Installing a Compressor on the roof

[nonepepsi]

Hi,

I have a 5 story building. The ground floor is a 1,400 sq ft restraunt and is looking to install a new air conditioning system and putting a compressor onto the roof.

Should I be concerned with how loud the compressor will be? Could the weight of the compressor damage the roof? How big is a compressor (5 ton unit or even a 10 ton)? How big will the piping be needed for the compressor?

Are there 5 ton compressors of different sizes and loudness?

Please advice if we should move foward or not

Thanks.

Josh

[Twoholing]

Please advice if we should move foward or not

Thanks.

Josh
the only person that can tell you if you should move forward or not is a qualified service company that goes out and looks at your building.

[miller-cold-filtered]

get a pro or 2

one thing for sure, not going to cheap.

good luck

[nonepepsi]

Thank you both for your advice. However, I believe I have explained my situation fully.

I will not be buying, installing, or using the Air Conditioner. The restraunt in the Ground floor will be doing that. He has simply asked permission to install the compressor for the AC on the roof of our building.

My concerns are whether or not having a compressor on my roof will affect the top floor.

The simple questions:

How much does a compressor (5 or 10 ton) usually weigh?
How big is a compressor (5 or 10 ton)?
How noisy is a compressor? Will people on the floor below be affected by the noise?

Are these reasonable concerns for a building owner, or is having a 5-10 ton compressor on the roof very standard and I should not be worried?

[ReferTroop]

Will definatly need to take into account oil entrainment concerns, if properly installed there shouldn't be a noise concideration. The weight of a 5 ton just as a wild guess will be around 200 lbs. Vibration absorbers and P-traps will address those concerns. Myself I would look for a better location due the oil...

JS

[freonguy]

Nonepepsi:

I hope you can appreciate why the established members of this forum are a bit touchy about giving out info; I watched this thread since last week - and no, you have not explained the situation fully. I will add a few facts and some questions for you to ask a pro or 2 or 3 who can come to your site and look at the big picture.

1) The equipment that goes outside ( or in your case, perhaps on the roof ) is called a condensing unit and contains the compressor and condenser,

2) The unit is rated in '' tons '' of capacity, and one ton = 12,000 btu/hr.,

3) A 5 ton condensing unit would weigh about 300 - 400 pounds and must be installed correctly so it does not sink into the roof,

4) As for noise, the new equipment can be very quiet if installed properly; that being said, someone who is reputable and can communicate effectively with both the restaurant owner and the building owner has to look at the big picture.

Questions -

A) Why does the condensing unit have to be on the roof? Where is the rest of the heating and ventilating equipment for the kitchen presently? In my opinion, putting a condensing unit 50 + feet higher than the evaporator is asking for trouble ( oil return for one ).

B) Is the so called 5 ton unit the right size for the application - has a proper heat load calculation been done ( to account for equipment and building load )?

C) Does the roof have the capacity to have a 400 pound load sitting on it? Will there be proper curbs installed ? Does an engineer have to be consulted?

If you aren't paying for this, make sure there is something in writing to answer your concerns - a reputable company can give peace of mind. These are just a start to the questions that need to be asked - Good Luck!

[nonepepsi]

Freonguy,

Thanks so much for your thorough answer...(I meant to say i have not fully explained the situation - i forgot the 'not' in my statement)

The restaurant owner does not want to install window units as they are ugly and he claims ineffective. He had a basement condensing unit, with a grill in the sidewalk, but he claimed that the unit did not get enough oxygen. As this is a manhattan building, there is no land around the building to put the unit. Thus, he is claiming that the roof is the only logical place that the compressor can go. Is this true?

I attempted to do the heat calculations, but the grills of the kitchen are beyond my knowledge. Nonetheless, the restaurant owner claims that a 5 or even a 10 ton compressor unit is a must (lets go with 10 ton). I do not know how the restaurant owner picked out this unit, but I assumed he is basing it upon the previous units he had installed in windows and in the basement.

I do not know whether or not the roof can hold 400 pounds. The restaurant owner claims it will not be a problem, but I am suspect of the situation. He has agreed to put the unit on I-Beams if necessary.

As you state, I must make sure my concerns are listed in writing. I feel my concerns must be listed as following:

A) The compressor unit must stay below ___db.

B) The compressor unit will not sink or damge the roof.

are their any other concerns I should have as the building owner?

Thanks.

Josh



Nonepepsi:

I hope you can appreciate why the established members of this forum are a bit touchy about giving out info; I watched this thread since last week - and no, you have not explained the situation fully. I will add a few facts and some questions for you to ask a pro or 2 or 3 who can come to your site and look at the big picture.

1) The equipment that goes outside ( or in your case, perhaps on the roof ) is called a condensing unit and contains the compressor and condenser,

2) The unit is rated in '' tons '' of capacity, and one ton = 12,000 btu/hr.,

3) A 5 ton condensing unit would weigh about 300 - 400 pounds and must be installed correctly so it does not sink into the roof,

4) As for noise, the new equipment can be very quiet if installed properly; that being said, someone who is reputable and can communicate effectively with both the restaurant owner and the building owner has to look at the big picture.

Questions -

A) Why does the condensing unit have to be on the roof? Where is the rest of the heating and ventilating equipment for the kitchen presently? In my opinion, putting a condensing unit 50 + feet higher than the evaporator is asking for trouble ( oil return for one ).

B) Is the so called 5 ton unit the right size for the application - has a proper heat load calculation been done ( to account for equipment and building load )?

C) Does the roof have the capacity to have a 400 pound load sitting on it? Will there be proper curbs installed ? Does an engineer have to be consulted?

If you aren't paying for this, make sure there is something in writing to answer your concerns - a reputable company can give peace of mind. These are just a start to the questions that need to be asked - Good Luck!

[Airmechanical]

units are put on roofs every day, but that being said, i would ask if there was any way to make it work on the ground

if the only reason it cant go on the ground is that it does not get enough fresh air,

then i would ask if there is a way to bring more air to it by cutting a hole or two

if it was my building, i would only put it on the roof if that was the only option left!

once you start penetrating the roof with refrigerant lines and electrical disconects and other stuff, if not done correctly

you could get roof leaks, and roof damage from oils that could eventually leak out of the system, (even if done correctly)



.

[nonepepsi]

units are put on roofs every day, but that being said, i would ask if there was any way to make it work on the ground

if the only reason it cant go on the ground is that it does not get enough fresh air,

then i would ask if there is a way to bring more air to it by cutting a hole or two

if it was my building, i would only put it on the roof if that was the only option left!

once you start penetrating the roof with refrigerant lines and electrical disconects and other stuff, if not done correctly

you could get roof leaks, and roof damage from oils that could eventually leak out of the system, (even if done correctly)



.

how do you recommend getting more air into the basement? As of right now two grill's (max) is installed in the sidewalk. Are their other options to bringing in oxygen?>

[Airmechanical]

how do you recommend getting more air into the basement? As of right now two grill's (max) is installed in the sidewalk. Are their other options to bringing in oxygen?>

you probably need a deflector ducted to exhaust the hot air thats being rejected from the condenser out of the fresh air space!

but i have not seen your application, how about some pictures?



.

[nonepepsi]

you probably need a deflector ducted to exhaust the hot air thats being rejected from the condenser out of the fresh air space!

but i have not seen your application, how about some pictures?



.

i will try and get photos later this week. Do you have any recomended professional that you know of in nyc that could take a look?

[miller-cold-filtered]

Josh,

as the building owner i would be focusing on safties. leave the cooling and heating for the pros.

1. make sure the roof is solidly strong. not just enough to hold 400 lbs or a 5 or a 10 ton condenser. i would make sure it can support the roof itself with major rain falls, snow, and especially safe for service guys like us to service the unit.

2. electrical is important too. get electrician for this. dont want your building to go up in smoke and flame then you wish your insurance premium can cover it.

3. i wouldnt worry too much about the noise. condenser units now today design alot more quieter than before. especially the higher seer.

[The Penguin]

hmmmmmm looks like not a lot of realistic answers here so far.

whats the roof made of - is it a metal roof , tar and gravel, torchon.

be sure to use the roofing company that holds the warrenty on the roof to install a roof jack - or its voided.

the roof top is standard for most commercial equipment - quite normal in fact.

your roof will easilly take the weight of a 5 or 10 ton condensor ( have an engineer sign off and make the rest pay for the engineer consult) snow loads are generally 200lb/per sq ft

10 ton units are commercial so they will be noiser than a 5 ton (anything over 5ton is strictly commercial.

the commercial HVAC co should address all concerns reg the piping wiring controls etc and the restrauraunt should pay.

noise/vibration have an engineer design a mounting system for the unit to sit on complete with isolation springs and to protect the roof membrane - have the commercial hvac company install vibration dampers in the piping - the restrauraunt pays

finally as the plumber said this won't be cheap

[nonepepsi]

hmmmmmm looks like not a lot of realistic answers here so far.

whats the roof made of - is it a metal roof , tar and gravel, torchon.

be sure to use the roofing company that holds the warrenty on the roof to install a roof jack - or its voided.

the roof top is standard for most commercial equipment - quite normal in fact.

your roof will easilly take the weight of a 5 or 10 ton condensor ( have an engineer sign off and make the rest pay for the engineer consult) snow loads are generally 200lb/per sq ft

10 ton units are commercial so they will be noiser than a 5 ton (anything over 5ton is strictly commercial.

the commercial HVAC co should address all concerns reg the piping wiring controls etc and the restrauraunt should pay.

noise/vibration have an engineer design a mounting system for the unit to sit on complete with isolation springs and to protect the roof membrane - have the commercial hvac company install vibration dampers in the piping - the restrauraunt pays

finally as the plumber said this won't be cheap

roof is tar and gravel. roof was just redone a year ago with a firestone torch down rubber and then a silver coating on top and has a 10 year warranty.

I am a bit confused, should the compressor be put on a mounting system with isolation springs, or on top of a roof jack?

[diesel65]

Condensor's are put on roofs all the time in every state, you must have an engineer sign off on your roof load.
You will need a stand of some sort that is mounted solidly to the roof structure, (there are many way's to do this) here in Florida we have uplift concerns and the stands have to be mounted to either the concrete roof or steel or wood trusses, so the roof has to be patched around the stand legs.
I don't know about NY.
You will have to have one hole cut in the roof for a line jack so the line set and electrical conduit can go down to the air handler, or maybe two if code dictates one for copper line set and one for electric.

You need proffesionals for this, an engineer for the roof load (safety) an electrician and a/c company to correctly determine the heat loads and installation of the system.

[fire]

Has anyone sugested a water cooled condesor. It wont have to go on the roof.. Some areas dont allow it because of the water consumption.

[The Penguin]

3 gallons per minute per ton (or is it two I don't remember) thats going to be allot of water man the meter is going to spin big time

30 gallons of water per min = 25,000 gallons per day based upon a 14 hr run time

the roof jack is for the electrical and the hvac copper piping - have your roofers do it or void your roof warranty
have your roofers roof in supports for the unit (warranty) if req by your building code have engineer engineer stand or method of support for the unit (to protect your building and roof - Insurance co may req this) send bill to restrauaraunt.

[fire]

I wont comment on the amount of water used calc. This ia a commercial kitchen and uses alot of water any way. There is a big difference form 5 to 10 tons obviously. What about a water tower instead on the roof.

[ChilledBeam]

I would check into the Daikin AC product, these ducted or ductless split systems can have the condensing units installed 135 ft above the indoor evaps.

www.daikinac.com (http://www.daikinac.com)

They also offer many types of indoor units that can be piped up to the condensing unit. You can install multiple indoor units to one outdoor unit.

Their 6 ton condensing unit weighs 666 lbs and is very quiet (60 dB at 3 ft) so you won't have to worry about sound. The dimensions are 48" wide x 30" deep x 64" tall so it could fit into an elevator if you have one going up to the roof. Double the weight and dimensions for a 12 ton unit.

A professional needs to look at the roof and sign off on whatever you're putting on it to manage risk.

[nonepepsi]

I would check into the Daikin AC product, these ducted or ductless split systems can have the condensing units installed 135 ft above the indoor evaps.

www.daikinac.com (http://www.daikinac.com)

They also offer many types of indoor units that can be piped up to the condensing unit. You can install multiple indoor units to one outdoor unit.

Their 6 ton condensing unit weighs 666 lbs and is very quiet (60 dB at 3 ft) so you won't have to worry about sound. The dimensions are 48" wide x 30" deep x 64" tall so it could fit into an elevator if you have one going up to the roof. Double the weight and dimensions for a 12 ton unit.

A professional needs to look at the roof and sign off on whatever you're putting on it to manage risk.


I appologize for my novice questions. What is the indoor evaporator? From my understanding the compressor/condessor will still be installed on the roof of the building (although noise will be kept to a minimum). How big is the piping that is needed?

[ChilledBeam]

Its the indoor piece of the unit that blows cold air.

[rimek]

It wouldn't be a bad idea to get a consulting engineer on the job- the placement of this unit on the roof is critical, and you need to consider existing loading-roof weight, other equipment, snow load, etc.- and load-bearing points across the footprint. Is there any other equipment on the roof?

I also suggest you look into the ductless split option, with condensing units hung on the wall, maybe? Not knowing your physical limitations, it's hard to see your options.
A 50-60ft vertical run is possible if done correctly, but not my first choice. You don't say what type of occupancy(resi, commercial, storage, vacant) you have in the intervening four floors, or the current condition. Would the piping be run inside the structure or as surface on an outside wall?
An advantage of the ductless splits is a zoning possibility for his space.

[secorp]

Tell the Kitchen guy to get you a quote and explanation from a pro.