No abstract

In the 21st century, the poultry sector is a vital concern for the developing economies including Pakistan. The summer conditions of the city of Multan (Pakistan) are not comfortable for poultry birds. Conventionally, swamp coolers are used in the poultry sheds/houses of the city, which are not efficient enough, whereas compressor-based systems are not economical. Therefore, this study is aimed to explore a low-cost air-conditioning (AC) option from the viewpoint of heat stress in poultry birds. In this regard, the study investigates the applicability of three evaporative cooling (EC) options, i.e., direct EC (DEC), indirect EC (IEC), and Maisotsenko-cycle EC (MEC). Performance of the EC systems is investigated using wet-bulb effectiveness (WBE) for the climatic conditions of Multan. Heat stress is investigated as a function of poultry weight. Thermal comfort of the poultry birds is calculated in terms of temperature-humidity index (THI) corresponding to the ambient and output conditions. The heat production from the poultry birds is calculated using the Pederson model (available in the literature) at various temperatures. The results indicate a maximum temperature gradient of 10.2 °C (MEC system), 9 °C (DEC system), and 6.5 °C (IEC systems) is achieved. However, in the monsoon/rainfall season, the performance of the EC systems is significantly reduced due to higher relative humidity in ambient air.

Thermally driven adsorption-based atmospheric water harvesting (AWH) is becoming an emerging technology to provide potable water. In this regard, various adsorbent materials including solid (MOFs, silica-gels, and zeolites), liquid (CaCl2 and LiCl), and composite adsorbents are explored in the literature. This study reviews recent advancements in adsorbent materials based on their water production capacity at different conditions that is air temperature and relative humidity (RH). The MOF of type MIL-101(Cr) shows water production capacity of 3.10 L/m2/day at RH ranging from 10% to 40%. Similarly, Zr-MOF-808 possesses water production capacity of 8.60 L/m2/day at RH more than 50%. Among the studied silica-gels, mesoporous silica-gel shows highest water production capacity that is 1.30 L/m2/day at RH ranging from 10% to 40%. The zeolite yielded water production capacity of 0.94 L/m2/day at RH ranging from 10% to 40%. On the other hand, liquid adsorbents like CaCl2 + cloth, K-LiCl showed water production capacity of 3.02 L/m2/day, and 2.9 g/g/day, respectively at RH of about 70%. Composite adsorbent modified with binary salts and functionalized carbon nanotubes resulted water production capacity of 5.60 g/g at RH of about 35%. The study will be useful to identify the energy-efficient adsorbent for the development of sustainable AWH device.

Water scarcity is a global concern that affects a large portion of the world's population. In order to provide fresh drinkable water, adsorption based atmospheric water harvesting (AWH) has become extremely important in recent years. The adsorption isotherm is significant to understand the water vapor uptake behavior of the adsorbents. A proper understanding and interpretation of adsorption isotherms are critical for overall improvement of pathways of the adsorption mechanism as well as efficient design of adsorption system. In this regard, adsorption isotherm modeling was utilized for the potential adsorbents including MOF-801, AQSOA Z01-zeolites, aluminum phosphate with LTA topology (AlPO4-LTA), and alum fumarate MOF. Langmuir, Freundlich, and Dubinin Radushkevich (D-R) isotherm models have been employed for best fit of experimental plots of adsorption isotherms for studied adsorbents. The results shows that the D-R model fit the experimental plots of adsorption isotherms of studied adsorbents as compared to Langmuir, Freundlich model.