There have not been major design changes in rooftop units for a while. Most have been around refrigerant changes, scroll compressors, VFD’s for fan control, and economizers. However, we are seeing more and more variable refrigerant flow split units being installed now.
Design / Replacement considerations & trends.
Capacity controlled Compressors and with VFD control compressors and high efficiency condenser
Chillers should be engineered for optimum performance and serviceability, over-sizing is not necessarily a wise choice. For any current performance or future sizing, whether for process cooling or building comfort.