port a cooler 3

7/31/2019 Port a Cooler 3

1/7

Post Harvest Cooling/Storage for Cut Flowers

David S. Ross, Extension Agricultural Engineer, University of Maryland

Refrigerated storages provide growers with the capability of extending the useful life of cut

flowers and therefore widening the market window for the product. Cut flowers are alive. At lowertemperatures flowers have a lower respiration rate and consume their stored energy much slower.

The flower stays alive longer at the cooler air temperature.

A refrigerated room should be well insulated to keep the outside heat from penetrating to add to the

heat load to be removed from the inside. Doors should seal tightly to keep cold air and moisture

from leaking out or warm, moist air from leaking in to condense on the cold surfaces.

Water vapor moves from high vapor pressure to low vapor pressure. Generally, the cooler the air,

the lower the moisture holding capacity and the vapor pressure are. A vapor moisture barriershould be placed on the outside wall side of the insulation to stop the penetration of moisture into

the insulation where it might condense and lower the benefit of the insulation.

High humidity is desirable in the refrigerated storage to prevent a water vapor differential between

the flowers and the air. Keep the humidity high so that the flowers do not dry out and wilt. Flowers

need to hold onto their vital moisture content to live.

Moisture inside a cold storage room moves from the flower to the air and from the air to the

cooling coils of the air conditioning/refrigeration system. The cooling coil (evaporator) typically

operates at a lower temperature than the storage room (necessary for heat transfer) and condenses

water out of the air onto the cold surface of the coil. The continual water loss contributes to the

lower humidity in the storage room air. Examples of this process are shown by condensate

dripping from window air conditioners, auto AC units, and regular household units. The airbecomes cooler and dryer with most systems.

After the air exits the cooling coil it is heated slightly by the storage room air. The greater thedifference between the air temperature exiting the coils and the storage room air, the lower the

relative humidity will be in the room. This lower relative humidity air has a lower vapor pressure

than the flowers and drying will occur again. This is a continuous process.

Cooling equipment must be selected correctly to obtain a high relative humidity storage room. The

refrigeration system must have a cooling coil (evaporator coil) with a large surface area for the air

to pass over. The evaporator must operate at a temperature very close to the storage room air

temperature. The temperature differential between the evaporator coil and storage air must be

small. The smaller temperature differential, the better conditions are for high relative humidity.

Typically, the air velocity is also relatively low for cut flowers so that the air movement does not

damage the flowers. The fan may be sized larger in diameter to maintain a large airflow at a lowvelocity. Large diameter, low velocity fans should be less noisy than smaller diameter high-speed

fans.

Moisture can be added by spraying water onto the storage room floor and letting it evaporate. Also,water can be sprayed or misted into the room air with a misting nozzle.


2/7


3/7


4/7

old Chain Management

What is a Cold Chain exactly? Cold Chain is a logistic system that provides a series of facilities for

maintaining ideal storage conditions for perishables, from the point of production to the point of

consumption in the entire chain.

The various components of a cold-chain are :

Procurement and delivery systems

Pre-cooling facilitiesRefrigerated vehicles

Chilled Store (Normally for temporary storage)

CA Store (Normally for long term storage)Grading, sorting and packaging

Warehouses

Information systems

Status of Cold Chain ManagementThe cold-chain management is perhaps still the biggest glaring-gap in India's agro-logistics. Cold storage

facility is there only for 10% of the produce. As per existing reports, over 3,500 existing cold storagewarehouses have only around 13 mn ton storage capacity with old storage technology.

Some imminent problems with the cold chain in our country are:The modern Post harvest management is almost non-existent in our country, except for parts.

Non-existence of world class Integrated Cold Supply Chain across the country - isolated stores without

logistics supportThe cold storages mainly work on old technology and hence are not that effective.

Cold stores are often used for storing low value products.

Many a time cold storages opt for short duration storages dictated by market imbalances.

Many a time cold storages opt for short duration storages dictated by market imbalances.There is absence of cold storage facilities at most of the airports. At present only six international

airports i.e. New Delhi, Mumbai, Chennai, Hyderabad, Bangalore and Thiruvananthapuram have these

facilities for perishable cargo. Under such circumstances several hours (sometimes even days) would lapsebefore the cargo could be loaded to the connecting flight. During this time the cargo would remain under

high temperatures and low humidity. The result is very obvious.

Constricted cargo space on flights: Airlines do not prefer to carry cargo which is seasonal, perishable, voluminous yet not in such large quantity. This is the exact nature of floral cargo. Because of the small

volume of flowers they mostly have to be transported on regular flights which have limited cargo-space.

Developing an efficient cold-chain: Strategic Advantage for Indian Floriculture The real spirit of the cold

chain process is to get the finest products on time, every time, in perfect or precise condition. Appropriateor new technology that can enhance the performance of the cold chain process is no doubt important.

However, implementing the right technology is not enough. Cold chain managers must take into

consideration that even a minor variation in the temperature can cause damage to the product andmaintaining the quality level of the product will be the key. In the times to come, the cold chain will

definitely be a strategic competitive advantage, and India has a lot to gain in terms of growth in profits as

well as reputation in efficiency and quality in the global floriculture market. The need of the hour is todevelop an model which provides a unbroken cold chain to flowers right from the point-of-origin (growers)

to the point-of-consumption (customers). Components & major players in the integrated cold chain (refer to

Diagram 2)1)Grower : The grower is a key player in the entire cold chain. Research studies indicate that in many cases


5/7

the problem may actually start at this point of origin. Specially in a country like India, where the awareness

level of the farmers is not very high and considering that commercial flower cultivation has not reallycaught-up in a big way like cereals and pulses, there seems to be considerable room for extensive extension

activities. The manner and the stage at which a flower crop is harvested may be critical in the chain.

Similarly awareness and facilities for modern post-harvest management are the need of the hour. 2.

Collection Centres : The primary task at the collection centre is pre-cooling to takeoff the field heat. Theflowers cannot be and must not be transported in the field condition and are required to be pre-cooled

before shifting them onto refrigerated vans/ trucks/ containers. 3. Refrigerated Transport : In case of road

transport we have to use refrigerated vans, and in case of rail transport we may use refrigerated containers.In our country, we need both refrigerated vans and containers in adequate quantity, especially at smaller

centres and not just in metros. 4. Terminal/Holding Cold Storages : Normally terminal or holding cold

storages must have a pre-cooling facility to reduce the quantity of harmful gases and also a humidityoptimizing unit to maintain the right level of moisture level. They also have grading, sorting and packaging

facilities. The terminal cold storages at Airports also need to be revamped both in terms of capacity and

number. Again the focus has to be on relatively smaller airports rather then focusing only on major airports.Only then a truly intensive network can be developed. 5. Air-Cargo : There is a critical need to create

adequate cargospace, both on domestic as well as international circuits. Without that both on domestic andprimarily on export front we cannot emerge as a floriculture force to reckon-with. I remember listening to a

extension-worker from Srinagar airing his concern an International Floriculture Conference way back in2005. He said that a freight of flowers was lying at Srinagar airport for about a week, since no airline was

ready to carry the cargo. His frustration was palpable, since he was actively involved in motivating the

farmers there to takeup flower cultivation. Another problem at airports is the enormous handling andloading time that is taken. This has also to be reduced considerably. APEDA's praiseworthy efforts:

APEDA is building cold storage facilities at more than a dozen airports in the country. Besides the six

international airports which already have cold-storage facilities, more airports will be covered. Biggerairports like Kochi, Kolkata, Guwahati will have elaborate cold storage facilities, including a receiving area

for perishable produce, weighing, X-ray, palletization and storage. Smaller airports such as Tiruchirapalli,

Srinagar, Jammu and later on Imphal, Dimapur, Agartala - will have refrigerated containers that can store 8-10 tonnes of perishable products. The facilties may cost the government in excess of Rs. 55 crore but the

more is expected to increase the exports of perishable food products by 25% in a year's time. 6. Receiving

Airports : Cold storage facilities must also be ensured at receiving airports. In case of shipping cargo,

refrigerated cargo container terminals may serve the purpose. Adequate and swift transportation to themarkets must also be ensured. 7. Market/Floral Retail Outlets : The cold chain must not be broken even

here. Although in India it may not sound so common, internationally even at florist outlets, cold display

boxes are there which have regulated temperature and humidity to maintain the freshness of the flowers.The boxes are transparent to ensure display at the same time. One such product is refrigerated display case

for flowers and the like. They are open-top, refrigerated case which may be mounted on a cart, booth or the

like. The display case includes a plurality of elongated bins placed side by side in a stepped array from an

upper bin at the rear of the case to a blower bin at the front of the case. The bins are thus advantageouslyarranged to provide a best possible display of merchandise within them. At the same time, the stepped

arrangement permits a slow flow of refrigerated air as from back of the case, from the upper bin, and

forwardly into the lower bin with the cool air cascading over merchandise especially within the lower bin.

The integrated cold chain seeks not only a change in infrastructure but also a change in mindset. The cold

chain management in India has to undergo a transformation, both in structure and approach. Let us lookthrough the prism some of the major players and their roles (future) for:

ConclusionCost may come as a limitation but research on successful cold chain models in other countries suggests that


6/7

the cost factor starts wearing off with economies of scale. It is just like getting out of the present vicious

circle into a virtuous cycle that we are dreamingoff. So with improvement in cold chain logistics the overalltrade (both domestic as well as export) will get a boost, leading to large volumes and improved bottom-

lines. The key is to integrate various elements and stakeholders of cold chain management, forge workable

partnerships (even public-private partnerships wherever possible) to realize the vision for an efficient and

integrated cold chain management for flowers throughout the country. Of course this has to be followed byaggressive marketing, to see that the demand for Indian flowers goes up both in domestic as well as export

markets. This would definitely be a very strong and concrete step forward towards our ex-president Dr.

Kalam's dream of seeing a blooming floriculture industry but also gradually make India a key player on theglobal floriculture scene.


7/7

port a cooler 3

Documents