کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
7044842 1457087 2018 36 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Heat transfer characteristics of an expanded graphite/paraffin PCM-heat exchanger used in an instantaneous heat pump water heater
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Heat transfer characteristics of an expanded graphite/paraffin PCM-heat exchanger used in an instantaneous heat pump water heater
چکیده انگلیسی
This study proposed to experimentally investigate the feasibility of an expanded-graphite paraffin phase change material (PCM) heat exchanger operating as a condenser in an instant air source heat pump water heater (ASHPWH). To improve the thermal conductivity of the PCM, a mold was first designed to manufacture the PCM-heat exchanger, and then the temperature distribution and volume expansion of an expanded graphite paraffin heat exchanger (EGPHE) were investigated and tested under different inlet water flow rates. The experimental results showed that the volume expansion rate of a 16 L EGPHE was 6.25% at 76 °C. The hot water discharge differences between the EGPHE and a traditional water tank were compared in detail. At an inlet flow rate of 0.5 L/min, the hot water volume increment rate was 83.12% and 194% for supplied water temperatures of 45 °C and 40 °C, respectively. When the inlet flow rate increased, the hot water volume increment rate decreased. Thus, EGPHE applied in ASHPWH can significantly reduce traditional water tank volume. However, in the PCM heat charging/discharging process, nonuniform temperature distributions played an important role in the heat exchanger efficiency. During the heat discharging process, the exergy efficiency and the heat transfer rate of EGPHE were also analyzed using experimental data. The EGPHE efficiency could be improved by minimizing the destroyed exergy.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Thermal Engineering - Volume 142, September 2018, Pages 644-655
نویسندگان
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