Greater emphasis will be placed on reducing operating costs, particularly energy costs, in the design and construction of the poultry houses of tomorrow. There are a lot of questions as to what the future holds for the poultry industry. One thing, however, is certain. Poultry houses will have to be designed and built with a much greater emphasis on operating costs, in particular, heating and cooling, than they were in the past, most experts agree, as increases in propane and electricity costs are here to stay.
When building a new poultry house, emphasis has traditionally been placed on containing construction and equipment costs and not on energy use. In many new developments, new technologies that have been proven to reduce energy usage are not adopted as if, they were, the added initial cost would appear to negatively affect a producer’s returns. The benefits of lower energy usage are rarely considered.
A new energy efficient tunnel fan, tunnel door or improved air inlet may increase the initial cost of a house. However, if operating costs are significantly reduced, the net cash flow of a house is improved, especially when a long-term view of energy prices is taken.
At a gas cost of $7.50 per litre or an electricity rate of 35 cents per kilowatt hour, a piece of equipment that may reduce energy usage by 10-20% may not seem to offer a great return on investment. But with propane and electricity prices likely to rise by 20% or more over the next few years, a little extra money spent upfront could offer significant future savings.
There are a number of proven as well as emerging technologies and building practices that have been shown to significantly reduce the cost of heating and/or cooling a poultry house. If a short-term view is taken, however, the ROI may, at times, look questionable.
When a long-term view is taken, with the high probability of increased fuel and electricity prices, many new technologies may prove a good investment for both poultry companies and growers.
- Circulation fan systems: A properly designed circulation fan system that thoroughly mixes the air within a house from floor to ceiling and from one end of the house to the other has proven not only to reduce fuel usage by 10-30% but to improve litter and air quality as well.
- Totally enclosed houses: In a curtain-sided house, 30-50% of the heat loss can be attributed to the side-wall curtains. By replacing side-wall curtains with well-insulated solid side walls, not only are heating costs dramatically reduced but the house will run cooler in the summer. In addition, the increased level of environmental control possible in a totally enclosed house tends to result in improved bird performance.
- Insulated tunnel doors: Replacing traditional tunnel curtains with insulated tunnel doors in a totally enclosed house has been shown to reduce fuel usage by 10% or more. Tunnel doors also generate increased air movement over the birds in the vicinity of the tunnel inlet during hot weather, resulting in cooler birds and drier litter.
- Larger houses: Wider houses cost less to heat during cold weather than traditional 40-foot-wide houses due to the fact that they have less overall surface area. With the increasing popularity of totally enclosed houses, producers have discovered that it is possible to build larger houses than previously thought possible, without having excessive temperature difference between the tunnel inlet and fan ends of a house.
Houses as long as 165 metres (550 ft) can have the higher air velocities required for the larger birds grown today at a lower initial investment and, more importantly, lower operating cost per bird, than in 120 metre (400 ft) and 150 metre (500 ft) long houses.
- Litter treatments: By using a litter treatment to limit ammonia production, ventilation rates during brooding can be kept to a minimum, reducing heating costs by 30%. This easily offsets the cost of litter treatment.
- Radiant heating systems: Radiant heaters have been shown to provide 10-30% fuel savings when compared with hot-air furnaces.
- Attic inlet systems: The attic in the typical dropped ceiling poultry house is 5 to 25 degrees Celsius warmer than outside during daylight hours. Attic inlets allow producers to reduce fuel usage during cold weather by 10-20%. Increased daytime ventilation rates result in drier litter, lower ammonia levels and overall improved air quality.
- Energy efficient fans: There are a number of tunnel fans on the market that have energy efficiency ratings of 6 cubic metres (21 cubic feet) per minute per watt or better at a static pressure of 0.254 centimetres (0.1 inches). Installing highly energy efficient tunnel fans can easily reduce the cost of ventilating a poultry house by thousands of dollars a year.
- Improved side wall air inlet systems: Traditional galvanised side wall and cooling inlets are not nearly as effective at distributing cool fresh air throughout a house during the cooler times of the year as many of the newer recessed European-style air inlets. By installing more efficient air inlets, producers are better able to control house temperature and air quality. This results not only in lower heating costs but also in improved bird performance.
- Dimmable fluorescent lighting: There are new high intensity (1,600 lumens) compact fluorescent light bulbs in the market that can reduce the cost of lighting a house by up to 75% while providing the wide dimming capacity that many modern producers require. In the typical 12 metre (40 ft) wide house, when operated at full intensity, two rows of high-intensity compact fluorescent bulbs (6 metres [20 ft] on centre) are capable of producing a light intensity at floor level of 60 cm (2 ft) candles or more. The bulbs can be dimmed to us as low as 30 cm (0.1 ft) candles. The durability of these bulbs, however, remains to be seen.
- Biomass heating system: Heating systems that burn waste wood products are currently being developed and/or modified for use in poultry houses. Most of these systems do not totally eliminate propane but they have been shown to reduce propane use by 80% or more.
Depending on the price of the biomass product used, fuel cost savings can be as great as 50%. Most of these systems have an installed price of $25,000 or more per house but payback can be within five years.
- Solar walls: One relatively popular form of solar walls consists of a finely perforated black sheet metal wall, constructed approximately a foot from the south side wall of a poultry house.
During the day, the sun heats the space between the perforated metal wall and the side wall to temperatures of 30C or more above outside temperature. The fine perforations allow outside air to be drawn into the heated air space and then into the house, utilising the air inlets on the south side of the house (inlets on the north side would not be used during cold weather).
The overall ventilation system needs to be designed so that the solar wall can be bypassed during moderate weather.
With an installed cost of $30,000 or more per house, these systems can have a long payback period. With modification, however, they may be able to be made more cost-effective.
- Variable speed exhaust fans: There are very specific laws that dictate the relationship between fan speed, air moving capacity and energy use for any fan.
For instance, fan speed and air moving capacity are proportional. A second fan law states that fan power is proportional to the cube of fan speed. This means that when fan speed is decreased by 10%, fan output is decreased by about 10% but power usage can be reduced by some 30%. In principle, it is possible to significantly lower fan operating costs by operating more fans at a lower speed than fewer fans at full speed.
There are still a few issues to be addressed but the fact of the matter is that varying the speed of all the tunnel fans in a house, as opposed to staging in fans one by one, could reduce electricity use by 20% or more.
- Solar power: Photovoltaic panels use sunlight to generate electricity. A 42kW PV system with 210 panels, for example, has been used to provide electricity for a Delaware broiler house since April 2007. Renewable energy credits ($200 per 1,000kWh) have been received for the “green” power produced. The PV technology has worked flawlessly. Systems cost is the obstacle preventing wider use of solar energy. The initial cost of equipment and installation is approximately $8 per watt.
- Wind power: Wind turbines designed and marketed for residential use are of a size that could be used to supply electricity for a typical poultry farm. However, the cost of purchasing and installing a wind-power system is approximately $5 per watt. This makes it a highly unlikely option without substantial government grants.
Written by Michael Czarick & Garet L. Van Wicklen.
Michael Czarick is an extension engineer at the University of Georgia while Garet L. Van Wicklen is an extension poultry engineer at the University of Delaware.
updated: Apr 07, 2010. This article appeared in Poultry International, April 2009. Copyright 2014, All Rights Reserved.
This article has been altered to accommodate metric measurements.