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The enhancement of energy systems in industrial zones is attracting the attention of researchers from all over the world. At the same time, optimization and advancement in heat recovery systems are now generating major interest in the energy sector. In this context, the present study suggests a new multiple heat recovery system should be applied to an industrial thermal peeling press machine. The new system consists of multiple sources of energy: the heat excess in the chimney, the exhaust gas of the chimney, and the exhaust gas of the boiler. To proceed with testing the potential of the suggested system, a hydraulic thermal peel press machine in the wood industry undergoes different tests to achieve the best configuration that will enable this machine to reach its operational temperature when heating. Five test configurations are proposed, designed, and applied experimentally on this machine. Many parameters were effective during the experimental tests, such as water flow rate, ambient air temperature, and initial water temperature. It was found that the application of the multiple heat recovery system increases the rate of heating from around 7 °C/min to around 13 °C/min. In terms of energy and economy, the "chimney + boiler only" configuration proved to be the best system to apply during the fall and winter seasons. [ABSTRACT FROM AUTHOR]

Photovoltaic panels play a pivotal role in the renewable energy sector, serving as a crucial component for generating environmentally friendly electricity from sunlight. However, a persistent challenge lies in the adverse effects of rising temperatures resulting from prolonged exposure to solar radiation. Consequently, this elevated temperature hinders the efficiency of photovoltaic panels and reduces power production, primarily due to changes in semiconductor properties within the solar cells. Given the depletion of limited fossil fuel resources and the urgent need to reduce carbon gas emissions, scientists and researchers are actively exploring innovative strategies to enhance photovoltaic panel efficiency through advanced cooling methods. This paper conducts a comprehensive review of various cooling technologies employed to enhance the performance of PV panels, encompassing water-based, air-based, and phase-change materials, alongside novel cooling approaches. This study collects and assesses data from recent studies on cooling the PV panel, considering both environmental and economic factors, illustrating the importance of cooling methods on photovoltaic panel efficiency. Among the investigated cooling methods, the thermoelectric cooling method emerges as a promising solution, demonstrating noteworthy improvements in energy efficiency and a positive environmental footprint while maintaining economic viability. As future work, studies should be made at the level of different periods of time throughout the years and for longer periods. This research contributes to the ongoing effort to identify effective cooling strategies, ultimately advancing electricity generation from photovoltaic panels and promoting the adoption of sustainable energy systems. [ABSTRACT FROM AUTHOR]

The thermal performance of fin-and-tube heat exchangers (HX) is a crucial aspect in a multitude of applications and fields; several design and operational parameters influence this performance. This study focuses on the issue of flow maldistribution and its effect on the HX thermal performance. For this purpose, an experimental setup is designed and implemented to emulate the conditions under which an automotive heat exchanger operates in regard to the non-uniform upstream airflow velocity distribution over the HX surface. The setup allows obtaining various configurations of airflow velocity non-uniformity of some desired mean velocity and standard deviation. The experimental results reveal that a higher degree of non-uniformity (higher standard deviation of the velocity distribution) causes an increased deterioration of the HX thermal performance. For example, at a water flowrate of 200 L/h and a mean airflow velocity of 2 m/s, increasing the standard deviation from 0 to 2 m/s (i.e., moving from the lowest to highest degrees of non-uniformity) causes a total deterioration of 27% in the performance (3.78 to 2.75 kW, respectively), which can also be observed in the increased level of outlet water temperature (53.8 to 58.2 °C, respectively). The obtained results confirm the numerical results reported in the literature. [ABSTRACT FROM AUTHOR]

The automotive domain is a very good candidate for energy management, particularly due to the huge amounts of energy lost by heat through exhaust and water-cooling systems. This makes the optimization of vehicle cooling modules directly related to energy consumption and carbon dioxide emission. In this context, contemporary designs that employ diffusers between the forward-facing of an automobile and its heat exchanger subjected to airflow are presented in this work. The ultimate aim is to reduce the fuel consumption and carbon dioxide emissions of vehicles. Based on the aforementioned design, the intensity of the air velocity would be decreased but distributed over a larger exchanger surface. Consequently, the velocity non-uniformity of the airflow upstream would decrease and therefore, the thermal performance would increase. The above-mentioned conclusion is a result of parametric numerical analysis and its associated numerical results that disclosed the enhancement of water-air heat exchanger thermal performance. To perform a parametric numerical analysis of the heat exchanger thermal performance for the new suggested configurations, a computational code was developed and validated to estimate the thermal performance for a known set of parameters. It was shown that for an automobile, with engine power ranging from 100–200 kW that is utilized for three hours a day and equipped with a diffuser, reduction of up to 2.91 kg (3.89 L) of gasoline consumption and 9.51 kg of CO2 emission can be achieved per day. The originality of the present work resides in the use of diffusers in cooling modules of vehicles, the thermal modeling of heat exchanger's thermal performance along with its associated code, and the parametric analysis performed to prove the potential enhancement related to the use of diffusers in the cooling modules. [ABSTRACT FROM AUTHOR]

This paper suggests a heat recovery concept that is based on preheating/precooling the cold/hot fresh outside air by means of the relatively hot/cold exhaust air in winter/summer weather conditions. To investigate the feasibility of such a concept, an experimental setup is established to simulate conditions similar to an All-Air HVAC system. The prototype consists of a 6.7-m3 air-conditioned chamber by means of a split unit of 5.3-kW capacity. The heat recovery module consists of a duct system that is used to reroute the exhaust air from a conditioned chamber to flow through the fin side of a fin-and-tube heat exchanger of crossflow type. At the same time, outside, fresh air is flowing through the tube side of the fin-and-tube heat exchanger. A parametric study is performed to assess the amount of heat that can be recovered by varying the mass flow rates on both the duct and heat exchanger sides. The results show that up to 200 W of power can be saved for an exhaust flow rate of 0.1 kg/s and a fresh, outdoor air flow rate of 0.05 kg/s. Environmentally speaking, this leads to a reduction in production of about 1 tons of CO2 per year when the system operates 24 h/day. From an economic point of view, the system is able to return its price after 1.5 years when it is used 24 h per day during hot days at 196-W thermal recovery, whereas it requires at least 6.3 years when it is used during cold days at a 60-W thermal recovery rate, which, in both cases, represents a duration less than the lifespan of an air conditioner. [ABSTRACT FROM AUTHOR]

The use of phase change material (PCM) as a thermal energy storage system integrated in new buildings, and as retrofits in old buildings, proved its merit as promising renewable energy source. Heating and cooling building applications of PCM have been studied by plenty of scientists, globally, on the basis of numerical and experimental analysis. The performed experiments have mainly focused on one application—active or passive—using permanent prototype design for a certain duration and weather condition. The current study is a new review that focuses on two complementary aspects: (1) Reviewing latest studies in PCM domain and assessing the thermal performance of implemented prototypes within the conducted PCM experimental studies, namely, the effect of the design on the number of acceptable variables and possible PCM applications; and (2) suggesting a new, advanced, flexible, and modular prototype designed to enable several applications of PCM to be adapted and combined within the model. It was implied that the new design allows different configurations that are lacking in the literature and serves for future PCM building applications of thermal analysis towards PCM integration optimization, as an attempt for transforming residential compartments into net zero energy buildings. The designed prototype overcomes the deficiencies found in previous reviewed experimental facilities. [ABSTRACT FROM AUTHOR]

Energy has become the backbone of humanities daily activities. Heating, ventilating, and air conditioning systems (HVAC), which consume around 39% of energy in the residential sector, have turned into an essential constituent for providing fresh air, especially after COVD-19, not only in hospitals but also in any simple construction. Thus, decreasing this percentage or recovering part of the energy lost is an essential issue in today's energy management scenarios. In this context, the present manuscript suggests a comprehensive review, classifications, critical analysis, and potential recommendations for energy recovery in air conditioning systems. It classifies energy recovery into two main categories: using lost energy for external uses, such as heating domestic water, or with other devices; and using lost energy for internal uses, such as the hot airflow which can be reused again for increasing efficiency of HVAC. In addition, this paper presents a summary of previous research and undertakes a review of the devices used for recovering energy. Furthermore, this review identifies superior devices in terms of climate and weather conditions. These objectives are accomplished by investigating around 190 published papers to conclude that energy recovery devices show a considerable effect on energy consumption in HVAC, mainly the heat pipe, fixed plate, and rotary wheel devices. [ABSTRACT FROM AUTHOR]

In the context of a world energy crisis, the only solution to control the situation is in the management of energy. One of the most important management keys is the optimization of electrical components. This article presents a complete numerical and experimental study aiming for the optimization of electrical water heaters for household use. The optimization conceives the minimization of energy consumption simultaneously with the minimization of time to heat water. Firstly, a thermal model well adapted for the case of heaters is constructed and validated experimentally and then a parametric study is conducted covering all the input power, the volume and the external area of the heater. Results are promising, showing significant energy savings are possible with an optimum setting of these parameters, thus presenting a firm tool for the optimization of heaters. [ABSTRACT FROM AUTHOR]