Collector Component Research Articles

Assessment of the energy production of a hybrid PV/T collector based on different fluids for Agadir climate

The aim of this paper is to evaluate the electrical and thermal energies produced by a hybrid PV/T collector for Agadir city climatic conditions. To achieve the goal a theoretical model based on energy balance equations applied on each collector component is developed. The discretization of the equations is done using the finite difference method and solved numerically by TDMA matrix algorithm. The validity of the model is examined by the comparison of the our simulation findings with the available literature results. The thermal and electrical powers outputted by the glazed and unglazed hybrid collector are evaluated over the course of a typical day for Agadir region climate (Morocco), using various heat transfer fluids (water, water-EG mixture and Cu−water nanofluid). It is obtained that the employ of the nanofluid Cu−water improves the energy production of the hybrid collector in comparison to other working fluids. In fact, the high daily thermal and electrical energies are obtained using the nanofluid by approximately 5.548 kWh and 1.273 kWh respectively. The results showed that the produced thermal energy of the solar collector with glass is 37.4% higher than unglazed one. However, the supplied electrical energy by the glazing collector is lower than the unglazed system by almost 11.5%. In Agadir region, we recommend choosing the unglazed PV/T to benefit from the weather conditions and the solar potential of this region.

CiteSpace-Based Visualization Analysis on the Trombe Wall in Solar Buildings

The Trombe Wall is the main solar collector component in solar buildings, and it has attracted much attention due to its ability to maximize solar energy utilization and reduce buildings’ energy consumption. Numerous research studies have been conducted. Bibliometrics and CiteSpace visual analysis software are used in this paper to summarize and find that the research process for the Trombe Wall can be divided into three periods: the preliminary development period, the ice-breaking period, and the comprehensive development period. Then, we visually analyze information, such as countries, institutions, authors, journals, references, and keywords, from 537 selected articles in the Web of Science (WOS) database during the period 1991–2023. The results show that current research in this area primarily focuses on “thermal comfort”, “BLC”, “PCM-Trombe Wall”, “PV-Trombe Wall”, and “BIPV system”. On this basis, potential development trends in this field and some future research issues that need to be addressed are proposed. Furthermore, the study identifies potential development trends in this area. By providing a comprehensive understanding of the current research status, research frontiers, research hotspots, and research trends in this area, this study provides valuable theoretical guidance for subsequent research.

Porous Metal Current Collectors for Alkali Metal Batteries.

Alkali metals (i.e., Li, Na, and K) are promising anode materials for next-generation high-energy-density batteries due to their superior theoretical specific capacities and low electrochemical potentials. However, the uneven current and ion distribution on the anode surface probably induces undesirable dendrite growth, which leads to significant safety hazards and severely hinders the commercialization of alkali metal anodes. A smart and versatile strategy that can accommodate alkali metals into porous metal current collectors (PMCCs) has been well established to resolve the issues as well as to promote the practical applications of alkali metal anodes. Moreover, the proposal of PMCCs can meet the requirement of the dendrite-free battery fabrication industry, while the electrode material loading exactly needs the metal current collector component as well. Here, a systematic survey on advanced PMCCs for Li, Na, and K alkali metal anodes is presented, including their development timeline, categories, fabrication methods, and working mechanism. On this basis, some significant methodology advances to control pore structure, surface area, surface wettability, and mechanical properties are systematically summarized. Further, the existing issues and the development prospects of PMCCs to improve anode performance in alkali metal batteries are discussed.

Investigation of carbon fiber anode materials for collector-free lithium-ion batteries

Abstract Lithium-ion batteries (LIBs) play a key role in grid-scale energy storage, making the development of LIBs with higher gravimetric energy density a necessity. Reducing the mass of the inactive collector component or even removing the collector altogether is important for improving energy density. This work proposes a 3D network electrode constructed based on the linear structure of carbon fiber (CF), which is directly used as an anode material without using a copper foil collector, and compared with the existing graphite anode material. The results show that CF has better rate performance, and the specific capacity of CF at high loading (1.3 mg/cm2) increases to a different degree along with the initial cycle. The comprehensive performance of the full battery assembled with CF electrode as the anode and LiFePO4 as the cathode shows that its overall energy density is higher than that of the graphite/LiFePO4 battery. The energy densities of CF/LiFePO4 and Graphite/LiFePO4 after 10 cycles at 0.1A/g current density were 198.7 Wh/kg and 132.7 Wh/kg, respectively. The energy density and power density of CF/LiFePO4 at other current densities are also greater than those of Graphite/LiFePO4.

Energy and exergy analysis of an atmospheric water generator integrated with the compound parabolic collector with storage tank in various climates

The drinkable water storages shortage is one of the main obstacles that many societies are envisaged with. In addition, the water content of humid air is known as the main storage of drinkable water for the future. In this paper, the energy and exergy analysis of a solar driven atmospheric water generator which contains an absorption refrigeration cycle coupled to a compound parabolic collector is performed. The mathematical model of the proposed system is developed in MATLAB software. In the solar thermal system provided in this paper, the storage tank is employed for extending the working hours of the system leading to improvement of total water generation rate. Furthermore, the performance of the system is evaluated in various climates included arid, semi-arid and Mediterranean, and for this purpose three cities of Iran named Bandar Abbas, Ramsar and Tehran were selected. Moreover, by comparing the water production in various months during the year, the highest value of water production during the year is held by Bandar Abbas city leading to owning the lowest values of specific power consumption and specific collector area. The maximum rate of water production of proposed system is approximately 400 lit per month in tropical climates with specific energy consumption of 3 kWh/lit. Based on the results of exergy analysis of whole system, the most exergy destruction rate belongs to compound parabolic collector component, therefore, large amount of energy is wasted through compound parabolic collector which can be recovered for generation of chilled water. Moreover, the impacts of geographical and environmental parameters on the energy and exergy efficiencies of the atmospheric water generator are also assessed.

Parametric study about performances of a solar photovoltaic/thermal hybrid using a spectral beam splitting technique

This study presents performance variations of a solar photovoltaic/thermal (PV/T) hybrid using spectral beam splitting (SBS) techniques. Compared with conventional solar PV/T hybrids (the one-sun flat-plate PV/T hybrid), the proposed hybrid simultaneously produces electricity and relatively higher grades of thermal energy. The majority of the studies related to SBS solar PV/T hybrids are in the early stages of design or proof-of-concept. Therefore, the proposed hybrid's operating characteristics must be investigated. This study provides comprehensive information about the influence of the main operating parameters on the proposed hybrid system's performance. The main operating parameters considered in this parametric study are solar irradiance, ambient temperature, thermal fluid mass flow rate, and inlet fluid temperature. While these parameters were well known to affect most solar technologies' performance, few studies have reported the extent of their impact on SBS solar PV/T hybrids. The results show that the ambient temperature is the greatest influence on the hybrid efficiency. When the ambient temperature increases from 0 °C to 40 °C, the hybrid efficiency decreases from 71.5% (the highest) to 63.7%. The overall efficiency of the hybrid was strongly dependent on the hybrid's PV component. As compared with the hybrid's parabolic trough collector (PTC) component, the PV performance was highly influenced by operating conditions. Nonetheless, compared with the original system design (pure PTC and pure PV), these operating parameters have relatively low impact on both PTC and PV in the hybrid system.

Rudimentary analysis for solar chimney enhancement

This paper presents fundamental results for solar chimney enhancement. Solar radiation proves to be an important factor in influencing the efficiency of the solar chimney power plant, but its effects on the ambient conditions outside the system has not been considered. Using the Discrete Ordinates radiation model on the semi-transparent collector component of the two-dimensional system, the work presented in this paper simulates the velocity and temperature inside the solar chimney as the ambient temperature of air outside is varied from 307 K to 314 K. At the highest ambient temperature, results show an increase in air velocity of 0.55 m/s at ground level and 1.85 m/s at a height of 1 m along the chimney. To further investigate of this study, a simulation model to include the ambient domain is proposed as a conclusion.

Energy and exergy analysis of solar heat driven chiller under wide system boundary conditions

In the paper, a solar driven ammonia-water chiller is investigated, as one of the systems having potential for reduction of resources depletion. An energy and exergy analysis is proposed for correct diagnostics while designing and operating the cycle. The boundary conditions for the analyses are set in accordance with Professor Szargut's primary instructions. They are however widened to solar collector component. Solar radiation is treated as the driving energy or exergy, respectively. The analyses are supplemented with a sensitivity diagnosis revealing the most significant parameters modifying the efficiency and irreversibilities distribution. According to the findings, design COP of the chiller equals 0.444 while its net exergy efficiency is 0.026. Solar collector component is the most burdened with exergy destruction and loss in the whole cycle.

LXCloudFT: Towards high availability, fault tolerant Cloud system based Linux Containers

Infrastructure-as-a-Service container-based virtualization is gaining interest as a platform for running distributed applications. With increasing scale of Cloud architectures, faults are becoming a frequent occurrence, which makes availability a challenge. LXCloudFT is a fault tolerant Cloud system, which is composed of LXCloud-CR, a Checkpoint–Restart model and GC-CR, a garbage collector component that eliminates old snapshots of containers. LXCloudFT is designed, originally, for scientific applications and all its components are decentralized. We want to adapt it to serve stateless loosely coupled applications such as web applications. Replication is a method to survive failures for such applications. This paper addresses the issue of replication and contributes with a novel replication model, LXCloud-Rep, in LXCloudFT. LXCloud-Rep is a replication model with versioning and garbage collection, which is able to replicate Linux Container instances on several nodes in a decentralized manner. Following a node failure, LXCloud-Rep restarts failed containers on a new node from distributed images of containers not from snapshots. It optimizes the use of storage space. Large-scale experiments on Grid’5000 improve the performance of applications.

Investigation into the failure of Inconel exhaust collector produced by laser consolidation

Among layer manufacturing techniques, Laser Consolidation (LC) finds its ideal application in the production of thin-walled metal parts for industrial niches characterised by high innovation and product complexity. To fully exploit the technological potential, developments must be made to assess LC’s repeatability and reliability. Previous studies proved that high strength parts of fine microstructure are obtained if appropriate build strategies are used. The aim of this research is to analyse a racecar exhaust collector, built in Inconel by LC, relating the failure modes and microstructure to the construction plan.The exhaust collector component was built using a custom strategy and was run on a dynamometer before failing after approximately 1200km. An investigation of the failure mechanism was carried out by a primary macroscopic analysis, aided by an X-ray control and dye penetrant test. Metallographic sections were then sampled from the critical areas to study the microstructure and relate it to the manufacturing process.Results proved that the distribution of primary microcracks associated with internal residual stresses caused by the build strategy and aggravated by differential shrinkage during the test thermocycles was responsible for ultimate failure. This issue was a result of build strategy and the non-coaxial laser head, therefore, alternative pathways could be developed capable of removing most, if not all, of the contributory factors. The analysed case suggests that LC build strategy selection is as critical to ensure low cycle fatigue resistance as component design and confirms that LC is effective in the production of advanced technological parts with high geometrical complexity given the correct build strategy.

Design and Development of a Novel Flow Field for PEM Fuel Cells to Obtain Uniform Flow Distribution

A new flow field design concept was discovered, based on the close coupling of the flow field geometry and gas transport through the MEA diffusion current collector component's in- plane permeability. The new flow field offers significant gain in uniformity of reactant distributions within PEM fuel cells. Computational fluid dynamic simulations of the two dimensional gas flow velocities over the MEA active areas are used to demonstrate the improvement in mass flow uniformity with the new design compared to more conventional flow field types. A math analysis based on Darcy's law applied to the new flow field design concept provided the basis for a quantitative estimate of how the effect depended on geometry, and further improvements to be made which compensate for down-the-channel consumption of reactants for any given stoichiometry. Experimental tests with version 1.0 of the new flow field design are discussed.

Dimensioning, thermal analysis and experimental heat loss coefficients of an adsorptive solar icemaker

The dimensioning, a thermal parameters analysis and the experimental heat loss coefficients of an adsorptive solar refrigerator prototype used for ice production are presented. The solar icemaker operates in an intermittent cycle, i.e. without recovering heat. It uses the activated carbon–methanol pair whose basic components are an adsorber coupled to a static solar collector, a condenser and an evaporator. Some innovations were considered, especially those brought about by French researchers, in which the adsorber was always box-shaped with extended surfaces, and air condensers were used. For the present system, the adsorber is bi-facially irradiated and covered with transparent insulation material (TIM), the geometric configuration of the main components is multi-tubular, and a water condenser is used. TIM polycarbonate covers are used on the top and bottom of the adsorber. The components of the prototype were dimensioned after the results from numerical simulations using meteorological data valid for the hottest six months in João Pessoa (7°8′S, 34°50′WG), whose climate is typically hot and humid. The machine was designed to produce up to 10 kg of ice/day per square meter of solar collection surface. Analyses of the thermal parameters influence on the ice production as well as parameters for dimensioning each component of the machine are presented. The overall heat loss coefficient by the top and the bottom of the adsorber–solar collector component are experimentally evaluated. The tests were performed using an incandescent lamp panel disposed on a 1 m2 surface, totalizing a thermal power of 3600 W. The results show a good efficiency of the TIM covers, achieving overall heat loss coefficient values between 0.54 and 1.90 W m−2 K−1.

A thermionic-field-diffusion model for Npn bipolar heterojunction phototransistors

This article describes the development of a thermionic-field-diffusion model for use in the analysis and design of abrupt, single heterojunction bipolar phototransistors (HPTs) for use in HBT-based optical receivers. In particular, included in this approach are the effects of a dc base bias on the optical gain and device performance. Taking into account the optical generation, the excess electron concentration at the emitter end of the quasi-neutral base is initially determined using a matching of the thermionic field emission across the emitter-base heterojunction with the diffusion current at the emitter end of the base. At the collector end of the base region, a finite electron concentration is used based on the collector current density. The results are used to determine the electron profile in the quasi-neutral base region and the diffusion components to the emitter and collector currents. To determine the device’s optical gain, the photocurrent and the small signal current gain are calculated. The dominant component in the photocurrent is found to be due to optical absorption in the base-collector space charge region. For backside illumination, the collector component becomes larger. The base width and electron diffusion length control the current gain and thereby the optical gain. The model is used to quantify the effects of the device’s structure on the optical gain.

A perspective of solar drying of crops— A country profile

A comprehensive study for the utilization potential of solar drying in Saudi Arabia has been accomplished. Data pertinent to solar insolation and important for the country's agricultural products (e.g. wheat, dates) are presented. Various solar drying systems of crops are discussed and four of these systems are proposed having features such as use of concurrent drying technique, use of heat pipes, thermal storage and boosters. A computer simulation study for a proposed system of concurrent drying of grains shows over 35% energy saving when heating is partially delivered by the solar collector component of the system.

Current costs of solar powered organic Rankine cycle engines

Solar energy can be used to heat and cool buildings, drive irrigation pumps, make electrical power, desalt sea water, and, in general, reduce energy demands on conventional energy sources. The organic Rankine cycle engine will play an important part in the conversion of solar energy to useful shaft power. Technical feasibility is here now, as shown by several demonstration projects; however, economic feasibility may be some years away. This paper addresses the technical and cost aspects of the organic Rankine cycle and its interaction with the solar collector as a power system. The efficiency and practical considerations of the combined collector and Rankine system show that collector temperatures of 93°C (200°F), 150–200°C (300–400°F), and 315°C (600°F) are optimum operating conditions for flat plate, concentrators, and tracking concentrators respectively. The peak solar conversion efficiencies of these systems are approximately 5, 10 and 11 per cent respectively. When comparing the cost of solar power systems, it is shown that the dominant factor in the system cost is the collector cost. It is estimated that in a production unit the Rankine cycle cost will be approximately one-third of the total system cost with two-thirds going to the collector component. Consequently, low-cost collectors are crucial for commercialization of solar Rankine systems. It is estimated that the installed cost of mass produced solar power systems would be in the neighborhood of $1600–$2500/peak kW output. These values do not relate to a solar cooling system since not all the collectors are charged to the cooling system; hence, the relevant cost comparison is the production costs of the Rankine and the absorption cooling systems. Therefore, the conclusions presented here relate primarily to power systems. Solar power systems are technically feasible now; however, when will they be economically feasible? It is this author's opinion that this will occur when there is no other alternative, which may not be long in coming. When this time does arrive, the organic Rankine engine is available to convert the Sun's heat into useful power.