The Silos

[Plutonic Panda]

I don’t know much about A/C units. What the alternative? One massive unit to supply air to all apartments?

[Pete]

I don’t know much about A/C units. What the alternative? One massive unit to supply air to all apartments?

Yes, just like in most office buildings.

Multiple units but one unit can cover tons of area if large enough.


I think this is Rover's business. Maybe he'll chime in.

[cinnamonjock]

But that wouldn't explain hotels.

There has to be a significant advantage up front.

My guess is with hotels its so that if one unit malfunctions, that's only one room that can't be let, whereas if it was a whole building unit, the entire place is out of service until it is fixed.

[Rover]

My guess is with hotels its so that if one unit malfunctions, that's only one room that can't be let, whereas if it was a whole building unit, the entire place is out of service until it is fixed.

There are a myriad of systems that can be used. Usually, packaged terminal units (through the wall (either vertical or horizontal) is a cheap system. A building with lots of the same unit can operate without a building engineer or any central system redundancies. If one goes out you likely have spare ones or can get an off the shelf one at any number of distributors. Any unskilled laborer can change them out. However, it is no where near the BEST system for an upscale hotel. As we always said, if it has PTACs its a motel, and if a central system a hotel. PTACs are louder (inside and out), provide inferior humidity control, and provide less comfort control. They can also enable moisture intrusion in the building. It is a lazy engineer's system. I am frankly surprised that this development's hotel has one.

By the way, the use of PTACs eliminates "diversity". That means you end up installing more tons of cooling than you need. Operationally, they can be fools gold.

Premium hotel systems are generally 4 pipe chilled/hot water central systems with fan coils for the guest rooms. Optimum comfort control with minimum controlls necessary. Large meeting rooms, common areas, make-up ventillation air, etc. can be serviced with other systems like standard rooftop air conditioner/heat pumps.

Depending on the size of the hotel, it is possible to use other systems like closed loop heat pumps, variable refrigeration volume systems, two pipe chilled water with electric heat, floor by floor heat pums, etc. Building size, use, climate zone, orientation, etc. are all conditional factors.

As for the apartments, split residential units are commonly used for many of the same reasons the packaded terminal units are. They are plentiful, relatively cheap, can be worked on by practically anyone, AND can be metered separately for billing. VRV systems can be used, which give superior room by room comfort with more zoning and possible diversity within a zone (some areas needing cooling while others need heat).

A good engineering firm suggests the appropriate alternatives and budgets to the developer but the developer decides based on cost, maintenance cost, life of equipment, etc. it isn't always what is best for the resident/guest.

By the way, premium systems tend to go into hotels where the owner is long term and their market is return visitors. If they are short term develop and flip, they tend to buy cheaper systems and let the next owner deal with the longer term costs, including loss of guests. If they are limited service hotels with business travelers who may or may not have a need to return then they tend to go cheap with packaged terminal units.

Some influence is in where they are. Packaged terminal units with 100's of condenser fans running is much louder in urban areas where sound is bouncing off other buildings and is discouraged more than suburban areas where the sound isn't as contained and less noticable.

Finally, packaged units have a negative aesthetic with tons of grilles on the outside wall. Cheaper units can also leak condensate and stain exterior walls. Condensate removeal systems can be added,at an expense some are not willing to experience.