Bioenvironmental Engineering Research Laboratory
L. L. Christianson,* R. J. Adrian, P. C. Harrison, J. W. Hummel, L. L. Hungerford, R. E. Isaacson, S. Landsberger, S. M. Larson, R. I. Mackie, M. T. McCulley, T. A. Newell, J. F. Reid, G. L. Riskowski, M. J. Rood, W. B. Rose, M. A. Smith, L. A. Spomer, J. F. Stubbins, G. D. Taylor
National Science Foundation; U.S. Environmental Protection Agency; American Society of Heating, Refrigerating, and Air-Conditioning Engineers; Center for Indoor Air Quality Research; U.S. Department of Agriculture; U.S. Department of Energy; University of Illinois
(In cooperation with the Departments of Animal Sciences, Horticulture, Civil Engineering, Mechanical and Industrial Engineering, Nuclear Engineering, Theoretical and Applied Mechanics, and Veterinary Medicine, and the Small Homes Council/Building Research Council)

An interdisciplinary research laboratory was established involving faculty from engineering and biological sciences. The purposes are to characterize and assess the microenvironment and its effects on organisms and biological products. Focus areas include animal and plant interactions with their microenvironments, sensors and instrumentation, indoor air quality, air and air contaminant movement, environmental conditioning equipment, and building materials.

A consortium of consumer products aerosol manufacturers is working with the U.S. EPA, Georgia Institute of Technology, and UIUC researchers to develop computer models and test methods that will predict the spray pattern, particle sizes, and ultimate deposition of particles from consumer aerosol cans. Particle image velocimetry (PIV) is used to measure the particle sizes, velocity, and movement as functions of time. Surrogate aerosols are used which represent most consumer products in spray characteristics.

Effects of various design (e.g., blade tip clearance and motor type) and operational (e.g., frequency of cleaning and wind effects) parameters on fan airflow delivery and energy efficiency were measured. A standard test method has been developed to compare air delivery and energy efficiency of commercially available 24-, 36-, and 48-in. fans. This information on fan performance is published in booklet form and distributed by extension engineers and electric utilities. This project is in cooperation with electric power suppliers, swine producers, and fan manufacturers.

A new tracer gas technique was developed to measure the fresh air delivery to locations within occupied commercial buildings. The theoretical analysis and preliminary laboratory experiments are complete. Currently the method is being proven in field tests and developed into a standard method of testing.

Experiments were conducted in the room ventilation simulator to evaluate the reliability of the EPA/RTI model for predicting indoor air quality. That model is two-dimensional and capable of operating on a desk-top computer. The model was compared with more complex three-dimensional models requiring supercomputers and with experimental data. Further experiments are planned to evaluate and refine the model for more complex and realistic room conditions.

The objectives are to evaluate ventilation systems and their effectiveness in pollutant removal and to develop the theoretical bases for understanding gas and dust emissions and absorption from surfaces in rooms. Typical office and residential rooms are physically modeled in the room ventilation chamber to measure the airflow patterns and velocities and the ventilation effectiveness for alternative ventilation systems. Surface emission and absorption rates as affected primarily by air velocity and turbulence characteristics over the surface are measured in convective environmental chambers.

New air speed sensors are being developed for measuring air speeds in the 0.05 to 0.5 m/s range, with the capability of estimating turbulence. Applications are for research and environmental control in plant and animal housing. Prototype instruments were constructed and tested in research environments.

The objectives were to measure the effectiveness with which fresh air is delivered to occupied space at different seasons of the year and as internal heat loads vary in typical commercial buildings with variable air volume (VAV) systems for air distribution. Tracer gas was used to determine the locations of leads in the air distribution. The amount of total air (fresh air plus recirculated air) was measured at each room diffuser in a multiroom, multistory building. The airflow patterns in selected rooms was also measured with tracers and flow visualization equipment.

An under-floor liquid manure pit in a swine building was used as a basic model unit to study the physical, chemical, and biological reactions occurring in the process of liquid manure decomposition; to develop mathematical models of gas evolution rates; and to apply the models for predicting the desorption rates of the gases from liquid manure storage facilities. Spacial and time variations of manure characteristics and hydrogen sulfide and methane generation rates were determined. Evolution rates of ammonia can be predicted at different environmental conditions and manure characteristics. Hydrogen sulfide evolution rates are also being studied.

A series of tests were conducted on how design and ap pli cation affect performance of ventilation equipment and structures. Equipment tested included agricultural fans, grain-drying fans, evaporative pads, air diffusers, and building ridge vents.

Fundamental causes of steel corrosion in animal facilities were determined by field and laboratory chamber studies. Field exposure tests in poultry, swine, and dairy buildings showed the dairy to be the most corrosive even though dust and ammonia levels were the lowest. The dairy building had the highest relative humidities and the widest range in temperatures. Three laboratory chambers were constructed for testing metals under precisely controlled environmental conditions. The metal samples were exposed to various levels of ammonia in the air. The lower the ammonia level, the higher the corrosion rate, so ammonia inhibited corrosion rather than accelerated it.

A detailed literature review was conducted of ventilation of animal housing facilities, including laboratory animal facilities. A survey of ventilation design experts and users was conducted to determine effectiveness of existing and emerging ventilation technologies. A summary analysis was conducted on research to date and an analysis of ventilation strategies was given. Future research needs were also identified.

Heat, moisture, and contaminate production from laboratory rats were measured in convective calorimeters at precisely controlled air temperature and velocity conditions. This information will be used by NASA in designing laboratory rat housing facilities in the space station. Additional studies were conducted to determine metabolic rates of laboratory rats at different air velocities and temperatures, and to determine quantities and properties of the laboratory rat wastes. NASA is using this information to design the Advanced Animal Habitat for the International Spacestation.

Feasibility studies are being conducted on an air scrubber for swine building exhaust fans. Most of the odor exhausted from swine buildings is carried on particulates and a low-cost method of modifying existing ventilation fans to remove these particulates is being investigated. Methods of scrubbing particulates from fan exhausts will be investigated in the laboratory, then field studies will be conducted to verify performance.

An environmental survey was conducted at several laboratory animal facilities. Variations in ventilation rate, air velocity, air temperature, contaminant levels, noise levels, and light levels were found for animals throughout each room. Laboratory studies were conducted on full-scale laboratory animal rooms to determine effects of various ventilation systems on cage air exchange rates. Room ventilation system configurations had little effect on cage air exchange rates.