Keeping Watch
Fuel cell technology powering outdoor fire protection systems
- By Peter Podesser
- Oct 01, 2009
In 2007, more than 440,000 wild fires in the United States caused more than $1 billion in damage, including destruction of crops, timber and structures, according to estimates by the National Fire Protection Association. Improved fire detection is needed to reduce future fire-related losses.
If a fire is spotted in its early stages, it is usually possible to extinguish it before it causes serious destruction. However, in uninhabited areas, such as national parks, forests or brush land, fires are hard to detect. In these remote areas, fires are often raging fiercely or are already out of control by the time they are detected.
Modern fire-watch systems can detect fires early by continuously searching for smoke. One current solution involves a specialized camera that scans a radius of up to 15 km/9 miles, thus enabling a single camera to continuously monitor an area of up to 700 sq. km/270 sq. miles. The camera is installed on a mast or tower overlooking the area to be monitored. By comparing a sequence of pictures, the camera’s image-processing capabilities can recognize smoke over great distances within seconds. As soon as smoke is detected, the system sends an alert to the operator.
Obviously, outdoor fire detection systems require a constant power supply for 24/7 operation and historically it has been difficult and costly to ensure a continuous power source, especially in a forest, far from the power grid.
At a device rating of 65 W, the system mentioned above has a power requirement of 1600 Wh per day if it is to run around the clock. In this example, a conventional battery will last only one and a half days before requiring replacement, forcing an operator to travel frequently to the camera site for the exchange.
Solar panels, though a very convenient off-grid power supply option, will not generate enough electricity to reliably run the system when the weather is bad. Moreover, solar panels must be positioned in the open to receive adequate sunlight, which exposes them to potential discovery, theft and vandalism and could compromise the effectiveness of the detection system.
Secure, Reliable Operation
A new, environmentally friendly power source is coming to the rescue for operators of outdoor fire protection systems. Direct methanol fuel cells (DMFCs) enable reliable operation of fire-watch cameras -- and many other devices that need to operate continuously off grid -- for days or weeks in any weather, without requiring any user intervention.
The fuel cell system is an intelligent power source that can easily be retro-fitted into existing battery-powered systems. The fuel cell is simply connected to the battery that powers the device and constantly monitors the battery’s charge state. If the battery voltage drops below a certain level, the fuel cell will automatically start recharging it. Once the battery is full, the fuel cell returns to standby mode. The power generation process is environmentally friendly, involving no moving parts or combustion and emitting only carbon dioxide and water in amounts equivalent to the breath of a child. In addition, the fuel cell is virtually maintenance-free, requiring only replacement when the fuel is low.
The fuel cell also reliably backs up solar panels. In a fuel cell/solar hybrid system, the solar module provides all the power when the sun is shining. The fuel cell remains in standby mode as long as the sun delivers sufficient energy. In inclement weather, darkness, and during winter, solar cells cannot deliver enough power for modern fire-watch systems. When the battery voltage drops below a certain threshold, the fuel cell automatically cuts in, recharges the battery, and then returns to standby mode. Such a hybrid fuel cell/solar system offers decisive cost advantages, including smaller solar panels and lower battery capability. In operation, the hybrid system is also economical. As long as the sun shines, no fuel is consumed.
The fuel cell, which can easily be concealed in housing, or even buried, connects to the device invisibly, making it theft-proof. The fuel cell works quietly and odor-free, which makes it virtually undetectable. Worry-free remote monitoring is possible even when the operator is miles away with a GSM modem or laptop computer.
Power From Renewable Resources
The fuel cell is powered by fuel cartridges offered in sizes ranging from 5 to 28 l (1.3 to 7.4 gallons). A 28-l or 7.4-gallon methanol cartridge contains a capacity of 31.1 kWh -- enough power to continuously operate the camera described above for almost three weeks. Methanol is an alcohol generated from natural gas, but increasingly also from renewable resources like second-generation biomass (bio-garbage) or even household refuse. Methanol features a high bio-degradability, therefore it is also allowed in areas where diesel fuel or gas are forbidden for ecological reasons.
Installed with remote, off-grid battery- or solar-powered monitoring systems, DMFCs can help government agencies and private owners reduce the destruction caused by wild fires with a clean, reliable and cost effective power source. As a result, they enable operators to focus on fire control rather than equipment.