Smart Lighting Owns the Ceiling – But What About the Walls?
The transition from traditional lighting to LED lighting has triggered a wave of innovation that will establish lighting as an Internet of Things (IoT) backbone in the building. High node density coupled with readily available power supply make lighting fixtures ideal nodes of a connected wireless mesh network.
This IoT network will transport information about the fixtures status but also about vital building parameters generated by connected sensors. This combination of smart LED lighting with sensors integrated into an IoT network is often referred to as the “Smart Ceiling”. Reducing the sensor and network infrastructure to a smart ceiling however misses one key part – the walls of the building together with the sensors and controls that have to be placed there. While the ceiling is ideal for placing occupancy or light level sensors, it is usually much less suited for temperature and air quality sensors and not at all for user interfaces such as thermostats or light switches. Therefore even the smartest building will typically require certain device types to be placed onto the wall from where they will communicate with the network in the ceiling. The key question then however becomes how to connect and power such devices. Three options are possible for that:
This is the classical way of connecting devices with each other and is still used today in many systems such as KNX. Relying on a wired connection however reduces or even eliminates the flexibility benefit offered by wireless systems. Every redesign of a building that affects those devices will result in a need for rewiring which is undesirable both from effort and down time perspective. Moreover, increasing the amount of wiring in the walls will strongly reduce the option of pre-fabrication and pre-installation ahead of the actual construction.
Wireless connection powered by batteries
Having a wireless network in the ceiling makes using wireless devices on the wall a logical extension. The communication distance to the next node in the ceiling network is typically very low and the communication therefore reliable.
Wireless systems provide significantly higher flexibility than their wired counterparts and can be installed or extended much quicker.
Power to the wireless devices can be supplied by batteries which will usually ensure a runtime of several years. The rise of new business models such as Lighting as a Service (LaaS) however means that the responsibility for operation shifts from the building owner to the company installing the lighting network. Therefore total cost of ownership and maintenance cost become critical factors that determine the profitability of each installation.
Maintenance events – and especially unplanned maintenance due to battery failure – typically result in significant cost for maintenance personal and possibly compensation for customer down time.
Wireless connection powered by energy harvesting
Energy harvesting wireless devices generate all energy required for their operation from their environment. The most obvious example is the energy harvesting wireless switch that generates its energy from the kinetic movement of being pressed.
Energy harvesting devices by their nature do not require maintenance and can therefore have a positive impact on total cost even though they are typically more expensive than their battery-powered counter parts. In the full paper, we will present the current status of such energy harvesting devices, explain typical use cases in smart lighting systems, discuss their limitations and give practical examples of their use both within lighting control systems and within the broader scope of smart buildings and IoT solutions.
Objectives of the lecture…
The transition from lighting control to data driven buildings. Hype, future or reality?
Wireless and maintenance free? The impact of reliability and maintenance in service driven business models.
Lighting as IoT data backbone – what data, where does it come from and who is going to pay for that?