Controlled Atmosphere Cold Storage

[Samarjit Sen]

I need informations on Controlled Atmosphere Cold Storages for Storage of Fruits and Vegetables. Further can any one suggest a Book from where I can know more about the Controleed Atmosphere and Modified Atmosphere Cold Storages.

[US Iceman]

Here is a very reasonably priced booklet.
http://www.nraes.org/nra_order.taf?_...oknum=nraes-22

Some other information...
http://energyideas.org/formats/defau...h,t,1,f,1,2343

http://www.intracen.org/Tdc/Export%2.../pafa01eng.pdf

http://www.icastorage.com/pdfs/Adver...20Ethylene.pdf

http://www.ipenz.org.nz/ipenz/public...eral/6chen.pdf

http://www.techstreet.com/cgi-bin/de...uct_id=1051107

Hope these are helpful.

[nh3wizard]

I believe that information can be obtained in the Commodity Storage Manual through http://www.iarw.org/hq/institute/

[willies boy]

Probably be easier for someone to explain in LAYMANS terms else ya might get some copper whose doing a bit of fridge on the side giving his two pennyworth

[Samarjit Sen]

Sorry willies boy. I could not catch on to what you wanted to say.

[Josip]

Hi, Samarjit Sen

I need informations on Controlled Atmosphere Cold Storages for Storage of Fruits and Vegetables. Further can any one suggest a Book from where I can know more about the Controleed Atmosphere and Modified Atmosphere Cold Storages.

This is not exact what you asked for, but I believe useful.

http://postharvest.ucdavis.edu/Produ...ts/index.shtml

Best regards, Josip

[Samarjit Sen]

Thank you Josip,

I already have this site It contains very useful information for Post Harvest treatment of various produces.

Thank you very much,

[john doersom]

Over the past 35 yrs. I have built CA storage rooms for apples and vegetables. Our rooms hold 35,000 bushels of apples.

Storage temp is +31 de. F. @ 95% Rel. Humidity.
Store for up to 9 months.
We use propane catalitic burner to convert O2 to N.

I can probably help you with your questions.

[Samarjit Sen]

Hello John Doersom,

We are installing a number of Precooling Rooms and Cold Storages for Fruits and Vegetables. For longer storage CA Cold Storages are required and I would like to know more about it as I have not designed or installed any as yet.

It would be very nice of you if you could guide me and give me informations as to such projects.

[john doersom]

It would be best if you would email me at jdoersom@yahoo.com

What size rooms are you planning on using for CA.

Our rooms are approx. 40 ft. by 40 ft. by 30 ft. tall.
To controll humidity, we use 2 ea. 10hsp. R-22 condensing units, each with 3 evaporators with elect. defrost. Condensate drains to the floors with hand valve to divert out of the rooms after humidity is established.

We hold approx. 15,000 bu of apples in 25 bushel wooden bins stacked 9 bins high. It is inportant that air flows thru the fork lift openings on the bottom of the bins. Airflow is directed toward the evaporators.

After the rooms are full the door is sealed and we use a catalitic burner to draw O2 from the room and send Nitrogen back in to the room, until the room contains 92 percent Nitrogen atmosphere.

The buildings are of stressed concrete with 6 inches of sprayed on polyurethane and then coated with a fire proof material.

john doersom

[Samarjit Sen]

It would be more convenient for me if we talk in terms of kg of weight instead of bushels.

To start with I am interested in having CA Cold Storage for Grapes and Promeganates. The quantity of each product would be 100 Ton. First I would like to know the dimension of the space required and secondly under the CA conditions what would be the maximum shelf life of these products.

[john doersom]

Howdy,

Each one of our CA rooms holds approximately 500 tons of apples. The apples come into the rooms in their wooden storage bins direct from the orchards. The apples are stored until approx March when international delivery is called for. Then one room will be opened and the bins of apples will be sorted and boxed and put into another regular storage room until shipment via container that is put onto boats.

A few years ago, we rented our rooms after the apple season ended in April or May. We stored grapes for a distribution company. At that time we CA'd the grapes for 3 months. The grapes arrived in cardboard boxes which wrapped on pallets. We stored approx. 100 tons of grapes.

We didn't have the time to use our catalitic burner to create the CA atmosphere, so, we used Nitrogen supplied by AIR PRODUCTS(tm) to fill the room.

Currently, we are storing apples from PERU in 3 of our regular storage rooms. They are boxed in 4/5 bu. boxes.
Approx, 1000 tons.

Hope this helps.

For your grapes, I would build a room 40x40x30 ft. tall.

I will have to convert pounds to Kg, later.

[john doersom]

SHELF-LIFE,

The term us used, here, to estimate the amount of time CA apples and/or fruit is marketable.

Shelf-life on apples/fruit for CA stored fruit is relatively short. Apples tend to deteriorate approximately 2 weeks after being removed from storage (CA storage)
Here, though, the apples are generally purchased and consumed before that time.

I prefer regular storage fruit over CA stored fruit/vegetables. Shelf life is longer for the consumer, provided the fruit/vegetables are stored in high humidity conditions in the household refrigerator. Plastic bag filled with product and some water helps in the normal refrigerator which has a relatively low humidity.

[Samarjit Sen]

I would like to ask you some questions.

1. You have suggested a room of 40 ft. x 40 ft. x 30 ft. ht. Supposing the rooms are only 12 ft. ht can we have 2 or 3 rooms measuring 50 ft. x 30 ft. x 12 ft ht for storage of 100 Tons of Grapes or Promeganate.

2. What is the refrigeration system suggested by you. We are using Forced Air system by putting a DX Coil, and a water cooled condensing unit with semihermetic compressor. For humidity we put an adiabatic humidifier. With such a system we are maintaining + 95 % RH and -1 Deg. C Room conditions.

3. What is the quantity of N2 required. Is there any standards of supplying the gas and exhausting the gases depending on the quantity of the products being loaded.

John I shall be bothering you a lot, so that I know more about this system.

Thanks.

[john doersom]

Howdy,

I think that your smaller rooms will work OK for you.

We have 2 refrig. systems in each of our rooms. After the product is cold, we use only 1 system to keep temp at 31 deg. F.

For your smaller rooms, I would suggest 2 smaller systems of approx 5 hsp. ea. with each having 2 dx evaporators. For humidity, I use the condensate drain to the floor.

We keep approx 2 inches of water on the cement floors of our cold storages. However, we also have overflow valves to divert condensate water out of the rooms after the floor is flooded.

Product load (heat) needs to be calculated for your grapes. How much product per 24 hrs? What is the temp of the product entering the rooms ?

Apples are normally entering the rooms at approx. 80 deg.F. We put approx 10 tons of apples ina room in 24 hrs.

After the room is loaded and the door sealed, we then start to remove the O2. It will take approx 30 days to chill the entire room to 31 deg. F.

I do not know the quantity of Nitrogen that is required to fill the room to 92%. It takes our catalitic burner approx 2 weeks to accomplich the task.

What size refrigeration system are you using? Tonnage?

Here in Pennsylvania, we start harvesting apples approx Sept. 1st. until October 30th. By November 30th the apples are chilled in all of the rooms. We just run 1 ref. system after that. I leave PA and go to Florida, where I maintain my WINTER office and monitor the cold storage rooms from there. If we have any emergencies, I can be at the orchard withing 8 hrs. Of course, with the rooms full of apples, sometimes it takes a week before any temperature/humidity changes will be noticed.

By the way......We stack 50 pound bags of lime on the top row of apples to keep the nitrogen level stable. The lime obsorbes and stores the Nitrogen in the room.

When it is time to open the rooms, we open the door for 24 hrs. before entering the room. Otherwise, you neede an oxygen mask and tank to enter.

In th past, we CA'd apples, pears, vadalia onions.
We were the first in the country to be able to convert an apple storage to store vadalia onions, successfully.
We worked the onions between apple seasons for 4 yrs.

[john doersom]

I forgot to mention........

Because our CA rooms are air tight, outside atmosphere pressures will cause the inside of the room to expand and contract. There is a 4 inch pipe exiting the room to which is attached a large plastic bag, approx 15 ft. long by 8 ft. high. This plastic bag will expand and contract with the outside barometric pressure changes.

Example......Inside room pressures will be higher when a low pressure system moves through the area, and conversly, the inside room pressures will be lower when a high pressure system moves thru the area.

Also, built into the walls of the CA room is an emergency pressure release incase the expansion bag system fails.

Otherwise, the CA room would actually blow apart.

[Samarjit Sen]

Hi John Doersom,

First the Grapes after grading and packing are precooled in a room where the temperature is maintained at -1 Deg. C with a RH of 95%. The grapes are precooled for 6 hours by when the core temperature is 0 Deg. C. For humidity we use an adiabatic humidifier. The Precooling Room can hold 5 to 7 Tons of Grape at a time and the size of the room is 15 ft. x 25 ft. x 12 ft. high. The refrigeration capacity is 80,000 BThU/hr. There is only one unit. After the Precooling of 6 hrs the grapes are shifted to a Cold Storage Room measuring about 30 ft. x 50 ft. x 12 ft ht. This can hold about 50 Ton of Grape. Here the temperature is maintained at 0 Deg C with a RH of 90%. The refrigeration capacity is 60,000 BThU/hr.

The rooms are constructed of Polyurethane Foam pre coated panels. These rooms are air tight.

For Grapes the CA requirements are 1-5% CO2 and 2-5% O2 and a RH of 90-95%

What I would like to know that is Nitrogen required for Grapes CA.

To attain the above what are the equipments required. The Grapes only after Precooling shall be shifted to CA rooms.

[john doersom]

Yes..Nitrogen will be required to bring the N level to approx 92%. You are correct with your percentages of CO2 and O2.

Being that nitrogen composes most of our breathable air on earth, some say to about 82%, we need to boost the CA atmosphere only to an additional 10% more N.

Now some interesting news................

I am not sure about the EASTERN COUNTRIES, but, here in the U.S., CA cold storage for fruits and veggies are becoming OBSULETE Technology.

For the past 3 yrs. or so some of our larger fruit growers are now using a chemical to wash-down the fruit and then put the fruit into regular storage rooms. The chemical is to do the same as CA storage fruit.

In fact, we are in the process of designing a new cold storage room for storing 3000 tons of apples that will use the new process.

I do not know the name of this new chemical process, however I can ask the Pennsylvania State University, fruit division to do a search. In fact they, the University, has all kinds of info. that they publish FREE. Grapes are becoming a major agricultural crop here, now.

Foreign competition has put a lot of our smaller growers out of the apple business.

[john doersom]

Since I will be gone for the next 2 weeeks, I suggest that you try this website for Pennsylvania State University:

http://tfpg.cas.psu.edu/77.htm

Good luck john

[Samarjit Sen]

Thank you John,

The site has very useful information on fruits and vegetables. I shall contact them to know and learn more. In case hey have some literatures, I shall procure them. I am already in touch with U C Davis Eductaion and have recieved some information.

This is an application of refrigeration which could benefit everyone.

In case you can locate the name of the chemical, please do let me know.

I shall keenly await your return so that we can carry on learning more.

[Ravi]

Heatcraft's engineering manual has excellent data and can be an invaluable tool for a cold room designer. I also suggest you to get a copy of CalcRite software from keeprite website. I have checked the results using Dossat's procedures and both concur to great extent.

The N2 calculation is not very difficult. suppose, if you go for 5% CO2 and 2%O2 then the N2 should be around 93%. Atmospheric air contains about 79% of N2 and if you have an area of 510cu.mtr, then extra N2 requirement is about 510x(0.93-0.79) = 71.4cu.mtr. However, this calculation assumes only O2 being replaced by N2 and not the air inside the proposed coldroom. You may require approximately 3 times this figure if you assume the N2 replaces air inside the coldroom.

I would go with a CO2 sensor controlling a CO2 injection valve and an O2 sensor controlling an N2 injection valve, for regualrly maintaining the above said concentrations.

The airlock refrigeration capacity seems to be a bit less if I assume to reduce to the grape temperature from 30C to 0C in 6 hours time.

PS: Specific heat of grapes is 0.86btu/lb F or 3.6kJ/kg K.

[Samarjit Sen]

Dear Ravi,

Thank you for the informations. I have the Heatcrafts Engineering Manual as well as the Dossats book. I am using only Heatcrafts Larkins Evaporators for all my projects. We have been asociated with them for a number of years.

Regarding the requirement of Nitrogen I have understood the same from what you have stated. I am trying to locate more informations.

For the Precooling of the Grapes from 30 deg. C to 0 Deg. C in 6 hours, the refrigeration plant is maintaining the conditions very nicely. I had manually calculated the load and also used Heatcrafts Probox software and Russells software. A number of plants installed by us are working very efficiently.

I shall very much appreciate if you could provide me with the website of keeprite as stated by you.

With best wishes,

[Ravi]

This is a good software for coldroom calculations.

http://www.k-rp.com/calcrite/RTcalc1.htm

[Ravi]

ah! seems I crossed the threshold quantum of posts to be allowed to post URLs.

[Samarjit Sen]

Thank you Ravi,

I have downloaded the software and will study it tomorrow.

In case you needany information or guidance, please do contact me.

[marcus64]

You can get many infos from UC Davis site (as reported above). You can also contact Fruit Control Equipments - Italy for techncial supports

[ifti4ku]

Hello everybody
Please can any body sent me few manufacturer of Controlled Atmosphere,also send some study material related to CA.I am new person of this form, must help me

From
Iftakhar ahmed

[Josip]

Hi, ifti4ku

welcome to RE forums..

Hello everybody
Please can any body sent me few manufacturer of Controlled Atmosphere,also send some study material related to CA.I am new person of this form, must help me

From
Iftakhar ahmed

please, try to make search on RE forums for CA ... for sure, you will find a lot of links related to your needs...

Best regards, Josip

[CEOAgristorage]

Dear Samarjit

I got your coordinates from a very interesting exchange you had, a few years back, on Refrigeration Engineer Forum on the subject of CA.
I am thinking of establishing a 300 ton CA storage in Pakistan, for storing different fruits and vegetables. I would be most grateful if you could guide me on the following issues :

How has your experience been with the CA Storage ?? Has it given the desired results ?
I assume you have managed both CA storages and regular Cold Storages. In terms of regular maintenance and operating costs, and breakdown of equipment, how would you compare the two types. From the literature it is clear that CA facilities are more sophisticated technologically. Also in terms of product quality at end of storage period --say for Grapes and Pomegranate--what were the key advantages that you found between these fruits stored in CA versus those stored in regular CS .
What is the electricity consumption -- Kwh per Ton-- for a typical facility that you have managed ?? A rough rule of thumb would do.Also do you have a standby generator. Out here electricity outages are 6-8 hours a day , and standby is a must.
What are key operational and maintenance issues that you face on a daily or regular basis, or emergency issues The reason I am asking some of these technical details is that our CA storage will perhaps be the first such unit in Pakistan, and we want to be sure that we don't get into a technology which becomes a nightmare in terms of operations and maintenance --getting trained operators, timely supply of parts , timely routine and emergency maintenance.

Also can I have your telephone number , so we can talk over the phone if you prefer to respond to the above by phone.

Thanks you for your time