Usually cylindrical in shape and made of concrete, metal, bricks or wood, grain silos are a type of facilities used primarily for the storage of silage – grass or green plants used to feed cattle. Grain silos may vary in size and shape, but they all depend on the same necessity – proper ventilation. Effective ventilation plays a crucial role in the preservation of grain, which is affected significantly by three major environmental factors – temperature, humidity and CO2 levels. Sentera offers a solution, which is developed specifically to ensure optimal grain storage conditions.
Preparation of grain for storage in silos
Before silage is ready for long-term storage, it needs to undergo a preparation process.
Once harvested, silage is transported to silos as quickly as possible since delays can result in nutrient loss and spoilage. Upon arrival, the silage is filled continuously in the silos, usually from the top, which creates natural compression due to its weight that guarantees lack of air in the pile. However, sometimes, natural compression is not sufficient, especially near the top where the weight of the silage is less than the one at the bottom of the silos. In such cases, the use of compression machinery is advisable. The silos are sealed further with silo doors and caps, which guarantee that air is completely excluded from the environment. With no air left in the silos, the fermentation processes, which usually last 2—3 weeks, begin. During this period, biochemical processes take place that result in lower pH levels, around 3.8—4.5, which create hostile environment for spoilage organisms. The silage is then ready to be preserved in silos for a long time.
Once harvested, silage is transported to silos as quickly as possible since delays can result in nutrient loss and spoilage. Upon arrival, the silage is filled continuously in the silos, usually from the top, which creates natural compression due to its weight that guarantees lack of air in the pile. However, sometimes, natural compression is not sufficient, especially near the top where the weight of the silage is less than the one at the bottom of the silos. In such cases, the use of compression machinery is advisable. The silos are sealed further with silo doors and caps, which guarantee that air is completely excluded from the environment. With no air left in the silos, the fermentation processes, which usually last 2—3 weeks, begin. During this period, biochemical processes take place that result in lower pH levels, around 3.8—4.5, which create hostile environment for spoilage organisms. The silage is then ready to be preserved in silos for a long time.
Environmental factors in silage storage
Temperature: Silage should be stored at around 10—15 °C, so its quality is preserved longer. However, factors such as climate conditions, fermentation processes and removal of silage in silos result in temperature fluctuations. Without a ventilation system, silos are solely dependent on outside climate conditions. During the warmer months of the year, temperature can reach peak levels, leading to pest infestation and fungal growth in silos. In contrast, lower temperatures slow down the fermentation process of silage, exposing it to a higher risk of spoilage and microbial growth.
fungal growth in silos. In contrast, lower temperatures slow down the fermentation process of silage, exposing it to a higher risk of spoilage and microbial growth. Humidity: The optimal humidity level for silage in silos is 11 % per weight. Increased moisture level in silos can lead to a poor fermentation process, which can create a favourable environment for clostridia bacteria growth and spoilage of the entire forage. In addition, the higher the humidity, the bigger the chance of mould and yeast growth, which can make silage dangerous for livestock.
In contrast, if the moisture level of silage in silos is too low, the silage will not compact sufficiently when filled in the silos, resulting in higher oxygen levels and incomplete fermentation.
Carbon dioxide (CO2): The levels of CO2 in silage storage determine if fermentation processes are effective. When CO2 levels are too high or too low, the growth of mould and yeast is more likely to happen, leading to silage spoilage. The suitable CO2 levels for successful silage storage in silos are 300—1000 ppm (parts per million). Measurements outside this range indicate insufficient fermentation processes.
Sentera’s solution
Sentera has developed an HVAC solution, which creates a suitable environment for grain storage in silos. The solution provides a demand-based ventilation system in silos, which is activated only when temperature, relative humidity and CO2 levels exceed the setpoint values. As a result, when the climate conditions in silos are optimal, fans are inactive, which reduces energy consumption and cuts electricity expenses.
When temperature level rises in silos, Sentera’s temperature sensors, placed on the vertical zones of the silos, transmit data to the controller, which activates the fans to cool down the environment. Once the setpoint temperature level is reached, the fans are deactivated. The fans will activate anytime temperature levels fall below or rise above the setpoint values, ensuring that the silage is stored in suitable environmental conditions. How long the fans will run depends significantly on the outside climate conditions, which affect the temperature levels in the silos as well.
Humidity levels determine the effectiveness of the silage storage process, therefore, constant monitoring of the humidity level of silage in silos is of great importance for sufficient ventilation. Located in the silos, Sentera’s moisture sensors transmit the measured values to a Sentera controller, which then actives the fan if the measurements are outside the range of the setpoint values. In this way, the ventilation system guarantees both energy-efficiency and optimal storage conditions.
Carbon dioxide (CO2) level is one of the most important parameters that indicates the state of the stored silage. Fermentation processes, which allow the silage to be stored for a long time, can be controlled and monitored via Sentera’s CO2 sensors, located inside the silos. Once the CO2 levels go above or below the setpoint values, the CO2 sensors transmit data to a Sentera controller, which activates the fans and ensures optimal CO2 levels.
The effective storage of silage in silos requires constant monitoring and control of temperature, humidity and CO2 levels. With Sentera’s solution, ventilation in silos is entirely run based on the measured values by Sentera’s temperature, relative humidity and CO2 sensors, placed inside the silos. This results in a minimised risk of silage spoilage and reduced energy consumption. Sentera’s solution for grain storage can be adjusted to meet your requirements in terms of silo size, grain type and local climate.