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This experiment was conducted to assemble and test a cooling system operating with a thermoelectric cooling system (TEC) used to preserve crops and agricultural products from April 14 to June 24, 2021 AD. The study included a test of adding Heat Sink to the cold side of the thermoelectric cooling plates (TEC) with two levels (without heat sink (A1) and with heat sink (A2)) inside the system. 6 cooling models (TEC) were used with 6 heat sinks distributed in the form of two groups, and each group includes three cooling model (TEC). The following characteristics were measured (internal temperature (Tin), temperature difference (∆T), relative humidity (RH), time required to cool (t), cooling capacity (Qc) and Coefficient of Performance (COP). The results reveated that the presence of Heat Sink (A2) was superior than without (A1) in the following characteristics: It gave the lowest temperature inside the system 6.55Cº by 35% over treatment (A1), and pointed the highest (∆T, RH, t, Qc and COP) by (24.19 Cº, 82.32% , 43.73W and 19.87%) respectively. All these obtained results give with a cooling time 4.6h which was higes about 14% than (A1). Where the electrical capacity used 220W.

The purpose of this study is to determine the performances of luffa and greenhouse shading netting (which can be used as alternatives to commercial cellulose pads, that are popular for cooling greenhouses), the contribution of external shading to the evaporative cooling performance, and the energy consumption of the direct evaporative cooler. In this experiment, eight different applications were evaluated: natural ventilation (NV), natural ventilation combined with external shading net (NV + ESN), cellulose pad (CP), cellulose pad combined with external shading net (CP + ESN), luffa pad (LP), luffa pad combined with external shading net (LP + ESN), shading net pad (SNP), and shading net pad combined with external shading net (SNP + ESN). The cooling efficiencies of CP, CP + ESN, LP, LP + ESN, SNP, and SNP + ESN were found to be 37.6%, 45.0%, 38.9%, 41.2%, 24.4%, 29.1%, respectively. Moreover, their cooling capacities were 2.6 kW, 3.0 kW, 2.8 kW, 3.0 kW, 1.7 kW, 2.0 kW, respectively. The system water consumption values were 2.9, 3.1, 2.8, 3.2, 2.4, 2.4 l h−1, respectively. The performance coefficients of the system were determined to be 10.2, 12.1, 11.3, 11.9, 6.6, 7.8. The system’s electricity consumption per unit area was 0.15 kWh m−2. As a result of the study, it was determined that commercially used cellulose pads have advantages over luffa and shading net materials. However, luffa pads can be a good alternative to cellulose pads, considering their local availability, initial cost, cooling efficiency, and capacity.

The paper presents the research results on the impact of the non-azeotropic mixture refrigerant (R410A) charging process on the cooling capacity of the residential air conditioning (RAC) system through experimental procedures. The RAC system was installed to experiment with two cases that commonly occur in reality regarding the refrigerant charging process. Based on the experimental data and subsequent calculations performed using EES software, the study the liquid refrigerant charging method enhances the specific cooling capacity and coefficient of performance (COP) by 13.137 kJ/kg and 0.404, respectively, compared with the vapor charging method, under the condition of an initially empty system. From there, the authors recommend the process of charging the non-azeotropic refrigerant for RAC systems to ensure compliance with technical procedures and improve system efficiency.

Due to their benefits in interior thermal comfort, energy saving, and noise reduction, radiant cooling systems have received wide attention. Radiant cooling systems can be viewed as a part of buildings’ maintenance structure and a component of cooling systems, depending on their construction. This article reviews studies on heat exchange in rooms utilizing radiant cooling systems, including research on conduction in radiant system structures, system cooling loads, cooling capacity, heat transfer coefficients of cooling surfaces, buildings’ thermal performance, and radiant system control strategy, with the goal of maximizing the benefits of energy conservation. Few studies have examined how radiant cooling systems interact with the indoor environment; instead, earlier research has focused on the thermal performance of radiant cooling systems themselves. Although several investigations have noted variations between the operating dynamics of radiant systems and conventional air conditioning systems, the cause has not yet been identified and quantified. According to heat transfer theory, the authors suggest that additional research on the performance of radiant systems should consider the thermal properties of inactive surfaces and that buildings’ thermal inertia should be used to coordinate radiant system operation.

The underground air tunnel system shows promising potentials for reducing energy consumption of buildings and for improving indoor thermal comfort, whereas the existing dynamic models using the computational fluid dynamic (CFD) method show computational complexity and are user-unfriendly for parametrical analysis. In this study, a dynamic numerical model was developed with the on-site experimental calibration. Compared to the traditional CFD method with high computational complexity, the mathematical model on the MATLAB/SIMULINK platform is time-saving in terms of the real-time thermal performance prediction. The experimental validation results indicated that the maximum absolute relative deviation was 3.18% between the model-driven results and the data from the on-site experiments. Parametrical analysis results indicated that, with the increase of the tube length, the outlet temperature decreases with an increase of the cooling capacity whereas the increasing/decreasing magnitude slows down. In addition, the system performance is independent on the tube materials. Furthermore, the outlet air temperature and cooling capacity are dependent on the tube diameter and air velocity, i.e., a larger tube diameter and a higher air velocity are more suitable to improve the system’s cooling capacity, and a smaller tube diameter and a lower air velocity will produce a more stable and lower outlet temperature. Further studies need to be conducted for the trade-off solutions between air velocity and tube diameter for the bi-criteria performance enhancement between outlet temperature and cooling capacity. This study proposed an experimentally validated mathematical model to accurately predict the thermal performance of the underground air tunnel system with high computational efficiency, which can provide technical guidance to multi-combined solutions through geometrical designs and operating parameters for the optimal design and robust operation.

The paper introduces the artificial intelligence (AI) approach as a general method for the design and optimization study of heat exchangers. Genetic Algorithms (GA) and Artificial Neural Networks (ANN) are applied in the paper. An AGENN model, combining Genetic Algorithms with Artificial Neural Networks, was developed and validated against the desired data on a large falling film evaporator. A broad range of operating conditions and geometric configurations are considered in the study. Four kinds of tubes are deliberated, including plain and enhanced tubes. Different tube pass arrangements, i.e., top-to-bottom, bottom-to-top, and side-by-side, are discussed. Finally, the effects of liquid refrigerant mass flow rate, as well as the number of flooded tubes on the performance of the evaporator, are analyzed. The total heat transfer rate of the evaporator, predicted by the model, is in good agreement with the desired data; the maximum error is lower than ±3%. The highest heat transfer rate of the evaporator is 1140.01 kW and corresponds to Turbo EHP tubes, and bottom-to-top tubes pass arrangements, which guarantee the best thermal energy conversion. The presented approach can be referred to as a complementary technique in heat exchanger design procedures, besides the common rating and sizing tasks. It is an effective and alternative method for the existing approaches, considering the complexity of analytical and numerical techniques as well as the high costs of experiments.

In this study, the thermodynamic behavior of a combined cycle power plant with integrated solar-driven inlet air cooling was simulated for Tehran, Phoenix, and Houston during warm-hot seasons. A considerable reduction in the output power was realized during hot ambient conditions due to the lower density of the air and lower mass flow rate to the turbines. The output power decreases from 306.6 to 260.8 MW as ambient temperature increases from 15 to 45 °C. This research focuses on utilizing solar cooling systems to achieve low inlet air temperature to generate high-electricity yields. Four different types of solar collectors and two different absorption chiller units were selected and simulated for each city to achieve the required goal. It was identified that integrating a solar inlet air cooling (SIAC) system can avert the reduction in output power with no impact on efficiency. The humid climatic condition in Houston and the low electricity cost in Tehran posed some challenges in designing a feasible SIAC system. However, by optimizing the solar collectors and cooling capacities, an optimal solution for utilizing inlet air cooling in humid climates is presented. In terms of overall impact, the evacuated flat plate collector (EFPC) coupled with a double-effect absorption chiller displayed the best economic performance among the four variants under study. In Phoenix, this combination can maintain output power during hot days with a DPR of 2.96 years.

This study investigated cooling capacity concerns in 2-pipe economy fan coil units used in Korea, prompted by frequent field replacement claims and HVAC design engineer feedback. Comprehensive field testing of approximately 100 economy FCUs revealed significant performance discrepancies. KS B 6377 certified models (n=49) performed 6.9% below ratings, while uncertified models (n=54) averaged 9.0% below rated airflow specifications. Detailed in-situ evaluation of selected models showed uncertified units achieving only 68% of rated airflow at maximum fan speed, whereas certified models delivered 138% of rated airflow. Laboratory testing of certified models revealed internal inconsistencies, with cooling capacity ranging from 85.4% to 118.2% of rated capacity as a result of varying airflow rates despite meeting NC-40 acoustic criteria. Reduced cooling capacity results from intentionally diminished airflow rates used for noise mitigation—a concerning compromise of thermal comfort for acoustic compliance. Recommendations include implementing advanced low-noise fan technologies and specifying precise fan flowrate conditions in KS B 6377 certification standards.