Air conditioning High Bay Warehouse

[Buildtech2]

I need some advice on HVAC system design of High bay warehouse. My queries are as follows.

Project background:
Finished good warehouse is an automated warehouse. As per project specifications, the commodities stored in warehouse are medicines packed in plastic bags enclosed in paper cartons and placed on racks with plastic/wooden pallets. This warehouse to be air conditioned with uniform temperature around the entire volume with 24 C +/- 2 F variations, 50% -60% RH.

1.The height of this warehouse is 28 m which is equal to 7 story building. I think we cannot use lighting heat gain as w/m² as normally we use for other project. This may undersize the cooling capacity.
2.The ventilation also to be considered in a different way as normal procedure of ventilation with 0.6 l/s/m² will not be sufficient.
3.What equipment heat gain can be assumed.

Please let me know if you have any other suggestions to be considered in the load calculation.

 

[Drazen]

is it somewhere in middle east? the demands you presented are outrageous and will cost a fortune.

you cannot use any usual load calculation for such height, all common load calculations assume stationary state that you cannot achieve, thermal lift will be one of the major influencing factors in any setup.

 

[Buildtech2]

Yes, you are quite right Drazen. This warehouse will be built in the middle east. Can you please give me some guidance on load calculations.

Thanks,

 

[ZDR1985]

Yes actual light loads will be useful as this will be higher than normal due to height of the structure. Forklifts and trucks are usually used inside warehouses, so you have to consider that also if they are electric or gasoline powered. If gasoline or any other fuel is used, then consider proper ventilation as this may be occupied most of the time. ASHRAE Applications Handbook chapter 3 recommends 1-4 ACH.

 

[dbill74]

I don't think you can assume much of anything. Just too many variables and options. You will need to be in close communication with the other design disciplines AND the owner.
With only a 2 degree allowance in temperature and 28m high space, temperature stratification will become an issue.
As ZDR mentioned, type of equipment will affect your ventilation rates.
You will need to know where equipment and shelving is located so you can optimize air distribution.
If you haven't already, send the architect and owner a list of questions and request information on ALL equipment that will be in the warehouse. Get cut sheets if you can. Google and call manufacturers if needed. The more you know what will be in the facility and how it will be used, the better the systems you design can be.

 

[MintJulep]

Absolutely you can't use "rules of thumb" for this.

You'll need to coordinate with the building and equipment suppliers to determine internal heat loads.

You'll need lots of air, at high velocity (relative to typical comfort HVAC velocities) to prevent stratification.

CFD and someone who really knows how to use it well will be your friend for this project.

 

[Drazen]

for such buildings i use some customary recommendations and formulas, i cannot submit it via tips, but in general, usual load calculations are useless - thermal lift is so high that you cannot calculate even ordinary transmission through walls, usual formulas do not apply.

so, it's guesstimate more or less. you cannot prevent thermal lift at 28 meter neither you can achieve uniform temperature in space, that would be against basic physical laws.

that you can do is designing some way of local conductive or radiant cooling at each and every pallet.

 

[BronYrAur]

Just an idea here. You probably need to distribute the air as though you have a multiple floor building. In other words, you probably need air distribution for each "floor" of the warehouse. This will require ductwork to be run at multiple elevations in order to get good air flow everywhere. I don't think that you will get enough circulation just using air rotation units on the floor, or Big Ass Fans at the ceiling. The vertical difference is to large. I'm guessing the automation of reaching pallets that high is extensive and won't allow much room for much ductwork throughout the space, but I don't see any other way.

You mentioned 28 m high. What are the other dimensions?