Application of interleaved circuitry to improve evaporator effectiveness and COP of a packaged AC system

Abstract

Highly constrained air flow pathways as experienced in tightly packaged air conditioning systems result in air flow maldistribution problems in the evaporators. The interleaved circuitry method, where the refrigerant from a circuit with high air flow is routed to a circuit with low air flow and vice-versa, has been investigated to passively reduce the air maldistribution effect. Air velocity measurements have been conducted in psychrometric chambers and the measurement locations have been defined by the log-Tchebycheff rule. The velocity profile was obtained by Lagrange Interpolation method as percentage values. The performance of the interleaved circuitry method was compared to the baseline circuitry at different operating conditions. The results show that the interleaved circuitry method uniforms the superheat of the individual circuits and improves the cooling capacity and COP by up to 16.6% and 12.4%, respectively. Furthermore, the tuned model predicted the evaporator cooling capacity within a mean absolute error of approximately ±10%.