Subcooled and saturated boiling of ammonia-lithium nitrate solution in a plate-type generator for absorption machines Articles uri icon

publication date

  • August 2012

start page

  • 4914

end page

  • 4922

issue

  • 17-18

volume

  • 55

international standard serial number (ISSN)

  • 0017-9310

electronic international standard serial number (EISSN)

  • 1879-2189

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 degrees 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 degrees 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.

keywords

  • ammonia-lithium nitrate solution ; subcooled boiling ; saturated boiling ; heat transfer ; fusion plate heat exchanger ; plate generator; absorption chillers