Which of the following best describes the heating and cooling capabilities of a two pipe system?

The best description of the heating and cooling capabilities of a two-pipe system is sequential heating and cooling. In a two-pipe system, there are two pipes: one for supplying hot water for heating and another for returning it, while the other handles chilled water for cooling in a similar fashion. However, due to the design of the system, it cannot provide both heating and cooling simultaneously. Instead, it operates in a sequential manner, where the system is either switched to provide heating or cooling, but not both at the same time. This is a fundamental characteristic of two-pipe systems, differentiating them from four-pipe systems that can deliver both heating and cooling simultaneously. Understanding this distinction is key in HVAC design and operation when determining which system best suits a building's climate control needs.