University of Wisconsin-Madison in the General Clinical Research Center at University Hospital (room D6/646).

Coming soon!

The chamber resembles a budget (8' x 8') hotel room (in Japan?), with a television, VCR, telephone, roll-away bed, folding chair, small table, reading lamp, toilet, and sink. Meals of known caloric and macronutrient (i.e. fat, protein and carbohydrate) content are provided by UW-Hospital Dietetic Services. An individual participating in one of the approved calorimeter studies remains inside the chamber for a period of 4-24 hours (depending on the particular study protocol), and his/her oxygen consumption, carbon-dioxide production, and level of behavioral activity is measured, and averaged across 5-minute intervals. These data provide a basis for calculation of total energy expenditure, macronutrient oxidation rates, and profiles of activity.
Chamber Floorplan

Coming soon!

The chamber shell volume is approximately 12 m³ with walls and ceiling constructed of panels utilizing 10 cm thick (HCFC22) polyurethane foam insulation sandwiched between two layers of 1 mm thick embossed aluminum (Norlake Scientific, Hudson, WI). Floor panels are constructed similarly, but with a smooth galvanized steel interior surface. Two windows (76 x 91cm) in the back wall provide a view outside, and a window (36 x 61cm) in the door provides visual contact between persons inside and outside the chamber. An cubical airlock measuring approximately 35 cm on a side, manufactured from 1mm thick galvanized steel, is mounted through the wall to allow passage of meals and other small items in and out of the chamber with minimal disturbance of ongoing measures. Mechanical ball-valves at the air inlet and outlet are adjusted to allow outside air to be drawn through the chamber at a rates of 35- 200 lpm by an in-line ventilation blower, and to produce a slight negative pressure (-5 to -7 mm H₂0) inside the chamber. Gas exchange is measured with Hartman and Braun Uras-4 CO2, and Magnos-6 O2 analyzers (Applied Automation, Bartlesville, OK). Sample air is dried by a semi-permeable nafion-membrane air dryer tube system (PermaPure, Toms River, NJ). Climate control is achieved by passing chilled water (9^o C) through copper dehumidification coils and radiator style heat exchangers. A variable speed squirrel-cage fan moves 3,000-10,000 lpm air over coils, heat exchangers and two 1000-Watt electric heating elements. The system is designed to cool and dehumidify continuously, with the reheating of recirculated air controlled by an electronic PID controller (Omega, Stamford, CT). Activity levels are monitored with a sonar-based motion detection system. Data collection is controlled by microcomputer using LabView software* and NB-TIO-10 data acquisition boards (National Instruments, Austin, TX). The chamber volume and rate of turnover allows reliable measure of total gas exchange over periods of 4-24 hours duration.

Air-Sampling Diagram, Air-Flow Diagram (Top View), Air-Flow Diagram (Side View).

[*Note: If you are interested in building a similar calorimeter system... further information regarding the chamber design and/or data collection system may be obtained from engineer Paul F.M. Schoffelen]