Abstract: A thin refrigeration air conditioner has a casing which houses a thin heat exchanger, an air intake chamber, an air exit chamber, a side chamber and an air port baffle. The thin heat exchanger in cooperative with the air port baffle or a return air branch port can control airflow to maintain a high temperature difference and low flow rate operation while the air and refrigerant flow through the thin heat exchanger to perform heat exchange process. Return airflow and airflow delivery can be maintained in an optimal temperature difference condition according to energy requirement of the air conditioning zone. Thus it can provide a most comfortable condition and also save energy. It also takes less installation space and improves airflow distribution.