اداء المبادل الحراري الارضي الاحادي المسار باستخدام موائع تشغيلية مختلفة == Peformance of A Single Pass Earth - Tube Heat Exchanger Using Different Working Fluids
Author name:
مصطفى جواد نعمة
Supervisor name:
غزوان احمد محمد | عباس خلف محمد
General topic:
Chemical Engineering
Specific topic:
Chemical Engineering
Degree:
Master
University:
University of Baghdad - College Of Engineering - Department Of Chemical Engineering
Language:
English
University location:
Baghdad
First pages:
38T316 - p.pdf
Abstract:
العديد من التقنيات استخدمت لتحسين معدل الانتقال الحراري لاختزال حجم المبادلات الحرارية وتشغيلها باقل كلفة0المبادلات الحرارية الارضية استخدمت وبشكل واسع وذلك لتحسين تقنيات التبادل الحراري في العديد من التطبيقات الصناعية0المبادل الحراري الارضي هو اداة تسمح | Several techniques have been applied to enhance heat transfer rate in order to reduce the size of heat transfer devices and also operating cost. Earth tubes have been used as one of the most widely used heat transfer enhancement techniques in several industrial applications. Earth tube heat exchanger is a device which permits transfer of heat from fluid to deeper layers of soil and vice versa.The results of the heat transfer characteristics in earth tube heat exchanger are presented. The experimental test section is made of 50 m carbon steel pipe of 19.05 mm inner diameters and 25.95 mm outer diameters. The pipe was buried 2 m deep below ground surface. Water and gasoil were used as working fluids in the experimental runs. Experiments were performed under conditions of volumetric flow rates ranging from 0.5 to 2 m3/h and inlet working fluids temperature is between 35 to 70?C at winter season and between 50 to 70?C at summer season. Working fluids temperatures were measured at five points with equal length by thermocouples placed inside the pipe. Also, soil temperatures were measured at these points by thermocouples placed 0.5 m apart from pipe. The effects of working fluid flow rate, inlet temperature, pipe length on the overall performance of the earth tube heat exchanger was investigated at winter and summer seasons, respectively.It was shown that the heat transfer rate of the working fluid increases as the pipe length and inlet temperature increase, or volumetric flow rate decreases. Furthermore, the heat transfer rate in the first half of the pipe represents (33.3 to 87.5%) from the total heat transfer rate, depending on working fluid operating conditions. Also, it was noticed that the heat transfer rate in summer days is less than in winter days. Coefficient of performance (COP) analysis was also carried out to characterize the system performance at different operating conditions. The experimental earth tube heat exchanger (ETHE) system was attained a maximum COP of 45.589 at winter tests and 17.818 at summer tests for water as working fluid. But, the maximum COP was reached only 28.52 for gasoil as working fluid at summer.
