I don't trust my contractors, HELP!

[AIRICCC]

I am building a 6000 sq ft facility that is split into a production and retail area. The cielings are 15' tall and the building is 75' square. The split is 1/3 retail and 2/3 production. The production side needs to be maintained at 60 degrees and the retail side is supposed to be maintained at 70ish, whatever is comfortable. The production side has several vessels that are maintained at 60 degrees or below by glycol jackets which is separate from this discussion. The building is metal construction with R13 walls and R19 ceiling. The floors are 6" concrete. There will be very little heat produced in the production facility to the extent that we did not take it into consideration when assessing our cooling needs. The doors will remain closed 98% of the time. We are located in Northern Indiana (for reference to outside temps)
First things first, they quoted me $9**** for equipment and installation. I have a friend who used to do general contracting that brought this to my attention as being overkill and a ripoff.
They have quoted a ductless cooling system (which I didn't ask for but they insist is necessary to maintain 60 degrees) which involves 3 separate 3 ton condensers which each power two sets of evaporator fans positioned on each wall in the production room. The condensers are mounted on a pad on the back side of the building which means we will have several hundred feet of copper pipe for the refrigerant. The retail area is quoted for a regular heat pump duct system with two condensers at 3.5 ton and two air handlers. This is the scope of work and I am not happy with the cost.
Why can't we just use a 9 ton heat pump with a large dump in the production space (no walls) and a 7 ton heat pump in the retail space to heat and cool? Why have so many separate condensers? Why must there be a ductless system to maintain 60 degrees? I think I am being taken for a ride... on top of that, I learned that my contractor subbed a contractor to sub out the work... hes just a middle man and I don't like him...
They told me that they already ordered the equipment and there is no turning back... as far as I am concerned, if it's not installed we can change course. I am by no means good at HVAC but I have been spending the last 4 days reading as much as I can so I am prepared to handle whatever answers I may get here as well as whatever BS they might try to throw at me at our contractor meeting on monday. Please help confirm my suspicions!

Pricing not allowed.

Mod

[second opinion]

I am building a 6000 sq ft facility that is split into a production and retail area. The cielings are 15' tall and the building is 75' square. The split is 1/3 retail and 2/3 production. The production side needs to be maintained at 60 degrees and the retail side is supposed to be maintained at 70ish, whatever is comfortable. The production side has several vessels that are maintained at 60 degrees or below by glycol jackets which is separate from this discussion. The building is metal construction with R13 walls and R19 ceiling. The floors are 6" concrete. There will be very little heat produced in the production facility to the extent that we did not take it into consideration when assessing our cooling needs. The doors will remain closed 98% of the time. We are located in Northern Indiana (for reference to outside temps)
First things first, they quoted me $ for equipment and installation. I have a friend who used to do general contracting that brought this to my attention as being overkill and a ripoff.
They have quoted a ductless cooling system (which I didn't ask for but they insist is necessary to maintain 60 degrees) which involves 3 separate 3 ton condensers which each power two sets of evaporator fans positioned on each wall in the production room. The condensers are mounted on a pad on the back side of the building which means we will have several hundred feet of copper pipe for the refrigerant. The retail area is quoted for a regular heat pump duct system with two condensers at 3.5 ton and two air handlers. This is the scope of work and I am not happy with the cost.
Why can't we just use a 9 ton heat pump with a large dump in the production space (no walls) and a 7 ton heat pump in the retail space to heat and cool? Why have so many separate condensers? Why must there be a ductless system to maintain 60 degrees? I think I am being taken for a ride... on top of that, I learned that my contractor subbed a contractor to sub out the work... hes just a middle man and I don't like him...
They told me that they already ordered the equipment and there is no turning back... as far as I am concerned, if it's not installed we can change course. I am by no means good at HVAC but I have been spending the last 4 days reading as much as I can so I am prepared to handle whatever answers I may get here as well as whatever BS they might try to throw at me at our contractor meeting on monday. Please help confirm my suspicions!

Listen to you HVAC contractor and not your friend who is a GC. Eliminating the pricing from you post is required.

You have two separate design criteria that need to be addressed by two separate approaches. Process cooling for the manufacturing and comfort cooling for the retail space. Whether or not the HVAC contractor has chosen the best design may need to be determined, but they are on the right track.

[just_opinion]

Seem to me you don't like/trust this HVAC contractor from the moment they give you the cost that over your budget. You should get an engineer to size up your equipment for you and you also let your buddy GC do the work. This way, there will be no followings: distrust, cut throat, cheating, dishonest, ripoff, screw-ups etc... Further more, this way will help you from becoming another engineering/technician/installer HVAC expert too.

Or you can just skip all the writing and get an engineering.

Good luck buddy.

[energy star]

If they ordered the equipment who approved the design? You? Your GC?


BTW....what are you doing at sixty degree temp. Only R-19 walls?

[Tommy knocker]

If there is no heat load why do you require any cooling at all?

[hcong]

I am building a 6000 sq ft facility that is split into a production and retail area. The cielings are 15' tall and the building is 75' square. The split is 1/3 retail and 2/3 production. The production side needs to be maintained at 60 degrees and the retail side is supposed to be maintained at 70ish, whatever is comfortable. The production side has several vessels that are maintained at 60 degrees or below by glycol jackets which is separate from this discussion. The building is metal construction with R13 walls and R19 ceiling. The floors are 6" concrete. There will be very little heat produced in the production facility to the extent that we did not take it into consideration when assessing our cooling needs. The doors will remain closed 98% of the time. We are located in Northern Indiana (for reference to outside temps)

I did some free engineering for you... quick and dirty calculations and I think there is something wrong with your numbers. I assumed high bay industry (40 workers) and retail space (66 customers) in your metal building with NO WINDOWS and you will already need 20 tons in the production area and 10 tons in the retail space. Without visiting the site, windows measurements, counting workers, having actual orientations my numbers can be anywhere from low or high (see attached for calculations). But for sure, there is no way 9 tons will work for a 6000 SF & 15 foot ceiling metal framed building. I don't know how critical it is to maintain 60 F everyday... are you are okay with 74-78 F on a 91 F day.

To answer your other question, one perk of multiple units is redundancy and energy efficiency. A single 9 ton have several problems. (1) Most manufacturers only makes 8.5 tons, then skips the 9 ton with the next being 10 tons. (2) I wouldn't be surprised if 3 ductless mini-splits are cheaper than a packaged heat pump. (3) They are also trying to avoid structural engineers, by not putting units on the roof. Your 9 ton will probably need to be on the ground too unless you want to hire a SE.

[Gib's Son]

With a space temperature requirement of 60 degrees there is no way I would install a DX system that is engineered for "Comfort Cooling". You need to ask, and understand, what is meant by a "Ductless System".

[beenthere]

A 3 ton A/C moving 1200 CFM will lose 19,968 BTUs of sensible capacity. leaving only 7,032 BTUs to lower/maintain temp at 60°F when its 95 outside. The rest of it capacity will be latent. So 3-3ton units would be needed, to get that room to 60, and thats without allowing for any lights, people, infiltration or required fresh air ventilation. Good chance that your A/c contractor could be a little low on his sizing and need to go to a larger size A/C.


Your buddy that use to be a GC, probably doesn't, and didn't design or size commercial A/C or refrigeration systems.

[BaldLoonie]

A/C equipment may have trouble getting the space as cold as
60 without frosting the evap. May need a chiller or refrigeration equipment with an evap designed to reduce frosting and a freezestat if it does frost.

Sent from my HTC VLE_U using Tapatalk 2

[beenthere]

A/C equipment may have trouble getting the space as cold as
60 without frosting the evap. May need a chiller or refrigeration equipment with an evap designed to reduce frosting and a freezestat if it does frost.

Sent from my HTC VLE_U using Tapatalk 2

I'm wondering if the "ductless" units they are talking about, aren't refrigeration units.

[Gib's Son]

I'm wondering if the "ductless" units they are talking about, aren't refrigeration units.

That's what I was thinking. Otherwise, a small Chiller. The OP needs to better understand what his contractor is proposing.

[AIRICCC]

If they ordered the equipment who approved the design? You? Your GC?


BTW....what are you doing at sixty degree temp. Only R-19 walls?

The GC approved it, the walls are thirteen, the ceiling is 19... I wondered about that too...

[AIRICCC]

Because it gets warmer than 60 outside nearly half the year.