کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
789226 1466396 2016 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Combined effects of fluid selection and flow condensation on ejector operation in an ejector-based chiller
ترجمه فارسی عنوان
اثرات ترکیبی انتخاب سیال و تراکم جریان در عملیات انژکتور در یک چیلر مبتنی بر انژکتور
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی مکانیک
چکیده انگلیسی


• Ejector-based chiller with R134a and R245fa demonstrates COPs between 0.1 and 0.2.
• COP increase >12%, >14 K driving temperature decrease with shift in ejector operation.
• One-dimensional analytical models of flow in motive nozzle developed to predict two-phase flow.
• COP depends on wet or dry working fluids and magnitude of detrimental two-phase flow effects.
• Best COP when motive nozzle inlet condition slightly inside the saturation dome.

This work investigates the optimization of the coefficient of performance of an ejector-based chiller through changes in the two-phase flow characteristics inside the ejector using wet R134a and dry R245fa fluids. Reducing the superheat at the motive nozzle inlet results in a 12–13% increase in COP with a 14–16 K drop in driving waste heat temperature. The roles of momentum transfer, heat transfer, and two-phase flow on performance are delineated. The change in COP appears to be a combination of the choice of fluid and the effect of phase change on momentum transfer effectiveness. Larger degrees of condensation reduce momentum transfer effectiveness; however, energy savings from reduced motive superheating compensates for the effect of condensation, and causes a net increase in COP. It is recommended that ejector-based chillers be operated such that the motive nozzle inlet is near saturation, and dry fluids like R245fa are used to improve performance.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Refrigeration - Volume 69, September 2016, Pages 1–16
نویسندگان
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