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The most common refrigeration system is the vapor compression refrigeration (VCR) system for a household refrigerator. The challenges for researchers are to minimize the power consumption of the compressor to improve the performance of the refrigeration system. This study aimed to assess and compare the energy and exergy analysis of VCR systems using multi-walled carbon nanotubes (MWCNT) and graphene nanosheets (GN) based hybrid nano-lubricants. The mass concentrations of each nanoparticle 0.3 g/L, 0.5 g/L, 0.7 g/L, and 0.9 g/L are mixed with 250 ml of polyolester oil (POE) separately and charged with 200 g of R134a refrigerant. Furthermore, the MWCNT and GN nanoparticles are mixed in a 50:50 proportion to prepare the same concentration of hybrid nanoparticles. The properties of refrigerants are obtained with the help of REFPROP 9.1 software. The pull-down time, compressor power, pressure ratio, exergy loss, relative irreversibility (RI), and second law efficiency (SLE) are variables that have been examined. The mass concentration of 0.7 g/L of hybrid nano-lubricants (GN-MWCNT /POE) is found to be optimal. It is noted that the pull-down time, power consumption, and pressure ratio of the refrigerator are lowered by 9.01%, 16.09%, and 5.68% respectively when compared to the pure refrigerant, whereas the actual COP and SLE improved by 11.29% and 8.22% at 0.7 g/L hybrid nano-lubricants. In addition, exergy loss and relative irreversibility are decreased for hybrid nano-lubricants. [ABSTRACT FROM AUTHOR]

Thermal comfort and energy savings are the important aspects of air distribution in a conditioned space. In conventional methods of air distribution, the supply air is used to provide a uniformly mixed thermal environment in the room. The conditioned air is supplied from the ceiling through ducts and the air is returned back from the ceiling itself. An alternative to this arrangement is the supply of air from floor-based diffusers and the returning air is extracted through the ceiling. In this arrangement the air is required to be supplied at the same or slightly less temperature than the temperature required for the comfort within the occupied space. The supply air mixes with the room air and produces a non-uniform thermal environment in the room. A two-layered stratification is thus produced and energy can be saved by conditioning of the occupied space only. The objective of this paper is to present the concept of this air induction technology. The turbulent plume and fountain theory is used for the conceptual model. By this method, energy can be saved in addition to increased human comfort. [ABSTRACT FROM AUTHOR]

The comparative thermal analysis of theoretical and experimental studies of modified indirect evaporative cooler having cross flow heat exchanger with one fluid mixed and the other unmixed is presented in this research paper. A heat and mass transfer mathematical model is developed to simulate the properties of indirect evaporative cooler. The theoretical result analysis was done by plotting the curves between various performance parameters. This work presents the fabrication and experiments carried out on the indirect evaporative cooler at various outdoor air conditions. The data acquired by experiment were analyzed by plotting the curves between various performance parameters. The theoretical and experimental results were compared and analyzed. The theoretical model can be used to predict the performance of modified indirect evaporative cooler. [ABSTRACT FROM AUTHOR]

All biotic species, including humans, requires energy for their survival and obtained from the process of metabolism. Present work deals with the thermodynamic analysis of the metabolic process of humans and establishes the relation for entropy generation. Further, this entropy generation is linked with the thermodynamics life cycle assessment of humans. Data used in this work is provided by the National sample survey office (NSSO), Government of India. Entropy generation is determined on the bases of per kg of carbohydrate, palmitic acid and 20 amino acids. Finally, the life span of humans has been determined on the grounds of the entropy generation. Entropy generated by Haryana people is maximum in all states, and Tamilnadu people have the minimum among all the states. Total entropy production for Haryana is 23.59 kJ/K-kg-food and for Tamilnadu 19.71 kJ/K-kg-food. People living in Haryana has a life span of 66 years, and Tamilnadu people have a life span of 79 years. The life span for other states ranging in 66-79 years. Variation of ±3% is recorded in the life span of people when compared with the NITI Aayog report. There is a minor difference of 1.22 years in case of life expectancy of Kerla when compared to the NITI Aayog report. In current research work effect of water and air, inhalation is not considered. So one can think these parameters and analyze the variation of the result., (© 2020 The Author(s).)