Wireless BMS:
Meeting The Challenges Of Today’s Built Environment
Wireless is not a new technology. In fact, its origins date right back to 1831 when Michael Faraday demonstrated electromagnetic induction. While there have naturally been significant advances since Faraday’s first DC generator, the adoption of wireless in BMS (Building Management Systems) has had something of a chequered history. However, the advantages that it brings, particularly given the shift towards buildings being repurposed and offices being reconfigured in light of the changing building landscape post-Covid, means that it is seeing something of a resurgence.
Historical Milestones
A notable point for wireless communication in BMS was 2003 and the release of the standard for low-rate wireless personal area networks (LR-WPAN). This provided the platform for the development of many of the protocols which are still widely used today, including Zigbee, Bluetooth & Wireless HART, and Thread.
Another important milestone in the development of wireless was the birth of the consumer smart home. This can be traced back to around 2012 with the launch of the Phillips Hue light bulbs, since when the adoption of IoT technology by the mass market has grown exponentially.
Networks
The basic principle of wireless transmission is electromagnetism, with the wave passing from a transmitter to a receiver. While this principle is unchanged, one of the biggest differences in, for example, a modern BMS, is the large chunks of information from potentially thousands of system devices which are sending and receiving information. That has resulted in a requirement for digital technologies with much higher bandwidth and quality of service (QoS). Another shift in wireless technologies is the move from simplex (one-way communication from a sender to a receiver) to half-duplex (wireless networks that can either transmit or receive data at one time) which is the format of most modern wireless communication. Modern wired networks are usually full duplex meaning they can communicate in both directions simultaneously.
In a typical wireless network, a user’s device such as a laptop, tablet or smartphone is known as the client. The access point, typically a wireless router, connects the client to a larger network. When this signal is received by a wireless router, it is decoded and sent to the internet using a modem via a physical, wired ethernet connection. Wireless networks come in a range of different types, including Wide Area Networks (WAN) and Low Power Wide Area Networks (LPWAN), Metropolitan Area Networks (MAN), Local Area Networks (LAN), Personal Area Networks (PAN) and Near Field (NF) networks.
Open Protocols
As already mentioned, there are many varied wireless technology protocols. Bluetooth, Wi-Fi and the cellular networks of the telecoms industry (4G and now 5G) are the most recognisable as they have been widely adopted in mass market applications. In BMS, probably the most widely known are Zigbee, KNX IoT, LoRaWan and Thread. One of the most important factors in modern BMS is the adoption of open protocols to enable more intelligent room devices and building solutions. Thread is a good example of this: an open source, mesh networking, IP-based protocol which allows network devices from different manufacturers to communicate seamlessly. The Thread Group alliance was formed in 2014 by a number of blue-chip international companies across the IoT industry, including Apple, Google and Siemens.
Each protocol has its advantages and disadvantages, with decisive parameters for selecting the most appropriate protocol being range, energy consumption, data rate, transmission power, latency, energy consumption, stack technology, security and legislation.
Picking up on the first of those, ‘range’ is one of the most important factors and has been one of the reasons why wireless communications have not been as widely adopted in BMS applications as they might have been. While wired systems can be affected by certain parameters, wireless signals can be interrupted by many factors. In buildings there are various obstacles which can cause signal absorption, penetration, diffraction, reflection, refraction and scattering, all of which can potentially dampen the signal. Such obstacles include walls, ceilings, windows, doors, humans, goods, furniture and other static or moving objects. The damping effect depends on the material’s composition, with wood, plaster and glass typically having a lesser impact on signal range while concrete, composite glass and metals have a higher impact. Interference from other electronic devices or reflections can also prove an issue. However, significant advances have been made in modern wireless technologies to address signal damping. Distance can also be an issue. LoRaWan is an example of a protocol which is particularly suited for applications involving long distances and low data rates.
Latency and energy consumption are another two important factors to consider when it comes to wireless signals in IoT for smart buildings. They are often considered in tandem given that reducing latency often increases energy consumption. Real-time data applications require low latency, while monitoring systems prioritise energy consumption. It is crucial to consider both factors when designing wireless IoT systems to select appropriate technology and power management strategies. By finding the right balance between latency and energy consumption, building managers can provide reliable and responsive IoT solutions while minimising energy consumption and reducing overall costs.
KNX And Thread Working Together
KNX (1999) was originally developed as an open and global standard for building automation. Its successor, KNX IoT (2022), adopts the semantics and device models from KNX but has been designed for modern IPv6 based IoT/IT communications such as Thread. This means that it offers the application know-how and interoperability of the well proven KNX standard, as well as the advantages of modern IP based communications.
Thread is an open standard for wireless communication providing an IPv6 based solution for reliable, cost-effective, low power, secure device-to-device communication. It is specifically designed for smart home and commercial applications where IP-based networking is desired and a variety of application layers can be used on the same network. Using true mesh network technology, it is possible to build up highly reliable self-healing network infrastructures, thereby avoiding a single point of failure. Thread is future-proof and driven by many of the world’s top tech companies and leading silicon vendors. It therefore has the potential to emerge as one of the most dominant wireless technologies for IoT.
The Advantages Of A Wireless BMS
Wireless technologies offer a number of advantages in controlling the environment in a building to improve the comfort of those present. Wireless devices can save considerable time – potentially months – in installing cumbersome wiring and manual installation of sensors, actuators, controllers, lighting, switches and other devices. This is a particular benefit when wiring routes are interrupted by obstacles such as windows, concrete and steel.
Their flexibility enables easy retrofitting of building automation equipment given that there is no need to remove wiring of old devices. There are also benefits in terms of security. Existing wired standards for building automation often utilise analogue or unencrypted digital protocols, which can result in faulty signals and exposure to security risks. Conversely, modern wireless technologies such as KNX IoT over Thread use IPv6 communication with end-to-end encryption, with over-the-air updates to ensure easy and automatic transmission of security updates to all devices.
Smooth connectivity is afforded by wireless systems, with next generation smart configuration capabilities which require minimal time and engineering expertise. Open interfaces allow seamless integration into the cloud or existing BMS.
A building’s carbon footprint can be improved by adopting a wireless approach. In an average 5-floor office building, over 12 km of wires are required for HVAC systems alone. This represents more than 500 kg of cable containing around 250 kg of pure copper. Wireless installations can save almost 80% of these resources.
Aesthetics is often a consideration for building interiors. Wireless devices such as room control units or sensors allow flexible placement, especially when mounting on glass or movable objects. They are also easily relocated if a building space is reconfigured to reflect changing needs. The flexibility of wireless also allows for a wide coverage of different applications. It can be deployed from small to large buildings, adaptable to many varied configurations, with the potential to expand across multiple buildings through the easy extension of the network.
Addressing Current Challenges
As stated in the introduction to this article, a current trend in commercial buildings is the significant increase in change of use and remodelling. Much has been written and spoken about the subject of Covid and its effects on the conventional working environment. The impact that home/hybrid working has had on the office environment is considerable. Large and small companies alike have re-evaluated their need for conventional office space. Some have relinquished it completely, requiring buildings to be changed from their original purpose; others have remodelled the structures of their working environments to reflect the different work models.
This is a market for which wireless BMS is ideally suited, offering a flexible, aesthetically pleasing solution which is easy to install and cost effective, with in-built future-proofing to provide the comfort required for the buildings of today and tomorrow.
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