Sentera offers wide range of solutions, suitable for temperature, humidity and air control. In this article, we will show an example of air control in wide-space, specialised storages for vegetables. How can a single solution be suitable for climate control in both potato and onion storage areas? The answer is simple – we have created the perfect combination of Sentera devices, suitable for storing both types of vegetables for a long time. The only difference can be found in the pre-defined parameters.
According to the “International Food and Agriculture Organisation”, the loss of perishable plant products (fruits, potatoes and vegetables) during storage in the world reaches 20-30 %, not to mention the unnecessary electricity consumption expenses, which come as a result of that.
Sentera’s solutions for climate control
One of the most important stages of vegetable storage is the preparation of the vegetables for long-term storage after their delivery to the warehouse. These are time-consuming and precision-demanding processes, which can be handled best by a Sentera controller, which can receive valuable data from sensors, installed in and outside the warehouse, and as a result, control the indoor environment.
Preparation of potatoes for long-term storage after their delivery to the warehouse
Potatoes, brought to the warehouse, require drying by continuous ventilation with ambient air. The drying time is no longer than 3 days.
After that, the dried potatoes undergo a curing process for 10-15 days, which requires temperature levels of 14-18 ºC and ventilation with ambient air at regular intervals of 4-6 times a day. During this period, superficial damage heals and the skin of the potatoes toughens. At the end of the curing process, the indoor temperature needs to be reduced by 0.5-1.0 ºC per day for no longer than 15 days so the potatoes are cooled enough to be stored successfully.
After that, the dried potatoes undergo a curing process for 10-15 days, which requires temperature levels of 14-18 ºC and ventilation with ambient air at regular intervals of 4-6 times a day. During this period, superficial damage heals and the skin of the potatoes toughens. At the end of the curing process, the indoor temperature needs to be reduced by 0.5-1.0 ºC per day for no longer than 15 days so the potatoes are cooled enough to be stored successfully.
Preparation of onions for long-term storage after their delivery to the warehouse
The first stage of onion storage is keeping the harvested onions at a temperature of 18-25 ºC in order for them to dry. Onions are considered dry when the moisture of their outer layer is 14-16%. The drying time should not exceed 8 days. To prevent neck rot, the onions are then stored at a temperature of 45-47 ºC after the drying stage for 10-12 hours. Lastly, onions should be cooled to 0-4 ºC storage temperature.
Even when the preparation stage is completed, it is still necessary to monitor and control the whole process of ventilation during the entire storage period in order to avoid crop spoilage. A Sentera controller accompanied by sensors can maintain the suitable storage conditions.
The maintenance of an optimal microclimate in a vegetable warehouse requires knowledge and constant responsible work. When managing the microclimate of the vegetable warehouse, we should assess the constantly changing natural conditions and the condition of the stored vegetables. The final condition of the stored vegetables depends highly on those factors. Different types of vegetables react differently to temperature changes. This explains why, after harvesting some perishable products, it is necessary to prepare them for storage immediately under precise conditions. The creation of the required microclimate, in the presence of constantly changing natural conditions, in such vegetable storage facilities is practically impossible without the use of artificial refrigeration devices. In the warm periods of the year, refrigeration systems are necessary when sensitive products that require rapid cooling and low storage temperatures are stored. It is also possible to take advantage of natural cold – when the ambient air cools down naturally and it has a suitable temperature for cooling the stored vegetables. Since a refrigeration system is not used in this case, relatively low energy costs are required to create a microclimate in the warehouse. However, it is sometimes more challenging to maintain the optimal storage temperature of vegetables in early autumn and spring without a refrigeration system since the minimum daily temperature does not fall below 5 °C. Thus, it is rather difficult to maintain the optimal temperature levels effectively since the natural conditions of the environment are constantly changing and the suitable temperature for storage is usually only present in the mornings. Therefore, a ventilation system is the necessity that can provide the optimal conditions for vegetable storage. The storage process can be optimised effectively with the usage of a Sentera controller in combination with Sentera sensors. As a result, the quality of the vegetables will be preserved longer, the losses of stored vegetables due to moisture evaporation will be reduced and the dormancy period of the vegetables will be extended – they start sprouting later in spring – with around 25-30 %.
Sentera's solution measures temperature, humidity and CO2 levels and in potato warehouses, every measured parameter is essential. The environment in the warehouse can be controlled based on the measurements of sensors mounted in and outside the warehouse, which transmit the data to a Sentera controller. In addition, after the controller analyses the data, each external product such as a humidifier, dehumidifier, heater, actuator, etc. receives the necessary command. Why are these three parameters so important?
Carbon dioxide measurement (CO2)Protection against rotting: High levels of carbon dioxide (CO2) can indicate that potatoes are beginning to lack oxygen, which can lead to rotting and growth of harmful microorganisms. Potatoes stay fresh longer when CO2 levels are controlled.
Maintaining quality: The better the conditions in the warehouse, the better the quality of the potatoes. Carbon dioxide levels should be monitored since they can affect the taste and texture of potatoes.
Prevention of fermentation: If there is too much CO2 in the warehouse, it can cause fermentation processes, which will affect negatively the quality and storage time of the potatoes.
Therefore, controlling CO2 levels in potato warehouses is necessary to ensure the quality and longevity of potatoes.
Humidity measurement
Rot prevention: High humidity promotes the growth of rot and mould, which can quickly destroy potatoes. By monitoring the humidity level, measures can be taken to prevent these destructive processes.
Maintaining quality: Optimum moisture levels help maintain the quality of potatoes by preventing them from drying out, shrivelling or becoming too wet, which could affect their taste and texture.
Safety: Excessive moisture can create favourable conditions for harmful bacteria that can be dangerous to health.
In conclusion, humidity measurement is an essential part of the potato storage process, helping to ensure that potatoes remain fresh and intact for a long time.
Temperature measurement
Ensuring the right temperature: The right temperature helps prevent the growth of rotting and harmful microorganisms. Higher temperatures can promote the growth of bacteria and mould, which can lead to storage losses.
Maintaining quality: Potato quality depends on the right storage temperature. On the one hand, if potatoes are stored at high temperature levels, their texture and taste can be affected adversely. In addition, they can soften and sprout. On the other hand, low temperature levels can cause frost damage, making the potatoes inedible.
Long-term storage: Optimal temperature levels allow potatoes to remain fresh and unblemished for a longer time, which is important for both suppliers and consumers.
Dependence on the time of year: Temperature can be affected by the time of year and climatic conditions. By constantly monitoring the temperature level, appropriate measures can be taken to maintain the right conditions.
Prevention of losses: Changes in temperature can lead to faster spoilage of potatoes – they can start to sprout, wither and rot, so temperature measurement and control help reduce financial losses.
Temperature measurement in potato warehouses is an essential factor that reduces the risk of possible losses and ensures potatoes remain fresh and of good quality for a long time.
Sentera can offer you a variety of solutions suitable for vegetable warehouses or tailor one to your needs, as every environment may require a unique combination of devices. We offer solutions for warehouses of various sizes since the Modbus system allows you to create a solution of more than two hundred devices, including controllers, sensors and converters.