Designing a 15000sqft facility....please help

[joe macclennan]

I don't think you misread it, I may have just miscommunicated the idea I was trying to get across. Like over exaggerating a concept. Sometimes I hyperbole a little and it bites me in the ass. This is one of those times.

Traditional A/C that pulls in outside air will not drop RH down to where you need it. 60F and 100% RH doesn't do you much good.
Minisplit can.

But, when the lights are off and you don't need cooling, all incarnations of A/C will not dehumidify, because they will not run..

ok, now I get you...agreed.

The fan coil units you use in water chilled systems can have heaters installed on them so you can run the fan coil to dehumidify without lowering the temperature of the room. Basically, think running a 1ton AC with a 1 ton heater at the same time.

this is interesting. I don't know much about water cooling honestly. I've never worked with many of these systems. It is something i'm looking into for future endeavors.

I know water cooling is far more efficient than standard condenser/evap ac systems.

 

[SnapsProvolone]

The ratio of dehumidification required to cooling required leans towards dehu even with lights on.

 

[joe macclennan]

5 gal / day / kw

pretty close to what I see

 

[SnapsProvolone]

Why would I want a ton of heating on a ton of dehu when putting evap and condenser in same place works. Sorry im sticking with traditional dehumidification.

 

[MisterBlah]

ok, now I get you...agreed.


this is interesting. I don't know much about water cooling honestly. I've never worked with many of these systems. It is something i'm looking into for future endeavors.

I know water cooling is far more efficient than standard condenser/evap ac systems.

I typically don't bring up the fact that water chilled systems are more effective simply because it is so hard to put actual numbers to it. But, I know all the salesman will tell you it is more efficient.

The ratio of dehumidification required to cooling required leans towards dehu even with lights on.

Typically, I see properly sized systems installed with about 30% of the fan coil units fitted with heaters to dehumidify with the lights off. That's not my responsibility though, but we haven't had any complaints.

 

[joe macclennan]

Why would I want a ton of heating on a ton of dehu when putting evap and condenser in same place works. Sorry im sticking with traditional dehumidification.

you know I think your advice is spot on snaps and I respect you a bunch. But water cooling is more efficient. And the guy makes a good point about extra equipment.

Standard dehumidifiers Put TONS of heat off anyway. It would be more efficient to run one main compressor outside on the chiller than run a bunch of little compressors inside on individual dehumidifiers...which all end up failing sooner or later.

I've replaced two in the last year after only a couple of years use.

 

[MisterBlah]

Why would I want a ton of heating on a ton of dehu when putting evap and condenser in same place works. Sorry im sticking with traditional dehumidification.

It depends on how you design the system. The heat kit you put on these fan coil units only runs with lights off, it costs less than traditional dehumidifiers, and your drain is already hooked up and ready to go at install. It's not something you do after the installation. So, if you are using a traditional dehumidifier, you will probably stick with that. As, well, less extra stuff to buy.

 

[joe macclennan]

I typically don't bring up the fact that water chilled systems are more effective simply because it is so hard to put actual numbers to it. But, I know all the salesman will tell you it is more efficient.

the mech. engineer I used to work with always said this.

he was also my professor @ school.

one of the smartest guys i've ever met.

 

[MisterBlah]

I'd like to add that for every 1 ton of cooling, it's a general rule of thumb that you are putting off 1.25 tons of heat.

 

[SnapsProvolone]

I dunno. I will have to defer on that.

 

[SnapsProvolone]

I've seen a shit ton of Phoenix 200's in warehouses. Probably not as efefficient but if one goes down you roll out another without need for a mega expensive backup.

 

[MisterBlah]

I'll add one more thing before hitting the sack.

No thermodynamic process is 100% efficient. The refrigeration process generates around 25% more heat than it does cooling. That actual number depends on the compressor, heat exchanger, etc. Basically, just depends on the design of the unit.

 

[MisterBlah]

I've seen a shit ton of Phoenix 200's in warehouses. Probably not as efefficient but if one goes down you roll out another without need for a mega expensive backup.

851 watts means ~2900btu/h or 1/4 ton of cooling.

The fan coils I see are 1ton - 3ton when made for dehumidification. And they also cost 1/2 as much as that. Also they don't require emptying.

 

[joe macclennan]

I've seen a shit ton of Phoenix 200's in warehouses. Probably not as efefficient but if one goes down you roll out another without need for a mega expensive backup.

I don't see how there would need to be any backups with water cooled air handlers and heat strips.

I think when he was referring to backup it was for general cooling capability. If i read it correctly.

I am tired though and could be wrong.

 

[joe macclennan]

I'll add one more thing before hitting the sack.

No thermodynamic process is 100% efficient. The refrigeration process generates around 25% more heat than it does cooling. That actual number depends on the compressor, heat exchanger, etc. Basically, just depends on the design of the unit.

sounds right.

and in a system where that extra 25% heat load is outdoors instead of in...the savings add up fast.

 

[MisterBlah]

I don't see how there would need to be any backups with water cooled air handlers and heat strips.

I think when he was referring to backup it was for general cooling capability. If i read it correctly.

I am tired though and could be wrong.

Backup would be the entire cooling system? I dunno, we usually put two fan coils made for dehumidification in a larger room.

 

[SnapsProvolone]

Cool. If you think it's the way to go I'm game.

 

[SnapsProvolone]

So we are pulling 2500 gallons a day and cooling half the time at say 150 tons with 500kW?

 

[joe macclennan]

well from what I learned in school water cooling is more efficient.

like I said I am not that experienced in it at all. I've helped install a couple of very large chillers but as too the design and layout...that's beyond me.

jrainman on the other hand would be a great person to have in on this covo.

I'll see if I can't drag him in

 

[SnapsProvolone]

What do you think would be the ratio of kilowatt hours used in lighting to kilowatt hours used for hvac?