Experimental and numerical investigaton of thermal and fluid flow process in biomass generator of absorption heat pump

[M. N. Ilić]

IV, [183] list.

Biografija autora: [183] list Bibliografija: list. 159-164

Thermodynamics, Heat and Mass transfer

In this doctoral dissertation, an experimental and numerical investigation of thermo-fluid processes in a hot air generator (GVV) within the absorption heat pump (AHP) system has been conducted. The working medium in this system is a mixture of ammonia and water. In the first phase, the substitution of gaseous fuel with solid fuel (biomass pellets) was successfully carried out, and modifications were made to the heat pump to connect it to the GVV. The goal was to optimize the geometry of the pellet stove combustion chamber, with significant assistance from companies (Megal and "AirCool") that produced and donated the stove. The stove was adapted into the GVV for AHP purposes. Inside the generator, a finned heat exchanger was added to enhance the heat exchange process. The experimental research was conducted in the Laboratory for Thermotechni cast the Fauclty of Mechaniacl Engineering in Niš. Multiple different operating modes were investigated in the experimental part. The GVV exhibits complex turbulent flow, with combustion products flowing through the heat exchanger tubes in three passes. Air flows around both finned and nonfinned heat exchanger tube bundles, getting heated to the required temperatures for the operation of the heat pump absorber. Measurements included fluid flows, temperatures of working fluids at the inlet and outlet of the system, as well as temperatures at defined locations within the generator. A mathematical model of heat and mass exchange was established, vital for conducting the numerical experiment in this work. Model validation was performed by comparing measured and calculated thermo-fluid quantities at selected locations in the GVV. Abstract: Considering the good agreement between experimental and numerical results, the model can be utilized for numerical simulations in similar heat exchange scenarios. In the numerical research section, software packages ANSYS and CFX were used. Towards the end of the study, thermal characteristics of the AHP system were determined, primarily focusing on exchanged heat fluxes and heating and cooling coefficients. These characteristics were analyzed in relation to the temperature of hot air entering the desorber of the AHP.

apsorpcione toplotne pumpe, generator, 3D simulacije, biomasa-pelet, obnovljivi izvori energije, poligeneracija, eksperimentalno istraživanje

Absorption heat pump, Generator, 3D Simulations, Biomass-pellet, Renewable energy sources, Polygeneration, Experimental investigation

536.242:[621.577:662.639(043.3)

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