Cross and Tunnel Ventilation – A Climate Control Concept
For the past 20 years, it has been well known that heat stress in high production dairy cows impacts milk production, fertility, health, and even the milk’s quality. During this period, researchers and farmers came up with various climate control concepts. Most of these ideas were based on cooling the cows directly. This approach solved the basic issues and worked (at least at a theoretical level) in different countries but it created other challenges: large amount of wasted water (including water that spills into the area in which the cows are standing), extra work, and significantly higher electrical costs.
Over the past seven years, a new climate control concept has arisen: “cross or tunnel ventilation”. In fact, the concept is not new; it was copied from the poultry industry. Moreover, we’re not sure who was the first one to try and implement the idea. Having said that, Munters is the only company that has embraced this idea, creating a full range of system designs and products to support farmers interested in applying the technique on their farms.
The concept is based on air moving from one side of the barn to the other side. Negative pressure is created by exhaust fans that suck air from a closed building. As a result of this negative pressure, fresh air is pulled into the building via cooling pads flushed with water. The net effect is increased humidity and reduced temperature, cooling the air as it enters the animal house.
Figure 1: Munters controller in the control room
Figure 2: Exhaust fans in a compost, cross ventilation dairy barn
Figure 3: Cooling pads in cross ventilation compost barn
Figure 4: New cows entering into cross ventilation compost barn
In dry climates, the difference between the inside and outside temperatures can be around 12-14°C, a significant difference.
Farmers in different countries have started to adopt this new technology, reporting great results. Principle benefits include temperature stability within the barn, less water consumption, no waste water coming from direct cooling, and lastly an increase in profitability. In the USA most new farms or houses include cross or tunnel ventilation climate control.
Munters’ controllers and sensors provide the system management; the basic idea is that when the outside temperature is cold, the air velocity in the building is low and cooling pads are inoperative. As the temperature increases, additional fans and cooling pads come into operation.
Until today, most (if not all) cross or tunnel ventilation houses were free stall buildings. Recently, Munters Brazil started to develop a system that works within close compost barn buildings. The initial results look promising especially when looking at the number of square meters per cow needed within this shed, the air speed, and the large air volume. In tests that Munters ran, we can see that the bedding is dry and comfortable.
It will take a bit more time to fully understand all of this system’s advantages. However, preliminary research and results show that this system will be as revolutionary to dairy farming as direct cooling was when it came out 25 years ago.
- In Brazil we have about 20 farms with full cross or tunnel ventilation systems, and about 30 more farms have ordered the system.
- In the USA there are hundreds of farms with cross or tunnel ventilation, including an extremely large herd under one roof consisting of 8,000 cows.
- In China this climate control system is also progressing very quickly. One of the largest companies in the field, Modern Dairy, was one of the first to adopt this concept.
- In Russia, many large firms are looking seriously into this concept and considering buying it. This system will also provide the perfect solution to the cold winters by isolating the building from the outside temperature.
Summary: The cross or tunnel ventilation climate control system is, worldwide, one of the most attractive new concepts with the modern dairy industry. This system increases farmers profitability by providing a high level of environmental stability. Farmers all over the globe are reporting extremely impressive results when using this system.
Munters – a global climate control company based in Sweden, is a world leader manufacturing complete systems for this concept. Moreover, Munters was one of the first companies to try this system, showing great results in compost barns.