How do you manage to "cool" a kitchen?

Went to one of those big Everrads Family themed pub/hotel complex last Friday. Problem is the kitchen, its too hot !

No doubt the kitchen is a very , very busy place with three huge 6 gas burner cookers, 12 overhead filter and extract fan systems, counter refrigerators.,etc

Designers tried to bring in fresh air from outside by installing a huge 30inch fan, ducted to several vents in the ceiling. Also two air extracter fans of size 24 inch diameter, take the air out. It is not doing the trick. Its still hot in there.

Now how do I cool this working environment sufficient enough to satisfy the cooks who are complaining bitterly about the heat. I am thinking air conditioner, something like the Hitachi Econofresh system located in the roof void, but Ill never get it in there, the roof space is not big enough.

Im thinking air conditioning, but I am loathe to specify an air conditioning system in case it doesnt work out. Then Im really in it.....

Im not sure if members have come across a similar scenario .

I would take a good look at the make up air parts. Maybe something is not working as designed. With kitchens, you really have to rely on inside to outside heat exchange.

Dan

Since this place is obviously a busy place... check the door knobs, rails or anything horizontal that grease may settle on. If you find grease on them... your air balance is wrong.

Has anyone done any remodeling... even such as adding a ventilation fan to a restroom or adding a restroom with ventilation etc? If so... the balance could have been undone... funny how airflow can be upset sooo easily.

How often are the filters over the fryer and ranges cleaned or changed? Are the blower motors belt driven and have they been changed recently or do they need to be changed maybe? Check the RPM's on your blower if belt driven, make sure the belts are the right belts and you have the correct number of belts on each blower.

If you are going to put in air conditioning... go with a mini split, ceiling mount system... sounds like you will need a few though.

Keep in touch..:)

The air make up system has to have cooling if it's indirect. If it's not, step one... First make sure that the other loads are accounted for. The math is easy if they are. If they aren't? Qualfiy the client! First question... Do they have lots to spend on cooling? Then go ahead, work out the loads and design a system.

One of the most difficult areas to condition is a kitchen - especially a commercial one. The problem is the extract over the cooking ranges - all they do is suck out your nice cool air!

Good kitchen ventilation is the most important thing with a design air change rate of between 30 and 60 air changes per hour, depending on the kitchen useage - if it's a very busy kitchen then go for 60 ACH down to 30 minimum for a light cook and sandwich room. Do the design on the extract and then size the make up air at about 90% of the extract as this will stop cooking smells from spilling into areas where they shouldn't.

As we know, the principle behind split type DX coolers is that they circulate the air in the room over and over and with each pass the air slowly reduces in temperature down to the set point. In kitchens this is not possible because the air is changed in the room upto 60 times an hour. The only real solution to introducing cooling into kitchens is to treat the make up air. I've been into kitchens where splits have been installed, usually wall mounted and all you can see is condensate dripping off the swing flap due to the high humidity in the kitchen.

If the temperature in the kitchen is, say at 30deg c then the leaving temperature from the split will be no lower than 23deg c - a normal 7deg DT.

If the kitchen is overheating with the current ambient temperatures then the first item thing to look at is the vent system. Don't forget that no matter how much cooling you introduce into the kitchen you will not be able to treat the radiant heat given off by the appliances - make the customer aware of this before you start!


Frank:cool:

"Qualify your client first"... I absolutely hate to waste my time researching anything if it doesn't have some reward in it. That is just me though... when there are no benefits involved... I give an off the cuff answer... why waste my time researching information etc. when it does absolutely no good. :mad: And God knows, I don't remember everything! But I can find it if I want to... LOL!

On the other hand... if the client is qualified... then I will give them 120%. ;)


"Why run when you can walk, why walk when you can stand, why stand when you can sit and why sit when you can lie down?"

Question: Should exhaust air and makeup air for kitchens, hoods, or whatever be evenly matched and then let the A/C unit provide the positive pressure? I was just thinking that it would benefit a kitchen to exert a slightly negative pressure. After all, a kitchen is a room developing expanding gases.

Interesting stuff to think about. I need to learn a tad more about hoods. Perhaps they have a rating such as they remove 75% of the heat from the device they are sized for.

Then, as Frank mentioned, there are the heat loads both radiant and latent that remain untreated which the A/C unit must deal with.

I think the primary work should be a proper balance between outside and inside air exchange and the secondary consideration be the sizing and design of the A/C unit.

That being said, I am really not sure what "proper" is.:)

Quote:

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I wouldn't bother with recirc AC such as a split system or similar

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I agree. Cooling is requisite, but just making air cold is not a good line of thought. A kitchen is an air moving phenomenon. Further, it must not impinge upon the area's comfort conditioning devoted to the public. It is a real balancing act, now that I think about it.

I know there are tables and expertise from the manufacturers that can be relied upon. But it is fun to think about what happens in a kitchen without consulting the experts, especially when they are we.:)

From what I've learned from books and personal expierience, kitchen vent systems are designed to keep cooking odors (smoke) from the dining areas. No consideration is given to comfort cooling for the kitchen staff.

Consideration for the comfort of the kitchen staff must be accounted for in the design of the entire buildings HVAC systems.

If the kitchen vent system is operating properly, the negative pressure that results will flush the kitchen staff with conditioned air from the dining areas.

In some cases, kitchen overheating is the result of insufficient minimum fresh air settings from the HVAC system serving the dining area.

Just a thought...

Cooling the kitchen, one of the greatest adventures in life.
I just quoted a new customer today for some new equipment
to cure his ("uncontrollable atmosphere") as he referred to it.
To start, I reviewed and confirmed an engineering firms test and balance report for his kitchen.
Total exhaust 11,400 cfm
Total Make-up 5,500cfm
Complaints of wind tunnel effect and huge temperature swings in the dining area. Last contractor had this info I just posted and
decided to add 12 additional tons of cooling but not address the
extreme negative pressure present.
Here's the point, If we properly balance the make up and
exhaust requirements, and they are sufficiently sized for all the cooking equipment, this will keep the complaints from the cooks to minimum. Ive found that 90% make-up air works best.
Its also important to note that the buildings roof top package heating and cooling units must be equipped with economizers. Since our kitchen is still slightly negative, we want to keep the condtioned air in the dining area.
Anyway, thats my opinion, hope it helps.

If the objective is to cool the cooks off, then spot cooling is the answer. These look like 6" flex hoses hanging from the ceiling with an adjustable hand damper control at the end of the flex. These are in use in factories where radiant heat and high ambient temperatures are encountered. The only drawback is that these are SPOT cooling only, There may be 6 drops in the space but they are useful only where someone is standing in a small area where the air can blow on them. You close them when not in use. This may be all they need just to have a place to get some cool air relief. The problem is, will the manager pay for installation and power to operate them?
Mike

I have seen a few kitchens with heat pump style water heater. They all need hot water. Heat the water and cool the air at the same time. Most kitchens I work in are air conditioned. That does not mean they are going to maintain 75 degrees. In the middle of the shift It gets a little warm, but there is less load on the dining room AC.