Distributed dynamic modelling of a refrigerated room
Abstract The prediction of velocity and temperature distributions in a refrigerated room generally requires the simultaneous solution of the equations governing the flow pattern (Navier-Stokes equations) and the energy equation. Basically these are interacting non-linear differential equations requiring simultaneous integration by an iteration process. The specific application of advanced computer packages for this purpose in refrigeration is still in the early stages; even for one steady-state simulation the computation times are high because of the very complicated shape of the air space in a refrigerated room loaded with produce. The method of simultaneous integration becomes unattractive, especially for non-steady-state thermal conditions, if many runs are to be made with different values of the input parameters. In instances where the air cooler fans dominate the flow pattern, the equations can be decoupled. Moreover, the energy equation can be linearized with reasonable model assumptions, and will then not require an iteration process for integration. The simulation described here includes a compression refrigerating machine with capacity control, and was validated by measurements taken from a laboratory-scale cold store.