Dual Heat Research Articles

'WASAP': WARM as soon as possible - A low-cost instant blood warmer based on dual tube heat exchanger and nanofluid technology.

'WASAP': WARM as soon as possible - A low-cost instant blood warmer based on dual tube heat exchanger and nanofluid technology.

Effect of dry heat and its combination with vacuum heat on physicochemical, rheological and release characteristics of Alocasia macrorrhizos retrograded starches

Retrograded starches have received increasing attention due to their potential excipient properties in pharmaceutical formulations. However, to evade its application-oriented challenges, modification of retrograded starch is required. The study emphasizes influence of dry heating and the dual heat treatment by dry heating amalgamation with the vacuum heat treatment on quality parameters of retrograded starch. The starch was isolated by using two different extraction media (0.05 % w/v NaOH and 0.03 % citric acid) from Alocasia macrorrhizos and then retrograded separately. Further, retrograded starches were first modified by dry heating and afterwards modified with combination of dry and vacuum heating. Modification decreased moisture, ash content and increased solubility. Modified Samples from NaOH media had higher water holding capacity and amylose content. X-ray diffraction revealed type A and B crystals with increasing crystallinity of retrograded heat-modified samples from NaOH media. Thermogravimetric analysis, differential scanning calorimetry confirmed thermal stability. Shear tests showed shear-thinning behavior whereas dominant storage modulus (G/) over loss modulus (G//), depicting gel-like behavior. Storage, loss, and complex viscosity initially increased, then decreased with temperature. In-vitro release reflects, modified retrograded starches offers versatile drug release profiles, from controlled to rapid. Tailoring starch properties enables precise drug delivery, enhancing pharmaceutical formulation flexibility and efficacy.

Numerical study of the melting rate enhancement of nano phase change material in a modified shell and tube heat exchanger

The current investigation employs numerical analysis using ANSYS Fluent software to explore the melting behaviour of phase change material (PCM) and nano-PCM in a semi-circular shell and tube heat exchanger, utilizing dual side heating for enhanced conduction and convection rates of heat transfer. The study incorporates aluminium oxide nanoparticles at volume concentrations of 2 %, 4 % and 6 % within paraffin wax and assessing their impact on melting and thermal energy storage rates. Notably, the 2 % nanoparticle volume concentration exhibits an enhanced storage rate as compared to higher concentrations. The increase in nanoparticle concentration from 0 % to 2 %, 2 % to 4 % and 4 % to 6 % results in percentage reduction in melting time of 21 %, 3.51 % and 2.8 % respectively. Semi-circular configuration shows significant improvement in the energy storage rate as compared to the circular triplex tube configuration. The maximum energy storage rate of PCM for the semi-circular and circular configurations is 1.15 kW and 1.04 kW respectively, marking a 9.56 % increase over the circular configuration. Moreover, the semi-circular and circular configurations using nano-PCM achieve a maximum energy storage rate of 1.19 kW and 1.14 kW, representing a 4.20 % increase over the circular configuration.

Performance investigation of a novel flat-plate solar air collector with L-shaped dual micro heat pipe arrays

To improve the thermal performance of solar air collectors by reducing heat leakage and fully transporting the heat absorbed in the evaporation section, this paper proposes a structural innovation based on previous research, that is, L-shaped dual micro heat pipe arrays integrated with a flat-plate solar air collector with a double glazing cover. Experiments are conducted to investigate the thermal performance of the proposed collector. The effects of solar irradiation, ambient temperature, and air flow rate on thermal performance are reported. Thermal resistance is analyzed theoretically. The application performance of the collector is evaluated based on a typical rural building heating model. The results show that the average heat collection efficiency is 49.72 %, 55.69 %, 59.37 %, and 61.48 % for air flow rates of 80, 120, 160, and 200 m3/h, respectively. The evaporation section temperature is reduced by a maximum of 25.28 °C under flow rates of 200 m3/h. The performance of the solar collector is more significantly influenced by solar irradiance than by ambient temperature. The average thermal efficiency is linearly related to the normalized temperature difference. The CO2 reduction over the lifetime of the device is 15040.09, 19287.80, and 5662.95 kg compared with the use of conventional bulk coal, electricity, and natural gas, respectively.

Hydrothermal analysis of archimedean spiral single and dual channel heat sink for CPU cooling

Engineering modeling and simulation represent a predominantly design tool in the modern manufacturing industry in which the actual system is reproduced using a mathematical and scientific model. This requires CPUs with higher computational capacities. However, increas-ing the computational capacities of CPU and GPU imposes challenges in the cooling process due to space limitations. CPU liquid cooling system has attracted more interest as an efficient heat dissipation tool. This work presents computational modeling of the conjugate heat and flow for the CPU liquid heat sink cooling. An Archimedean spiral channel is grooved into the cold plate of the heat sink. Single and dual channel passes are used in this work. The out-er diameter of the cold plate is 105 mm and the channel depth is 5 mm for both single and dual-channel configurations. The conjugate heat sink model was constructed to have four different domains: CPU (alumina), glue layer (ethoxy), cold plate (copper), and liquid cool-ant (water). To incorporate the effect of turbulence, the flow rate varied to cover a range of Reynolds number from 3000 up to 15000 at a constant inlet temperature of 25 °C. The used turbulence model was the Shear Stress Transport (k-ω) to better capture the viscous, high-fre-quency flow fluctuation in the near-wall region. The bottom surface of the CPU is subjected to 450 W of heat energy. The results showed that the channel configuration and Reynolds number have a decisive impact on controlling the CPU temperature. The CPU temperature decrease as Reynolds number increases, however, the pressure drop increases at an exponen-tial rate. These findings are supported by Darcy–Weisbach equation for internal flow in which the pressure drop depends on the square of the average fluid velocity and it was noticed that the pressure drop in the dual channel was three times higher than that in the single channel. The hydrothermal performance of the Archimedean spiral channel rapidly decreased with Reynolds number and the single-channel had a slightly better performance compared with the dual-channel.

Analysis of porous magneto-thermoelastic solid cylinder via dual phase lag heat transfer model

Analysis of porous magneto-thermoelastic solid cylinder via dual phase lag heat transfer model

Transient Characteristics and Performance of a Dual Compensation Chamber Loop Heat Pipe under Various Heat Loads

The dual compensation chamber loop heat pipe (DCCLHP) technology shows great promise for efficient thermal management in a variety of applications. This study focuses on refining the startup performance of the DCCLHP, particularly for low heat load conditions in terrestrial settings, by utilizing dual bayonet tubes. Empirical investigations examined the DCCLHP’s operational characteristics and improved thermal transfer capabilities across different orientations of the evaporator and compensation chamber (CC), including vertical, 45‐degree tilt angle, and horizontal configurations. Key results demonstrate the DCCLHP’s ability to manage low heat loads across diverse orientations, achieving over 400 W of heat transfer across a distance of 2.0 m while maintaining stable operation. Notably, the DCCLHP operation did not exhibit any significant instability issues. This work enhances the startup performance of the DCCLHP in various orientations and provides valuable insights into the confined natural circulation phenomenon, crucial for improving the overall thermal management capabilities of the system. In summary, the study highlights advancements in DCCLHP design and its potential to address thermal management challenges in diverse applications, particularly in the aerospace industry, through improved startup performance and enhanced heat transfer capabilities.

Internet of things temperature control of indirect dual tank heat storage system in solar photo-thermal power plant

In order to study the temperature control of the IoT for indirect dual tank heat storage systems in solar thermal power plants, the author proposes a refined design method for heat storage systems. Through CFD software FLUENT analysis, the author proposes a temperature control scheme for storage tanks in solar thermal power plants and applies this method to the temperature control and salt injection processes of actual commercial power plants. The refined design of a systematic heat storage system mainly involves precise calculation of molten salt content and refined analysis of overall and local stresses in the storage tank. For molten salt storage tanks with a diameter of about 30 m, every 1 cm of liquid level design error will result in economic losses of tens of thousands of Yuan. In addition, the design process of storage tanks should fully consider temperature control, salt injection, and some special operating conditions during operation. By numerically simulating the flow process of flue gas and molten salt in the storage tank and the real-time wall temperature of the storage tank, a temperature control scheme that does not exceed the maximum allowable wall temperature difference of the storage tank is obtained to reduce thermal stress during the temperature control process of the storage tank, reduce the risk and failure rate of the storage tank. The temperature control scheme has achieved good results in practical projects.

Scheffler reflector based solar cooking system with dual sensible heat storage material for night cooking application: an experimental investigation

Scheffler reflector based solar cooking system with dual sensible heat storage material for night cooking application: an experimental investigation

Investigation of Dual Coil Induction Heating for Enhanced Temperature Distribution Optimization

Investigation of Dual Coil Induction Heating for Enhanced Temperature Distribution Optimization

Scheffler reflector based solar cooking system with dual sensible heat storage material for night cooking application: An experimental investigation

Scheffler reflector based solar cooking system with dual sensible heat storage material for night cooking application: An experimental investigation

Controller Performance of Air Blowing Heater Applicable on Forming Process of UHMW Sheet Material

This paper presents the performance of an airblowing heater controller used with UHMW sheet material. Temperature control is implemented within the range of 80°C to 110°C to achieve the re-crystallization temperature of the UHMW sheet material. A PID controller was applied, and its performance was analyzed by varying the temperature set point (SET VALUE), the fan’s flow capacity, and the use of dual heaters to heat both surfaces of the UHMW sheet simultaneously. This paper also examines the effects of auto-tuning and selftuning PID methods on control performance. The test results indicate that balancing the fan’s flow capacity and the heat generation of the heater unit is the dominant factor in PID controller performance. In addition, with the use of double heaters, the material’s energy accumulation becomes the main factor, causing a slower PID controller response in reaching the target temperature. Implementing self-tuning PID constants yielded better controller performance compared to the auto-tuning method.

Is waste heat recovery a promising avenue for the Carnot battery? Techno-economic optimisation of an electric booster-assisted Carnot battery integrated into different data centres

The transition to intermittent renewable energies will necessitate the integration of storage. An interesting technology is the Carnot battery (CB), a novel power-to-heat-to-power system, capable of harnessing waste energy streams. While initial studies have indicated that, under ideal conditions, CB can be competitive with conventional technologies such as chemical batteries, their economic viability in real-world applications remains uncertain. To fill this gap, this work explores the techno-economic potential of electric booster-assisted CB integrated within data centres. Motivation for this case study is the recovery of waste heat, leading to an improved electrical storage efficiency. To maximise the energy self-sufficiency and the internal rate of return, we have applied multi-criteria optimisation to the system design, under three different thermal integration scenarios and for two sets of climatic conditions, using a thermodynamic model and time series from a real data centre. Our analyses suggest that current projections for electricity prices and CB costs yield payback periods exceeding a decade, but that these could fall below ten years if the CB capital costs were halved. Furthermore, it turns out that the choice of optimum charging system (i.e. right balance between heat pump and electrical heater) is contingent on the heat source temperature and availability. For higher temperatures (e.g. 60 °C), heat pumps emerge as the financially most attractive option, thanks to their superior coefficient of performance, whereas for lower temperatures (< 25 °C), resistive heaters are preferable. Results also show that when the aim is to increase the energy self-sufficiency, there exist an efficiency/charging capacity trade-off, which causes a dilemma for the system design. On the one hand, heat pumps are vital to increase the efficiency of the CB, but on the other hand, as the amount of thermal energy available at its source is limited by the data centre operations, electrical boosters are indispensable to increase the charging capacity. To soften this dilemma and enhance the techno-economic performance of thermally integrated CB, future research should explore more efficient booster configurations, such as dual heat source heat pumps.

Experimental Analysis of the Dual Source Heat Pump with Varying Water Temperature

Purpose: The aim is to examine how water temperature influence the coefficient of performance (COP) of a dual-source heat pump (DSHP) and to show how water temperature influence the relationship between heating capacity and power consumption of the DSHP. Methods: An experimental method to examine an installed 5kW DSHP system with an attached converters and other connected components, which arrangement properly controls for the indoor temperature and relative humidity of the laboratory. Results and Conclusions: The findings reflects that the COP of the DSHP pumps increases at low water temperature. As water temperature increases, the heat loss to water and compressor power consumption decreases, and in turn reduce the COP. The average temperature increases from 36.55oC to 59.15oC and COP reduces, by 40%, from 2.83–1.12. Implications: The implication is that the DSHP which is shown to be energy efficient is environmentally friendly, and as a result, would remain very useful in the fifth generation of heating systems with the use of smart technology in future. Originality/Value: The value of the article lies in its focus on the performance of the DSHP as an energy and efficiency device for in heating and cooling in buildings.

Analysis of the Influence Factors of the Crude Oil Temperature Maintenance System of Solar Sewage Heat Pumps in Cold Regions

Traditional crude oil heating methods that use fossil fuels or electricity have the disadvantages of high consumption of nonrenewable resources, low energy utilization, and high carbon emissions. Therefore, it is urgent to develop green and sustainable crude oil heating technologies. In this paper, a solar synergistic sewage heat pump (SSHS) dual heat source crude oil temperature maintenance system is proposed. The system utilizes clean and sustainable solar energy to heat crude oil while combining sensible heat storage technology and the waste heat utilization technology of a sewage source heat pump to solve the unstable fluctuation of the solar heating problem. A simulation and analysis model is established to analyze the influencing factors of the SSHS, and the optimal operation scheme is provided. The results show that the efficiency of the solar collector decreases and the proportion of crude oil heating increases with an increase in the solar energy guarantee rate, while the unit flow rate of the pump has a large impact on the performance of the sewage source heat pump. In order to avoid energy waste, it is more appropriate to adopt a 30% guarantee rate and an A3 pump unit flow rate, under which the solar collector efficiency is 50.18%, the proportion of solar heating of crude oil is 47.16%, the average temperature of crude oil is 42.59 °C, and the COP of the sewage source heat pump is 4.65. Further increases in the COP of the wastewater source heat pump can be realized by increasing the temperature of the wastewater supply. The results of this study provide a valuable reference for the optimization of crude oil storage heating systems.

Simulation-based analysis of thermochemical heat storage feasibility in third-generation district heating systems: Case study of Enschede, Netherlands

In this article a dual heat storage system comprising thermochemical heat storage (TCS) and hot water storage for managing the mismatch between heat generation and demand in district heating systems (DHs) is evaluated. TCS is known as technology suitable for long-term heat storage due to its high energy density and negligible heat losses over a longer period. However, the integration of TCS in DHs is significantly influenced by the operating conditions of DHs. Here we evaluate the feasibility of integrating TCS into DHs in the Enschede region of the Netherlands. DHs models are established to simulate heat generation, demand, and storage, and a control strategy is designed to manage storage coordination. The obtained results show that the dual storage system outperforms the single hot water storage system in reducing peak load generation. Depending on the TCS's operational condition, annual energy generation from peak load in dual storage systems could drop by 30–60 % compared to the single hot water storage system. It is achieved mainly by managing the energy capacity remaining in the storage system. The technical feasibility and benefits of implementing a TCS system in DHs with a dual storage system are shown to be more energy efficient.

Modeling of the heterogeneous hypergolic ignition with particle packing model

The ignition process of a hypergolic hybrid rocket fuel presents a significant challenge due to its complex and interconnected nature. However, understanding its underlying physics is crucial for accurately estimating the delay time and ignition performance. In this study, we employed an approximate analytical method to directly address the transient conduction problem with nonlinear surface heat generation. By using the Arrhenius equation and considering dual heat flux directions in both the liquid and solid domains, we propose a model for determining the delay time of heterogeneous hypergolic ignition. Our solution is straightforward and computationally efficient. Notably, when subjected to identical initial conditions and property settings, our results exhibit similarity with the solutions derived from other models. Moreover, we advance our approach by developing a particle packing model through the utilization of a well-established algorithm. By simulating the particle arrangement within the pellet, the surface layer properties and the thermal time constant of certain fuel designs can be modeled. This simulation serves the purpose of incorporating the particle size effect of the fuel pellet into our ignition model. The results generated by our heterogeneous hypergolic ignition model, in conjunction with the particle packing model, demonstrated impressive agreement with the experimental data derived from droplet tests. Novelty and significance statementThis study utilized a novel solving method to address a transient conduction problem with non-linear heat generation on the surface during a heterogeneous hypergolic ignition process. The study successfully derived an analytical solution, providing a simpler method for calculating ignition delay times. A scenario involving different initial temperatures was also examined. Additionally, the research integrated particle packing model data and thermal time constants to assess the effect of particle size. The model results were in agreement with the experimental data, confirming its accuracy and offering a reliable method for estimating the heterogeneous hypergolic ignition delay time.

Efficient coal-based power generation via optimized supercritical water gasification with chemical recuperation

Supercritical water gasification (SCWG) is promising as a clean coal technology and is an emerging topic of interest in sustainable energy. Here, we introduce a clean and efficient power generation system that optimizes SCWG of coal through chemical recuperation. Central to our approach is the innovative utilization of both exhaust and a portion of the syngas as dual heat sources for gasification, simultaneously producing the requisite supercritical water. This chemical recuperation strategy effectively enhances the transformation of coal chemical energy into syngas. The introduced system achieves power generation and exergy efficiencies of 56.64 and 55.30%, respectively, outperforming those of a baseline system by 8.43 and 8.23%, respectively. This gain is primarily attributed to the irreversible losses in the gasification, air separation, and heat-exchange processes of the introduced system, which were reduced by 8.75, 2.47, and 4.17%, respectively, compared with the corresponding values of the baseline system. In order to elucidate and validate the reduced irreversible losses in the introduced system compared with those in the baseline system, we incorporated the energy utilization diagram methodology into our analysis. In summary, the introduced system represents a pivotal advancement in clean and efficient coal-based power generation and underscores the need for continuous innovation in this sector.

Simulation analysis of a photovoltaic/thermal-air dual heat source direct-expansion heat pump

Simulation analysis of a photovoltaic/thermal-air dual heat source direct-expansion heat pump

Thermal performance experimental study of a serrated micro-groove ultra-thin aluminum flat heat pipe under different heater locations

ABSTRACT An ultra-thin aluminum flat heat pipes (UAFHP) with dimensions of 180 × 20 × 2 mm (length×width×thickness) were fabricated by extrusion. The thermal performance of the UAFHP was experimentally tested at different inclination angles and heater locations, which is considered for single and dual heater, respectively. The thermal resistance and wall temperature of the UAFHP decreased in dual heaters operation compared to single heater operation. The locations of the heater have an important influence on the thermal performance of the UAFHP in both single and dual heater operation. The experimental results can provide guidance for the application and design of the UAFHP.