At the time this manual was written (June 2011), the metabolic centre of the University of Zurich and the Swiss Federal Institute of Technology Zurich is still under construction.
In its first stage it will be situated at a temporary location and it will consist of two large chambers for cattle, two medium chambers for sheep and goats and two small chambers for smaller animals (piglets etc; not discussed in detail in this manual). It is planned to enlarge the metabolic centre to four chambers per size. Facility air flow is about 910 m3/h and temperature ranges from 20 °C to 26 °C without humidity control. The chamber casings are constructed with insulated sandwich panels. Windows are inserted into the casing on each
side of the chamber. Chamber volume of the large and medium chambers is about 22.4 m3 and 9.2 m3, respectively. The chambers will be operated at a slight negative pressure (maximal 100 Pa below ambient pressure). Air flow through the chambers will be between 300–1000 L/min (large chamber) and 40–250 L/min (medium chamber). Each of the chambers forms an independent system with its own flow generator, air conditioning unit, animal welfare monitoring and data logging. The two large chambers share a common gas analysis and data acquisition system, so do the two medium chambers. From the flow generators a sub sample is directed to the analyser system by the means of a multiplexer at regular intervals. The duration of these intervals is not yet known. Concentration of water vapour, CO2, CH4 and O2 are measured with a four-gas analyser. Intervals of gas analyser calibration and recovery tests are not yet defined and will be set according to the dynamics of the chamber and the gas analysers. The large and medium chambers are planned to suit the needs of research animals and operators while enabling monitoring of CH4 emissions for a maximal time during