Logic unconstrained multi-zone evaporator and condenser models

The multi-zone model is widely used in evaporator and condenser modeling. The basic two-zone evaporator model and three-zone condenser model might reduce to one-zone or two-zone model depending on the operating conditions. In the traditional multi-zone models, logic constraints are invoked to separate the possible running modes and trigger mode changes from one to another, which will lead to the complicated logic in implementation. A logic unconstrained multi-zone model has been developed in this paper. In the new model, all the logic constraints are transformed into continuously differentiable equations. As a result, all the equations can be solved simultaneously without any logic constraints. Numerical examples show that the new logic unconstrained multi-zone models are in good agreement with the traditional ones.