Thermal Source Research Articles

GHG emissions estimation and assessment of Pakistan's power sector: A roadmap towards low carbon future

Growing population, burgeoning economic growth and technological advancements have caused a surge in electricity demand worldwide. In recent years, Pakistan, contributing less than 1 % to global Greenhouse Gas (GHG) emissions, has endured severe weather, including the 2022 floods that affected nearly 30 million people. Pakistan is a developing country and signatory of Paris accord has made an international commitment to cut down its GHG emissions. To date, the total electricity generation of Pakistan is about 122,934 GWh, from which 60.9 % (744,862 GWh) is met by thermal sources (coal, oil gas), 23.7 % (29,181 GWh) by hydel, 12.4 % (15,182 GWh) by nuclear and 3 % (3709 GWh) of electricity generation is done through renewable energy sources. The demand for electricity in Pakistan is rising exponentially, and around 60.9 % is fulfilled by hydrocarbons. This study explores a novel approach by assessing the electricity sector's GHG emissions using CO2, CH4, and N2O, expanding beyond the traditional focus on CO2 alone. This work uses a time-varying carbon intensity approach to calculate the GHG emissions and, subsequently, carbon intensity from fossil fuel-driven electrical systems. One notable aspect of this approach is its capability to calculate GHG emissions and carbon intensity with a more frequent temporal resolution, frequently. The peak GHG emissions are observed in January and December at values 650gCO2-eq/kWh and 550gCO2-eq/kWh respectively, causing smog issues in the country. Results show that the carbon intensity in Pakistan is relatively higher during January, February, October, November and December due to unavailability of hydel resources.

Development of water hyacinth as an alternate biomass source for power generation: Saguling Reservoir Case Study

Abstract Energy security consists of three aspects: the availability of energy sources, the affordability of energy supplies, and the sustainable development of new renewable energy. This paper proposed to help overcome energy problems while solving environmental problems using water hyacinths at Saguling Dam in West Java province, Indonesia. Using an integrated community empowerment approach, the scheme for using water hyacinth is to be developed into an energy source for electricity generation or other thermal energy sources. This scheme is a new concept in developing water hyacinths as an alternative to renewable energy. To ensure the sustainability of this scheme, community support and financial benefits must be established. The results showed that the scheme to use water hyacinth as a source of heat energy is a new scheme in addition to benefiting the community by encouraging local economic development and solving the problem of water hyacinth that disrupts the operation of the Saguling Dam. Utilizing water hyacinth as an alternative energy will improve the community’s economy, which will contribute to increasing the economic activities of a region. This paper steps to develop a design scheme for the use of water hyacinth as alternative energy, especially in rural areas in low- and middle-income countries. Finally, using water hyacinth as alternative energy can guide local communities to encourage them to use biomass resources as an incentive for regional economic prosperity.

Loss model of low pressure compressor for mechanical vapor recompression system

Abstract Low pressure compressor (LPC) serves the role of enhancing pressure levels of secondary steam at nominal pressure ratios (1.5), procured from the evaporator as a primary thermal energy source. A loss model has been proficiently proposed to rapidly predict the performance of the LPC. Instead of conventional lump sum loss equations, the model adopts well-established one-dimensional (1D) loss formulations scattered across scholarly publications. Given an explicit configuration of the LPC, the environmental conditions, rotational velocity, and capacity, static and total temperatures, static and total pressures, pressure reductions, polytropic head, and efficiencies of each individual segment of the compressor can be calculated. Validation of this model was done using computational fluid dynamics (CFD) analysis. This model renders it feasible to conduct a parametric examination of the impact of each loss apparatus on the LPC’s capability, thereby aiding designers in substantiating design choices that minimize these losses and consequently positively influencing the comprehensive efficiency.

Quantum Key Distribution with Displaced Thermal States.

Secret key exchange relies on the creation of correlated signals, serving as the raw resource for secure communication. Thermal states exhibit Hanbury Brown and Twiss correlations, which offer a promising avenue for generating such signals. In this paper, we present an experimental implementation of a central broadcast thermal-state quantum key distribution (QKD) protocol in the microwave region. Our objective is to showcase a straightforward method of QKD utilizing readily available broadcasting equipment. Unlike conventional approaches to thermal-state QKD, we leverage displaced thermal states. These states enable us to share the output of a thermal source among Alice, Bob, and Eve via both waveguide channels and free space. Through measurement and conversion into bit strings, our protocol produces key-ready bit strings without the need for specialized equipment. By harnessing the inherent noise in thermal broadcasts, our setup facilitates the recovery of distinct bit strings by all parties involved.

Interference characteristics of leaking SF6 on photoacoustic detection of dissolved C2H4 in transformer oil

AbstractSF6 leaked from gas insulation equipment will interfere with the detection of dissolved characteristic gases in transformer oil. In order to determine the impact of SF6 on the detection of dissolved C2H4 gas in oil, a photoacoustic (PA) C2H4 detection system based on the combination of mid‐infrared thermal radiation source and near‐infrared laser was constructed. The excitation light from two bands was incident on a non‐resonant PA cell. The thermal radiation light source and the laser light source were switched to evaluate the interference level of SF6 on the detection of C2H4. The experimental results show that SF6 has significant interference to C2H4 when using a mid‐infrared thermal radiation light source. The interference coefficient is 2014%. The near‐infrared laser based on PA detection method can effectively suppress the interference of SF6 on C2H4. The minimum detection limit of C2H4 reaches 0.6 ppm when the average time is 60 s.

Procedural and outcome impact of body mass index on pulsed field ablation of atrial fibrillation: insights from the EU-PORIA Registry

Abstract Introduction Pulsed field ablation (PFA) is a "single-shot" non thermal ablation modality for atrial fibrillation (AF). In general, obesity is associated with increased risk of AF recurrence after catheter ablation with thermal energy sources. Purpose We aimed to assess the impact of body mass index (BMI) on procedural characteristics, safety, acute efficacy and long-term outcomes of PFA for symptomatic AF. Methods Of 1233 subjects enrolled in the EU-PORIA registry, in our subanalysis we included 1055 patients undergoing de novo pulmonary vein isolation (PVI)-only ablation procedure for symptomatic AF using the pentaspline PFA catheter from March 2021 until May 2022 at seven high-volume European centers. Patients were divided into two groups based on BMI: normal weight (nW, < 25 kg/m2) and overweight (oW, ≥ 25 kg/m2). Overweight patients were further categorized into three subgroups: pre-obesity (pOb, 25-29.9 kg/m2), obesity (Ob, 30-34.9 kg/m2) and severe obesity (sOb, ≥ 35 kg/m2). Clinical and procedural characteristics, complications and follow up data were collected. Results A total of 1055 patients (39% female, mean age 65,7±10,9 years, 65% paroxysmal AF) were enrolled. 32% of patients were normal weight (nW) and 68% overweight (oW). Among oW group, 438 subjects (41%) were assigned to pOb group, 204 (19%) to Ob, and 71 (7%) to sOb. Acute PVI was achieved in 100% of cases. The median skin-to-skin procedure and the median fluoroscopy time were similar between nW and oW and in all investigational subgroups, but radiation exposure increased in line with BMI (p<0.001). Periprocedural complications were 5% in nW, 1.6% in pOb, 3.9% in Ob, and 2.8% in sOb (p=0.06). The Kaplan-Meier estimate of arrhythmia-free survival was 80.2% in nW and 71.9% in oW (p=0.017). Each unit increment in BMI was associated with 4.2% increase in risk of AF/AT recurrence. Severe obese patients presented the highest 1-year AT/AF recurrence rate (37.2%). In the sOb group the rate of recurrence was not influenced by the type of AF (PAF 65.7% vs. pers AF 59.4%; p=0.484). Conclusion Overweight patients seem to experience more AF recurrences even after PFA PVI, mainly driven by a higher recurrence rate for BMI ≥ 35 kg/m2. Weight reduction programs remain crucial, nevertheless, reduced procedural times, good safety profile and acceptable 1-year observed AF/AT freedom make PFA a feasible strategy for AF rhythm control in patients with BMI ≥ 25 kg/m2.Freedom from AF/AT recurrence

Biochemical markers of neuro-myocardial damage after pulmonary vein isolation: the effect of different energy sources

Abstract Background Pulmonary vein isolation (PVI) by thermal energy, both radiofrequency (RF) and cryoenergy(Cryo), is associated with a significant release of myocardial and collateral neural injury markers. Damage to periatrial ganglionated plexi also results in a substantial change in cardiac autonomic regulations. On the contrary, pulsed electric field (PEF) energy tends to spare cardiac neural tissue. Purpose To quantify the impact of different ablation energy sources that are used for PVI on neuro-myocardial damage by the assessment of specific biomarkers. Methods A study enrolled 85 patients with paroxysmal atrial fibrillation who underwent PVI (age: 61 ± 12 years, 74% males). In 23 patients, RF energy was delivered by the irrigated-tip catheter, while 30 patients were ablated using a second-generation cryoballoon catheter. In 32 patients, PVI was performed using a multipolar pentaspline catheter and PEF energy. Peripheral venous blood samples for assessing the plasmatic levels of S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), high-sensitivity troponin I and T (hsTnI and hsTnT) were obtained before, immediately after the PVI, and the next day (usually 18-24 hours after the procedure). Study groups were compared regarding absolute biomarker levels and hsTnT/S100B ratio (a surrogate of cardioselectivity). Results Following successful PVI, a significant increase in plasma levels of all biomarkers was observed: DhsTnT = 1040±434 ng/L, 1731±830 ng/L and 1010±397 ng/L; DhsTnI = 1504±918 ng/L, 16464±11911 ng/L and 10789±7589 ng/L; DS100B: 0.04±0.02 mg/L, 0.03±0.04 mg/L and 0.14±0.08 mg/L; DNSE: 34±72 ng/mL, 27±53 ng/mL and 45±52 ng/mL (all with P <0.001) for RF, PEF and Cryo groups, respectively. A direct comparison of maximal biomarker levels between study groups is depicted in the Figure. The hsTnT/S100B ratio was 23±14, 12±6, and 6±3 in PEF, RF, and Cryo groups, respectively (ANOVA P <0.01), indicating that PEF was 1.9-times and 3.8-times more cardioselective than RF and Cryo, respectively. Following the PVI, the heart rate accelerated by 2±8, 13±14, and 9±11 bpm in the PEF, RF, and Cryo groups, respectively. No correlation was observed between S100B release and HR acceleration (R = 0.07, P = 0.55). Conclusion Compared to thermal energy sources, PEF energy induces more specific damage to cardiomyocytes than cardiac nerves. There was no correlation between S100B release and HR acceleration.

Electrophysiological characteristics and durability of index pulsed field ablation lesions from redo procedures for atrial arrhythmia recurrences

Abstract Background Catheter ablation for atrial fibrillation (AF) has been performed using mainly thermal energy sources (radiofrequency, cryo, or laser). Pulsed field ablation (PFA) is a novel energy with interesting safety and effectiveness demonstrated in previous preclinical and clinical trials. Purpose We sought to assess the electrophysiological characteristics and durability of PFA index procedure procedures using a pentaspline PFA catheter as assessed based on redo procedures in patients with AT/AF recurrences. Methods A total of 169 patients (paroxysmal AF (PAF), 120; persistent AF (PsAF), 49) who underwent PFA using a pentaspline PFA catheter in the index procedure from November 2021 to July 2023 were studied. Pulmonary vein isolation (PVI) was performed with PFA in all patients with additional PFA lines: i)posterolateral mitral isthmus (MI) ablation in 25, ii) posterior line in 40 patients. Twenty-seven patients (PAF, 11; PsAF, 16) had atrial arrhythmia (atrial tachycardia (AT) or AF) recurrence after a 3-month blanking period (16%). We analyzed the electrophysiological characteristics of previous PFA lesions in 18 (PAF, 8; PsAF, 10) out of 27 patients in whom an activation and voltage mapping using 3-D electroanatomical mapping system was available. Results PV reconnections were identified in 7 of 18 patients (13PVs/69PVs ,18.8%) at the PV-LA junctions and carina regions of both left PVs and right PVs, mainly at the anterior aspect of right PV carina (n=6). In 6 out of 10 redo cases, posterolateral MI line using PFA was performed in the index procedure based on our strategy for PsAF ablation. In these 6 cases with previous MI line using PFA for PsAF ablation endocardial PFA was combined with marshall vein ethanolization(Et-VOM). Additional RF endocardial ablation and in the CS was needed to achieve MI block in 2 (33%) in the index procedure. 3D mapping of redo cases showed MI line gaps in 6/6 (100%). In 3 of those patients, the clinical arrhythmia recurrence was a perimitral AT (50%). Nine of the 10 PsAF patients who underwent a redo procedure had an index procedure complete posterior line. Remapping demonstrated durable block in 7/9 (78%). One of these patients presented with a roof dependent AT diagnosed in the redo procedure. Durable posterior lines received a significantly larger number of PFA deliveries during the index procedure: 16.4±3.3 vs 10.0±2.8 respectively, p=0.041). Conclusion This study based on redo cases after PFA using a pentaspline PFA catheter shows that PFA is associated with high durability for PVI and posterior line ablation. However the durability of MI line are poor, even when combined with VOM ethanolization. Further research is needed to define the optimal number of deliveries required to achieve durable posterior line block.

Transmission of quantum-secured images

The secure transmission of an image can be accomplished by encoding the image information, securely communicating this information, and subsequently reconstructing the image. Alternatively, here we show how the image itself can be directly transmitted while ensuring that the presence of any eavesdropper is revealed in a way akin to quantum key distribution (QKD). We achieve this transmission using a photon-pair source with the deliberate addition of a thermal light source as background noise. One photon of the pair illuminates the object, which is masked from an eavesdropper by adding indistinguishable thermal photons, the other photon of the pair acts as a time reference with which the intended recipient can preferentially filter the image carrying photons from the background. These reference photons are themselves made sensitive to the presence of an eavesdropper by traditional polarisation-based QKD encoding. Interestingly the security verification is performed in the two-dimensional polarisation-basis, but the image information is encoded in a much higher-dimensional, hence information-rich, pixel basis. In our example implementation, our image comprises of 152 independent pixels. Beyond the secure transmission of images, our approach to the distribution of secure high-dimensional information may offer new high-bandwidth approaches to QKD.

Numerical analysis of multiple slip effects on CuO /MgO/TiO2-water ternary hybrid nanofluid with thermal and exponential space-based heat source

In contemporary science, the efficiency of heat transfer holds paramount importance across various engineering applications, where nanofluids play a significantly influential role. Therefore the present study focuses on the significance of multiple slip in heat transfer of3-Dnatural convectional ternary hybrid nanofluid flow across a stretching sheet. The study investigates the implications of a temperature-dependent and exponentially space-based heat source, coupled with non-linear thermal radiation effects. Impact of magnetic field is further considered for the present investigation. The three dissimilar nanoparticles (CuO,MgO&TiO2) are dispersed in water as base fluid to improve the heat transfer. The system of partial differential equations is developed under considered assumptions. The Partial differential equations (PDEs) are transmuted into nonlinear coupled dimensionless system of ordinary differential equations (ODEs) by applying similarity transformations. The reduced dimensionless nonlinear equations are numerically solved by employing shooting scheme via bvp4c built-in function MATLAB. The properties of flow controlling parameters via velocity and thermal profiles are elaborated through graphs. The results designated that the x-direction velocity slip declines the velocity. The momentum profile (velocity profile) is declined for greater stretching ratio parameter. Furthermore, it is analyzed that the thermal field is boosted up for larger amounts of temperature base and exponential space-based heat source. It is concluded that heat conduction capacity is higher in ternary hybrid nanofluid than hybrid and mono nanofluids. Additionally, Prandtl number serves to enhance the Nusselt number with augmentation in Thermal radiation parameter. The physical applications of the considered model in solar energy, heat pumps, heat exchangers, air purifiers, the automotive industry, electrical chillers, turbines, nuclear networks, broadcasters, ships, and biotechnology.

Far-field superresolution of thermal sources by double homodyne or double array homodyne detection

We propose two schemes for estimating the separation of two thermal sources via double homodyne and double array homodyne detection considering the joint measurement of conjugate quadratures of the image plane field.By using the Cramér–Rao bound, we demonstrate that the two schemes can estimate the separation well below the Rayleigh limit and have an advantage over direct imaging when the average photon number per source exceeds five.For arbitrary source strengths, double homodyne detection is superior to homodyne detection when the separation is above 25/4σ/N s , σ is the beam width, N s is the average photon number per source.A larger separation can be estimated better via double array homodyne detection with the superiority of flexible operation compared with other schemes. High-speed and high-efficiency detection enables the measurement schemes with potential practical applications in fluorescence microscopy, astronomy and quantum imaging.

Numerical simulation of chemical reactive flow of Boger fluid over a sheet with heat source and local thermal non-equilibrium conditions

In this article, the effect of nonlinear heat source on chemical reactive flow of magnetized Boger fluid over a sheet with Marangoni convection and porous medium is explored. In the modelling, local thermal non-equilibrium (LTNE) conditions and heat sources are taken into account. The unique heat transport for both liquid and solid phases is provided by the LTNE model, which is based on thermal equations. As a result, various temperature profiles are used in this work for both the solid and fluid phases. It is essential for streamlining industrial procedures, improving material processing methods, comprehending biological systems like blood flow for medicine delivery, determining the environmental impact of pollutant dispersion, and increasing the effectiveness of oil and gas transportation. This model supports crucial decision-making processes in numerous disciplines by offering insights into the intricate interplay between reactive fluids, heat transmission, and chemical reactions. The appropriate similarity variables are used to compress the model equation system, and the shooting method and the conventional bvp4c solver are then used to solve the system numerically. Optimal homotopy approach is used to achieve residual errors. There are suggested best estimates for auxiliary variables. Results show that for larger values of the solvent fraction parameter, Boger fluid exhibits an enhanced velocity profile and a declining thermal profile of the liquid phase. The concentration and thermal profiles of both the solid and liquid phases are declined and enhanced the velocity of the Boger fluid for higher values of the Marangoni convection parameter.

Numerical Analysis Study of Chemically Radiative MHD Williamson Nanofluid Flow over an Inclined Surface with Heat Source

The design and optimization of systems such as nuclear reactors, solar collectors, and thermal power plants may benefit from an understanding of the behaviour of nanofluids with chemical processes, thermal radiation, and magnetic fields over inclined surfaces with heat sources.This review looks at the magnetohydrodynamic (MHD) flow of a Williamson nanofluid over an inclinable stretched sheet and the impact of thermal radiation, heat source, and chemical processes. The outcomes of the generation of heat or absorption, as well as thermal radiation, are all factored into account in the energy equation. On the other hand, the mass transport equation also takes into account chemical interactions.The similarity substitution serves to turn the governed partial differential equations for velocity, temperature, and concentration into ordinary differential equations, which are then numerically resolved with Mathematica's NDSolve program. Changes in temperature, concentration, and dimensionless velocity as a function of various factors are graphically touched upon. The temperature diminishes while the Prandtl number accelerates as the thermal boundary layer thins and the viscosity enrichment. The temperature contour develops along with the magnetic field strength. When all the parameters were compared for a particular case, a very good association was discovered. Depending on the precise conclusions and understandings drawn from the investigation of chemically radiative MHD nanofluid flow over inclined surfaces with a heat source, the applications may range greatly. It's important to remember that such research often aids in the creation of more effective and environmentally friendly solutions in a variety of sectors.

Experimental Characterization of Commercial Scroll Expander for Micro-Scale Solar ORC Application: Part 1

In order to reduce greenhouse gas emissions and achieve global decarbonisation, it is essential to find sustainable and renewable alternatives for electricity production. In this context, the development of distributed generation systems, with the use of thermodynamic and photovoltaic solar energy, wind energy and smart grids, is fundamental. ORC power plants are the most appropriate systems for low-grade thermal energy recovery and power conversion, combining solar energy with electricity production. The application of a micro-scale ORC plant, coupled with Parabolic Trough Collectors as a thermal source, can satisfy domestic user demand in terms of electrical and thermal power. In order to develop a micro-scale ORC plant, a commercial hermetic scroll compressor was tested as an expander with HFC-245fa working fluid. The tests required the construction of an experimental bench with monitoring and control sensors. The aim of this study is the description of the scroll performances to evaluate the application and develop optimization strategies. The maximum isentropic effectiveness is reached for an expansion ratio close to the volumetric expansion ratio of the scroll, and machine isentropic effectiveness presents small variations in a wide range of working conditions. The filling factor is always higher than one, due to leakage in the mechanical seals of the scroll or other inefficiencies. This study demonstrates that using a commercial scroll compressor as an expander within an ORC system represents a valid option for such applications, but it is necessary to improve the mechanical seals of the machine and utilize a dedicated control strategy to obtain the maximum isentropic effectiveness.

Nonlinear heat radiation and mass transfer characteristics on MHD Walters’ B fluid flow through a porous medium over a stretching sheet

To handle the continuous thermal power supply is very important in thermal systems and industries, so magnetized heat transport with non-Newtonian fluid is an appropriate platform for thermal power energy. In view of this usefulness, this paper provides a numerical assessment of electrically conducting Walter's B fluid flow through nonlinear permeable stretching sheet subject to mixed convective, porous medium, and Newtonian heating phenomena. Thermophoresis and Brownian motion effects have been included in energy and species diffusion equations to account for the impacts of nonlinear thermal radiation, joule heating, heat source and chemical reaction. The system of governing equations has been reduced to dimensionless nonlinear coupled equations using similarity transformations. The bvp4c technique has been used to obtain the solution for velocity, temperature, and concentration distributions. We consider both regions of assisting and opposing flow and provide various tables and graphs to examine the impact of varying values of emerging factors. Heat source and thermal radiation characteristics are found to enhance the thermal boundary layer thickness, which may be used to dissipate heat. The magnetic parameter augmented the fluid temperature and decelerated the velocity field. The chemical reaction parameter accelerated the concentration distribution. Further, the Sherwood number, Nusselt number, and skin friction coefficient have been determined and compared well to prior research that has been published.

Heating and storage of medium-deep borehole heat exchangers: Analysis of operational characteristics via an optimized analytical solution model

This study focuses on investigating the thermal storage potential of medium-deep borehole heat exchanger (MDBHE) to address the issues of temperature attenuation of thermal reservoir and heating capacity reduction during the one-way heat extraction process in the heating period. By establishing an MDBHE heating system that integrates an external thermal storage source, a comprehensive analysis of the heat transfer progress and operational characteristics of the MDBHE is conducted, including optimizing burial depth, thermal storage scenarios, and aquifer conditions. The calculated solution under the typical thermal storage conditions (S60–30) in this study reveals that the average heat supply capacity increasement of a 1200 m MDBHE is 37.2 % higher than that of a 2000 m MDBHE, and the power consumption of the circulating water pump also can be reduced by 40 % in heating period. Furthermore, the enhancement of storage temperature and flow rate both contribute to a noticeable improvement in the heating performance of the MDBHE during the heating period. The heat transfer power and energy efficiency of MDBHE both increase with the elevation of seepage velocity and aquifer thickness during the energy storage and heating period. The significance of this research lies in its contribution to the enhancement of thermal storage and heat transfer efficiency in MDBHE and offering novel insights for the multi-thermal energy storage systems.

Numerical modeling of mixed convective nanofluid flow with fractal stochastic heat and mass transfer using finite differences

This study presents the first comprehensive numerical simulation of heat and mass transfer in fractal-like mixed convective nanofluid flows. The flow of non-Newtonian nanofluids over flat and oscillating sheets is modelled mathematically, and a finite difference scheme is used to solve this model. The two-stage scheme can tackle fractal and fractal stochastic mathematical models of partial differential equations. The consistency in the mean square is proved, and Fourier series stability analysis is adopted to find stability conditions for fractal stochastic partial differential equation. The scheme is applied to solve the unsteady Casson nanofluid flow over the flat and oscillatory sheet, which affects thermal radiation, heat source, and chemical reaction. The existence of the solution is also provided for the Navier-Stokes equation of the considered flow model using fractal time derivative. The graph illustrates that the proposed fractal technique achieves faster convergence than the Crank-Nicolson approach. Applications in energy systems, materials science, and environmental engineering are just a few of the domains that could benefit from a better understanding of mixed convective nanofluid flows with fractal features, and that is what this research study hopes to accomplish. Scientists and engineers may better develop efficient and environmentally friendly systems by simulating and analyzing these complicated processes with the suggested finite difference technique.

Analysis of the Cooperation of a Compressor Heat Pump with a PV System

The decarbonization of heating systems is one of the present political and legislative directions of the European Union and its Member States. The main activities concern the energy performance of buildings and energy efficiency. The mentioned UE directives are the basis for the financial support of high-emission fossil fuel thermal energy source replacement with emission-free ones, in particular heat pumps. Other aspects are the support of PV installations and the thermal insulation of buildings. 85% of EU buildings were built before 2000, and among those, 75% have poor energy performance. Therefore, a significant number of buildings have only high-temperature wall radiators, and this was a motivation to prepare this article. The main innovation of this research was a new theoretical design of a high-temperature heat pump based on ecological refrigerants. The presented solution allows wall radiators to receive a hot water supply with temperatures of up to 85 °C during external temperatures of up to −20 °C. Typical heat pumps do not have these kinds of parameters, so the authors decided to verify the possibility of operating this device in such a wide temperature range. Another important aspect was the analysis of PV support. Finally, this paper investigates the possibility of heating an energy-efficient house with the newly designed high-temperature heat pump. Depending on the location in Poland, i.e., Suwałki, Warsaw, and Wrocław, the total electric energy supplied to the compressors was 2538–3364 kWh. The energy provided by the PV to supply power to the compressors is 482–570 kWh. The achieved PV energy self-consumption is 16.9–19.0%. The Seasonal Coefficient of Performance (SCOP) of the heat pump is 1.825–2.038 without PV and 2.515–2.970 with PV.

Analysis for bioconvection due to magnetic induction of Casson nanoparticles subject to variable thermal conductivity

Owing to valuable significance of bioconvective transport phenomenon in interaction of nanoparticles, different applications are suggested in field of bio-technology, bio-fuels, fertilizers and soil sciences. It is well emphasized fact that thermal outcomes of nanofluids can be boosted under the consideration of various thermal sources. The aim of current research is to test the induction of induced magnetic force in bioconvective transport of non-Newtonian nanofluid. The rheological impact of non-Newtonian materials is observed by using Casson fluid with suspension of microorganisms. The chemical reaction effected are interpreted. The thermal conductivity of material is assumed to be fluctuated with temperature fluctuation. The flow pattern is endorsed by stretching surface following the stagnation point flow. Under the defined flow assumptions, the problem is formulated. A computational software with shooting technique is used to present the simulations. A comprehensive analysis for problem is presented. It is claimed that the interpretation of induced magnetic force exclusively enhanced the thermal phenomenon.

Plasmonic Nanoparticles Boost Solar-to-Electricity Generation at Ambient Conditions.

Sunlight-to-electricity conversion using solar thermoelectric generators (STEGs) is a proven technology to meet our ever-growing energy demand. However, STEGs are often operated under a vacuum with customized thermoelectric materials to achieve high performance. In this work, the incorporation of plasmonic gold nanoparticle (AuNP) based solar absorbers enabled the efficient operation of STEGs under ambient conditions with commercially available thermoelectric devices. AuNPs enhanced the performance of STEG by ∼9 times, yielding an overall solar-to-electricity conversion efficiency of ∼9.6% under 7.5 W cm-2 solar irradiance at ambient conditions. Plasmonic heat dissipated by AuNPs upon solar irradiation was used as the thermal energy source for STEGs. High light absorptivity, photothermal conversion efficiency (∼95%), and thermal conductivity of AuNPs enabled the efficient generation and transfer of heat to STEGs, with minimal radiative and convective heat losses. The power generated from plasmon-powered STEGs is used to run electrical devices as well as produce green hydrogen via the electrolysis of water.