Study on Improving the Performance of the Cascade Heat Pump Cycle using Ejectors

Jang, S. W.; Lee, Y. L.

doi:10.17485/ijst/2015/v8i30/73895

Cited by 1 publication

(1 citation statement)

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“…Enormous number of researches has been conducted to focus on the improvement of the COP of the Cascade heat pump by some modifications or techniques implemented to the heat pump cycle. Ejectors were used ejectors as a part of the heat pump unit arrangement circulating R134a and R404a refrigerants [1]. The numerical analysis showed that applying ejectors to both the high and low temperature cycles increase the COP by (26.9%) when compared to standard cascade cycles.…”

Section: Introductionmentioning

confidence: 99%

Perspective Performance Evaluation Technique for a Cascade Heat Pump Plant Functions at Low Temperature Heat Source

Tarrad¹

2017

IJEEE

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Abstract:The present investigation deals with the performance assessment of Cascade heat pump plants. The overall power consumption for a Cascade system for typical heat pump characteristics was studied. Four environment friendly refrigerant pairs R717/R134a, R410A/R134a, R407C/R134a, and R717/R600a were investigated at low temperature cycle (LT) evaporator and high temperature cycle (HT) condenser temperatures of (-15 to -4)°C and (70)°C respectively. A preliminary heat pump plant is suggested to produce (500) kW heat output load as hot water demand at (65)°C with (25)°C temperature lift and a proper circulation rate. The investigation was carried out at cascade heat exchanger intermediate temperature (IT) of (33)°C and (35)°C. Sea water at (7)°C was used as a sustainable low temperature heat source and (30%) ethylene glycol-water brine at temperature of (5)°C as a thermal fluid heat carrier at the LT cycle evaporator. The evaluation of the thermal performance of the refrigerant pairs was based on a fixed heat pump extraction load at the LT cycle. The heat pump heating coefficient of performance (COP) revealed an increase fell within the range of (5-7.5)% higher than that of the plant heating COP value for the studied refrigerant pairs at the whole investigated operating conditions range. The higher IT exhibited the highest heat pump and plant heating COP than those at the lower value. R717/R600a showed the highest heating COP, lower power consumption and lower global warming potential (GWP) among other investigated refrigerant pairs. The power consumed by auxiliary pumps to circulate thermal fluid heat carriers through a heat pump may account to (4-4.5)% and (2-3)% of the extracted and output heating loads respectively, higher values could be expected for real plant. Two polynomial correlations for the assessment of the pumping power in terms of the extracted and output heating loads were derived from the present work.

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Section: Introductionmentioning

confidence: 99%

Perspective Performance Evaluation Technique for a Cascade Heat Pump Plant Functions at Low Temperature Heat Source

Tarrad¹

2017

IJEEE

View full text Add to dashboard Cite

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Study on Improving the Performance of the Cascade Heat Pump Cycle using Ejectors

Cited by 1 publication

References 5 publications

Perspective Performance Evaluation Technique for a Cascade Heat Pump Plant Functions at Low Temperature Heat Source

Perspective Performance Evaluation Technique for a Cascade Heat Pump Plant Functions at Low Temperature Heat Source

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