Design of ammonia-water condenser with a fluted tube

Yong Tae Kang, Weibo Chen, Richard N. Christensen

Research output: Chapter in Book/Report/Conference proceedingChapter

10 Citations (Scopus)

Abstract

This paper develops a design model of an ammonia-water condenser in absorption heat pump systems. An ammonia-water mixture enters the condenser through a helically coiled fluted tube as a superheated vapor, cools, and then condenses into a liquid, which is further subcooled. The hydronic fluid flows in the annular channel around the coiled tube in confined cross-flow. The helically coiled fluted tube was used to enhance heat and mass transfer in the mixture and heat transfer in the hydronic side. The ammonia-water condenser was divided into four different regions according to the characteristics of the heat transfer mechanism-superheated vapor, rectification, condensation, and subcooled liquid regions. This paper studies the effects of heat transfer coefficients in each region, the inlet concentration of vapor, and the geometric details of the fluted tube on the heat exchanger size. The design results show that the molar concentration of ammonia in rectifying vapor is between bulk vapor concentration and liquid concentration, i.e., x 1<z<x vb, and that the molar concentration should be calculated by combined heat and mass transfer analysis. The heat transfer rate per unit length in the rectification region was the highest due to the effect of mass transfer. As the inlet concentration of ammonia in the vapor decreases, the length of the condenser decreases. The heat transfer coefficient in coolant flow, h c, has the dominant effect on the condenser size, while h v has the most significant effect on the rectifier size. It also was found that the condenser size decreases with increasing D bi, decreasing D eo, D c, N s, and pitch of the fluted tube.

Original languageEnglish
Title of host publicationASHRAE Transactions
PublisherASHRAE
Pages587-595
Number of pages9
Volume102
Edition2
Publication statusPublished - 1996
Externally publishedYes

Fingerprint

Ammonia
Vapors
Water
Heat transfer
Mass transfer
Heat transfer coefficients
Liquids
Condensers (liquefiers)
Heat pump systems
Coolants
Heat exchangers
Flow of fluids
Condensation

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

Cite this

Kang, Y. T., Chen, W., & Christensen, R. N. (1996). Design of ammonia-water condenser with a fluted tube. In ASHRAE Transactions (2 ed., Vol. 102, pp. 587-595). ASHRAE.

Design of ammonia-water condenser with a fluted tube. / Kang, Yong Tae; Chen, Weibo; Christensen, Richard N.

ASHRAE Transactions. Vol. 102 2. ed. ASHRAE, 1996. p. 587-595.

Research output: Chapter in Book/Report/Conference proceedingChapter

Kang, YT, Chen, W & Christensen, RN 1996, Design of ammonia-water condenser with a fluted tube. in ASHRAE Transactions. 2 edn, vol. 102, ASHRAE, pp. 587-595.
Kang YT, Chen W, Christensen RN. Design of ammonia-water condenser with a fluted tube. In ASHRAE Transactions. 2 ed. Vol. 102. ASHRAE. 1996. p. 587-595
Kang, Yong Tae ; Chen, Weibo ; Christensen, Richard N. / Design of ammonia-water condenser with a fluted tube. ASHRAE Transactions. Vol. 102 2. ed. ASHRAE, 1996. pp. 587-595
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