Air solar collectors

In the current study, an experimental analysis of exergy performance for different absorber plates is done. Three types of absorber plates are supplied with different fin arrangements with a variable air mass flow rate. The exergy analysis to evaluate the exergy performance of the solar air heaters uses experimental data for conventional and finned solar air collectors with different arrangements of fins. The main aim of the current study is to compare the exergy performance of the conventional solar air collector with those equipped with fins. The introducing of the fins in different arrangements enhances the absorber surface area, which leads to increased heat transfer. Also, fins induce air turbulence in the flow field, which improves the exergy performance of solar air collector. It is found that the exergy reduces and exergy efficiency enhances with increasing the airflow rate. The traditional flat absorber plate has undesirable exergy loss and exergy efficiency for all ranges of airflow rates. Thus, the flat plate collector presents the most substantial irreversibility, for which the exergy efficiency is the least. However, the results show that the exergy efficiency of inclined staggered turbulators is higher than that of in‐line and staggered turbulators. The optimal value of exergy efficiency is recorded at nearly 77% for the solar air collectors equipped with inclined staggered turbulators compared with other types of configurations.

Experimental and numerical study of the effect of integrating plus-shaped perforated baffles to solar air collector in drying application

Alternatives to traditional fossil fuels are being explored, and a switch to solar energy systems is seen as one of the most promising. Solar energy devices, such as solar air collectors (SACs), have been widely employed in various residential, commercial, and industrial settings until quite recently. Unfortunately, the most up-to-date research shows that SAC efficiency rates are still quite low. This chapter attempts to obtain better performance of trapezoidal absorber-based SAC in this chapter. Further, the effectiveness of these SAC systems has been improved with the help of some metaheuristic algorithms. This chapter uses the entropy with the JAYA approach, a hybrid MCDM technique, to model and optimize the SAC. Here, the entropy approach is employed for weight extraction, and JAYA is used to optimize the parameters. In light of this, we have conducted 17 experimental trials, with output metrics including energy, exergy, sustainability index, and environmental impact factor. Trial no. 6 outperforms the others statistically, resulting in the highest total score. The energy efficiency of 17.92%, exergy efficiency of 12.51%, sustainability index of 1.14, and environmental impact factor of 0.87 correspond to the optimal settings of 0.0039 kg/s mass flow rate, 45° tilt angle, 790.40 W/m2, and input temperature of 30.6 °C.

In this research, an experimental study has been performed in order to enhance the thermal performance of a double-pass solar air collector by employing extended surfaces. In order to increase the heat transfer area, triangular-shaped fins were mounted on the longitudinal direction of the absorber plate. Four models of the solar air collectors were made of aluminum with different fin configurations. The experiments were carried out at the winter season in the climate of Iraq - Ramadi city with longitude 43.268 and latitude (33.43). The used range of mass flow rate in the experiments was from 0.027 kg/s to 0.037 kg/s. The comparison with previous studies in terms of thermal efficiency showed good agreement where the percentage of error does not exceed 1% between them. The results also provided that the existing of fins was a good technique for enhancing the thermal performance of double-pass solar air collector with a marginal increase in pressure drop. Consequently, it is possible to adopt this kind of solar air collectors for many agricultural applications such as solar dryer.

Design a low-cost, medium-scale, flat plate solar air heater: An experimental and simulation study

Solar air collectors have various applications: on one side, they can be used for air heating in cold seasons; on the other side they can be used in summer to evacuate the warm and polluted air from residential, offices, industrial and commercial buildings. The paper presents experimental results of a solar collector air, in climatic conditions from South Eastern Europe. The relationships between the direct solar irradiation, the heat flow resulted, the air velocity at the outlet, the air flow rate, the time of input in nominal regime of the collector and efficiency of conversion of solar energy into thermal energy are highlighted. Thus, it was shown that after maximum 50 minutes, solar air collectors, with baffles and double pass of air can reach 50 % efficiency for solar irradiation of 900-1000 W/m. 2The article also presents a mathematical model and the results of a computational program that allows sizing solar collectors for the transfer of the air, for their purpose to improve the natural ventilation of buildings. The article is completed with a case study, sizing the area to be covered with solar collectors to ensure ventilation of a house with two floors or for an office building. Also, the ACH coefficient was calculated and compared.

Design and assessment of an adapted absorber solar air collector tailored for sustainable drying applications

Energy and exergy analysis of forced and natural convection indirect solar dryers: Estimation of exergy inflow, outflow, losses, exergy efficiencies and sustainability indicators from drying experiments

Determination of thermal performance calculation of two different types solar air collectors with the use of artificial neural networks

This study presents a design for an absorber used in a solar air collector for an indirect solar dryer. The absorber comprises two aluminium plates corrugated and joined together to form parallel cylinders, enabling airflow within the collector. This research aims to experimentally examine the drying process of two types of bananas, one from Morocco and the other from abroad, using the designed solar air collector. Additionally, the study aims to investigate the peculiarities of the drying process and the performance of the solar dryer employed. The experiments were conducted by subjecting the bananas to the designed solar air collector, and the evolution of drying was monitored. The initial mass of the bananas used was 631.6 g for the Moroccan banana and 713.6 g for the Export banana. After the drying process, the mass of the Moroccan banana reduced to 77.5 g, while the Export banana reduced to 137.3 g, indicating significant moisture removal. The percentage of the amount of water extracted (Q) from the bananas was found to be 87.7% for the Moroccan banana and 80.8% for the Export banana. These results demonstrate the effectiveness of the corrugated aluminium plate absorber in facilitating the drying process in the solar air collector. The significant reduction in the mass of the bananas and the high percentage of water extraction highlight the efficiency of the solar dryer in removing moisture from the agricultural produce. The findings of this study contribute to the understanding of the drying process of bananas and offer valuable insights for the design and optimization of solar drying systems for agricultural applications.

An oriented-design simplified model for the efficiency of a flat plate solar air collector

Exergy efficiency and sustainability indicators of forced convection mixed mode solar dryer system for drying process

This paper aims to study the heat collecting efficiency of the solar air collector with ten groups of single pipe in parallel. The simulations and experimental verification are carried out to obtain the best angle and air inlet flow rate. The result is that when the angle of the collector is 45 °and the inlet flow rate is 48.6 m3/h (2.7 m/s), the heating effect is the best for the solar air collector we have studied in this article. The average collection efficiency of it during stable operation can reach 65%.The simulation results are consistent with the experimental results. In practical application the results can provide a theoretical foundation to choose the appropriate flow rate and angle of the collector.

Performance of a new type of solar air collector with transparent-vacuum glass tube based on micro-heat pipe arrays

Mathematical models have been developed to evaluate the dynamic behavior of two solar air collectors: the first one is equipped with a V-porous absorber and the second one with a U-corrugated absorber. The collectors have the same geometry, cross-section surface area and are built from the same materials, the only difference between them being the absorbers. V-corrugated absorbers have been treated in literature but the V-porous absorbers modeled here have not been very often considered. The models are based on first-order differential equations which describe the heat exchange between the main components of the two types of solar air heaters. Both collectors were exposed to the sun in the same meteorological conditions, at identical tilt angle and they operated at the same air mass flow rate. The tests were carried out in the climatic conditions of Bucharest (Romania, South Eastern Europe). There is good agreement between the theoretical results and experiments. The average bias error was about 7.75 % and 10.55 % for the solar air collector with “V”-porous absorber and with “U”-corrugated absorber, respectively. The collector based on V-porous absorber has higher efficiency than the collector with U-corrugated absorber around the noon of clear days. Around sunrise and sunset, the collector with U-corrugated absorber is more effective.