Mixed Use?

[larrytecher]

I have a couple of questions about designing HVAC systems for mixed use buildings...

When working on a mixed use project:

a) what kinds of HVAC systems are possible for apartments if rooftop cooling towers/units are not wanted? (I'm an architecture student, so I want to know what types of systems I can work with if I want to do something different with the roof structure)

b) each use requires its own HVAC system, correct? For example, if a building has restaurants on the lower floors, commercial offices above, and apartments on top, then 2-3 HVAC systems are required?

Thanks.

[fruecrue]

The possibilities are endless as far as dividing your systems. Unless you want air cooled condensers on the ground or on the roof, you will need another medium to serve your heat rejection needs. Geo-thermal heat rejection may be an option. Eliminating toweres is a real trip up point, maybe some creative relocating would suit your project better, if rooftop space is at a premium.

[Crazy4thenucks]

You might want to look at a variable refrigerant flow system, such as the LG MultiV, or similiar units...The units are not as large as a cooling tower, and you would be able to "hide" them on a roof with a little creative thinking.

[mrllyonsden]

I would reccomend the Geothermal system, nothing outide of the building except for the wells. You could then have seperate systems for each application, heatpumps, one main air handler with a vav reheat system, many possibilities, where I work we specalize in these type of systems. Someting to consider.

[Tech Rob]

Geothermal was the first thing that came to my mind, although it's not necessarily the only option. Some larger buildings in heavily developed metro areas use some form of river water and large heat exchangers for the condenser loop, as well.

[flip2cho]

You might want to look at a variable refrigerant flow system, such as the LG MultiV, or similiar units...The units are not as large as a cooling tower, and you would be able to "hide" them on a roof with a little creative thinking.

When new designs for buildings are made a lot of people are going with what they call the "Chiller Killer"
Variable refrigerant flow systems. They are popular because the are extremely efficient, they have the technology to heat one room using refrigerant (heatpump) while cooling another at the same time. Another benefit building designers are liking is the added space to to building when you take out the room needed for ducts and AHU mechanical rooms. More space means more revenue for the building owner.
For a maintenance standpoint, line sets and leaks throughout the whole building would be a headache. For a benefit side, if a repair or maintenance needs to be performed the whole system does not need to be shutdown and the whole building does not suffer. Like a lot of the newer scroll chillers this style unit works off banks of scrolls that can be shut down and isolated if repair work needs to be done.