• Pennsylvania

PRODUCTSHumidification & Refrigeration

Why should you humidify the air?

Humidification is a plus especially from an economic point of view. Air humidification in potato, vegetable and fruit storages can generate profits if used correctly. From a financial point of view, the principle is simple – the larger the amount of quality products is delivered from a storage facility, the larger the profit is.

The Theory of Cooling and Humidification

Produce is biological matter that creates heat while breathing. It is necessary to remove that heat by cooling a stored product in order to slow down biological processes and maintain high quality for as long as possible. However, the cooling process, although necessary, causes the largest losses in weight and quality. No matter how a storage area is cooled, whether by refrigeration and evaporators or by ambient air, the stored product always dries when it is cooled down. The reason for this is that the cooling air is only partially saturated with water, and it can therefore take in extra water in the form of water vapour. Water evaporated through pores of produce during breathing is then taken out of the storage area by air circulation during the cooling process, and this results in the loss in the product’s weight. The water is „lost“ either by condensing on the coolers (evaporators) during refrigeration or is taken out together with warm air through outlet hatches during ambient ventilation.

Our goal is therefore to reduce the amount of „lost“ water to a minimum and thus save substantial money to store keepers.

No-Droplet Humidification

Agroel manufactures humidification systems that work without producing water droplets. Water evaporates from special cross-fluted porous pads that are continuously being saturated with water while air passes through their unique structure.

Our approach is to supply only enough water to the air as is able to evaporate. No water droplets are supplied to the storage area and therefore the risk of disease spreading (e.g., molds) on wet produce is significantly reduced.

The saturation efficiency of humidifying pads in our systems is up to 95 %!

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COMPONENTS OF BULK STORAGE

Agroel supplies complete solutions for box storage. Below you can find information on their main components:
  1. 1. A fan distributes air throughout the storage.
  2. 2. An inlet control hatch lets the fresh outdoor (ambient) air enter the storage area. The ambient air can be mixed by the hatch with indoor air in order to achieve the required temperature of the air that enters the storage area(compare to a bathroom water valve). The hatch is operated by an electric linear or radial actuator with a position sensor.
  3. 3. An outlet hatchlets the warm air leave the storage area. The hatch is usually placed near the storage ceiling in one of the outside walls, often in the same wall as the inlet hatch. It is also operated either by a radial or a linear actuator.
  4. 4. An evaporator (cooler) cools recirculated indoor air that passes through it. An evaporator consists of copper pipes for refrigerant distribution and lamellas for heat transfer.
  5. 5. Air-humidifying panels not only humidify the air that passes through them, but can also provide a significant cooling effect.
  6. 6. Hatch toothed drive rackscan be used for operating multiple inlet and outlet hatches. Racks are not needed if linear electric actuators are installed, because usually one linear motor controls one hatch.
  7. 7. Radial or linear electric actuators are used for operating hatches.
  8. 8. Retaining walls. The walls of some storage facilities are not constructed to withstand the high pressure of a produce pile. For that purpose, Agroel supplies removable retaining walls. These removable retaining walls can also be used to partition a large storage unit into smaller cells.
  9. 9. Pressure chamber (plenum)is a very important part of a ventilation system. It distributes air pressure into lateral ducts. The pressure chamber, mixing chamber and lateral ducts are subject to qualified calculation and design.
  10. 10. Ventilation ductscan be placed above or below the floor. For storage adaptations, where the concrete floor is usually finished, the above-floor ducts are usually more favourable. In other cases, we recommend underground ducts.
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STORAGE SOLUTIONS AND A PROJECT PREPARATION

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A professional design of a ventilation system is fundamental for your future storing success. Agroel specialists will be glad to offer their advice to solve any of your storage problems and help you meet your needs. We provide consulting services free of charge to all our customers.It is not a simple task to correctly design and calculate aspects of storage facilities. We have already created hundreds of alternatives for customers with bulk storage facilities – let us create alternatives for you as well.

Design and calculations. The following details outline what calculations and designs are necessary to successfully create an appropriate storage facility to suit our customers‘ needs.

  • Calculating the required air volumes for all storage phases and choosing the right fans
  • Calculating the inlet and outlet hatch areas
  • Calculating and designing the mixing chamber
  • Calculating and designing the pressure chamber
  • # Selecting and designing ventilation ducts. This process includes the calculation of gaps in the ducts for even air distribution along the whole length of a storage area.
  • Correct programming and setting of the Agroel control system with regards to the storage type and requirements for the particular product that is going to be stored

The use of humidifying pads provides more benefits, as well. Water evaporation also results in cooling the air that passes through the pads. This simple physical principle leads to further substantial savings for storage keepers. Air cooled this way can be used to cool produce and preserve its water content! Agroel has introduced the humidifying pads in a wide range of air-treatment systems. The cooling effect feature is also useful in ventilated storage areas. During suitable weather conditions even outside air that is warmer then the produce can be used for cooling. Its temperature can be decreased by several degrees and humidified at the same time. This way of cooling is significantly more economical than cooling with refrigeration systems. Agroel now supplies systems that are equipped with all three cooling methods: ventilation, refrigeration and humidification, and our system is one of the most advanced on the market.

In general, produce that requires high levels of humidity benefits from our system, especially in the reduction of softening and the loss of weight. These concerns mainly impact potatoes, root vegetables and apples, whose specific biological storing stages must be guaranteed. Agroel control systems are equipped with many product-specific modes and contribute to successful storage.

Refrigeration must be used if a constant produce temperature cannot be guaranteed by ambient ventilation alone. In such cases, a refrigeration system functions as a backup to a ventilation system and provides an alternative source of cool air in case it is not available outside. A mass of cooled stored material has a large temperature capacity, and it can maintain its temperature for a certain time even in those periods of warmer weather. Not every storage facility must be equipped with refrigeration. We recommend considering these issues in making a decision about installing a refrigeration system:

  • Storing temperatures and storing seasons – availability of cool outside air changes during the year
  • Geographical location of the storage facility
  • Storage economy – refrigeration is not affordable for some products, while for others it is crucial to maintain top quality
  • Sensitivity of the stored product to temperature changes
  • Frequency of loading and unloading

Stored products form organic substances (e.g., ethylene and CO2) that negatively affect the quality of the produce or speed up unwanted ripening. Agroel therefore recommends a combination of ventilation and refrigeration systems so periodic exchanges of storage air can be performed and concentration of gasses reduced.

Agroel refrigeration systems are designed with respect to the arduous conditions under which they are often operated. Refrigeration can be installed in the pallet storage units (ISK models CP) as well as in bulk storage areas.

Main specifications of our refrigeration systems:

  • Installed compressors are hermetic types, made by renowned producers like Maneurop or Copeland
  • The „Scroll“ compressor technology guarantees smooth operation in difficult conditions
  • Robust evaporators with large surface areas provide long lifespan and high efficiency
  • Fast service throughout Europe in cooperation with partner companies