Application of fans in agriculture
Energy-efficient ventilation and cooling supports health and performance of farm animals. Fans are applied in the shed, milking parlour and living zone.
Reading time: 9 minutes
- Why do you need active ventilation the barn?
- Climate in the barn
- Types of fans suitable for agriculture
- Several ceiling fans vs. single large fan
- Harmful ammonia gas
- Actively supporting ventilation for dairy cattle
Why do you need active ventilation the barn?
In buildings for livestock the temperature, humidity content and concentration of harmful gas and microorganisms in the air is much higher than outdoors on the grazing land. In addition to adequate feeding and animal welfare, the climate inside the barn for intensive livestock farming has a heavy impact on the well-being of the animals. Stale, stagnant air is harmful to the health of animals and humans alike and reduces economic performance. Particularly breeding cattle and fat stock require optimum interior air condition.
Natural ventilation and chilly wind let in by opened gates and windows is not enough. If the building is constructed with a heat-insulating building material, it is not easily implemented either. Active cooling and if necessary humidification of the animals can be regulated by fans: Ventilation systems for agriculture remove heat and supply fresh air in the summer, in the winter they reduce humidity and the content of ammonia gas while recovering heat. Flies and flying insects however are expelled from the shed and milking parlour due to the constant air circulation.
Reasons for active ventilation in the barn:
Controlled cooling/warming of the animals
Leads off heat emitted by animals
Removes ammonia gas, humidity and stale air
Air circulation reduces the number of insects
Removes germs, virus, bacteria, fungal spores
Prevents mould growth
Heat recovery in winter
Ensures vital air change
Reduces dust, hairs, dander, etc.
Prevents stress from heat, ensuring stable milk yield
Improved fertility / life
Animals feel well, low stress
Bad interior air condition results in disease, unusual behaviour, low fertility and performance as well as increased mortality of embryos.
Climate in the barn
The airflow rate required from the ventilation system depends on several parameters, for example the construction of the building (insulted/not insulated), climate of the region, size and heat released by the animals. Depending on the species other factors must be considered as well: Poultry disperse dust and loose feathers, pigs cannot tolerate draught, cows already experience physical stress due to heat starting from temperatures of 20°C. Young animals like calves have a lower weight and can handle higher temperatures in the loafing area, however they are more susceptible to overheating. riding horses require temperature by about 2°C higher than dobbins in order to feel well. Each species should receive the air circulation, temperature, relative humidity, concentration of harmful gas and lighting it needs. An adjustable fan control (accessory) is another necessity.
Types of fans suitable for agriculture
There are various options concerning ventilation appliances and their installation. The airflow and throw distance of the fans must be adequate for the building to prevent insufficient performance. For example, the fans near sleeping and feeding areas should cool without drying out the food. If wall-mounted or inline fans are applied, the width of the building must be sufficient. An energy consultant will help plan the layout with regard to electricity costs and gain.
Fans for application in agricultural environments
- Ceiling fan
- TDA ceiling fan
- Wall-mounted fan
- Inline fan
- Axial-flow fan
- High performance extractor fan
- Oscillating fan
- Reversible fan
Pedestal fans and floor fans are not suitable for small sheds used for a private or hobby breeding since they raise dust and polluted particulate matter.
Wall-mounted extractor fans are applied in damp rooms, cattle sheds and warehouses. It is important to add a suitable controller to adjust the fan’s settings to summer, winter and transitional seasons. We recommed:
- Infinitely variable speed controllers, step transformers
- TDA temperature sensors
Thermostats make it easy for you to estimate the temperature inside the shed as well as the start of the fan system or control of the speed. As farm animals require different air conditions depending on their age, size, weight and performance, it makes sense to control the systems individually. In mews with animals sensitive to heat such as dairy cows, fans should be switched as soon as possible after the critical temperature has been exceeded.
Where are the fans applied in agriculture?
- Barn, milking parlour, silo, warehouse, shelter
- Livestock breeding, mast
- Stored foodstuffs
- Fan with UV light used as flykiller in the farm’s shop, store, counter
Fans in agriculture and livestock farms have to deal with more challenging conditions than fans for residential purposes: Chemical pollution due to gas, humidity, dust and dirt, bristle, feathers, dander and scattered food must be kept away from the motor by a reinforced housing. Sealed and stainless bearings made of steel or aluminium withstand changes in temperature, spraying water and mist.
Requirements for ventilation appliances in agriculture:
Splashing water protection and particle protection minimum IP54
Positive energy balance
Sufficient air circulation
Long service life
Water and particle ingress protection
Ease of use
Easy to clean
Minimal maintenance work required
Easy to set up and assemble
Protective grille or fins
Synchronised control of several fans
Size, airflow rate, pressure rate
Seeing that fans are operating full-time during the summer months, the following factors are taken into consideration along with the purchase price and service life:
Power consumption, efficiency
Air circulation in the entire room
Several ceiling fans vs. single large fan
Axial-flow fans for industrial and agricultural purposes can reach diameters of up to seven metres. One large fan creates a strong air circulation near the motor, however the airflow diminishes over a longer distance. In spacious buildings there will be a risk that corners and walls are not ventilated sufficiently due to the lack of airflow. Several ceiling fans that are positioned all over the room ensure harmonious movement and ventilation.
The smaller ceiling fans suitable for industrial application (diameter ranging from 1.2 to 2 metres) are equipped with a protection against ingress by foreign bodies and water and provide a high airflow rate while consuming little power. Models in our creoven shop for example require a maximum of 85 Watts on high speed and reach an airflow rate of 22,050m³/h (NORDIK HEAVY DUTY IP55). These ceiling fans can be connected to TDA controllers for a fully automated operation. Two temperature sensors measure the temperature at the ceiling and the ground and begin to run as soon as a preset value is exceeded. Up to 15 ceiling fans can be controlled in one or several sheds at the same time. In the winter the sensors detect the temperature difference at the top and floor. The fan begins moving at a low speed to force heat down from the ceiling and back into the room (heat recovery). The existing heat is distributed evenly, saving heating costs and keeping the energy balance clean.
Suitable fans in our creoven online store: Nordik ceiling fans and TDA Control for agriculture. Drop rods available for high ceilings.
In small sheds and locations a conventional outdoor ceiling fan with an IP protection is already sufficient. DC motors consume a maximum of 30 Watts and operate quietly without any wobbling. These fans are sometimes equipped with a light kit. Suitable devices for small businesses and hobby breeders are available in our category For damp rooms & outdoor areas. Tick the box and select the parameter IP rating: Yes.
The positioning of the fans in the application area depends on the construction of the shed (heat insulated/not insulated), height of the ceiling, length and width of the building. Ceiling fans should have a minimum distance of 2.7 metres to the ground. The throwing range (clearance) must be appropriate for the length of the building, meaning the number of fans might need adjusting. Furthermore, locations with nooks and crannies or dividing walls require careful placing of the fans as well.
Harmful ammonia gas
Ammonia gas is created if manure and urine are decomposed by bacteria. The gas is without colour, but it is immediately noticeable by its distinct pungent, unbearable smell in the shed. Irritation of the respiratory tract and a burning sensation in the eyes are actually some of the more harmless effects. In fact, the gas is so acidly that it can even affect horns and hooves. The farmer is also in danger when mucking out the stables, since it means daily exposure to the chemicals. A content of 5000 ppm ammonia in the breathing air is lethal (to humans and animals).
Other harmful gases in cattle breeding are hydrogen sulphide created by decomposition and clearing out of excrement as well as carbon dioxide as a natural byproduct of breathing. The maximum permissible concentration of these gases is regulated by for each animal species. Gas can be measured by sensors available from different providers.
Actively supporting ventilation for dairy cattle
Good for cattle: A fan increases air circulation and reduces humidity
High-output dairy cows are bred in a way that lets them metabolise food into a high quantity of milk. In the olden days 1 to 2 litres per day were a delight for dairy farmers, nowadays this number has increased to 50 litres per day – with an upward trend. Just like top athletes, cows work best under ideal conditions. Dairy cows and calves prefer a temperature range from +4 to 17°C, so not particularly warm. Cows bear bacteria in their first stomach. These bacteria become more active under high ambient temperatures. This creates additional heat, the body temperature of the cow rises up to 40°C.
Starting at a temperature of 20° Celsius, a relative humidity of 70% and insufficient ventilation inside the shed, livestock begins experiencing stress due to excessive heat.
Noticeable symptoms for stress caused by heats:
Damp to wet fur
Reduced food intake
Increased need for liquids
Animals seek refuge from and avoid warm boxes in the shed
Cows sweat faster than humans. What we perceive as a pleasant interior temperature, already feels uncomfortable for the ungulates. If available, the animals will lay down in the shade on the psture. In an enclosed barn the cattle try to counteract the heat by increasing the breathing rate. By comparison: A human takes an average of 17 breaths per minute, a stressed cow up takes up to 80 breaths. It is nothing like a panting dog though, instead the term “pumping” is more accurate. If there is enough fresh water available, the animal with use another natural strategy: The cow drinks more water to make up for the fluid loss. The animals have many perspiratory glands on their skin where water vaporises. This allows the cow to cool down a bit. Furthermore, cows are able to give off part of the heat through their horns because there is a steady blood supply inside the horns even though they might seem dead. The hot blood cools off slightly away from the body (inside the horns) and then flows back into the body.
A side effect of the thirst is that the cow has less appetite and time to feed, causing the production of dairy to decline with measurable economical loss.
The use of a ventilation system reduces the humidity content in the air and in the ground, the fur of the sweaty livestock dries. The ideal humidity level for cattle is between 60 and 80%, in a shed with heating it is 40 to 70%. The optimum airflow varies due to the own weight of the animals and thus ranges from 18 to 224m3/h (mast under summer temperatures). Dairy cattle requires up to 431m3/h depending on their weight and milk output. In the winter the necessary airflow drops, however it does not go away completely due to harmful gas. The ultimate goal of ventilation is to keep the performance of the cattle and milk yield at a high level. Side effect: Flies and other flying insects do not tolerate the increased air circulation and will avoid the building. This makes for a considerable relief for animals and farmers alike.
The operational noise of the ventilation system should be as low as possible, particularly during the resting periods and if cows in calf are present to prevent any additional stress. The stress of the females has a negative impact on the unborn calves as well, the birth weight is too low, problems with metabolism and premature death can be a result.
Preventive measures against heat:
active ventilation in a shadily shed
pasture with shelter
not letting livestock out if outdoor temperature is too high
a sufficient amount of readily available clean water
Increased risk for:
High milk output (dairy cattle)
Lack of drinking water
Black fur + ca. 5-6 °C
The main aim of improved air conditions inside the barn is to keep animals healthy. Customised ventilation with fans prevents stress due to overheating and constributes to a steady milk yield even if the outdoor temperatures are high in summer. Starting at about 24°C cattle welcomes addition cooling by spraying water from a sprinkler system, water hose or “bathing” facilities.
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