Solar Power Solutions
A noise monitoring terminal’s (NMT) low power consumption and its ability to operate fully without power hungry cooling and heating units inside its enclosure mean that it is suitable for power from solar panels. The NMT may be continuously powered by battery which in turn is kept charged via solar energy. This solution is most appropriate in areas where there is a large amount of solar energy. Such solutions have been installed in Italy, Greece and Southern France.
Solar/Wind Hybrid Solutions
However, as latitude increases it becomes less viable to operate units continuously with solar power only. An installation, for example, in Manchester, UK would require six solar panels and a large battery array to operate continuously throughout reduced daylight hours in winter.
An alternative solution is a hybrid solar energy and wind power system which, with a battery pack, can provide a viable source of continuous power for NMTs remote from land line power.
For the Manchester area, three solar panels, each measuring approximately 1.2m high by 0.5m wide would be required. The panels would be mounted on each side of the microphone mast, approximately half way up.
The installation would have an additional enclosure mounted on the concrete base to house a 135 Ahr lead acid 12 V battery to provide up to five days of battery backup to power the unit at night time and in times of low solar energy.
Solar energy would be used to charge the NMT’s battery pack during the months of March to September. During the other months a wind generator would provide the power requirements.
The wind generator could either be mounted half way up the microphone mast or on its own mast. The generator itself makes a small amount of noise but this is typically below the wind induced noise at the microphone due to the same wind speed. However, for very low level measurement (<30 dB), caution over mounting arrangements may be needed.
The number of solar panels needed and the additional wind generator and backup battery requirements will depend upon the location, historical amount of solar radiation, wind speed profiles and the allowable downtime in periods of low solar radiation.
This hybrid arrangement would provide an effective means of continuously powering NMTs over a wide range of locations without the need for costly land lines. Coupled with the options available for wireless communication, this would enable a complete stand alone installation that would eliminate expense and the risk of delays to the NMT installation.
The following considerations should be taken into account:
- Even slight shading significantly reduces the output from the solar panels. For reliable operation a free aspect must be present
- Solar panels will be prone to vandalism and should not be used in built up areas
- Installation may be subject to additional planning restrictions
- A security fence may need to be installed around the equipment The full range of NMTs from Brüel& Kjær support the use of solar panels and wind generators for supplementary power.