Forced air heat may not be the best means to keep your medical facility warm. Such systems can collect dust and allergens, grow mold and recirculate germs. In fact, Legionnaire's Disease often grows in cooling towers (air conditioning units for large buildings). This means that your hospital air conditioning system can incubate and spread a very serious infection. This is not a good means to take care of the health of your patients or staff, so you can make plans now to use passive solar for your medical facility construction.
Passive solar design elements can help keep a building at a comfortable temperature with fewer inherent dangers. It is a methodology that relies upon warmth from the sun, thermal mass and various design tricks to keep the physical structure itself at a comfortable temperature, thereby reducing the need to try to manipulate the internal air temperature directly. If the building itself is neither too hot nor too cold, the air is much less likely to be uncomfortably warm or cold.
As a bonus, passive solar design typically results in lower bills. There is less need to burn energy when the building simply stays a comfortable temperature because of good design, without being constantly fed new inputs to warm or cool it. Plus, passive solar design tends to result in a fundamentally more comfortable space.