Advertisement

News and analysis on the global poultry
and animal feed industries.
0809EIretro1
© Peter Zigich I Dreamstime.com
on September 10, 2008

Electrical retrofit can save money

Total Energy Optimization retrofits can reduce the risk of losses and contribute to greater efficiency in power use.

Modern in-line egg production complexes incorporate numerous electronic and electrical components including control panels, sensors, computers and motors in both chicken houses and processing plants. Transient high voltage can be either catastrophic, resulting in failure of the electrical supply to ventilation systems or erosive increasing breakdowns and the need to frequently replace circuit boards and motors. Total Energy Optimization retrofits can reduce the risk of losses and contribute to greater efficiency in power use.

Transient voltage surge suppression

Electronic equipment is highly sensitive to lightning strike, voltage spikes and internally generated transient surges. The Institute of Electrical and Electronic Engineers recommends surge suppression at the main service point and within control panels. In addition, all electrical installations should be grounded to achieve 10 ohms to ground, exceeding the national electric code, which specifies 25 ohms. Surge suppressors must have a fast reaction time, measured in picoseconds and have a voltage clamping capacity to remove spikes of 20 percent over line voltage. Studies have shown that 80 percent of transients are generated within an installation.

These occur when electric motors, relays and other equipment are activated. Frequently occurring internal transients which may last milliseconds degrade electrical equipment resulting in breakdowns, increased maintenance costs and reduced operating life. A second problem associated with transient spikes relates to the inductive loading which is generated. This increases apparent electrical consumption as measured by disk-type watt meters, resulting in higher costs for power.

Transient voltage surge suppressors are recommended for all breaker panels and motor controllers. Given the harsh operating environment in chicken houses, which are subjected to high humidity, ammonia and dust, surge suppressors should be constructed to high standards, approximating marine or military specifications.

Power factor correction

Electrical equipment operating on alternating current consumes both real power and reactive power. The latter increases the current flowing between the power source and the load, such as a motor. Power is lost through distribution lines on return to the source during each cycle of alternating current. Apparent power which can be measured is effectively the vector sum of real and reactive power.

An egg production complex with a combination of installations with high reactive power values pays more for electricity than an operation with correct design and efficient function of motors and lighting systems. The rate charged by a utility depends on the power factor, which is the ratio of true power measured in kW to apparent power measured in kVA. Under ideal conditions, the power factor is almost equivalent to unity.

For any installation, power factor can be determined from measuring load voltage and current with voltmeters and ammeters respectively and power can be measured with a wattmeter. Reactive power can be calculated from these readings and the appropriate rating of capacitors to be inserted in a circuit can be determined. In most installations 75 percent to 80 percent of energy consumed by motors is actually used to perform work such as lighting, driving an auger or operating motors for ventilation fans and refrigerator compressors. Capacitors cancel the inductive effects of the load applied to working components increasing their efficiency of operation and reducing cost.

Total energy optimization

Transient voltage, which is suppressed using metal oxide varistors, ensures a constant voltage supply free of transients. Installation of power factor correction condensers contributes to efficient application of power. Since utilities charge customers according to peak demand multiplied by rate, decreasing reactive power across all electrical components will lower utility bills.

Watch for voltage fluctuation

Problems indicating the occurrence of transient spikes in voltage include flickering lights, the need to replace ballasts and tubes frequently and motors which operate at a high temperature requiring frequent replacement or rewinding. Computer breakdowns and the need to replace circuit boards usually suggest an unstable power supply as these installations may undergo arcing and melting.

In extreme cases breakdowns within control panels can occur, resulting in failure of ventilation systems and catastrophic loses in houses holding 100,000 to 250,000 hens.

A recent retrofit of a Total Energy Optimization System by V-Blox Corporation on a six-house, in-line unit holding 800,000 hens was reviewed. The total cost of the components including surge suppression and power factor correction extending from the main supply through all panels and motors in excess of 5 HP amounted to $110,000.

Installation was carried out by a combination of local electricians and maintenance personnel under the guidance of the supplier of components for an additional $10,000. The initial pre-installation projected a reduction in utility costs estimated to yield a payback of between two and three years.

The first month after commissioning the system it was calculated that the differential in power consumption for the entire complex was equivalent to the consumption of two of the houses, suggesting a more favorable return on the investment. Reports from industrial users including cold storage companies feed mills, government and military installation and hospitals confirms a reduction in utility payments and maintenance.

In selecting a supplier of components it is necessary to evaluate the capability of supplying a full range of products and to obtain written warranties on the durability of equipment and possible reimbursement for consequential loses arising from equipment failure.

Watch for tax incentives

Projects should be carefully planned in consultation with an electrical engineer to ensure appropriate sizing and location of surge suppression and power factor connection modules. All installations should conform to National and state codes, preferably with inspection by a qualified engineer at the time of commissioning. The possibility of tax incentives should also be evaluated since many installations qualify in terms of IRS section 179.

Comments powered by Disqus