Producer question: I’m looking to save every penny. What can I do with my ventilation system to cut costs?
Zulovich’s answer: During times of economic hardship, you have to closely evaluate production costs to determine what can be reduced or cut. Energy costs make up 1 percent to 5 percent of total production costs depending upon your operation. The ventilation system uses a major share of the total energy for fan operation and supplemental heating. You can reduce production costs by improving energy efficiency.
Three areas to examine:
1. Heater operation
2. Exhaust fan maintenance
3. Curtain maintenance
However, you don’t want to push this too far; production costs may actually increase if you compromise pig health while trying to cut energy costs.
Heater operation and management
Setting heater thermostats or controller settings for efficient energy use will depend on your situation. The settings of concern with respect to target air temperature are: the difference between the heater-off temperature and stage-two-fan on temperature; and the difference between common hallway temperature and room temperature.
If those differentials are incorrectly set, heating energy use will increase. Another setting that can save energy is actual heater output.
There must be a temperature difference within an integrated controller or between different thermostats to separate the operation of the heater from the stage-two fan. The stage-two fan provides the first increased ventilation rate above the required minimum rate. If the variance is too small, the stage-two fan will cycle on and off within a few minutes or simultaneously with the heater.
The room’s temperature dynamics will vary depending upon heater size, air distribution and equipment placement, and will dictate the temperature differential. The heater should cycle on and off without increasing the ventilation rate. The set temperature difference between the heater and the stage-two fan needs to be wide enough for proper heater and fan cycling.
Setting a common hallway air temperature is important when air from the hallway supplies several rooms. If you have a common hallway in a facility where all the rooms are set at the same temperature, the hallway heater should be set to maintain the room temperatures.
If you have a common hallway in a facility where rooms are set at different temperatures, the hallway temperature should be set to the coolest room’s temperature. Otherwise you’ll be using additional ventilation above minimum rates in rooms with the lower temperatures. That will increase energy usage.
A heater will operate more efficiently if the “on-time” of an on/off cycle is fairly long. The longer the cycle’s on-time, the more efficient the heater system.
Yet another way to improve heater efficiency is to examine output. Some heaters can be set at various output levels. You can increase a heater’s on-time by reducing its output. You only need to increase a heater’s output if the current output cannot maintain the desired room temperature.
Exhaust fan maintenance
Exhaust fans are the foundation of mechanical ventilation systems. You should clean fans and their accompanying shutters and grill guards on a monthly basis. Dirt on fan blades and shutters can reduce airflow by as much as 40 percent of the fan’s rated capacity.
You also should conduct any other fan maintenance, such as belt tightening and lubrication, on a monthly schedule.
Curtain management and maintenance
Curtain leakage problems begin during warm and hot weather. You should raise and lower all open sidewall curtains on a weekly basis during hot weather. Raising the curtains will dump any water from the curtain folds, as well as discourage rodents from building nests there.
A rodent control program also is necessary for curtain maintenance.
Each fall, make the following steps part of your maintenance routine.
Repair all holes. Fixing small holes is easier than repairing large tears.
Inspect and repair or replace the ropes and cable system.
Adjust ropes to remove any curtain sags. If the curtain sags anywhere along its length, the sag can serve as an uncontrolled opening to ventilate the facility.
Inspect and repair the pockets on the end of curtains. If the end pockets are not tight, excessive ventilation will occur around the curtain ends.
Inspect and repair tie-down ropes to keep curtains from flopping in the wind.
This may seem like an extensive amount of curtain maintenance, but it should minimize the chance of curtain failure during a winter storm.
You can reduce production costs by improving the energy efficiency of your ventilation system. But remember, if you compromise environmental conditions inside the building as a result, your overall production costs can actually increase because of increased health costs and decreased pig performance.
Pro Center Talk is part of the PORK’99 producer education program presented at World Pork Expo: The Pork Pro Center.