Measurements of heat and mass transfer coefficients during absorption of water vapor by lithium bromide and (Li,K,Na)NO sub 3 mixtures

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5199439

Zaltash, A; Ally, M R; Linkous, R L; Klatt, L N

A knowledge of heat and mass transfer coefficients in heat pump fluids, plays an important role in the design of absorption machines. Heat and mass transfer coefficients as well as subcooling are measured for absorption of water vapor in (Li, K, Na)No{sub 3} and Lithium Bromide (LiBr) mixtures.The rate of absorption of water vapor is obtained from the difference in concentration of mixtures between inlet and outlet streams across the absorber. In situ concentrations of aqueous salt mixtures over temperature ranges between 80 to 135 {degrees}C were calculated from density measurements. This technique of measurement is a reliable and convenient but not a very accurate ({plus minus}0.8 wt% salt) method of measuring the in situ salt concentration. Results show that the subcooling at the absorber exit is not only a property of the fluid, but depends strongly on the process conditions. The subcooling in LiBr mixtures without additive is shown to vary between 2.2 and 24.3 {degrees}C and the film heat transfer coefficient between 1365.2 and 801.1 W/m{sup 2}.K respectively, depending upon process conditions. These empirical results will prove to be of value to heat pump manufacturers because they have a strong bearing on costs and performance. Heat and mass transfer coefficients in aqueous salt solutions ate presented as a function of dimensionless numbers. 12 refs., 3 figs., 4 tabs.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5199439
• Report Number(s): CONF-911213-3; ON: DE91014212
• Resource Relation: Conference: American Society of Mechanical Engineers (ASME) annual winter meeting, Atlanta, GA (United States), 1-6 Dec 1991
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
HEAT TRANSFER FLUIDS
HEAT TRANSFER
MASS TRANSFER
WATER VAPOR
ABSORPTION
AQUEOUS SOLUTIONS
DENSITY
HEAT PUMPS
LITHIUM
LITHIUM BROMIDES
MIXTURES
NITROGEN OXIDES
POTASSIUM
SALTS
SODIUM
ALKALI METAL COMPOUNDS
ALKALI METALS
BROMIDES
BROMINE COMPOUNDS
CHALCOGENIDES
DISPERSIONS
ELEMENTS
ENERGY TRANSFER
FLUIDS
GASES
HALIDES
HALOGEN COMPOUNDS
LITHIUM COMPOUNDS
LITHIUM HALIDES
METALS
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SOLUTIONS
VAPORS
420400* - Engineering- Heat Transfer & Fluid Flow