ABSTRACT
It is evident from the previous chapters that the way buildings are ventilated determines the levels of thermal and air qualities as well as the energy requirement to achieve them. To quantify these levels requires the measurement of many physical parameters either in physical models of the ventilation system and building module or on site during commissioning and post-commissioning to ensure that the design targets are achieved. The evaluation of the thermal quality, air quality and energy consumption depends on the measurement of parameters such as temperature, vapour pressure, air velocity, air flow rate, thermal comfort, air contamination and the visualization of the air flow in the space being ventilated. The measurement of any physical parameter requires the use of a sensor, i.e. an input transducer and an output device, i.e. an output transducer. A transducer, whether of the input or the output type, is basically a device, which converts energy from one form to another. For example, the junction of a thermocouple represents an input transducer and the temperature indicator is the output transducer.
