Environmental sensors make smart buildings more comfortable

Citation

(2010), "Environmental sensors make smart buildings more comfortable", Sensor Review, Vol. 30 No. 1. https://doi.org/10.1108/sr.2010.08730aad.002

Environmental sensors make smart buildings more comfortable

Article Type: New products From: Sensor Review, Volume 30, Issue 1

Carlo Gavazzi has introduced a range of sensors to measure environmental variables including CO₂ levels, humidity, temperature, and airflow. The new CGES sensors complement the company's existing offerings to provide complete solutions for energy management, HVAC and smart building applications (Figure 1).

Figure 1 The new CGES sensors from Carlo Gavazzi measure environmental variables to ensure comfortable conditions and high-quality air supply are maintained in buildings and offices

When CO₂ levels rise to an unacceptable level it creates poor air quality and stuffy rooms. CO₂ and airflow sensors can control extra ventilation to increase the fresh air supply and improve the indoor air quality. Similarly, these new devices can be used to control humidity level in wet climates: improving comfort and discouraging the growth of mildew.

Standards introduced by the American Society of Heating, Refrigerating and Air-Conditioning Engineers define a maximum CO₂ level of 1,000 ppm; and the ASHRAE 62-1989 norm has been widely adopted in countries including Sweden, France, and Japan as well as the USA. CGESCO2 sensors use non-dispersive infrared (NDIR) technology to provide measurement ranges 0-2,000 or 0-5,000 ppm. Using a patented auto-calibration procedure to compensate for drift caused by ageing, the sensors ensure traceable high accuracy and outstanding long-term stability. Operation in a closed-loop airstream avoids pollution of the CO₂ sensor.

Humidity measurements are based on a thin-film polymer, which releases or absorbs water vapour according to the ambient humidity, varying its dielectric properties accordingly. The instruments' electronics measure the resulting change in capacitance, with excellent reproducibility that delivers accuracy of ±3 percent from 10 to 90 percent RH. High quality HC101 sensors guarantee excellent long-term stability and resistance to chemical pollutants.

The air velocity sensors utilise the principles of thin-film anemometry, in which a heated resistive mesh is maintained at a constant temperature above that of the medium. Air flowing over the resistor cools it and the power required to maintain the offset is used to determine air speed. Carlo Gavazzi's cutting-edge thin film technology guarantees excellent accuracy over working ranges up to 20 m/s. Moreover, the sensor is insensitive to dust and dirt, and has low-angular dependence. Measuring range and response time are selectable by jumpers.

Temperature measurement is available using Pt100, Pt1000, PTC or NTC resistance elements, ensuring typical accuracy of ±0.3°C at 20°C.

The sensors are available in duct or wall mounting formats, and a switching output offers an alternative to the standard 0-10 V DC voltage or 2-40 mA current analogue outputs. Environmental sensors can be combined in either wall or duct-mounted units. For example, the CGESHTPD duct-mounted model features HC101 humidity sensors combined with passive Pt100/Pt1000 temperature measurement; whilst the CGESCO2TW provides CO₂, temperature and humidity functions in a simple-to-install room transmitter on the wall.

All the CGES family benefit from traceability through international standards such as NIST, PTB, and BEV: the sensors carry CE marks and are RoHS-compliant.

For more information regarding Carlo Gavazzi and its range of products, please visit the new format and easy to navigate web site: www.carlogavazzi.co.uk