TY - GEN

T1 - Compensation of airflow maldistribution in fin-and-tube evaporators

A1 - Kærn,Martin Ryhl

A1 - Tiedemann,Thomas

AU - Kærn,Martin Ryhl

AU - Tiedemann,Thomas

PY - 2012

Y1 - 2012

N2 - Compensation of airflow maldistribution in fin-and tube evaporators for residential air-conditioning is investigated with regards to circuitry design and control of individual channel superheats. In particularly, the interlaced and the face split circuitry designs are compared numerically using a linear velocity profile and a CFD predicted velocity profile obtained from Kærn (2011d) in dry and wet conditions. The circuitry models are validated experimentally in wet conditions, and for this purpose a test case interlaced evaporator (17.58 kW) was reconstructed in order to become a face split evaporator by modifying its U-bend connections. Furthermore, a 14% and 28% blockage of the face split evaporator is studied experimentally with control of individual channel superheats. It is shown that the face split circuitry with compensation gives the best performance in both dry and wet conditions, however with lower gains in wet conditions (around 3% in cooling capacity and 7-9% in UA-value). This performance gain in cooling capacity is below the uncertainty in standard experiments, however the gain may be revealed and/or validated by the possible area savings experimentally, i.e. in terms of overall UA-value.

AB - Compensation of airflow maldistribution in fin-and tube evaporators for residential air-conditioning is investigated with regards to circuitry design and control of individual channel superheats. In particularly, the interlaced and the face split circuitry designs are compared numerically using a linear velocity profile and a CFD predicted velocity profile obtained from Kærn (2011d) in dry and wet conditions. The circuitry models are validated experimentally in wet conditions, and for this purpose a test case interlaced evaporator (17.58 kW) was reconstructed in order to become a face split evaporator by modifying its U-bend connections. Furthermore, a 14% and 28% blockage of the face split evaporator is studied experimentally with control of individual channel superheats. It is shown that the face split circuitry with compensation gives the best performance in both dry and wet conditions, however with lower gains in wet conditions (around 3% in cooling capacity and 7-9% in UA-value). This performance gain in cooling capacity is below the uncertainty in standard experiments, however the gain may be revealed and/or validated by the possible area savings experimentally, i.e. in terms of overall UA-value.

KW - Evaporator

KW - Maldistribution

KW - Compensation

KW - Modeling

KW - Modelica

BT - Proceedings of the 14th International Refrigeration and Air Conditioning Conference

T2 - Proceedings of the 14th International Refrigeration and Air Conditioning Conference

SP - Paper 2178

ER -