Heat Pump Dehumidifiers of drying specialty crops such as dry herbs, fruits, vegetables, seeds, seafood, noodles, etc., need to be dried at low temperature between 30 – 45oC for product quality optimization. This is an important consideration as they have a relatively high commercial value. Heating ambient air to use for drying although a simple cost effective procedure is of limited application particularly at higher ambient air relative humidity because of the low allowable maximum temperature conditions under high ambient moist air conditions, it may not even be possible to dry the material conventional means. High temperature drying deteriorates the material structure and can render it unsuitable for further use. Low temperature drying of specialty crops reduces the risk of loss in nutrient content and damage to physical properties.
Heat Pump Dehumidifiers and Drying systems incorporates a dehumidification cycle that have been developed to conserve energy and handle the material gently. The dryer operates using a heat pump where both sensible and latent heats are recovered from the exhaust air. The heat is then recycled back through the dryer by heating the air entering the dryer. The heat pump drying system is a combination of heat pump dryer. Scanair heat pump dehumidifier machine adopts international standard quality which is suitable for small and medium scale production. The smallest type can be operated by only one person, and this machine need no installation, plug and play it can put into production directly when the machine is delivered. The customers can purchase one or more dryer according to your needs. Also we offer customized dryer for them. The machine can settle the technical data of temperature and humidity in the drying process which will truly dry the materials in high quality.
Scanair heat pump dehumidifiers and dryers are widely used to dry herbs, fruits, vegetables, seeds, seafood, noodles, etc,. The materials after drying are having good quality and nice appearance. Also it has less energy consumption. Compared with the traditional dryer, it can save 70 % energy and the drying capacity can improve 50 % compare with other models. Scanair Heat pump dryer running cost just as 40% of oil burner dryer, 50% of coal burning boiler, 30% of electric boiler heat pump dehumidification drying method of the closed cycle, saving costs, no exhaust waste heat emissions, no noise pollution, environmental protection. Scanair low temperature drying technology (15-50oC/60 oC /80 oC) similar like nature drying but faster drying time cycle. Adopt closed type circulating air heating and cooling, drying, suitable for inflammable and explosive materials, poisonous material. Pungent odor of materials easily oxidized material etc,.
Drying process material no deformation, no cracking, no-discoloration, no deterioration, and no oxidation, thorough drying after drying and dehydration, less loss of nutrients, the long storage period, more than any conventional drying equipment to more effectively protect the color of the dried material, smell, last, individual form and active ingredients. installation and operation easily, just need connecting with drying chamber plug and play. Scanair India has designed a Stainless Steel Re-circulation Dryer for application use in agro processing where there is no dryer available and only open drying is being followed. Industrial Dryers, Conveyor Dryers, Tunnel Dryers, Batch type Dryers, Tray Dryers, Multi-band Conveyor Dryer, Tilting Louver type Dryer, and Tower type Dryer, continuous Type and batch type dryers The product could be dried cotton seed, soya been, soya wadi, Potato chips and dal papad, fish, mango bar, meat, fruits and vegetables, herbal products, turmeric, ginger etc,. The product is introduced into the dryer through multi-layer stainless steel trays carrying trolleys. The dehumidified hot air is introduced into the dryer and forced to go through the product for fast drying capability. Automation is introduced to create optimum temperature inside the drying chamber thus ensuring quality of products.GINGER DRYING PROCESS
Native properties of the type grown. Gingers grown in different parts of the world can differ in their native properties such as flavour, aroma and colour and this affects their suitability for processing. This is most important when preparing dried ginger, which needs rhizomes with a strong flavour and aroma. Size of rhizome is an important factor to consider when drying ginger – medium sized rhizomes are the most suitable for drying. Large rhizomes often have a high moisture content which causes problems with drying.
The traditional method is to lay the pieces on clean bamboo mats or on a concrete floor and sun-dry until a final moisture content of 10%. Drying may take anything from 7 to 14 days depending upon the weather conditions. During drying, the rhizomes lose between 60 and 70% in weight. In rainy conditions, a mechanical drier such as a tray drier should be used to accelerate the drying process. Sliced ginger pieces take only 5-8 hours to dry when a hot dehumidified air drier is used. Whole peeled ginger rhizomes take about 16-24 hours to dry in a mechanical drier. It is important to monitor the air flow and temperature during drying. The drying temperature should not exceed 60°C as this causes the rhizome flesh to darken.
Industrial Heat Pumps For Low-Temperature Heat Recovery
Industrial heat pumps can significantly reduce fossil fuel consumption and greenhouse gas emissions in drying, washing, evaporation and distillation processes in a variety of applications. They can also be used to produce steam and to provide process water heating and cooling. Industries that can benefit from this technology include food and beverage processing, forest products, textiles, and chemicals, industrial heat pumps are used in heat recovery to transfer heat from a relatively low-temperature source and “upgrade” it to a higher temperature, and to recover from high-humidity streams. Heat ex-changers and Recovery Systems in contrast are used to transfer heat from a warm stream to a cooler one.
What are the basic steps in the installation for a heat-pumps in your project?
As with any heat-recovery project, once a heat-pump opportunity is identified, the project needs to undergo a feasibility study and a detailed engineering design. However, a few areas warrant special attention:
Sizing: It is better to have a small, base-loaded installation with high operating hours than a unit that works at part load, part time.
Back-up: A process operation must still be able to run should the heat pump break down address the need for a back-up.
Alternates: A heat-pump installation will usually be more expensive than a passive-heat recovery project because heat has to be transferred twice (in and out of the heat pump), and a piece of rotating equipment may be needed.
A thorough heat-pump evaluation includes confirmation that a better alternative project has not been overlooked. Use of heat integration methods such as Pinch Technology, are useful for this type of evaluation. Pinch Technology, in particular, provides a set of systematic analytical methods and tools that help identify both heat-recovery project opportunities and heat-pumping opportunities. When heat pumps are used in drying, evaporation and distillation processes, heat is recycled within the process. For space heating, heating of process streams and steam production, heat pumps utilize (waste) heat sources between 20ºC and 100ºC.The most common waste heat streams in industry are cooling water, effluent, condensate, moisture, and condenser heat from refrigeration plants. Because of the fluctuation in waste heat supply, it can be necessary to use large storage tanks for accumulation to ensure stable operation of the heat pump.
Types of Heating and Drying
Space heatingHeat pumps can utilize conventional heat sources for heating of greenhouses and industrial buildings, or they can recover industrial waste heat that could not be used directly, and provide a low- to medium temperature heat that can be utilized internally or externally for space heating. Mainly electric closed-cycle compression heat pumps are used.
Process water heating and cooling
Many industries need warm process water in the temperature range from 40-90ºC, and often have a significant hot water demand in the same temperature range for washing, sanitation and cleaning purposes. This can be met by heat pumps. Heat pumps can also be a part of an integrated system that provides both cooling and heating. Mainly electric scanair compression heat pumps are installed.
Scanair Heat pumps are used extensively in industrial dehumidification and drying processes at low and moderate temperatures (maximum 80ºC). The main applications are drying of pulp and paper, various food products wood and lumber. Drying of temperature-sensitive products is also interesting. Heat pump dryers generally have high performance (COP 5-7), and often improve the quality of the dried products as compared with traditional drying methods. Because the drying is executed in a closed system, odors from the drying of food products etc. are reduced. Both closed-cycle compression heat pumps and cascade systems are used.
Evaporation and distillation processes
Evaporation and distillation are energy-intensive processes, and most heat pumps are installed in these processes in the chemical and food industries. In evaporation processes the residue is the main product, while the vapors distillate is the main product in distillation processes. Most systems are open or semi-open MVRs, but closed-cycle compression heat pumps are also applied. Small temperature lifts result in high performance with COPs ranging from 6 to 30. Scanair heat recovery systems absorb the wasted heat from refrigeration and air conditioning systems and converts it to free hot water by super heating the discharge vapour before the condenser. You can save money and the environment.
Since good design is essential for the long-term reputation of the technology, Scanair shall be addressing ourselves as installers, manufacturers and consulting engineers. found solutions for drying applications with Low/High Temperature Process drying Heat Pump Dryers. There are several limitations associated with traditional sun drying. During periods of intermittent and particularly during continuous rainfall season, crop drying is not possible and the risks or crop losses are very high. Sun drying is slow and weather dependent compared to other alternative drying systems. Crop quality may be low due to contamination by dust, dirt, stones and insects, while direct crop losses from theft and livestock consumption can be high. Sun drying also suffers from a high labour requirement and excessive crop handling particularly in periods of inclement weather which can result in high costs, crop damage and a loss in quality.
Scanair found the solution to the heat pump dryer in the industry with National invention patent that has safety, environmental protection, high temperature refrigerant, high efficiency heat ex-changer, no pollution and the security and stability of the heat pump structure. Our high temperature capable of 80 ˚C, heat pump drying machine is mainly used for tobacco, leather, cloth, clothing, mosquito coils, mushroom, dehydrated vegetables, grains, fertilizer, pharmaceuticals, sludge, coal, lignite, wood drying etc,. The unit has high energy efficient, economical, safety and stability. General electric boilers oil fired boiler drying energy consumption from 1/4 to 1/3of consumption.
Scanair heat pump dryer is specifically designed for use in low temperature process drying applications. The unit can operate in temperatures up to 40˚C used in conjunction with a Scanair process drying PLC control panel to create the perfect drying environment for your product, and we manufacture a standard range that can operate at up to 70˚C which have also been used successfully in many process drying applications. Scanair designed fabricate walk in Drying Chamber/tray dryer/drying room/drying equipment according to the customer requirements. Elevated Temperature, Cold room with humidity control, heated room with humidity control etc,. Chamber with Hot / Cold / Dry / Wet with full digital control features.
Heat Pump Dryers Introduction
Heat pump dryer running cost just as 40% of oil dryer, 50% of coal burning boiler, 30% of electric boiler. Heat pump dehumidification drying method of the closed cycles saving cost no exhaust waste heat emissions, no noise pollution environmental protection. Scanair used multi flow refrigerant injection technique heat pump circulating heating & dehumidification, wider application of a dehumidifier in industrial drying, drying performance better than ordinary heat pump dehumidification drying energy saving 40% and above .Medium and low temperature drying method from15-50˚C/60˚C/80˚C,similar like nature drying. Drying process material no deformation, no cracking, no-discoloration, no deterioration, and no oxidation, thorough drying, after drying and dehydration, less loss of nutrients, the long storage period, more than any conventional drying equipment to more effectively protect the color of the dried material, smell taste, individual form and active ingredients.
Scanair drying room adopt closed type ductable circulating heating or cooling drying air for suitable inflammable and explosive materials, poisonous material, pungent odor of materials, easily oxidized material etc,. Installation and operation easily, just need connecting with drying chamber by dry air duct hose pipe and electrical plug and play method. Adopt international branded scroll technology compressor, heat ex-changer, fan motor, controllers, expansion valve etc., Many protections like phase protection, low and high volt protection, overload protection, high and low pressure protection elegant design, small dimension, intelligent controller etc, make sure heat pump dryer stable working.
Application of Heat Pumps in Cardamom Drying
This is a far the most important section in the process after the cardamom capsules washed with pure water the stalks will be removed. Soaking the cardamom capsules in 2-5% sodium bicarbonate for ten minutes improves colour retention. The inability to adequately dry the produce will at the very least slow down the whole process and possibly lead to mould growth any cardamom with even a trace of mould cannot be used for processing. The sale value of mould cardamom can be less than 50% the normal value. In extreme cases the whole crop can be lost. Green dried cardamom receives a premium quality in West Asia. so drying has to be done in such a way as to preserve the green colour. The drying temperature is 50°C. The present system involves allowing the humidity of the drying chamber to build up for 2 hours and then to bring the humidity down. It is thought the initial high humidity ‘cooks’ the cardamom and inactivates the enzymes that break down the chlorophyll. Also no light is allowed in the drying chamber.
Scanair Water Source or Ground Source Heat Pumps can be designed with closed or open loops systems, and those loops can be installed either horizontally or vertically. The type chosen depends on the available land areas and the soil and rock type at the installation site. These factors will help determine the most economical choice for installation of the ground loop. For closed loop systems, water or antifreeze solution is circulated through plastic pipes buried beneath the earth’s surface. During the winter, the fluid collects heat from the earth and carries it through the heat pump system and into the building. During the summer, the system reverses itself to cool the building by pulling heat from the building, carrying it through the system and placing it in the ground. This process creates free hot water in the summer and delivers substantial hot water savings in the winter. Open loop systems operate on the same principle as closed loop systems and can be installed where an adequate supply of suitable water is available and open discharge is feasible. Benefits similar to the closed loop system are obtained.
Scanair Water Source Heat Pumps are the definition of Green Technology. Our heat pumps can harvest the free energy provided by the earth and sun to produce the most energy efficient water heating available. We utilize non-ozone depleting refrigerant to transfer energy from a low quality heat source to a high quality hot water supply. Scanair heat pump water heaters have zero emissions and further reduce your carbon footprint by maximizing efficiency and minimizing electricity consumption. The application of a water source heat pumps for aquaculture water heating is the most energy efficient way to heat up fresh or salt (sea) water. You can heat up your pond for only minimum of the cost that other traditional methods might costly solution. Each year we receive more and more requests and inquiries for heat pump applications in aquaculture. The benefits are many and your investment will pay back immediately in monthly savings varies LPG gas or electric element heaters.
Scanair water source heat pumps manufactured for rugged, round the clock working units because our products have a Titanium Heat Ex-changer, Titanium being the safest metals to use in fresh or sea water applications to protect the aquatic life from the harmful components or metals like copper that most common heaters have. We use digital display thermostats and world class scroll compressors with titanium heat ex-changers all designed to keep the right temperature in warm and in cold weather. These components will assure the long life and reliability of your equipment and will let you feel at ease knowing that your investment is being taken care of. Our heat pumps come in HEAT and COOL versions a full range of capacities, and models available depending on your application and needs.
When sized properly your heat pump will provide a stable and constant temperature for your maturation section or water pond. The digital display thermostat will make it easier to operate with a touch of the button. The heat pump operates by collecting the free heat from the air or from the earth and moving it to the water using very less electricity to run the unit. Because of the ability to maintain optimum temperatures and reduce high costs of conventional heating methods, our heat pumps are suitable for, Hatcheries, Hydroponic Operations, Research or Government Institutions, Aquaculture Facilities, Public Aquariums, Large Personal Aquariums or Ponds
Alternate to conventional heating & cooling system Scanair Air Source Heat Pumps have proved to be the most cost effective energy saving systems the country wide. Scanair air source heat pumps will maintain the temperature range from 24°C To + 80° C ± 2° C, capacity from 3 Kw to 150 Kw from 10 Lpm to 300 Lpm with different from capacity. Easy and practical to open side panels for servicing each plumbing, refrigeration accessories, electrical accessories. Compressors incorporate in a variety of safeguards that ensure durability including an internal pressure relief valve, motor temperature protections superior oil management functionality. These heats pumps are ozone friendly, packaged type have been designed for many years of trouble free operation. Scanair air source heat pumps are ideal and most suitable for a wide spectrum of applications in industries like Swimming Pool, Household water heating, commercial building water heating, industrial application preheating, for Seed Drying, Food, Pharmaceutical powder drying ,Laundry Drying, Latex Drying, Ceramic Drying, Mattress Drying, Paint Shop Drying, Tumble Drier, Fish Drying, Spices Drying, Mango Drying, Dhal Drying, Meat Drying, Fruits/Vegetable Drying, Tea Leaves Drying, Herbal Drying, Turmeric Drying, applications etc.
Air source Heat Pump water heater is built on a new power-saving technology, which regard as the fourth-generation water heater. Heat pump water heater makes use of the cycle principle, absorbing outside heat from the atmosphere air with the processing of compressor and refrigeration liquid, transmitting the heat to produce hot water. Heat Pump is a machine or device that effectively “moves” thermal energy from one location called the “source,” which is at a lower temperature, to another location called the “sink” or “heat sink”, which is at a higher temperature. A heat pump is an electrical device that extracts heat from one place and transfers it to another. The heat pump is not a new technology it has been used in India and around the world for decades. Refrigerators and air conditioners are both common examples of this technology. Heat pumps transfer heat by circulating a substance called a refrigerant through the cycle of evaporation and condensation. The compressor pumps the refrigerant between two heat ex-changer coils. In one coil, the refrigerant is evaporated at low pressure and absorbs heat from its surroundings. The refrigerant is then compressed to the other coil, where it condenses at high pressure. At this point, it releases the heat it absorbed earlier in the cycle.
Process water heating and cooling
Many industries need warm process water in the temperature range from 40-90ºC, and often have a significant hot water demand in the same temperature range for Laundry washing, sanitation and cleaning purposes. This can be achieved with Scanair Air Source Heat Pump Systems are installed. Heat pumps can be a part of an integrated system that provides both cooling and heating.
Scanair Air Source Heat Pump Systems are used extensively in industrial dehumidification and drying processes at low and moderate temperatures (between 20 ºC to 80 ºC). The main applications are drying of pulp and paper, various food products wood and lumber. Drying of temperature-sensitive products is also possible with it. Heat pump dryers generally have high performance COP 5to7, and often improve the quality of the dried products as compared with traditional drying methods. Because the drying process is executed in a closed loop system, safe odors spared outside from the drying of food products etc. are reduced. Both closed-cycle compression heat pumps and cascade systems are implemented.
Swimming Pool Heat Pumps warms your swimming pool or spa with Scanair heat pumps and cools during winter and hot summer season reliably and efficiently with the most trusted brand. We are offering to have our client an excellent quality range swimming pool heat pumps. With high-quality titanium, SS 316L grade heat exchangers are made from high-quality raw materials which ensure high durability at its user ends. Our temperature range from 25˚C To +65˚C ± 1˚ C, capacity from 1Kw to 150Kw From50LPH to 15000LPH with different heating capacity widely finds its valuable application in various sectors applicable to swimming pool, SPA or fish, Aqua cultivation, Hatcheries. People install them for pools of their houses. and in GYM are also heated by heat pumps. Even in aquaculture farms, heat pumps are installed for fishes, for they need stable and warm water to grow quickly constant heating and cooling functions.
Do you know the earliest success of heat pump water heaters for swimming pools, because the water volume in a pool is huge, so was heating, they need a huge amount of energy. Diesel, gas boiler, electric heater, which is higher running costs not for economical use. Secondly, the water temperature requirement is not high, less than 34 C degree will be OK. In other words, the terminal temperature of heat pumps will not be too high. These two reasons bring the application of heat pumps for swimming pool. In fact, you will say “what an ideal product designed for pools” when you know the performance of this kind of products. The COP of swimming pool heat pumps reaches 5, which means 1Kw electric power consumption can bring 5Kw heating output energy. The number of traditional water heaters (broilers or electric water heaters) will not be more than 1Kw heat energy output. Nowadays, swimming pool heat pumps are popular in India.
Why a HEAT PUMP is Prefered over a Traditional water Heater.
HPWH/Traditional water heaters economy comparison
Heating 1000 Ltrs water from 20oC to 55 oC requires 35000kcal
|Heater Type||Wood Boiler||Diesel Boiler||Gas Water Boiler||Electric Geyser||Electric Boosted Solar||Scanair HPWH|
|Energy Source||Wood||Diesel||Gas||Electricity||Solar & Electricity||Electricity & Air|
|Life Span||5 Years||8 Years||8 Years||5 Years||8 Years||10 Years|
|Fuel value||2500 kcal/kg||10500 kcal/ltr||12500 kcal/kwh||860 kcal/kwh||860 kcal/kwh||860 kcal/kwh|
|Heat Value||1250 kcal/kg||8925 kcal/ltr||10625 kcal/kg||817 kcal/kwh||2580/kcal/kwh||3010 kcal/kwh|
|Unit Energy Cost||Rs.5/kgs||Rs. 42/ltrs||Rs. 57/kg||Rs.6/unit||Rs.6/unit||Rs.6/unit|
|Energy consumption||28 kgs||4.1 ltrs||3.3 kgs||43 units||13.6 units||11.6 units|
|Energy Cost/ton||Rs.140/-||Rs. 172/-||Rs. 188/-||Rs. 258/-||Rs.82/-||Rs.70/-|
|Annual energy coast||Rs.51,100/-||Rs.62,750/-||Rs.68,620/-||Rs. 94,170/-||Rs.29,930/-||Rs.25,550/-|
|Annual Lab our Cost||Rs.48,000/-||Rs.36,500/-||Rs.36,500/-||NIL||NIL||NIL|
Low-temperature drying, also known as near-ambient drying, is one of in-storage drying methods. There are four major factors which influence low temperature drying the variability of weather, the harvest moisture content, the air flow in the storage bin and the amount of heated air. Scanair low-temperature heat pump dryers are built to dry grain as slowly as possible, while in the same timeless spoilage on the grain. It is suggested that low-temperature drying system is better operated when the average daily temperature is between 30°C and 50°C. Rather than control the drying air temperature, the low-temperature drying focuses on the relative humidity in order to achieve equilibrium moisture content (EMC) in all grain layers. Low-temperature drying process usually takes 5 days to one month depends on several important variables weather, airflow, initial moisture content and amount of heat used. Among which, airflow is the key factor. Without appropriate airflow rate, spoilage will occur before drying is completed. By using heated dried air with Scanair Solar Assisted Heat pump Dryers the relative humidity of the drying air is better controlled to achieve the desired moisture content in the air of drying process.
CARDAMOM DRYING PROCESS
Cardamom curing is a process in which the moisture of freshly harvested capsule is reduced from 80% to 10to 12% at an optimum temperature of 50oC so as to retain green colour to the maximum extent. This is the most important part of the process as it affects the quality of the final product. It is important to dry the cardamom capsules as soon after harvest as possible to prevent the loss of flavour. It is also important that the drying process is as short as possible so that mould does not grow on the capsules and the bright green colour is retained. The drying temperature should not be above 50°C as this affects the colour and delicate flavour of the final product. In most places, cardamom capsules with a good green colour can be sold for a premium price.
The moisture content of a fresh cardamom capsule is about 85%. This needs to be reduced to 10% in the dried product so the cardamom capsules can be stored. If the drying period is too long mould can start to grow on the cardamom. There are several options available to the small-scale processor, depending upon the size of the business and the local weather conditions at the time of processing. Each method has different advantages and disadvantages.
Humidity-controlled drying Scanair drying chamber has been developed that helps to reduce colour loss and to produce high-quality pods. The cardamom capsules are placed in the drying chamber, which is at a temperature of 50°C. During the first two hours of drying, the humidity builds up within the chamber. This allows the cardamoms to ‘cook’ and at the same time destroys the enzymes that break down the chlorophyll (chlorophyll gives the pods their green colour). No light is allowed into the drying chamber. After two hours the humid air is blown out of the chamber and the humidity reduced. The capsules are left in the chamber to dry until they have a final moisture content of 10% in the drying chamber
PEANUT DRYING PROCESS
The combination of average drying conditions of 34.6ºC temperature and 27% relative humidity were very effective in drying peanut. There was no loss of seed coat colour and darkening of the cotyledons The physiological quality of the peanut seed was maintained by the new technology dryer. Drying with low temperature and relative humidity at recommended air flow rate did not reduce the observed that slow drying or low temperature/low humidity drying reduced physical damage and maintained high vigour and viability during storage. The maximum recommended plenum temperature is 35°C and the minimum plenum humidity is approximately is 50% in peanut seed vigour index based on germination speed when the drying temperature was increased from 43.33 to 104.44°C in a hot air drying system. A slight increase in germination percentage from 82 to 89% was observed which could be attributed to seed pathogen control due to the HPT drying process. The seeds after drying produced no abnormal seedlings due to fungi infection as observed in the test with wet seeds dried peanut seed at 34.1°C and 40% RH and obtained germination value of 76% which was 13% less than observed using the HPT dryer system. Peanut seed drying provided by the heat pipe technology is an efficient process and caused no detrimental effects on seed physiological quality.
Drying is an energy-intensive process which involves the removal of moisture from a crop until the moisture content of the crop is in equilibrium with the surrounding air. Crops are usually dried to a moisture content that will allow safe storage and/or further processing eg. Milling .The drying behaviour of different crops depends to a large extent on the physical characteristics of the crop for example particle size, internal structure and composition. These characteristics are crop specific, and so the drying behaviour of crops is usually different. In order to select an appropriate dryer and the drying parameters such as drying time and temperature, it is important to understand the drying behaviour of the material to be dried. This principle forms the basis of many drying studies, which are conducted to determine moisture loss characteristics, physical and biochemical changes of specific crops.
The traditional method for crop drying in the tropics is sun drying. Sun drying usually involves the spreading in thin layers of crops such as paddy, coconuts, coffee, shrimp and fish on concrete floors, large trays, galvanized sheets or simply on pitched roadsides until the crop is sufficiently dried. This method has its inherent advantages of no operational energy cost for moisture evaporation, together with a low or negligible initial investment, except for the larger sun drying installations such as those used in Guyana for paddy or in Grenada for cocoa beans. These may require as much as 180 m2 of drying floor space per ton of paddy.
There are several limitations associated with traditional sun drying. During periods of intermittent and particularly during continuous rainfall, crop drying is not possible and the risks or crop losses are high. Sun drying is slow and weather dependent compared to other alternative drying systems. Crop quality may be low due to contamination by dust, dirt, stones and insects, while direct crop losses from theft and livestock consumption can be high. Sun drying also suffers from a high labour requirement and excessive crop handling particularly in periods of inclement weather which can result in high costs, crop damage and a loss in quality.