Hello. I am doing reseacrch for a class project and I am trying to gather as much information on hvac systems as I possibly can. I have a few general questions that I need help with. One question is, " What type of hvac unit is used in a hospital??" Another question is," What is the most efficient type of hvac and how does it work?" Thanks for your time and I would appreciate some good advice. Have a happy thanksgiving.

To your first question, the question is loaded. Simple answer: Central plant

Complex answer: Various, because of the different areas with different requirements. Operating rooms, patient areas, cooking areas, common areas, entrance areas to name a few.

Most efficient HVAC. That is a loaded question too. You can always answer it as resistance heat. Electricity is almost 100% converted to electrical heat.

Most efficient is not the same as the most cost effective. Even when you use the words cost-effective it can mean different things to an institution such as a college campus or a cabin in the woods Is it cost-effective for the short term or for long-term ownership?

For residential, I'd have to say a dual fuel ground water heat pump with a variable speed blower. This system would include an ERV/HRV. See: Energy and Heat Recovery Ventilators (ERV/HRV)

This would be combined with thermal storage and renewable energy systems and good building practices.

Know anybody that's got one?

Still it may not work in Antartica or the International Space Station.

Have a compressor with a heat recovery capabitity, instead of sending most of the heat to the cooling tower it is use for heatings