Energy and exergy analysis of the transient performance of a qanat-source heat pump using TRNSYS-MATLAB co-simulator

2022 ◽  
pp. 0958305X2110681
Author(s):  
Maryam Karami ◽  
Hajar Abdshahi
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Flow Rate ◽  
Exergy Analysis ◽  
Coefficient Of Performance ◽  
Helical Coil ◽  
Transient Performance ◽  
Air Source Heat Pump ◽  
Coil Heat Exchanger ◽  
Coil Heat

In this study, the transient performance of a qanat source heat pump is investigated using a TRNSYS-MATLAB co-simulator. The water/ethylene glycol-to-air compression heat pump and the helical coil heat exchanger, which is used to inject heat to or to extract heat from the qanat water, are mathematically modeled in matrix laboratory (MATLAB), and then, coupled to transient systems simulation (TRNSYS) model to evaluate the system transient performance and calculate the heating and cooling loads of the case study building. Comparison of the performance of the qanat source heat pump with an air source heat pump showed that the coefficient of performance of the qanat source heat pump is at least 5% and at most 34% higher than that of the air source heat pump. By increasing the flow rate of the working fluid in the helical coil heat exchanger from 2 L/min to 8 L/min, the coefficient of performance of the qanat source heat pump increases at least 12% and at most 34.1%. The maximum increase in energy efficiency ratio and free energy ratio of the system by the similar increase in the flow rate is 46.4% and 24.8%, respectively. The exergy analysis of the qanat source heat pump reveals that the minimum and maximum exergy efficiency of the system is 32% and 85.5%, respectively. The findings also indicate that the most exergy destruction occurs in the condenser in heating mode and in the evaporator in cooling mode.

scholarly journals Experimental Research on Heat Transfer Characteristics of Helical Coil Heat Exchanger with Varying Pitch for laminar Fluid Flow

2019 ◽  
Vol 8 (3) ◽  
pp. 315-320
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Flow Rate ◽  
Transfer Rate ◽  
Helical Coil ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Coil Heat Exchanger ◽  
Coil Heat

To Study on rate of heat transfer in heat exchanger using helical coils has been studied by many researchers. There is less published literature available on varying pitch helical coil heat exchanger and detail characteristics of helical coil varying pitch by keeping constant curvature ratio considering heat exchange between fluid to fluid heat exchanger for laminar flow condition not available in the present available literature. Hence in present study three different coils with varying pitches are used to investigate the heat transfer characteristics of a Helical Coil Heat Exchanger. Hence coil of 25mm, 30mm, 35mm are used by keeping constant curvature ratio (=0.0667), experiment is conducted to study the influence of varying pitch on effectiveness, heat transfer rate, over all heat transfer co-efficient and Nusselt Number. The experiments is conducted in horizontal counter steady flow condition and changing the flow rate of hot fluid, pitch of helical coil heat exchanger. The results show that the varying pitch of helical coil heat exchanger has influence on heat transfer characteristics. The effectiveness of the helical coil heat exchanger is decreases with increase in mass flow rate of the hot fluid inside helical tube for varying pitch considered for study. The heat transfer rate of the helical coil heat exchanger is increases with increase in Dean Number of the hot fluid inside helical tube for varying pitch considered for study. The overall heat transfer coefficient increases with increasing hot water mass flow rate. The Nussult Number at different dean number increases for increasing helical coil pitch however the trend of average heat transfer rate for increasing M Number for varying pitch observed similar. By increasing the coil pitch of helical coil heat exchanger decreases Nussult Number, inside overall heat transfer coefficient, heat transfer rate and effectiveness.

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