Air Collector System Research Articles

Bridging the gap: A comparative analysis of indoor and outdoor performance for photovoltaic-thermal-thermoelectric hybrid systems

This research evaluates the performance of a hybrid thermal-thermoelectric photovoltaic air collector system (PV/T-TE) through experimental investigations. By integrating photovoltaic (PV) panels with thermoelectric (TE) modules, the system aims to enhance efficiency and energy output by converting waste heat into additional electricity. The study examines the impact of radiation intensity, ranging from 455.65 to 795.18 W/m2, on the system's performance, utilizing output temperature (To) and plate temperature (Tp) as key metrics. Managing waste heat in PV technology remains a challenge, impacting efficiency. Traditional PV/T systems generate both electricity and thermal energy but suffer efficiency losses due to inadequate heat management. Integrating TE modules into PV/T systems offers a promising solution, but optimal configurations and performance impacts under varying conditions are underexplored. Limited research focuses on PV/T-TE hybrid systems, with most studies addressing PV-TE systems. The objectives of this research are to experimentally assess the impact of integrating TE modules on the thermal and electrical efficiency of PV/T systems under varying radiation intensities and air mass flow rates. The methodology involves setting up a PV/T-TE hybrid system, conducting experiments under controlled conditions, and analyzing key performance metrics. The study explores optimal TE module configurations and installation techniques to maximize heat transfer and electricity generation. Comparative analysis with conventional PV/T systems establishes the superiority of the hybrid system. Findings indicate significant benefits from incorporating TE modules, enhancing energy output and efficiency by maintaining optimal PV panel temperatures.

Experimental analysis of the synergistic impact of fan and nocturnal thermal insulation on enhancing the thermal performance of latent-energy-storage solar air collectors

Solar air collectors equipped with energy storage functionality are widely utilized to address the mismatch between heat demand and supply periods during winter, effectively facilitating heating needs. However, phase change energy storage flat plate solar air collectors are hindered by inefficiencies, primarily due to the low rate of convective heat transfer and substantial nocturnal energy losses, which considerably undermine the overall energy efficiency of these collectors. In response to these challenges, a forced convection approach utilizing a fan was adopted to augment the convective heat transfer rate, and insulation was applied to glass panes overnight to curb energy wastage. Two solar air collector systems were constructed and examined: a natural convection-based energy storage solar air collector (NCSAC-PCM) and another solar air collector incorporating forced convection with nocturnal thermal insulation (FCSAC-PCM-NTI). Comparative experiments revealed that the combination of forced convection with nighttime insulation in the latter design led to an elevation in the mean indoor temperature by 1.4 °C, alongside a decrease in the temperature gradient variation within the space during the test period. Furthermore, this integration significantly enhanced the energy efficiency by 53.71 % and the exergy efficiency by 11.45 %.

Towards real-time airborne pathogen sensing: Electrostatic capture and on-chip LAMP based detection of airborne viral pathogens

Considerable loss of life, economic slowdown, and public health risk associated with the transmission of airborne respiratory pathogens was underscored by the recent COVID-19 pandemic. Airborne transmission of zoonotic diseases such as the highly pathogenic avian influenza (HPAI) and porcine reproductive and respiratory syndrome virus (PRRSV) has caused major disruptions to domestic and global food security. Current ambient air pathogen monitoring systems involves the collection of air samples from indoor settings suspected of viral contamination, followed by subsequent processing of capture samples to determine the presence and species of airborne viral matter. Nucleic acid amplification techniques are considered the gold standard for pathogen diagnostics. Currently, the necessary extraction and purification of viral RNA from air collector systems prior to sample analysis is both time consuming and performed manually. A monitoring system with separate air sampling and biochemical detection procedures is prone to delay the response to emergent viral threats. In this paper, we present a pathogen monitoring system that overcomes these limitations related to extraction and purification of viral samples and lays the groundwork for a real-time monitor for airborne viral pathogens. We demonstrate a high flow electrostatic precipitator system, that uses small collection wells as counter electrodes for pathogen collection. Integrated reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) is used for detection of captured viral matter within wells. On-chip heating of collection wells is enabled by integrated planar heaters and small volumes of reagent (30 μL) directly to the collection wells. We present the design of such a system and show experimental results that demonstrate the use of this device for detection of aerosolized SARS-CoV-2 virus like particles (VLPs), a model pathogen for SARV-CoV-2.

Investigation of Techniques for Enhancement of Efficiency of a Hybrid Photovoltaic and Solar Thermal System: Literature Review on Applications and its Advancement

Abstract: Over the most recent couple of decades, tremendous consideration is drawn towards photovoltaic–thermal systems because of their advantages over the solar thermal and PV applications. This paper intends to show different electrical and thermal aspects of photovoltaic–thermal systems and the researches in absorber design modification, development, and applications. From the previous review articles, it has been concluded that the heat energy exhausted from the PV module can be further utilized in different ways and helps in achieving better efficiency. Furthermore, the types of photovoltaic–thermal systems such as air collector, water collector, and combi system, coupling with heat pump and their application to buildings are also stated. This paper also discussed certain design aspects like modifications in the flow channel by adding fins, thin metallic sheets, rollbond absorber, and porous media and the effect of these modifications on the hybrid system’s efficiency. Further- more, the use of the latest technologies such as nano fluids, thermoelectric generators, and phase-change materials improves the overall system performance. The role of soft-computing techniques is forecasting the impact of various parameters on the photovoltaic–thermal system is also discussed.

Towards Achieving Sustainable Development Goal-2030 Agenda-Thirteen: A Review of Technological Advances from the Built Environment Professionals

Natural resources are increasingly under pressures to cater for the growing human population and their corresponding, often conflicting needs. However, the need to conservatively utilize these resources without deteriorating the environment to the disadvantage of the future generations has prompted some actionable steps at the global level, the prominent of which is the promulgation of the United Nation’s Sustainable Development Goal 2030 (SDG-2030) Agenda, having seventeen (17) inter-related actionable areas of human endeavours (i.e., Agenda). Of particular interest within this context is the Agenda Thirteen (Agenda-13) which encompasses the need for urgent action to combat Climate Change and its impacts across various areas of human engagements. This is necessary as Climate Change impacts are characterized with anthropogenic carbon emissions resulting in global temperature rise, sea level rise, flooding, desertification, droughts, and other related disasters. Within the precinct of Built Environment, it is established that building construction and operation alone account for about 40% of the global emissions. This calls for concerns and requires urgent collaborative actions to curtail the trend. This submission, which is review based therefore, highlights various joint efforts particularly, integration of technological advancements by the relevant building professionals, towards attaining the goal of Agenda-13. This is with a view to limiting climate change enablers for reduced environmental impacts. These collaborative efforts are categorized into pre-construction and post-construction activities from the relevant professionals in the built environment. While the former includes Indoor Thermal Comfort Simulation, Integration of Daylighting Technologies, and adoption of Computational Fluid Dynamics integrated architectural design process, the latter consists of design of Double Skin Facades, development of Building Integrated Photovoltaics façade, integration of Evacuated Tube Solar Air Collector System, adoption of Phase Change Material on Building façade, and implementation of Life Cycle Energy Analysis Policy, among others. These endeavours aim at reducing carbon emissions at the building micro level for overall clean, safe and sustainable global environment.

Energy performance and economic assessments of a solar air collector and compression heat pump-integrated solar humidifier desalination system

This article presents the energy performance and economic assessments of a solar air collector (SAC) and compression heat pump (CHP)-integrated solar humidifier desalination system. The influences of solar heat flux, ambient wind speed and ambient temperature on the energy performance of the system are investigated. The quality of distilled water obtained from the system was assessed. The results showed that the proposed configuration has the maximum distillate output of 22.3 l per day in 14 hours of observations during the summer months. Moreover, the system delivers 100 l of hot water at 46 ± 2°C. The effectiveness of a solar humidifier was raised from 0.16 to 0.97. The coefficient of performance of the CHP was fluctuating between 2.40 and 2.77. The gain output ratio (GOR) was raised from 0.9 to 3.35 during the summer months. The proposed system has a payback duration (PBD) of 27.62 months for 14 hours of operation per day during 252 days in a year. The environmental impact assessments revealed that the system will release 32.35 tons of carbon dioxide emissions during 15 years life span. The quality of water obtained from the system was found to be good and suitable for drinking enriched with minerals.

Review on the structure and application of solar photovoltaic air collector

ABSTRACT At present, people use a large amount of coal, oil and other energy while causing a series of environmental pollution problems. In response to the national 3060 policy, improving the utilization of solar energy is imminent. Solar photovoltaic air collector can not only collect heat efficiently but also reduce the surface temperature of solar cells to improve the photoelectric conversion efficiency. The research progress of solar photovoltaic air collector system improvement and application scenarios are reviewed. The theoretical and experimental research of solar photovoltaic air collector in improving photoelectric/photothermal conversion efficiency is analyzed, the current application scenarios and advantages of solar photovoltaic air collector are discussed, and the research direction of solar photovoltaic air collector is prospected.

Parametric study of a solar dryer system for the development and application of solar energy in Sierra Leone

A transient mathematical model has been evaluated to determine the principle of a solar crop dryer for drying vegetables (onion). Considering the meteorological conditions of Freetown (Latitude 8.4840 N, Longitude -13.2300 W), the model was developed to determine air temperatures and other operational parameters of the drying system for a day of March 21st. However, the investigated system had effectively reduced the drying process of onion. The developed double-pass solar air collector system showed a low-temperature output in the morning hours and displayed high-temperature results in the afternoon hours. From 8:00 to 16:00, the solar collector generates fluid output temperatures above 50 0 C, with a peak value of 96 0 C occurred at 12:00. The influence of the mass flow rate on the system's thermal efficiency was investigated. It was noticed that for a certain solar radiation value, an increased in the mass flow rate caused an exponential increased in the solar air collector thermal efficiency. Findings also revealed that an increased in the solar collector length led to a slightly decreased in the outlet air temperatures at a mass flow rate of 0.02 kg/s. The influence of increasing drying air temperatures and air velocity within the drying chamber reduces drying time significantly. The drying time for products dried in the first tray is lesser than for products dried in the subsequent trays, owing to temperature variations. The computation findings were verified to previous studies in the literature and observed to be strongly comparable.

Research on the thermal performance of interlayer ventilated PCM component coupled with solar air collector

The application of solar energy for heating in buildings has the problem of heat supply and demand time mismatch. In this paper, an interlayer ventilated phase change material (PCM) component (IVPC) that can be coupled with solar air collector was proposed. The thermal performance of IVPC was tested through experiments. The results show that if IVPC completes latent heat storage, the optimal air supply temperature of solar hot air is 35 ∼ 45℃ and the air supply speed is 3 ∼ 4 m/s. The latent heat release time can be maintained for 5 h. To build an IVPC coupled with solar air collector system (IVPSS) in TRNSYS, to simulate the improvement effect of IVPC on heating temperature fluctuations, a rural building in cold regions of China was selected. IVPSS can maintain the indoor temperature of the building in the range of 8 ∼ 16℃. Compared with buildings without IVPSS, the room temperature throughout the day can be increased by 5 ∼ 8℃. IVPC can effectively use solar energy to peak load shifting, reduce room temperature fluctuations, improve indoor thermal comfort, and provide solutions for farmhouses in cold regions to use clean energy for heating.

Artificial neural-network based model to forecast the electrical and thermal efficiencies of PVT air collector systems

In the recent decade, Machine Learning techniques have been widely deployed in solar systems due their high accuracy in predicting the performances without going through the physical modelling. In this work, the Artificial Neural Network (ANN) method is adopted to forecast the electrical and thermal efficiencies of a photovoltaic/thermal (PVT) air collector system. Indeed, two accurate modelling techniques have been used to generate the output results for training and validation. Both deployed electrical and thermal models have been validated experimentally and demonstrated high accuracy. Then, real climatic samples of one year with a 10 minute step of the Jordan valley location have been adopted to generate the electrical and thermal efficiencies. These latter are used in the training and validation of the developed ANN model under various combinations of the weather variables. The solar irradiance and the module temperature are the most important variables to consider as input in a NN-based model respectively. The developed ANN model shows MAE of 0.0078% and 3.3607% in predicting the electrical and thermal efficiency respectively. The electrical efficiency can be predicted with higher accuracy than the thermal efficiency. Further, the results demonstrate that the ANN outperforms the LS-SVM in forecasting the PVT air collector performances.

Numerical investigation of four photovoltaic/thermal integrated structures from energetic point of view

Photovoltaic/Thermal (PV/T) module is considered to be one of the most recent technologies which offers harness and production of both electric and thermal energy. In the current study an energetic analysis is carried out to compare between four different configurations which are: the single pass single glazed (PV/T-I), the single pass double glazed with air gap (PV/T-II), the single pass double glazed with argon gap (PV/T-III) and the double pass double glazed (PV/T-IV) hybrid photovoltaic/Thermal air collector systems. A 3 dimensional numerical model is built up and validated with both the numerical and experimental results coming from the literature. The numerical simulations have been accomplished to investigate the energetic performance with a detailed thermal and electrical study taking in account an inlet coolant temperature the same as the ambient temperature for a coolant (air) mass flow rate equals to 0.025 kg/s of a typical day in August from 9:00 to 17:00 under the ambient conditions of Beijing, China. The results show that the single pass single glazed configuration has the highest electrical efficiency, whereas the double pass configuration has the greatest thermal and energy efficiencies among the proposed configurations. The average daily energy efficiencies are 53.14%, 75.92%, 77.63% and 82.19% for the (PV/T-I), (PV/T-II), (PV/T-III) and (PV/T-IV) configurations, respectively.

Thermal performance and environmental assessment of a hybrid solar-electrical wood dryer integrated with Photovoltaic/Thermal air collector and heat recovery system

Improving the energy efficiency of the drying industry is considered as one of the most efficient and promising ways for reducing carbon emissions from the industrial sector. In this context, the present work is aimed at investigating numerically the thermal performance and the environmental impact of a novel forced-air convection hybrid dryer for wood drying industry under realistic environmental conditions. The proposed dryer system consists mainly of a Photovoltaic/Thermal (PVT) solar air collector for thermal and electrical energy production, an insulated drying chamber, an air-to-air heat recovery system and fans. To simulate the functioning of the dryer system, a transient model based on energy and mass equations is developed and validated with experimental data. Annual dynamic simulations were carried out under weather conditions of the Ajaccio city and the effect of recovering waste heat from the dryer unit during both solar drying and hybrid drying processes was presented and analyzed. Results show that using the heat recovery system with an effectiveness of 0.8 leads to reduce the solar drying time by about 40% in summer and up to 32% in winter. For hybrid drying functioning, integrating of both heat recovery system and PVT air collector reduces the energy consumption of conventional dryer up to 86.5% during summer and up to 73.5% during winter. Finally, it was shown that the proposed hybrid wood dryer with PVT air collector and heat recovery system is suitable for wood drying industry and leads to improve the energy efficiency of conventional dryers and to reduce annually the amount of CO2 emissions up to 78.5%.

Artificial neural-network based model to forecast the electrical and thermal efficiencies of PVT air collector systems

Artificial neural-network based model to forecast the electrical and thermal efficiencies of PVT air collector systems

Theoretical approach model of building integrated photovoltaic thermal air collector

Over recent years the photovoltaic technology has obtained significant development, especially in building integrated photovoltaic thermal (BIPVT) system. Photovoltaic thermal (PVT) air collectors are advantageous because of their efficiency. Various studies have been conducted to determine the ideal parameters of PVT air collectors. Few theoretical approach models of PVT air collector systems were used to help detect occurrences in a PVT collector system and calculate the optimal parameters. The heat transfer and energy balance of PVT air collectors were analysed and reviewed based on the model, quantity of cover, channels and forms of the collector. A mathematical model was developed to describe actual working situations and to examine new shut PVT collectors. The first law of thermodynamics is the principal equation in the model. Different analysis methods were utilised to evaluate PVT performances, which are generally based on energy and exergy analyses. This review focuses on theoretical approach model of single-pass PVT air collector.

Photovoltaic\u2013thermal (PV/T) technology: a comprehensive review on applications and its advancement

Over the most recent couple of decades, tremendous consideration is drawn towards photovoltaic–thermal systems because of their advantages over the solar thermal and PV applications. This paper intends to show different electrical and thermal aspects of photovoltaic–thermal systems and the researches in absorber design modification, development, and applications. From the previous review articles, it has been concluded that the heat energy exhausted from the PV module can be further utilized in different ways and helps in achieving better efficiency. Furthermore, the types of photovoltaic–thermal systems such as air collector, water collector, and combi system, coupling with heat pump and their application to buildings are also stated. This paper also discussed certain design aspects like modifications in the flow channel by adding fins, thin metallic sheets, roll-bond absorber, and porous media and the effect of these modifications on the hybrid system’s efficiency. Furthermore, the use of the latest technologies such as nanofluids, thermoelectric generators, and phase-change materials improves the overall system performance. The role of soft-computing techniques is forecasting the impact of various parameters on the photovoltaic–thermal system is also discussed.

Study on design and thermal characteristics of vacuum tube solar collector intubated with heat storage tube

In this work, a heat storage vacuum tube solar collector intubated with heat storage tube is designed, which consists of solar vacuum tube, phase change material insert tube, and heat holding cover. The internal energy conversion, transmission, and storage theory are established based on the structure of the heat storage vacuum tube. The parallel and series-parallel solar air collector system prototype consisting of nine heat storage solar vacuum tube solar collectors is designed and tested. The test results showed that the daily average conversion efficiency of the parallel and series-parallel prototype reached 56.9% and 48.46%, respectively. Compared with nonheat storage prototype, the heat storage parallel and series-parallel prototype had higher conversion efficiency by, respectively, 10.9% and 7.8%, longer effective heating time, and better heating stability and practicability. At the same time, the heat storage solar collector has compact structure, which is convenient to use.

Performance evaluation of a semi-transparent photovoltaic thermal (SPVT) inverted absorber flat plate collector (IAFPC) for constant collection temperature (CCT) mode

In the present communication an analytical model, to analyze the system performance of self-sustainable single-pass inverted conventional air collector integrated with semi-transparent photovoltaic thermal (SPVT) module has been developed. A comprehensive quasi-steady state performance analysis, based on the energy balance equation for each of the components (semi-transparent photovoltaic thermal (SPVT) module-partially covered, integrated with inverted air collector system for the operation at constant collection temperature (CCT) mode) has been studied. In the present study, an analytical modelling for exergy of the partially covered SPVT-IAFPC air collector system has been proposed and used for determining the performance at constant collection temperature (CCT) mode. Effect of the mass flow rate on the outlet temperature, electrical efficiency, cell temperature, rate of thermal efficiency has been studied and their thermal energy performance with overall exergy efficiency has been determined by developing a MATLAB program based on the analytical modelling. The inverted absorber semi-transparent photovoltaic thermal (SPVT) air collector has been analyzed for the following cases:1.Conventional inverted absorber FPC.2.Partially covered SPVT-IAFPC air collector.3.Fully covered SPVT-IAFPC-air collector.

Effect of a new solar air collector system on the indoor living environment and air quality for the kindergarten building

The kindergartens, characterized by large scale and daytime usage, possess evident typicality and necessity for the application of low cost solar energy. As the main learning place for school-age children, the indoor air quality of kindergarten has significant influence on children’s physical health. To verify the effects of a new flat plate solar air collector system (SACS) with metallic heating panels on the improvement of indoor living environment in kindergarten buildings, the indoor temperature, humidity and air quality in kindergarten were tested and investigated in this paper. Two indoor activity units with the same conditions in kindergarten of Shandong Jianzhu University, were selected as the test rooms. The working conditions of solar air collector in these two test rooms were taken as the reference variable. The systematic monitoring and analysis of air quality parameters such as temperature, humidity and carbon dioxide concentration in 12 reasonably distributed sampling positions were carried out during the continuous five days. The results show that the SACS possesses evident auxiliary heating function for indoor air. The maximum value of the average temperature raise nearly reaches 15%. The preheated air near the air outlet exhibits 10°C higher temperature than outdoor air. Besides, the system leads to slightly lower indoor humidity. In addition, the value of indoor CO2 concentration significantly decreases up to 800 ppm due to the filtration of the system. Instead of air conditioning to a certain extent during transition seasons, this system can effectively reduce the building energy consumption. It can provide children a more healthy and comfortable indoor air environment through the effective use of green solar energy. The research results in this paper can provide important reference for the wide application of solar air collector system in the special building environment of kindergartens.

Design and experimental study on thermal characteristics of thermal storage flat-plate solar collector

A thermal storage flat-plate solar collector is designed to improve working stability of the solar air drying system, which consists of an absorber plate, a transparent cover plate, a heat insulation layer, phase change materials, a tube bank and a shell, etc. The daily thermal characteristics of thermal storage flat-plate air collector system were tested under natural conditions. The results show that heat storage flat-plate solar collector can effectively extend collector heating time, with daily heat efficiency reaching 49.8%, which is 4.6% up as compared to 45.21% of non-thermal storage heat collector.

1D model for the energy yield calculation of natural convection solar air collectors

Abstract A one dimensional model has been developed and presented to calculate the seasonal energy yield of solar air collectors. This model takes into account local meteorological conditions, the effects of geometrical configuration, materials used as well as the orientation of a solar air collector system. It can provide the temporal variation of the operating temperatures, heat transfer rates and ultimately the energy yield of the system for the duration of a whole heating season. The model is used to conduct a parametric investigation of the system efficiency, assessing the effects of wall-glass spacing, wall thickness, solar-absorbing surface material and orientation. The energy yield of a reference system installed in a ”hot” or a ”cold” climate is examined and discussed. It was found that the efficiency of the collector was more sensitive to the material of the solar-absorbing surface than any other parameter examined. Moreover, it was found that although in cold climates the daily efficiency of the system was lower, because of the extended heating season, the seasonal energy yield of the system was comparable to hotter climates.