View Full Version : Storage space between pallets

30-09-2004, 09:39 AM
Anybody knows a link somewhere on the www where I can find optimum space between pallets for long term appel storage (15 to 18 fts high) to assure proper air ventilation between the pallets?

30-09-2004, 12:32 PM
Hi Peter

Not really my cup of tea but I found this on the net

Ventilation should be used after packing. The Washington industry has removed most of the hand-holes in the boxes, leaving no ventilation. This is an unwise policy in my opinion since it impairs cooling palletized fruit. It would be better to have boxes with vent holes and to use forced air to cool the fruit as is done in the California berry and stone fruit industries

Another alternative is to loosely stack the boxes on the pallet, using the same techniques as the pear industry. The separation of the boxes on the pallet would allow the air to circulate along the sides of the boxes rather than simply speeding past the outside.

Fruit cooling rooms should have a great deal of air circulation, and holding the temperatures below 30F would help speed cooling. Fruit should be carefully monitored and removed when cool.

Here's the linkhttp://postharvest.tfrec.wsu.edu/topical.php?variety=storage&keywrds=apple&token=Apple%20Storage

01-10-2004, 06:09 PM
Thanks Frank.
Perhaps a more common question: what space between pallets/goods do you advise your clients in a normal storage cold- or freezer room?
What space on the opposite wall of the evaporator (the side where the cold wind blows and hits the wall?
I always thought a space equal on the height of the evaporator.

01-10-2004, 08:15 PM
load them high so you can walk on top and get to valves ;)

01-10-2004, 08:38 PM
no matter what they are 'advised' come christmas time every freezer and coldroom will be packed to the gunnels

ever see a blast chiller loaded in a busy kitchen ??



01-10-2004, 09:00 PM
Hi Peter.

In marine freezer containers you have a mark on the wall for maximum hight, maybe 5 Cm to the ceiling and about the same on the floor.
Between the pallets, there is the space for lifting them so I think you don't need more space for air to move.

The boxes of fruit also should have holes in them for better air movement and another important factor is air velocity.

I think that at the bottom line, the more fruit you can store under desired conditions, the more efficient the cold store is.

Chemi :)

01-10-2004, 11:10 PM

I dont know if this helps, but a few years back I went to Cape Town and they have these huge apple orchards there.......The cold stores need to be seen to be believed..........they are enormous.

The apples are stored there for months until ready for shipping to Europe. Someone from up there might have the answer you looking for.

Maybe some South African engineers..........Try a Del Monte site for starters

02-10-2004, 09:25 AM
5% of the volume around each stack

04-10-2004, 04:16 AM
You should consider 40%~60% free space in the room for air circulation. More important than the distance between pallets, is that boxes on the pallets have holes big enough to let cold air circulate between the fruit. If they don't, the pallet surface may still be at desired temperature while the inner apples are getting spoiled. Big fruit companies spend a lot of money designing the adequate cartons.

Best regards,


04-10-2004, 04:33 PM
For long term fruit fruit storage, with the crates stacked in lines there should be 10cm betwen the lines of boxes, a 25cm gap from the walls and a 75cm gap between the ceiling panel.

The most important thing is that the airflow is ducted over the top of the boxes and pulled back through.

What are the apples being stored at, my data says 0.5'C and 95% humidity and are the apples being pulled down in temperature in the same room?


04-10-2004, 06:25 PM
It is important to notice the difference between precooling the fruit and storing it. As it has been mentioned, it is important to make air pass through the apples, but that is expensive.

In precooling rooms, we use upto 60HP centrifugal fans to cool down pineapples from 27C to 8C in five hours, but afterwards, fruit is sent to storage rooms where pallets are stacked before dispatch. This holding rooms use less than 10 HP in fan motors as this coils are sized not to cool down the load, but to hold it removing the infiltration and respiration of fruits.

The main issue is not only the 50HP in direct power consumption, but you should also recall that a lot of electrical power is transformed in thermal energy, that should be removed from the chamber, too. So, bigger compressors are required, which means bigger condensers, bigger coils, bigger pipes...

04-10-2004, 06:55 PM
I agree with the comment regarding the difference between precooling and storing however there are a couple of additional points.

A lot of growers only use one room, especially for short term storage. They pre cool then when the product has dropped to the required temperature the fan speed is lowered and the compressor(s) is unloaded to achieve a stable TD (4K normally).

With long term storage (up to 6 months for apples) it is usual to use the same type of strategy as pre-cooling to achieve the required standard of product. It is essential that the air pulled through the boxes and the TD is short enough to keep the humidity at the required level.

It is also possible to use a cooling tunnel within the cold room and use some of the discharge air to cool the general storage area, if done correectly it can be quite economical.


04-10-2004, 07:07 PM
We keep on working with "issues"... :) The problem on using the same chamber reducing the fan speed is that your TXV is selected, and adjusted, at full load. If load variation is going to be large, you better have an split coil, with two, or more, TXVs. In large systems, DX is not usually considered as an option when you have variable loads.

04-10-2004, 07:34 PM
I would use a split coil, 2 TEV & 2 compressors on a basic job even I was just a long term storage room without any pre-cooling.

Have you ever used ozone in any storage rooms to clean the product after it has been pre-cooled?

To satisfy my curiosity can you give me a couple of examples of typical applications that you install.


05-10-2004, 05:59 AM
If room is only a holding chamber, I would have gone for two separate systems, 50%~75% each. In case one fails, the other could still have acceptable performance.

Our experience in controlled atmosphere relates mostly to ethylene on ripening rooms. We have experience with ozonized water for washing fruits.

I am a consulting engineer, and we do mostly industrial jobs. Two examples are banana ripening rooms with a capacity of 200 tons/day of fruit each, and pineaple precooling chambers of 20 tons of fruit per batch per room (5 hours). This are ammonia systems with screw compressors. But we do smaller (and bigger) systems, too.

john doersom
23-01-2005, 11:00 PM
In our apple rooms, we always position the pallets/bins so that the fork lift faces the evaporators. We stack the 25 bu. bins 9 high. Each room holds 30,000 bu.

Air is drawn thru the fork lift openings. The bins are stacked tightly together, side by side. To check air draw, thru the bins, watch smoke be drawn up to the evaporators. We store apples at 31 deg. F. with 95 % RH. for upto 9 months.

john doersom
23-01-2005, 11:09 PM
We generally stack apple bins 9 high with the fork-lift openings faceing the evaporators. Air flow is thru the fork-lift openings back to the evaporators. We usually store 35,000 bu. in each of 5 rooms.

We store the apples for up to 9 months at 31 deg.F 95%RH. The bins are stacked with approx 6 inches between rows. Approx. 2 ft. from rear wall.

Hope this helps.

24-01-2005, 07:25 PM
I did*t read nothing here about controll of CO2 ,O2 wich is important too.,I think.

john doersom
24-01-2005, 07:38 PM
Our rooms are CA. Where-in we keep the apples under a nitrogen environment. Approx. 98% nitrogen atmosphere. We utilize a catalitic burner to convert the oxygen into nitrogen.