Sizing and energy efficiency as well as the proper equipment (pit fan,
wall fan, with or without shutters, wind protection, etc.) should be
considered when selecting or upgrading a ventilation system.
A summary of key points for getting the most out of your ventilation equipment
By Steve Clarke, Dan Ward
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| Is it the right size? Sizing and energy efficiency are important factors when choosing ventilation equipment. Advertisement
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Sizing and energy efficiency as well as the proper equipment (pit fan, wall fan, with or without shutters, wind protection, etc.) should be considered when selecting or upgrading a ventilation system.
Do not use amperage to compare fan efficiency – many other factors also affect performance.
Wherever possible, use 240V (not 120-V) motors to increase the efficiency of energy use. Higher voltages will decrease the energy that is lost in the wire itself.
All wiring should be minimum #12 gauge, to reduce line losses.
When different fans are compared, consider (1) how much air can be moved and (2) how much energy is required to move (CFM/W (cubic feet of air per minute per watt) or L/s/W (litres per second per watt)).
Use one large belt-driven fan instead of several small direct-drive fans to reduce energy use, initial capital investment and maintenance costs. Direct-drive fans should achieve an efficiency of 10 CFM/W, whereas belt-driven fans should achieve closer to 20 CFM/W.
The pressure difference created by ventilation fans between the inside and the outside of the building is called static pressure. Most ventilation systems for farm buildings are designed to operate at a static pressure of 1.25 – 1.5 mm (0.05-0.06 in.) water gauge. Compare all fans at the same static pressure. The higher the L/s/W or CFM/W value, the more efficient the fan is.
If the building is located in an area of high prevailing winds (and thus pressure on the fans is high), install windbreaks or wind hoods to ensure optimum airflow.
How big is TOO big?
Sizing of fans is very important. Oversized fans waste energy and cannot control the room temperature effectively since they cycle on and off constantly. Undersized fans also have difficulty controlling room temperature and will not provide the necessary airflow.
Fan diameter is not an indication of the fan output capacity or fan efficiency. One energy-efficient fan may not be stable or may not offer consistent energy efficiency over a wide static pressure range compared to another energy-efficient fan.
How many fans?
In livestock buildings ventilated by fans, the quantity of fans should be enough to provide at least four stages or levels of ventilation between the ventilation rate for humidity control (Stage 1) and ventilation rate for temperature control (Stage 4).
The Benefits of Electronic controllers
- The ventilation system is continuously being managed
- Users have the ability to control temperatures more precisely
- The heating and ventilation systems can be interlocked to avoid wasting energy
- More energy-efficient equipment can be used, which can be properly sequenced for optimum operation
Maintenance
A poorly adjusted belt can result in a 30 per cent reduction in airflow. Clean fan blades and louvres regularly to improve the efficiency of the ventilation system. Dirt and dust accumulation can greatly reduce airflow and insulate the motor, causing overheating.
This content is from a factsheet available at the PIC. Full copies of this factsheet can be obtained from the PIC website at www.poultryindustrycouncil.ca or by fax – simply call PIC on 519-837-0284 for a copy.
ThisFactsheet was developed with sponsorship from Hydro One and in partnership with the Ontario Power Authority, the Ontario Federation of Agriculture, the Ministry of Energy and the Ministry of Agriculture, Food and Rural Affairs.
PIC pics
The London Poultry show was great. Thanks to all our exhibitors for their fantastic effort – the booths were terrific. We sincerely hope you had a fruitful couple of days and we’re sorry the bar at the exhibitor’s appreciation night closed early on Day 1. We’ll work on rectifying that for next year.
The attendance was pretty much as usual (about 2,000) but the mood this year was definitely bullish – sadly I think it had more to do with the weather than the economy. It was great to see so many visitors from south of the border and elsewhere across the world. Thanks for coming and hopefully we’ll see you back next year. The product promotions were a hit and miss affair: we’ll have another go next year via a ballot, so watch for the e-mail asking for expressions of interest in early 2010.
With summer on the way, this month we’ve featured a summary of information on ventilation and really hope those of you who are looking at changing or updating your ventilation find this useful. Please visit our website for the full document.
You’ll receive this edition just a couple of days shy of our research day, which this year focuses on food safety – this is a “must hear” for those of you involved in industry who have any interest whatsoever in this important topic. It’s at the University of Guelph Arboretum, it’s as cheap as chips to come along and it’s only a half-day so really no excuses for not attending – again please visit our website for details, but at this 11th hour, perhaps it is better to call us at 519-837-0284.
This year we’ve received 38 research proposals a few less than last year, they’re currently out for external review after which they’ll be reviewed by an industry-only panel for their “fit” with the R&E Strategy. The results of this year’s grant competition will be published in Canadian Poultry in August.
As always – contact us with your ideas, for information or to enquire about what’s next from PIC. You can reach us at 519-837-0284 or pic@poultryindustrycouncil.ca.
| Value-based marketing decision support through characterization of broiler growth and yield
By Kimberly Sheppard, research coordinator Many manufacturing supply chains carefully measure relationships between inputs and outputs with the goal of fine-tuning processes to maximize profitability. This approach can be applied in agricultural systems, although variation in biological processes is generally much greater, making small improvements harder to measure. This slows the optimization process. Live production accounts for approximately half of the cost of wholesale chicken (whole bird); just under 40% of the wholesale price is feed. Thus, there is room for nutritional improvements to benefit the bottom line of the broiler supply chain by reducing cost, increasing value, or both. Toward this aim, Dr. Martin Zuidhof and his research team at the University of Alberta conducted an experiment to determine the effect of nutrition (cost) on broiler growth rates and yield dynamics (value). They fed one of two prestarter diets to Cobb x Avian 48 broilers, based on breeder specifications for either reducing feed cost or maximizing growth rate and feed efficiency. After that, at eleven days of age, three levels of dietary energy and five levels of dietary balanced protein were phase fed. Over 2,200 birds were processed at various ages to characterize how yield changed with body weight and nutrition. Their findings? Prestarter nutrition was very important for body weight and yield. The diet designed for maximizing growth rate and feed efficiency increased the value of birds persistently, as measured by increased breast yield. Saving a few pennies on feed in the first eleven days of a broiler’s life (by using the diet designed to reduce feed cost) improved profits neither for the producer nor the supply chain. Dietary balanced protein was very important for breast yield. Reducing amino acid levels below Cobb’s recommended levels for maximizing growth rate and feed efficiency resulted in reduced breast yield in males and females. Increasing amino acid levels above these recommendations did not significantly improve breast yield in females. However, 1.075 x recommended balanced protein levels increased breast yield in male broilers. High protein levels reduced fat pad weights at low body weights, but increased fat pad weights at higher body weights. High dietary metabolisable energy levels were most important in the first four weeks of broiler production. Lower than recommended energy levels increased body weight and breast yield after twenty eight days of age. In addition to nutritional analysis, Dr. Zuidhof and his team developed an extensive system of equations that can be used to predict scenario-specific body weight, yield, and feed intake to fifty six days of age, in response to a broad range of broiler nutrition programs. Dr. Zuidhof believes that changes to the current marketing system that reward quality traits such as high yield and reduced fat would improve the industry’s ability to benefit from the results of the current study. To read more on this study, please visit www.poultryindustrycouncil.ca . Dr. Martin Zuidhof was featured in the April 2009 issue of Canadian Poultry magazine. |
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