Abstract:Direct evaporative cooling is widely known for being an energy efficient air conditioning solution for arid and/or semi-arid climates. Commercialized evaporative cooling pads vary in material and construction characteristics, while existing research proposes several alternative wetted media and configurations. The most studied factors on the evaporative cooling pads operation are the air velocity or air mass flow rate, air psychrometric conditions; the pad thickness, its geometric characteristics and configura… Show more
“…It is an environmentally friendly air conditioning system that uses induced heat and mass transfer processes, where water and air are working fluids. With this cooling system, the temperature drops significantly and the humidity rises to levels suitable for short-term storage of perishable goods on the farm (Tejero-González & Franco-Salas 2021). Figure 5. Average temperature (a) and relative humidity (b) versus the day of the experiment of the cooler and the ambient.…”
Injera is Ethiopian ethnic traditional staple food, made from teff and other crops. The country’s superfoods are highly regarded in many Western countries for their excellent nutritional properties (‘very low gluten’), and mineral composition. Injera provides sufficient conditions for fungi to grow and ruin injera by changing the texture and making it inedible. This study aimed to develop an evaporative cooler clay chamber (ECCC) used to extend the shelf life of injera by controlling temperature and relative humidity (RH). This system is an economical and efficient way to lower the temperature and increase RH. The results show the maximum daily ambient temperature reduced from 28.98 °C to 22.90 °C and increased the RH of the storage chamber from 28.78% to 80.94%, respectively. The temperature drops up to 6.08 °C, and the RH rises to 52.16% observed. Additionally, the effects of temperature, RH and potential of hydrogen were studied for identified rotten injera and designed for injera storage. ECCC can store freshly made injera for 9 days before any visible mould stains appear, significantly reducing weight loss with an average cooling efficiency of 79.31%. Therefore, this study might help to develop low-cost cold storage for injera preservation at farms end in Ethiopia.
“…It is an environmentally friendly air conditioning system that uses induced heat and mass transfer processes, where water and air are working fluids. With this cooling system, the temperature drops significantly and the humidity rises to levels suitable for short-term storage of perishable goods on the farm (Tejero-González & Franco-Salas 2021). Figure 5. Average temperature (a) and relative humidity (b) versus the day of the experiment of the cooler and the ambient.…”
Injera is Ethiopian ethnic traditional staple food, made from teff and other crops. The country’s superfoods are highly regarded in many Western countries for their excellent nutritional properties (‘very low gluten’), and mineral composition. Injera provides sufficient conditions for fungi to grow and ruin injera by changing the texture and making it inedible. This study aimed to develop an evaporative cooler clay chamber (ECCC) used to extend the shelf life of injera by controlling temperature and relative humidity (RH). This system is an economical and efficient way to lower the temperature and increase RH. The results show the maximum daily ambient temperature reduced from 28.98 °C to 22.90 °C and increased the RH of the storage chamber from 28.78% to 80.94%, respectively. The temperature drops up to 6.08 °C, and the RH rises to 52.16% observed. Additionally, the effects of temperature, RH and potential of hydrogen were studied for identified rotten injera and designed for injera storage. ECCC can store freshly made injera for 9 days before any visible mould stains appear, significantly reducing weight loss with an average cooling efficiency of 79.31%. Therefore, this study might help to develop low-cost cold storage for injera preservation at farms end in Ethiopia.
“…One barrier to their success as a sustainable alternative to AC, however, is the possibility of infiltration of outdoor PM 2.5 and its associated health effects. Prior research on ECs primarily focuses on system efficiencies such as air flow rate and pressure drop, water consumption, heat and mass transfer, and degradation of pad materials [52][53][54]. Our findings suggest a need for studies focused on EC design specifically to decrease infiltration of particle-phase pollutants.…”
Global use of energy-inefficient mechanical vapor-compression air conditioning (AC) is increasing dramatically for home cooling. Direct evaporative coolers (EC) offer substantial energy savings, and may provide a sustainable alternative to AC for homes in hot, dry climates. One drawback of ECs is the potential for infiltration of outdoor air pollution into homes. Prior studies on this topic are limited by small sample sizes and a lack of comparison homes. In this study, we used aerosol photometers to sample indoor and outdoor fine particulate matter (PM2.5) from 16 homes with AC and 14 homes with EC in Utah County, Utah (USA) between July 2022 and August 2023. We observed a significantly larger infiltration factor (Fin) of outdoor PM2.5 in EC vs. AC homes (0.39 vs. 0.12, p = 0.026) during summer. Fin significantly increased during a wildfire smoke event that occurred during the study. During the wildfire event, EC homes offered little to no protection from outdoor PM2.5 (Fin = 0.96, 95% confidence interval (CI) 0.85, 1.07), while AC homes offered significant protection (Fin = 0.23, 95% CI 0.15, 0.32). We recommend additional research focused on cooling pad design for the dual benefits of cooling efficiency and particle filtration.
“…Air Jet Impingement Cooling appears to be a suitable cooling method for battery tab cooling as it is capable of dissipating heat with extremely high rates per unit surface area [109]. It produces a thin boundary layer on a component surface, which results in improvement in both local and area-averaged heat transfer coefficients that are up to three times higher than conventional convection cooling [110]. Air pressure, Air Jet Velocity, Air nozzle diameter, Distance between jets, Distance between nozzle and surface, frequency of jet impingement are the design key parameters.…”
The thermal concerns, such as capacity loss, uneven temperature distribution and thermal runaway of the battery packs made of lithium-ion batteries (LIB) used in electric vehicles (EV), limits its applicability, especially in situations of high-power demand. This article analyses the causes of heat generation in lithium-ion battery packs, focusing on their dominance over total heat generation. It discusses the thermal issues arising from heat generation, their root causes, and influencing parameters. Further, it examines the effect of cooling systems on peak battery temperature and temperature uniformity, as well as their design, operating, and performance parameters. The review suggests that, when designing a cooling system, entropic heating should be considered alongside Joule heating during low discharge rates and high temperatures, which are the conditions that prevail when an EV cruises on highways in hot weather. Capacity fade of battery is caused by temperature-dependent factors such as the growth of the SEI layer, rise in separator resistance, and active material loss. Hence an effective battery cooling system should maintain a temperature range of 15°C to 35°C and ‘ΔTmax’ below 6°C. Out of the reviewed cooling systems, air cooling is found to be simple and cost effective, but inefficient for large battery packs. PCM based cooling technique offers greater temperature uniformity but is sensitive to melting point. Liquid cooling is most efficient but adds cost and complexity. Evaporative cooling can serve as a middle ground between air and liquid cooling with further research to put it into practice. The future research in battery thermal management may focus lowering the energy consumption of the cooling systems by taking into account, the precise cooling needs as per the modes of battery operation.
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