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Open-cycle absorption solar cooling: Natural convection heat and mass transfer from falling films in vertical channels. Final report

Technical Report ·
OSTI ID:10179247
In the design of solar collector/regenerators for use in open cycle absorption refrigeration (OCAR) units, the problem of predicting evaporation mtes and solution temperatures is of paramount importance in determining overall cycle performance. The governing equations for natural convection flow in a vertical channel bounded by a heated falling film (simulating a glazed collector/regenerator) were solved using several different finite difference techniques. The numerical results were validated against existing experimental and numerical results for simplified boundary conditions. The appropriate nondimensionalization for the falling film boundary condition was established, ostensibly for the first time, and a parametric study for an air-water vapor mixture has been presented. Curve fits to the numerical results were determined for engineering design applications. To further confirm the validity of the numerical solutions, an experimental apparatus was constructed using electric resistance heat to simulate the constant heat flux of the solar source. Water was introduced at the top of this heated vertical surface at various flow rates and under various supplied heat fluxes, and a natural convection channel flow generated between the heated falling film and a parallel, plexiglas surface. Film temperatures and moist air velocity profiles were measured at various streamwise (vertical) locations for comparison with the numerical results.
Research Organization:
Arizona State Univ., Tempe, AZ (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
FG03-86SF16345
OSTI ID:
10179247
Report Number(s):
DOE/SF/16345--5; ON: DE92040999
Country of Publication:
United States
Language:
English