A transient numerical model for sensible fixed-bed regenerator in HVAC applications

Abstract Fixed-bed regenerators (FBRs) are energy recovery exchangers that can significantly reduce the energy required to condition outdoor ventilation air in HVAC systems. FBRs have high sensible effectiveness but produce an outlet air temperature that varies with time. In this paper, a numerical model is developed to evaluate the performance of FBRs, and more specifically, the transient nature of their operation. This transient nature poses difficulties for experimental testing; thus, the developed model consists of an exchanger (FBR) model and a sensor model to differentiate the actual exchanger performance from the performance that would be measured in an experiment. The developed numerical model is validated with experimental data and correlations from the literature. The numerical model is capable of capturing the transient behavior of FBRs and temperature sensors to accurately predict the measurement errors that can occur due to the transient response characteristics of FBRs and sensors at different operating conditions in HVAC applications.