Utilization of waste heat in compressed air production
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Journal Title
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Volume Title
Insinööritieteiden korkeakoulu |
Master's thesis
Authors
Date
2022-06-13
Department
Major/Subject
Mcode
Degree programme
Master's Programme in Mechanical Engineering (MEC)
Language
en
Pages
56
Series
Abstract
Compressed air is widely used in various industries. Compressed air production is estimated to contribute about 8–14% of industrial overall electrical energy consumption. The European Commission has set a target for 2030 to reduce primary energy consumption by 39% and final energy consumption by 36% compared to 2020. Compressed air production is known to be inefficient and expensive. On the other hand, industry is releasing large amount of low temperature waste heat to wastewater and ventilation. In this research, utilization of waste heat in the production of compressed air was investigated. The waste heat compressor system was created with Matlab Simscape software in a physical multidomain environment combining hydraulic, gas, mechanical and thermodynamic components. In addition, test equipment was designed based on the equipment of the previous project to verify the results and validate the design. In the simulation, the difference between the work done and obtained by hydraulic work was studied. Compression and expansion cycles with different durations were simulated to determine the optimal cycle time. During short compression and expansion cycles, a hydraulic fluid flow of 180 L/min was generated. The maximum expansion volume of the gas was 35 L. By changing the cycle time, the amounts of work required for compression ranged from 24 to 26 kilojoules. The result was hydraulic work on the compression and expansion cycles and included hydraulic losses of about 5%. The coefficient of performance was obtained from all simulations and ranged from 1.55 to 1.8. The waste heat compressor produced more work than was used for it. Compared to adsorption heat pumps with a coefficient of performance between 1.5 to 1.8, a thermal compressor with 1.5-5 or a mechanical heat pump with 2.5-7.5, the results were good.Description
Supervisor
Kuosmanen, PetriThesis advisor
Kajaste, JyrkiCalonius, Olof
Keywords
compressed air, simulation, waste heat compressor, nanoporous materials