Simulated performance of absorption heat pumps using a mixed aqueous nitrate working fluid
A new aqueous ternary mixture consisting of 53 wt % LiNO/sub 3/, 28 wt % KNO/sub 3/, and 19 wt % NaNO/sub 3/ is available for high-temperature heat pump applications. The pressure-composition-temperature (P-X-T) and the specific enthalpy-concentration-temperature (H-X-T) data in the form of correlated polynomial expressions are used in a computer program to simulate results of a temperature amplifier heat pump with LiBrH/sub 2/O and ternary nitrateH/sub 2/O mixtures as working fluids. Although the limits of applicability of the two fluids are different, there is a region of commonality where the comparison can be made. The difficulties are lack of adequate thermophysical data on both mixtures in the temperature ranges of interest. In the absence of adequate thermophysical data, for the mixtures, the study serves as a ''best case'' first approximation. The results show that the ternary nitrate mixtures potentially have approximately a 10% advantage in COP and a 15% advantage in temperature lifts over aqueous lithium bromide mixtures at high temperatures. Ternary nitrates are hampered by crystallization at low waste heat temperatures and cannot operate competitively in the low lift and temperature boost regions. This potential performance advantage at high temperatures for the ternary nitrate mixtures is justification for additional work to obtain adequate thermodynamic transport and corrosion data.
- OSTI ID:
- 5111568
- Report Number(s):
- CONF-871234-
- Country of Publication:
- United States
- Language:
- English
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ALKALI METAL COMPOUNDS
AQUEOUS SOLUTIONS
CHEMICAL REACTIONS
COMPUTER CODES
COMPUTERIZED SIMULATION
CORROSION
CRYSTALLIZATION
DISPERSIONS
ENTHALPY
FISSION
HEAT PUMPS
HIGH TEMPERATURE
LITHIUM COMPOUNDS
LITHIUM NITRATES
MIXTURES
NITRATES
NITROGEN COMPOUNDS
NUCLEAR REACTIONS
OXYGEN COMPOUNDS
PERFORMANCE TESTING
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
POTASSIUM NITRATES
SIMULATION
SODIUM COMPOUNDS
SODIUM NITRATES
SOLUTIONS
TECHNOLOGY ASSESSMENT
TERNARY FISSION
TESTING
THERMODYNAMIC PROPERTIES
THERMODYNAMICS