This paper reports on the development of a transient mathematical model of an MEAC system and a
simulation study on a novel control strategy to improved indoor humidity control, using the model
developed. When carrying out the simulation study on developing the control strategy for improved
indoor humidity, a previously developed control strategy for a SEAC system for improved humidity
control, High-Low (H-L) speed control [7], is applied, for determining the speeds of the compressor and
indoor air fans. However, in this paper, the H-L control strategy to an SEAC system is presented. Since
the study on applying the strategy to a DEAC system is underway and will be reported in future.
Since an MEAC system can have any number of evaporators, a dual-evaporator air conditioning
(DEAC) system, using R22 as refrigerant, is used here as a typical example for modeling and controller
development. A schematic diagram of the DEAC is shown in Fig. 1.