Abstract
This paper presents the experimental heat transfer evaluation during subcooled and saturated boiling of ammonia-lithium nitrate solution in a fusion plate heat exchanger, acting as a vapor generator under operating conditions representative of single-effect absorption machines. The solution flow rate and outlet temperature were modified in the ranges of 0.041-0.083 kg/s and 78-97 °C, respectively. The region where vapor bubbles begin to arise is estimated using a correlation for the wall superheat required for the onset of nucleate boiling. Results show that subcooled boiling is present in the generator. The initial boiling temperature is about 3.1 °C lower than the saturation temperature. The influence of the heat and mass fluxes on the boiling heat transfer coefficient is analyzed. The paper offers a correlation for the Nusselt number, including the subcooled and saturated boiling regions.
Original language | English |
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Pages (from-to) | 4914-4922 |
Number of pages | 9 |
Journal | International Journal of Heat and Mass Transfer |
Volume | 55 |
Issue number | 17-18 |
DOIs | |
State | Published - Aug 2012 |
Keywords
- Absorption chillers
- Ammonia-lithium nitrate solution
- Fusion plate heat exchanger
- Heat transfer
- Plate generator
- Saturated boiling
- Subcooled boiling