60 degree warehouse

[codgy]

I have a customer who currently warehouses chocolate at 68 degrees and is currently interested in building a new warehouse and wants 58-60 for longer shelf life. I used 5 ton ac w/ fancoil units for his previous job w/ good success. I am concerned about humidity control if I go to warehouse style evaps. What systems have you seen for this application? I thought about using a/c condensing units w/ epr valves to maintain evap temp at 33 or so w/ conventional fancoils. All product is boxed and humidity control is needed to prevent sagging pallets of boxed product. Job is approx 10000 sq. ft and multiple units will be used, any ideas will be appreciated.

[itsamine]

Why don't you have the supply house size it for you? Give them the specs and they will take care of the rest instead of trying to make it work.

[MikeySq]

Why don't you have the supply house size it for you? Give them the specs and they will take care of the rest instead of trying to make it work.

What's the fun in that you don't learn nothing that way!!




I'd Start with getting all the Requird information, herat loads and operating conditions weather patterns and see what you can come up with your self.

If Humidity control is neccessary you should look in to possible Re Heat type set ups. or does it matter if you get colder then your desired temp setpoint trying to achieve proper humiditity levels

Of your 10000sq feet how high is the roof? How many Doors? Atre they open often? Any operating machinery? What type of Lighting? What are the walls floor and roof made of and insulated with?

Mike

[Dowadudda]

the action verb is redundancy, whatever you do.

I would do a top to bottom load calc, at those desired conditions to come away with a good answer as to what to engineer.

I am thinking this would be a very good fit for a Dectron or Munters unit. Good solid air circulation should be well thought out too. Warehousing is one of those fine arts in this business. People, think, it's just a big walk in cooler. Your talking about product integrity at the manufacturing and distribution level, extremely important. But I can tell you from pretty good experience, your customer will need some solid thinking.

[itsamine]

What's the fun in that you don't learn nothing that way!!

Your right just a pissed off customer if it doesn't work.:rolleyes:

[MikeySq]

Your right just a pissed off customer if it doesn't work.:rolleyes:

But it's all about research, this stuff isn't rocket science, I wouldn't do anything unless I Know it is going to work. And that means I would research my plans and have it reviewed by more than one person for input and suggestions. Ever hear of a Supply house person make wrong decisions on Deciding on Equipment?? hahaha :P

Mike

[codgy]

Hey guys, I'm just looking for info on proper system design, load is 260,000 btu/hr and I would like to use 4 units for redundant design. The main concern I have is reliability w/ humidity control. I thought of using medium profile evaps w/ a 12-15 td but I would like to add 1" filter racks to protect coils and ceiling from streaking w/ dirt. What designs have you seen and what works best?

[icemeister]

Hey guys, I'm just looking for info on proper system design, load is 260,000 btu/hr and I would like to use 4 units for redundant design. The main concern I have is reliability w/ humidity control. I thought of using medium profile evaps w/ a 12-15 td but I would like to add 1" filter racks to protect coils and ceiling from streaking w/ dirt. What designs have you seen and what works best?

Humidity control is by far the more important factor to consider with candy storage. The storage temperature can vary or a wide range but the humidity will greatly affect quality and shelf life.

Here's an excerpt form the ASHRAE 2006 Handbook on Refrigertation:

Humidity Requirements

Sugar ingredients are stable over a wide range of storage temperatures,
but they are sensitive to high or low humidity. The initial
moisture content of candies largely determines the optimum relative
humidity of the storage atmosphere. Candies with a moisture content
of 12 to 16% (marshmallows, gumdrops, coconut sticks, jelly
beans, and fudge) should be stored at 60 to 65% rh to avoid becoming
(1) sticky, runny, or moldy or (2) hard and crusty. Candies with
a moisture content of 5 to 9% (most fine candies, nougat bars, nut
bars, hard and soft creams, bonbons, and caramels) should be stored
at 50 to 55% rh to retain their original weight, finish, and texture.
Candies with a moisture content below 2% (milk chocolate bars,
chocolate-covered nuts, and all kinds of hard candies) should be
stored at 45% rh or lower.

Also, the evaporator TD you'll need for 50-55% RH will be in the 20ºF-25ºF range. I suggest looking at built-up air handlers rather than unit coolers. Get together with your local sales rep and he can help with design and selection of the proper equipment to do the job. Bohn/Heatcraft used to offer these but I'm not sure if they still do. I know Kramer/Russel/Witt does. The air handler approach would lend itself much better to adding filters as well.

I agree with Dow on looking into Munters for the humidity control. They are very effective at maintaining proper RH in this type of application. Just keep in mind while they will handle the latent load they will add to your sensible load somewhat.

[Airmechanical]

after what ice said;

i agree with Dow, "Dectron" is the answer

better sell a maintanance contract with it too



.

[icemeister]

Dectron makes a nice package with their reheat and all the cool controls, but this application may be a tad too low a dewpoint for them to handle well.

I'll be the first to admit I'm no psychrometric whiz, but 60ºF/50% RH will give you a dewpoint temperature of around 40ºF, which means to effectively wring any moisture out of that air your DX cooling coil must be 5-10ºF below that. This places the evap temps too close to freezing by my thinking.

This is why I'd opt for a dessicant type dehumidification system...ie, Munters, as opposed to a DX system.

[codgy]

Customer has a munters unit for a process application. I was thinking simple minded and would use standard 5 ton a/c fancoils w/ an epr to prevent freeze-ups. An accumulator could be field added along w/ low ambient controls. I would just have to de-rate the units for the lower indoor temps. I prefer direct drive motors to reduce pm and service cost. I could use a heat kit in the air handlers for reheat and better humidity control. Munters seems overkill for this app. Thanks for your input, as for having supply houses figure equipment this is something I would never do, as the customer is paying me and I am liable if it doesn't work.

[Dowadudda]

with all due respect, your description of what you would do seems a bit hackish as compared to providing a quality long term package like we have discussed. Please, I mean this with the humblest of respect.

I don't know the customer, or their willingness to get something at the A level, Affording the B level, but only wanting to pay for the C or D level. I dunno.

When you said chocolate I conjured up this idea of a fancy purveyor type. I have done work for specialty food type distributors from small to medium and they all were very picky on the perishable aspect and demanded correct and proper and were willing to pay for it. This may not be your customer. I dunno.

The requirement, the money at stake under load, I would want to to do this right, and build a name for yourself also, not that you don;t have one now but. This could be a niche you get into.

10 grand of square feet. Munters has smaller tonnage equipment. You also should be thinking of redundancy too.

[icemeister]

You're definitely not going to be able to make this work with standard 5-ton A/C units.

Also, I wasn't referring to your local supply house counter guys...I meant call the Factory Sales Rep. He will be the one to help you out here.

Please...call Munters. They KNOW how to control humidity.

[codgy]

OK I know it sounds "hackish" to suggest this as a reliable system. Multiple small units would give the reduntant capacity needed. I was thinking to simple and didn't see the need for for a custom oem system. I like the K.I.S.S. method sometimes to well for my own good.

[itsamine]

But it's all about research, this stuff isn't rocket science, I wouldn't do anything unless I Know it is going to work. And that means I would research my plans and have it reviewed by more than one person for input and suggestions. Ever hear of a Supply house person make wrong decisions on Deciding on Equipment?? hahaha :P

Mike

Your right it's all about research. I'm glad you have the time to sit down figure this out. Some people don't have the time to do this. As for the supply house making mistakes yes they do but on the other hand they probably designed more chillrooms than most of us here. So I wont waste my time trying to figure something like that out I'll just let them do it. Oh by the way they haven't been wrong yet.;)

[Dowadudda]

I would want to keep this project under my hat. And the easiest way to let the world know that there is a new warehouse being considered for, just take it to the supply house guy. Every customer who deals in that work will know by the end of the week.

Supply houses, can be awful places to keep secrets.

[Dowadudda]

Having said that, there is a place for a supply house sales rep I suppose as you suggest. But you know, I want to know how the numbers line up myself. It would make me more comfortable to do the design initially and if it were just too difficult I might ask for help.

As far as having time for that kind of thing, well, there are contractors who do and they do a fine job, while others are geared completely different, as your saying, you have little time to design something like this.

Contractors who consider work like this, make time for the designs of these system. Because why? There is huge money in a fine job.

[cletus31]

:oIf you go with munters get a maint. contract because these are high maint. and if you use gas fired reheat run it about 120 and no higher or you will have desicant wheel problems :o:eek:

[DaveCR]

From the ASHRAE article, your customer needs lower humidity to extend product life not lower temperature. I'd suggest doing a tad more research and have a talk with your customer about the subject. If they are ok with higher temps Carrier has RTUs with hot gas reheat (Humidi-MiZer) that may work in this application. Also, if your local climate allows, an economizer could save your customer some operating cost.

ps
when it comes to humidity control the tightness of the building envelope is critical to success

[itsamine]

There are contractors geared up for this kind of work and I know it's a good pay day. But they have a team of people doing the research and the design for this. I would have to do this after my regular work day so for me it does not work as it would for a bigger operation. But to each it's own I guess.

[Dowadudda]

There are contractors geared up for this kind of work and I know it's a good pay day. But they have a team of people doing the research and the design for this. I would have to do this after my regular work day so for me it does not work as it would for a bigger operation. But to each it's own I guess.

Oh now I gotya, you don't have time for this. I was confused before. :rolleyes:

[codgy]

Thanks for the input, I enjoy doing something new and am currently designing this building. Wish me luck

[itsamine]

Oh now I gotya, you don't have time for this. I was confused before. :rolleyes:

No need to be confused. If I had nothing to do all day than I would have time but since I don't I let them size the euiptment and I install it.... See no confusion at all and still make the money.:rolleyes: