How to get cool...during winter
I was recently called to a 5 story building in down town New York City. They are requesting an A/C system on the 4th floor office area....approx. 1,500 sq.ft. We cannnot disturb 5th floor tenants ....so a rooftop unit is out of the question.
What are my options?
How are the other 4 floors cooled, if they are at all? Sounds like an older building.
First thing I would look at.....
There are 3 ways to do anything in life; Good, Fast, Slow: You can pick any 2.
How about operable windows? Better IAQ is an added bonus.
Seriously, it doesn't make sense to run refrigerated a/c in the winter when air exchange will accomplish the same thing at a fraction of the cost.
Not an HVAC pro but having a industrial facilities background I think I can offer a suggestion here. All the systems I dealt with had an "economizer" function so if outdoor air met cooling requirements it would use outdoor air instead of mechanical cooling. Not sure if this could apply but worth a thought
No other floors are cooled. NO window a/c's allowed. A ductless minisplit system looks like answer but what about low outside temp. Will it work? Never have installed a A/C unit during winter.
Air exchanger will require ducting ....not an option
How is the building heated?
My though is why is it they require cooling when they should not? I know it's the 4th floor but is there something producing heat?
Last edited by stvc; 12-27-2007 at 01:44 AM.
Reason: added thought
So you have been painted into a corner with the following,
Originally Posted by omaretwn
slim pickins and a few not so realisitic options:
1. Go outside once an hour or so
2. Open the windows
3. Air exchanger or ERV
4. Add a wall exhauster fan with make-up.
__ NO one said it had to be Pretty.
5. Movin Cool model CM12 [ Ceiling Mounted 12,000 BTUH] or similar ceiling units with outside air provided through the wall.
Two or three (?) one-ton units for 1,500 square feet
6. CARRIER model 50AH RoomTop unit in 3 to 5 ton capacities
7. Daikin A/C ... 1,500 square feet may require 3 ceiling units
Rooftop condenser location and running refrigerant lines are also required.
However, this is a 4th floor office so refrigerant lines would have to pass through a small part of the 5th floor.
Last edited by dan sw fl; 12-27-2007 at 05:46 AM.
It's Not Rocket Science, But It is SCIENCE
with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE
Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
The fujitsu ductless splits can operate down to an ambient of 0 degrees F.
They have ceiling mount so the offices do not need wall hung evaporators. Nice equipment.
Reasonable priced as well. Condensers can mount on the roof, or even off the side of the building if permitted.
ductless mini split is definitely the answer. No a/c in this building??!!
Anyway, as was mentioned, these can be ordered with low ambient accessory. There are a number of manufacturers that have these available and can be ceiling, wall, or console mounted. All that would be routed between indoor and outdoor is power and control wiring along with refrigeration lines. Also condensate pump is used for condensate removal. Keep in mind where you will route this line.
Don't anyone go crazy on me, but I have seen the outdoor units mounted successfully above a drop ceiling and they operated just fine. Also, low ambient became a non-issue.
all the best, Irish.
Everyone has a purpose in life..........even if it's to be a bad example.
Seek first to understand, before seeking to be understood.
For small systems, you could use a domestic water source for a condenser loop. This can be expensive and is somewhat wasteful, but I've seen a few. The water goes to waste.
I cringe when I see this but I have seen them as well. I guess if there is some type of exhaust fan for the area it could be entertained. Cross ventilation of some sort if the property manager allows.
Originally Posted by Irishmist