The utilization of monitoring systems is one of the most important methods of gathering real-time information about the current conditions in any critical facility. Whether collecting data on temperature, humidity, airflow, etc., the traditional approach has been to employ hardwired solutions. Given the state of wireless monitoring technology in the past, this is no surprise. Until recently, wire-free solutions have been expensive, fairly unreliable, had limited range, and short battery life, and they ran the risk of potentially interfering with other wireless systems deployed in the building. However, new advancements in wireless monitoring are showing facility managers that the technology is worth another look.

THE LEGACY SOLUTION: WIRED MONITORING SYSTEMS

The use of traditional wired products remains the dominant technology when monitoring critical facilities. It’s not surprising, as the benefits of wired solutions are long established:

• Solid security: The degree of control that wired products offer is one of their greatest attributes. With no wireless network broadcasting data, hacking into a wired monitoring system is extremely difficult. All connections are physical, and so facility managers control who has access to the monitoring system and its data.

• Reliability: Traditional wired monitoring products have been evolving and improving for decades, and significant advancements have been made to ensure that wired offerings are extremely reliable. They use direct physical connections and do not have to account for interference on the same scale as wireless produces.

• Cost-effective equipment: With no batteries to replace, wired sensors have typically enjoyed a longer active life than their wireless counterparts. In addition to replacement costs, labor costs have also been less as staff do not have to spend time identifying and replacing expired units.

• Speed: In general, wireless networks have always been slower than wired. Wireless signals can be affected by outside influences, such as walls, floors, and cabinets in the facility, as well as suffer interference from other electronic devices. Wireless data transmission is also distance sensitive, and so performance will often worsen the farther away sensors are from wireless access points.

NO TECHNOLOGY IS PERFECT: THE CASE AGAINST WIRED

For all their benefits, wired facility monitoring products still pose significant limitations:

• Lack of mobility: Because wired monitoring relies on a physical network of cables, there is a lack of flexibility when changes need to be made. Redeploying cable is often a time consuming endeavor, depending on how much needs to be rerouted and the barriers between access points.

• Difficulties with scalability: The larger the wired network needed for facility monitoring, the greater the investment will be in planning and constructing it. Just the cost of the cabling can be excessive. As a monitoring network grows, facility managers have to contend with issues like port availability, cable management, switch configuration, etc. Wired systems rely on hardware which needs to be purchased, installed, and configured as the network becomes increasingly complex. As the network grows, so does the cost.

• Cable damage: One of the largest points of failure in wired monitoring systems, damage to cables connecting the system are a noteworthy vulnerability. They may become unplugged or loosened due to human error, or more significantly, become cut or otherwise damaged in the process of network expansion.

• Installation and maintenance costs: The initial costs of installing a wired monitoring system can be high. The same applies for its long-term maintenance. Cables need to be run through walls, under floors, and in some cases buried. The labor costs associated with these projects can be prohibitive, and if a problem is later discovered, gaining access to the cables can provide significant challenges.

ADVANCES IN WIRE-FREE MONITORING

Wire-free products for critical facility monitoring have suffered from numerous issues in the past. In industries where seconds of downtime add up quickly, it’s not surprising that facility managers have placed their faith in established hardwired monitoring systems. However, recent advancements in these key issues, like security and battery life, are creating new acceptance of wire-free products.

COMMON COMPLAINTS OF WIRE-FREE MONITORING SYSTEMS

• Short battery life: One of the most common complaints in wire-free monitoring sensors, short battery life has been a headache for facility managers. As the data transmission rate increases, the life of the sensor batteries decreases. Facility managers have often been left with the choice of not utilizing sensors to their full potential or using valuable man hours to replace dying batteries before there is an interruption in the data stream.

• Signal conflict: As wireless monitoring networks grow, the number of sensors broadcasting real-time facility conditions can create transmission issues. The larger the network and closer the distance between sensors results in a large amount of signal conflict that the monitoring staff have to contend with.

• Slower speeds compared to wired monitoring: When analyzing the real-time conditions of a critical facility, it’s imperative to receive the data stream as fast as possible. On the whole, wired connections have almost always been faster than their wireless counterparts. In specific circumstances, technology has been available to create comparable speeds in wireless data transmission, but the cost of that technology has been high.

• Security vulnerability: The flexibility of broadcasting facility data that wireless monitoring offers has always come at a price. To gain access to information that is being broadcast over a wireless network, one only has to be in range of the signal to intercept it. Once hijacked, wireless sensors can be programmed with malicious settings or have its data spoofed. In contrast, data transmitted over wired connections necessitates physical interaction with a cable to access the same information. It has always been easier and more cost-effective to protect a cable than a wireless signal. With such a gap in security between these two methods, wired monitoring has always enjoyed a substantial edge.

• Complex to configure: Configuring wireless sensor networks to achieve optimum performance is an ongoing challenge for anyone in the field. When new variables are added into the sensor network, as they often are, facility staff has to redeploy and reconstruct the network to ensure that the sensors are maintaining data transmission at best possible speeds.

• Limited signal range due to interference: Wireless data broadcast over the radio frequency (RF) spectrum has always had to deal with a wide variety of obstacles. Walls and doors in shielded areas can lessen signal strength and lower transmission speed. Other devices that operate on the same frequency will create conflicts. Distance between sensors and the facility monitoring hub is a limiting factor. A large gap between these two points can result in a degradation of data.

BENEFITS OF THE NEW GENERATION OF WIRELESS MONITORING SENSORS

Significant advancements in wireless monitoring systems have made wire-free sensors more prevalent than ever before. The latest generation of monitoring sensors are designed to combat threats to a mission critical facility’s environment and ensure continuous business function. Significant improvements have been made to remediate the problems of older sensors, especially in the areas of security and battery life.

• Improved battery life and energy harvesting: Substantial improvements in battery life and energy harvesting in wireless sensors are one of the main reasons that the technology is becoming more widely implemented. Modern sensors now enjoy battery life three to five times greater than standard wireless sensors. In addition to longer lasting power sources (lithium batteries with a lifespan of 10 years or more), modern sensors possess battery sharing capabilities to prolong sensor life. Moreover, monitoring sensors can now harvest a variety of energy within facilities to extend battery life: solar, thermal, vibration, and RF. The evolution of the technology is leading to a day when facility monitoring sensors will harvest all of their power from the surrounding environment, rendering batteries obsolete.

• Easier to physically deploy: One of the main advantages of a wire-free monitoring system is the ability to convey facility data without having to run cable across rooms, through walls, floors, and ceilings. New wireless sensors are also utilizing plug and play technology, including auto discovery and configuration, further helping to reduce installation time. Sensors can now be shuffled from different cabinets or walls with minimum effort. Facility managers no longer have to spend time on managing or repairing cables.

• Easily scalable: Growth in wireless sensor networks is no longer the hurdle it once was. Just as with the advantages of deploying a wireless monitoring system, the growth of the system shares many of the same benefits. Multiple sensors can be connected to a single node and numerous nodes can comprise a single network. The need for running additional wiring to accommodate network expansion is removed. Modern wire-free monitoring networks are capable of receiving data from 400 individual sensors, greatly diminishing the need to create multiple monitoring networks in a facility.
• Now cost effective: In addition to lower deployment, maintenance and scalability costs, the sensors used in wire-free monitoring networks have also been decreasing in cost as the technology has become more widely adopted. Improvements in batteries and energy harvesting have also created power savings that were not available even a few years ago.

• Multiple wire-free signal options: Wire-free monitoring systems can now use one of several different signals to transmit data: 868 MHz, 900 MHz, 2.4 GHz.

• Extended range capability: Substantial progress has been made in extending the range of wire-free sensor networks. Advances in high-performance routers have created a dramatic increase in the range of wireless transmission over the last generation of equipment, decreasing the need to install repeaters and signal boosters throughout a facility.

• Reliability through fault detection: Early identification of faulty sensors and nodes within the wireless monitoring network are key to preventing threats to critical facilities. Modern wireless sensor networks now enjoy this ability and communicate deficiencies in the network to the facility manager as they occur, and repairs can be made quickly. In fact, many wire-free monitoring networks are now self-healing and when one sensor goes down, the remainder of the network is still functional.

• Enhanced security: Advancements in wireless network security have led to increased deployment of wire-free monitoring sensors. The newest generation of sensors operate on their own signal, separate from the infrastructure in the building, as they communicate with each other and back to the facility manager. They also utilize 128 bit encryption to further ensure that only the appropriate facility managers have access to the monitoring data.

CASE STUDY: ENERGY SAVINGS FROM UTILIZING WIRE-FREE SENSORS AT A DEMONSTRATION  FACILITY

The largest operating expense for most data centers is energy. The United States General Services Administration (GSA) anticipates that “data center energy use will grow at an annual rate of 15%, a doubling of energy use every five years.”¹ In 2012, the GSA conducted a study to establish whether providing data center operators with “detailed, realtime measurement of environmental parameters and power consumption”² would identify opportunities for improvement. To collect this data, the GSA deployed wireless sensor technology at the USDA’s National Information Technology Center (NITC) in St. Louis. The GSA picked wireless sensors over wired because “in contrast to wired sensor technology, it can deliver the data in a cost-effective, facility-friendly way.”³ Information from the wireless sensors led to the identification of efficiency measures. When these measures were implemented, the resulting energy savings were impressive.

•  Cooling load was reduced by 48%
•  Total power usage decreased by 17%
•  Annual savings of 657 megawatt-hours (MWh)
• Carbon footprint was reduced by 542 metric tons annually

The cost savings from using wireless monitoring sensors at the demonstration facility were evident, as “… the return on the $101,000 investment (ROI) was 29%, with a simple payback of 3.4 years.”⁴

CONCLUSION

Wire-free monitoring has come a long way in a relatively short period of time. Thanks to new advancements in a number of areas, a strong argument can be made that it is the preferred solution for the modern mission critical facility. Unlike its cable heavy counterpart, wireless monitoring sensors are much less labor intensive to deploy, require less time to manage and repair, and can more easily scale with the growth of the business. With improvements to signal strength and security, many of the traditional problems with wire-free systems no longer apply. Most importantly, improvements to battery strength and the development of energy harvesting make wire-free sensors more environmentally and budget friendly, which benefits all of us. 

Works Cited

1.U.S. Environmental Protection Agency. 2007. “Report to Congress on Server and Data Center Energy Efficiency Public Law 109-431.” ENERGY STAR Program. August 2, 2007.

2.General Services Administration. “Wireless Sensor Network for Improving the Energy Efficiency of Data Centers.” 2012. p.1.

3.General Services Administration. “Wireless Sensor Network for Improving the Energy Efficiency of Data Centers.” 2012. p.1.

4.General Services Administration. “Wireless Sensor Network for Improving the Energy Efficiency of Data Centers.” 2012. p.29.