Outdoor monitoring ...indoor benefits

Will Perrott introduces the potential offered by current environmental monitoring systems.

The importance of monitoring environmental conditions is obvious in many applications.

Rain levels will influence river flow which in turn influences the dissipation of discharges from industrial plant.

Likewise, wind speed and direction will control the area over which air-borne pollutants released from industrial stacks are carried.

In fact, many industrial processes rely on, and have a legal requirement for, such monitoring over time.

All landfill sites throughout England and Wales, for example, have a legal requirement to monitor environmental conditions.

Typically, sites will utilise an automatic weather monitoring station, incorporating sensors for a wide range of parameters including rainfall, temperature, barometric pressure, wind speed and direction.

This allows predictions to be made in terms of the likely distribution of odour, litter and other potential pollutants, which may arise in the form of leachates.

In addition, data recorded can be used both to help ensure the most efficient site management possible, and to indicate whether a site was associated with a particular incident, should any complaints about odour or pollution arise.

In this way, information recorded by the environmental sensors is typically used to assist in process control and efficiency, by monitoring either the effects of processes on environmental conditions or of conditions on the processes themselves.

With the increasing volume of European environmental legislation the use of monitors in this way is likely to continue.

However, the potential use of external sensors to influence internal conditions is perhaps only now being realised.

One location where sensors are being used in this way is the National Centre of Popular Music (NCPM) in Sheffield.

The first interactive visitor and education centre in the world to celebrate the art, diversity and influence of popular music, the centre has an unusual and contemporary building design in keeping with its modern outlook.

The centre, which is expected to attract 400,000 visitors each year, consists of four separate, circular exhibition buildings or "drums" that will house exhibition space, education facilities, a cafe? and shop.

The design of each drum is such that its roof can be rotated to face into the wind, using the existing weather conditions to assist in the air conditioning and ventilation of the buildings.

ELE wind speed and direction sensors play a vital role in this system.

A roof mounted wind monitoring system is positioned on the main building, where it continuously monitors the speed and direction of the wind.

The system incorporates both a stainless steel three cup anemometer and a dual fin wind direction sensor, which continuously measure wind characteristics with a high degree of accuracy.

Similar to many environmental monitors, the basic operation of the wind sensors is simple.

For example, the direction sensor is constructed with two fins that are turned by the wind, to provide an accurate representation of wind direction with minimal flutter.

This simplicity ensures reliable operation throughout the lifetime of the sensor, and ensures that the sensor continues to monitor wind direction accurately, even in low wind speeds.

Wind behaviour detected by the sensors is registered using integral electronics, which produce a current proportional to speed and direction.

Readings are taken continuously, and transferred to the building management system via a 4-20mA transmitter, which ensures that there is no loss of signal over the long cable length.

Using the information transmitted, the direction of the roofs can be adjusted every ten minutes if required.

The sensors have been in operation since the opening of the NCPM earlier this year, utilising prevailing environmental characteristics to produce a more "environmentally friendly" air conditioning and ventilation system for the centre throughout the year.

The simplicity and flexibility of sensor design renders them ideally suited to continuous monitoring applications.

With a relatively low unit cost, environmental sensors can be combined in a network to create a more comprehensive picture of conditions over a wider area, or linked directly to a building management system, as in the case of the NCPM, or to a data logging device or automatic environmental monitoring station.

Consequently, the use of environmental monitoring in this way is likely to increase as companies realise that after years of modifying the performance of industrial products and processes to minimise their effect on the environment, they may now be able to use environmental conditions to reduce the energy requirements and potential costs of internal building facilities such as air conditioning and ventilation.

Back to top