HI_RISE ac compressors on roof 100 apts

Status
Not open for further replies.
Hi everyone,

question i have to run power and low voltage for 100 apts on a new building 10 stories, i was going to run a 1/2 for L.v. and 3/4 emt from each apt to roof but i will end up having 200 conduits on roof for this compressors, any ideas on how to get power from each apt. to roof.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Probably the reason you never see anything like that. Usually the building has a chilled water system for A/C that is included in the common charges. +

... Or packaged units.

-Hal
 

nickelec

Senior Member
Location
US
each unit has its own condenser on the roof I find that hard to believe 100 units on the roof would take up quite alot of space

Sent from my SM-G950U using Tapatalk
 
each unit has its own condenser on the roof I find that hard to believe 100 units on the roof would take up quite alot of space

Sent from my SM-G950U using Tapatalk

Yes, first time seeing this, usually is a cooling tower here in s. Florida, I guess I have no choice to run separate conduits. I was thinking of sharing power for t. Stat and 208v using same type of wire conductors
 

Attachments

  • Screenshot_20181009-204944_Procore.jpg
    Screenshot_20181009-204944_Procore.jpg
    138 KB · Views: 1

nickelec

Senior Member
Location
US
Can you run one conduit per floor maybe how many app on each floor and how big are the units

Sent from my SM-G950U using Tapatalk
 

kwired

Electron manager
Location
NE Nebraska
Your link shows the inside air handling units, OP has 100 outdoor units being placed on same roof, which only has 10 units per floor, you would think they will be a little crowded up there.

I can't imagine what this will cost, that is a lot of tubing and refrigerant to get from roof to units on the bottom level. Not even sure if compressor is rated to pump through such long circuit without derating and/or increasing line sizes to compensate for losses - which makes even more refrigerant necessary.

Owner probably thinking they are saving $$ and wanting a circuit from each tenant space to their respective cooling unit so they don't pay the energy bill. Though they are putting a small fortune in the initial investment, and depending on how tenant/leasing agreements work out, maybe still going to have a lot of maintenance cost down the road compared to a system more suited for the application.
 

retirede

Senior Member
Location
Illinois
Your link shows the inside air handling units, OP has 100 outdoor units being placed on same roof, which only has 10 units per floor, you would think they will be a little crowded up there.

I can't imagine what this will cost, that is a lot of tubing and refrigerant to get from roof to units on the bottom level. Not even sure if compressor is rated to pump through such long circuit without derating and/or increasing line sizes to compensate for losses - which makes even more refrigerant necessary.

Owner probably thinking they are saving $$ and wanting a circuit from each tenant space to their respective cooling unit so they don't pay the energy bill. Though they are putting a small fortune in the initial investment, and depending on how tenant/leasing agreements work out, maybe still going to have a lot of maintenance cost down the road compared to a system more suited for the application.

I agree. This setup is crazy.
Maintenance will be a nightmare.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Your link shows the inside air handling units, OP has 100 outdoor units being placed on same roof, which only has 10 units per floor, you would think they will be a little crowded up there.

I can't imagine what this will cost, that is a lot of tubing and refrigerant to get from roof to units on the bottom level. Not even sure if compressor is rated to pump through such long circuit without derating and/or increasing line sizes to compensate for losses - which makes even more refrigerant necessary.

Owner probably thinking they are saving $$ and wanting a circuit from each tenant space to their respective cooling unit so they don't pay the energy bill. Though they are putting a small fortune in the initial investment, and depending on how tenant/leasing agreements work out, maybe still going to have a lot of maintenance cost down the road compared to a system more suited for the application.



They also contain a compressor and coil- all in one. Thats how they do it around here in high rise when there isn't a central chiller or boiler room.
 

kwired

Electron manager
Location
NE Nebraska
They also contain a compressor and coil- all in one. Thats how they do it around here in high rise when there isn't a central chiller or boiler room.
Ok, I didn't look close enough. Still need to have something to the exterior to get rid of heat during cooling mode or to take in heat if they have reversing valve to use as a heat pump.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Ok, I didn't look close enough. Still need to have something to the exterior to get rid of heat during cooling mode or to take in heat if they have reversing valve to use as a heat pump.



Yup, a wall sleeve which just shows up as a grated vent on the exterior.


http://www.magic-pak.com/products/m-series/wall-sleeves.asp

http://www.flexenergy.ca/pdf/m-series-architect.pdf


Around here the units are placed in either a mechanical closet or laundry room which faces an exterior wall or a small dedicated space with door access on the balcony. I know this is not what the OP has, but honestly I am at a loss as to why they would do it like that when other more cost effective options exist.


Sleeve grates:

Arboretum.jpg



Dedicated balcony MER closet. This is often reserved for luxury units because its quieter and frees up space inside.


The Lodge of Northbrook.png
 
Last edited:
Your link shows the inside air handling units, OP has 100 outdoor units being placed on same roof, which only has 10 units per floor, you would think they will be a little crowded up there.

I can't imagine what this will cost, that is a lot of tubing and refrigerant to get from roof to units on the bottom level. Not even sure if compressor is rated to pump through such long circuit without derating and/or increasing line sizes to compensate for losses - which makes even more refrigerant necessary.

Owner probably thinking they are saving $$ and wanting a circuit from each tenant space to their respective cooling unit so they don't pay the energy bill. Though they are putting a small fortune in the initial investment, and depending on how tenant/leasing agreements work out, maybe still going to have a lot of maintenance cost down the road compared to a system more suited for the application.


Yes they are trying to save money but like you said future is that they will have lots of issues with distance, I will say longest pull for ac contractor and electrical will be 100ft.
 

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
Hi everyone,

question i have to run power and low voltage for 100 apts on a new building 10 stories, i was going to run a 1/2 for L.v. and 3/4 emt from each apt to roof but i will end up having 200 conduits on roof for this compressors, any ideas on how to get power from each apt. to roof.

I've seen a single large (maybe 6") penetration between 4 units. Both the low voltage and the line voltage stubbed through then sealed off. You go from 200 individual penetrations to 25. Try and get the AC contractor to orient the unit tie in corner to the stub.

picture.jpg
 
Status
Not open for further replies.
Top