologies committed to emissions reduction in heat production.

Flexibility is the key to decarbonizing heat supply: A case study based on the German energy system

Decarbonizing the heating sector is a key challenge in Europe and Germany and lags significantly behind the electricity sector regarding the share of renewable energies. This is also due to municipal heating planning being still in progress in many places, and decision-makers being uncertain about efficient technologies. We apply an advanced energy system model with linear optimization to the German energy system with special consideration of district heating. Our goal is to determine the near-optimal solution space in the heating sector, which we define as solutions within a 1% increase in optimal system cost. We show that the optimal share of district heating on the German heat demand is only 8.3%, but 27.2% of the demand can be supplied in the near-optimal solution. Larger shares are inefficient due to higher investments caused by lower heat density in sparsely populated regions. The wide range of solutions at comparable costs must encourage urban authorities to implement and communicate consistent heat planning regardless of the choice between centralized and decentralized heat supply. Direct electrification dominates both centralized and decentralized heat generation in all scenarios. Combined heat and power (CHP) plants are part of the optimal solution, but their heat production is limited by high fuel cost. It is therefore risky to plan with high shares (>20%) of CHP in heating networks. Alternative flexibility options such as water-based seasonal heat storage and the use of excess heat from power-to-x plants show promising results. They increase the district heating share in the near-optimal solution to 42.2%, but are limited by the amount of land required and the monetary value of the excess heat, respectively.

Study on the effect of thermoactivated conditions on the properties of hardened cement powder

The performance of thermoactivated hardened cement powder (HCP) is the basis for studying the performance of thermoactivated recycled concrete powder (RCP). Previous studies have mostly focused on thermoactivated RCP, while thermoactivated HCP is taken as the research object in this paper. The effects of different thermoactivated conditions on the mass loss rate, density, initial and final hardening time, standard consistency water powder ratio, and compressive strength of the test block made from thermoactivated HCP were studied. Furthermore, the mineral composition, microstructure, chemical elements, hydration heat, and hydration products of thermoactivated HCP made from different thermoactivated conditions were analyzed. The test results indicated that the average initial harden time of the 600, 800, 1000, and 1200 °C of thermoactivated HCP are 15, 1160, 85, and 13 min, respectively. In terms of phase change of HCP at different heating temperatures, when the heating temperature reached 800 °C, the diffraction peaks of C-S-H and CaCO3 disappear, while the diffraction peaks of C3S, β-C2S, and αC2S began to appear. AFt and Hydrotalcite are completely decomposed and C-S-H loses adsorbed water with temperature from 35.9 to 201.7 °C. Ca(OH)2 is completely decomposed with temperature from 413.3 to 457.4 °C. CaCO3 is completely decomposed with temperature from 457.4 to 731.6 °C. In terms of changes in the proportion of chemical elements after hydration of thermoactivated HCP, the values of Ca/Si of hydrated cement is 1.78. The average values of Ca/Si after hydration of 1000 and 1200 °C thermoactivated HCP are 3.32 and 3.33, respectively, while the average values of Ca/Si after hydration of 600 and 800 °C thermoactivated HCP are 2.74 and 2.6. These research conclusions provide a foundation for the application of thermoactivated HCP. HIGHLIGHTS The mass loss rate, density, and compressive strength of hardened cement powder made from different heating conditions were studied. The standard consistency water powder ratio, initial and final hardening time of hardened cement powder made from different thermoactivated conditions were analyzed. The mineral composition, microstructure, chemical elements, hydration heat, and hydration mechanism of hardened cement powder made from different thermoactivated conditions were revealed.

Determination of Plastic Pollutants in Solid Biofuels

Many countries widely use biomass for household heating and heat production in district heating systems. Unfortunately, the steady increase in annual plastic waste production has a negative impact on the quality of solid biofuels. This is due to the increasing contamination of these fuels with wastes from plastic and wastes from furniture production, such as laminates and medium-density fiberboard made from wood fibers, among others. The design of specialized biomass combustion systems does not allow for the burning of waste fuel, or the reduction in hazardous organic compounds emitted when burning contaminated biofuels. The study demonstrated the detection of polymeric impurities in solid biofuels through analytical pyrolysis (Py-GC-MS). The study was conducted on model samples that contained increasing proportions of plastic waste, ranging from 0.1 to 10.0% w/w to biomass. Markers were identified and described to indicate contaminated fuel, and the interactions between the sample matrix and plastic were studied. Unique markers were detected that indicate the presence of contamination, even at low concentrations like 0.1% w/w of plastic waste in solid biofuel. These results suggest that direct analytical pyrolysis of solid biofuels, which are already on the market but not covered by the relevant regulatory system and are contaminated with polymeric ingredients, is a method that is not only possible but also gives quick confirmation.

Vulcan gets grant for lithium, heat production

Vulcan gets grant for lithium, heat production

Suppressing ROS Production of AIE Nanoprobes by Simple Matrices Optimization for CNS Cell Observation and Minimized Influence of Cytoskeleton Morphology.

The visualization of the central nervous system (CNS) has proposed stringent criteria for fluorescent probes, as the inevitable production of reactive oxygen species (ROS) or heat generated from most photoluminescent probes upon excitation can disturb the normal status of relatively delicate CNS cells. In this work, a red-emitting fluorogen with aggregation-induced emission (AIE) characteristics, known as DTF, was chosen as the model fluorogen to investigate whether the side effects of ROS and heat could be suppressed through easy-to-operate processes. Specifically, DTF was encapsulated with different amphiphilic matrices to yield AIE nanoprobes, and their photoluminescent properties, ROS production, and photothermal conversion rates were examined. BSA@DTF NPs possessed 1.3-fold brightness compared to that of DSPE-PEG@DTF NPs and F127@DTF NPs but its ROS generation efficiency is markedly decreased to only 2.4% of that produced by F127@DTF NPs. Meanwhile, BSA@DTF NPs showed a negligible photothermal effect. These features make BSA@DTF NPs favorable for long-term live cell imaging, particularly for fluorescent imaging of CNS cells. BSA@DTF NPs were able to sustain the normal state of HT-22 neuronal cells with continuous illumination for at least 25 min, and they also preserved the cytoskeleton of microglia BV-2 cells as the untreated control group. This work represents a successful but easy-to-operate process to suppress the ROS generation of red-emissive AIEgen, and it highlights the importance of minimizing the ROS generation of the fluorescent probes, particularly in the application of long-term imaging of CNS cells.

Main Heat Transfer Mechanisms in Hot Stamping Processes: a Review

Objectives: The article reviews heat transfer mechanisms in the hot stamping process, highlighting models to calculate the interfacial heat transfer coefficient (IHTC), crucial for optimizing the cooling and quality of formed products. Theoretical Framework: In hot stamping of high-strength steels, the IHTC is affected by variables such as contact pressure, roughness and temperature. Cooling efficiency directly impacts the temperature distribution and martensitic microstructure of the material, essential for structural strength. Method: The review compares IHTC calculation methods, such as inverse heat conduction analysis and Newton's law of cooling, detailing the convection, radiation and conduction mechanisms at each stage of the process: transfer, positioning and forming. Results and Discussion: The inverse heat conduction analysis proved to be the most accurate for determining the IHTC, compared to the finite element method (FEM). The study suggests that efficient cooling channels and high conductivity materials in the matrix reduce cooling time and improve the quality of the final product. Research Implications: Findings provide a basis for improving thermal management in hot stamping, reducing cycle time and increasing productivity. Originality/Value: This work contributes a comprehensive reference on IHTC, assisting researchers and engineers in optimizing heat transfer and production efficiency in the manufacture of automotive components.

Thermodynamic analysis of a solar-fed heat upgrade system using the reverse air brayton cycle

This analysis focuses on exploiting solar energy to meet industrial energy needs. It is based on upgrading solar heat production using surplus electricity from renewables to generate high-temperature industrial process heat. The approach involves the use of efficient evacuated flat plate solar thermal collectors coupled with a thermal storage tank to power a reverse air Brayton heat pump for high-temperature heat production. A Matlab algorithm has been developed to dynamically analyse energy balances across the system. The analysis is conducted for the location of Komotini, Greece and the results regard the operation of a system for a typical summer week. For the baseline design point with a 1000 m2 collecting area and 50 m3 thermal tank volume, the average daily process heat production for the industry is 8.63 MWh, while the average daily coefficient of performance (COP) for the heat pump is 1.478. Moreover, the present work includes results regarding the parametric performance of the system for different combinations of collecting area and thermal tank volume. It was demonstrated that with the optimization of the solar thermal collector area and thermal tank volume, the daily average COP can be increased up to 23.1 %. Finally, the influence of the units of transfer area of the heat exchangers on the coefficient of performance has been investigated.

Performance comparison of battery cold plates designed using topology optimization across laminar and turbulent flow regime

Liquid cooling with cold plates offers an efficient solution for battery thermal management. However, conventional cold plates in turbulent regime often result in inadequate temperature uniformity within battery modules and generate significant pressure drops. In this study, we employ the turbulent conjugate heat transfer topology optimization method based on the k-ε turbulent model for cold plate design. Then we derive two novel cold plate designs based on the laminar and turbulent topology optimization method, respectively, and the effectiveness of the two design methods are compared. A multi-objective function which minimizes pressure drop and average temperature is established to balance the thermal and hydraulic performance of the cold plates. The electrochemical-thermal coupled model is utilized to simulate heat production of the battery pack. The fluid flow and heat transfer performance of turbulent topology-optimized cold plate (TTCP) during constant rate discharging is analyzed and compared with that of laminar topology-optimized cold plate (LTCP), serpentine cold plate (SCP), and rectangular cold plate (RCP). Numerical simulation results show that TTCP gives the best overall cooling results among all the designs despite a slight disadvantage against LTCP at very low flow rates. At high-speed turbulent flow (8.488 × 10−2 kg/s), the performance evaluation criterion (PEC) number improvements for TTCP, LTCP, and SCP compared with RCP are 86.7 %, 78.5 %, and 85.4 %, respectively. Hence, cold plate topology optimization using turbulent conditions and methods is recommended for power battery systems, especially those with fast charging/discharging requirements.

Experimental study of a novel design bi-fluid based photovoltaic thermal (PVT)-assisted heat pump dryer

This study evaluated the performance of a novel design bi-fluid (air and refrigerant)-based photovoltaic thermal assisted heat pump dryer (BfPVTA-HPD), combining a compact bi-fluid PVT using curved directional fins that direct air at different points to the evaporator/waste aluminum material and HP system with a PVT air outlet mounted micro-channel condenser. BfPVTA-HPD was analyzed regarding energy, exergy, and drying characteristics at two different times, in clear and partially cloudy weather conditions. Mint leaves (Mentha piperita L.) were dried to evaluate BfPVTA-HPD's drying capabilities. The average electrical, thermal, and exergy efficiencies of PV and PVT for Exp-1 and Exp-2 varied to 15.97, 16.54 %, 18.21, 18.23 %, 55.36 %, 42.04 %, 30.95 %, and 25.08 %, respectively. In Exp-1 and Exp-2, respectively, while an increase of 12.32 % and 9.29 % in the average electrical efficiency was achieved by using PVT, an average of 3.15 and 2.86 were reached in the coefficient of performance (COP) of the heat pump. The exergy indicators (the improvement potential, sustainable index, and waste exergy ratio) for the Exp-1 are 839.52, 1.39, and 0.82. The exergy indicators for the Exp-2 are 1166.14, 1.30, and 0.84, respectively. The experiment's average mass transfer coefficients were obtained as 1.17 × 10−8 and 7.75 × 10−9 m/s respectively. The experiment's average effective diffusivity coefficients were obtained as 2.90 × 10−11 and 2.04 × 10−11 m2/s, respectively. The recommended BfPVTA-HPD can be used as a new model to improve the ecological footprint and green manufacturing. Furthermore, the electricity and heat production required for the sustainability of the drying system in spring and winter can be realized.