Quasi-steady modeling of data center heat exchanger under dynamic conditions

The transient modeling of cross flow heat exchangers requires the use of complicated analytical solutions or complex numerical schemes to solve the set of coupled partial differential equations representing the air, coolant and wall temperatures. Since most of the dynamic mass flow or temperature perturbations encountered in data center environment are slow compared with the timescale of the heat exchanger, using a simpler quasi-steady model instead of a complex transient solution represents a good alternative. The present work shows the use of a quasi-steady heat exchanger model to recreate the transient response of a 12×12 in heat exchanger core under ramp and sinusoidal perturbations. A criteria to identify the regimes where the quasi-steady model is valid is developed. Finally the model is used to model a rear door heat exchanger and the results compared with experimental results.