Pairing variable speed drives (VSDs) with high-efficiency motors to control ventilation fans can help fine-tune the conditions inside poultry houses. Not only does this improve animal welfare, but it can also reduce energy use by a typical 30 to 40 percent and cut maintenance needs.

Pinpoint matching for changing daily needs

Chickens are highly susceptible to changes in temperature. Therefore, ventilation systems must provide the desirable air quality inside the poultry houses by eliminating excess heat, moisture, and unwanted gases.

Fan motor operation can be adapted with VSDs to provide an exact match for fluctuating daily needs triggered by the changing requirements of poultry and external weather conditions.

In the layer house, where chickens can roam freely both inside and outside if local conditions allow, the demands on the system are relatively simple. The roof inlet and outlet ventilation system only need to draw in the fresh air and extract CO₂, ammonia, moisture, and particulate matter while equalizing the overall inside pressure.

In contrast, broiler houses require sophisticated ventilation control to accommodate the varying needs of up to 50,000 broilers as they progress from the brooding stage – where the chicks weigh 50 g each – to mature chickens of up to 3.5 kg. Chicks need very little air and, therefore, a low ventilation level, so they will usually be spread across several houses where a few fans will only be switched on for a few minutes at a time.

Main ventilation

One of the main ventilation needs for layer poultry houses is the roof inlet/outlet system. VSDs are used to control the speed of the inlet and outlet fans to regulate the climate. Maintaining an equal pressure enables the free movement of chickens between the house and the outside.

Should an emergency occur, the VSDs can enter an override mode. This means that the fans will run to a selected strategy, ignoring warnings and faults. The capability to provide an extended fan runtime in the event of a fire or a mains dropout is an important safety feature.

Tunnel ventilation

In countries where humidity and temperature regularly exceed 80 percent and 35°C, respectively, tunnel ventilation systems are the preferred option to provide a wide range of air exchange throughout the poultry house. Should the temperature rise significantly, the standard ventilation system switches off. Multiple fans mounted on the walls are then used to create a high air velocity, typically 3 m/s, to increase the cooling effect.

VSDs for increased energy efficiency

Ventilation, feeding machines, and lighting constitute the largest energy consumers in poultry production, making energy efficiency an increasingly important consideration for farmers. Efficient heating and ventilation systems can realize substantial savings.

This is also central to a virtuous cycle that impacts overall productivity. Birds that are too hot drink more water and gain less weight, while birds that are too cold consume more food, which is the most expensive part of poultry farming. Egg production suffers too, since hot and humid conditions – apart from being dangerous – cause chickens to lay smaller and fewer eggs.

Although high-efficiency fan motors fulfill an essential function, they only yield five to eight percent energy improvements. Fans controlled by VSDs, on the other hand, result in considerably higher energy savings because a slight reduction in motor speed translates into a proportionally much more significant energy reduction. It is, therefore, good business sense to ensure that the speed of any fan is matched closely to its required duty.

Banking on energy savings

It is possible to extend the energy-saving effect of reducing the fan speed even further by establishing fan banks. In effect, multiple fans controlled by VSDs are banked together to deliver the same level of air movement as a single fan running at full speed. The potential energy savings in this scenario are enormous.

As a practical example, a typical 1.4-meter diameter axial fan commonly found in poultry houses consumes 1,451 Watt (W) at full speed (100 percent). When reduced to half-speed (50 percent), it uses just 171 W.

Banking together two of these fans running at 50 percent move the same air volume as a single fan at full speed. Yet, the difference in energy consumption is enormous: they will consume only 2 x 171 W = 342 W – yielding a saving of over 75 percent.

While purchasing and installing VSDs come at a higher initial cost, the energy savings alone deliver an almost immediate return on investment. In addition, because the fans operate at a slower speed, they require less maintenance and run smoothly with less noise.

Driving for energy efficiency

ABB variable speed drives, with their high reliability and built-in safety and protection functions, are rapidly growing in importance for poultry house ventilation systems. In addition to creating the ideal conditions for enhanced animal welfare, they save energy, contributing to greater profitability and helping to reduce the carbon footprint of the poultry industry.

For further information, visit:

https://new.abb.com/drives/segments/food-and-beverage/poultry-farming