Evaluating Livestock Housing Mechanical Ventilation Systems for Energy

Grant# 96-01
Principal Investigator: Steven J. Hoff
Organization: Iowa State University
Technical Area: Energy Efficiency

Project Objectives:
The purpose of this research project is to investigate the energy and air distribution efficiency of current fans, inlets, and controllers used in mechanically ventilated livestock housing systems. The specific objectives are to:

(a) Develop a ventilation system-testing laboratory to quantify fresh-air, temperature, and airspeed distribution, and electrical energy usage of current livestock fan, inlet, and controller systems; (b) Quantify electrical energy and thermal distribution efficiencies for livestock building fan, inlet, and controller systems currently existing in the market place; (c) Develop a livestock system ventilation performance parameter that quantifies the combined electrical energy and thermal distribution efficiencies; and finally, (d) Disseminate research findings to producers and fan, inlet, and controller manufacturers .

Summary of Work:
Objective one has been completed and tasks are currently being conducted to complete objectives two and three. The first phase for disseminating our research findings to producers and ventilation manufacturers (objective four), will be conducted at the 1998 Iowa Farm Builders Conference.

Specific activities currently in progress include: (a) completion of testing for seven commercially available ventilation systems associated with this research project and (b) evaluate results and formulate guidelines for manufacturers. Progress towards each task is summarized below:

Development of the Air Dispersion Laboratory
Objective one was to develop a full-scale testing chamber for conducting ventilation efficiency studies. This chamber, called the Air Dispersion Laboratory (ADL), has been completed. The specific features of the ADL are included in an informational flyer available from the PI or the IEC.

Identify and Solicit Ventilation Systems
Objective two involves testing of commercially available livestock ventilation systems. Seven major livestock ventilation companies have agreed to participate in this research project. Each company was asked to design a ventilation system for the ADL and to supply all necessary components related to their design. In exchange for this equipment “loan,” each company will receive a ventilation system performance report that compares their system to the others tested. All “other” ventilation systems will be kept confidential to ensure anonymity. The companies who have agreed to participate are listed below.

Company Location Contact
Aerotech, Inc. Mason, MI Bob Mitchell
Automated Production Systems Assumption, IL Mark Oberrueter
McKay Equipment, Inc. Saskatoon, Saskatchewan Eldon McKay
Del-Air Systems, Inc. Humboldt, Saskatchewan Troy Gullet
Double-L Group, Ltd. Garnavillo, IA John-Brian Priest
Osborne Industries, Inc. Osborne, KS Ron Thibault
Ray Dot, Inc. Cokato, MN David Raisanen

Donations Received
Several auxiliary components were needed to equip the ADL. Various companies were asked to donate equipment and the result is given below:

Auxiliary Equipment Item Company Donating
Feed Lines Chore-Time Equipment, Inc.
Feeders New Concepts, Inc.
Space Heater LB White, Inc.
Pen Gating New Concepts, Inc.

The Testing Protocol:
The testing protocol has been established and guidelines have been sent to each participating company. Two major items of interest will be quantified with this research: energy and air distribution efficiency. The general testing protocol given to each ventilation company is listed below:

1. Airflow pattern testing ¾ Neutrally-buoyant helium/air bubbles are introduced to the building to observe airflow patterns. Still photographs and video are taken to record patterns.

2. Air velocity distribution ¾ Air velocity is recorded continuously at six locations within ADL. Air velocity is measured 10 inches above the floor, representing the animal occupied zone (AOZ). Air velocity as a function of ventilation rate is analyzed for airspeed uniformity.

3. Air temperature uniformity ¾ The ADL is instrumented with several temperature sensors and comparisons are made between the set-point temperature maintained with each controller used and the temperatures located within the AOZ. Temperature uniformity statistics are calculated to further assess air distribution.

4. Air-jet penetration ¾ Air-jet throw, defined as the location where the incoming air-jet dissipates to 50 fpm, is measured as a function of ventilation rate. The air-jet throw is used to define the air- jet’s momentum and potential for developing proper fresh-air distribution patterns.

5. Airflow rate versus static pressure ¾ The ADL has controlled attic openings that consist of calibrated orifices. These controlled openings provided an easy method for quantifying ventilation rate in the building. Simultaneously, the ADL static pressure differential is measured and plots of CFM versus static pressure are developed to create a “Ventilation System Characteristic Curve.”

6. Controller response ¾ The controllers are tested for set-point temperature control after the set-point is changed to 20° F and 40° F above the current ambient air temperature. Response time, defined as the time required to reach 67% of the final set-point temperature, and temperature uniformity, are evaluated and summarized for each system tested.

7. Energy usage ¾ Continuous watt meters monitor all electrical energy use for each ventilation system. Energy consumption as a function of ventilation rate is recorded and summarized in a CFM/Watt rating.

Two complete ventilation systems have been tested. The remaining five ventilation systems were scheduled to be completed by May 1998 at which time work was to begin summarizing all results into a proposed ventilation performance standard; an activity currently ongoing within the American Society of Agricultural Engineers.