Is it all about energy?

During a recent conversation on controls, I was asked a question with regard to energy saving. The request was for document to show the savings that could be achieved by a typical lighting control system.

 I did explain there are numerous studies available that prove that the correct use of controls can deliver significant savings. The challenge I guess is that often these are based on a generic office, classroom or retail space; they don’t always reflect the real world.

True there are tools that calculate your energy footprint such as Energy Performance Building Directive (EPBD) and for Lighting we have the Lighting Energy Numerical Indicator (LENI) each providing a measure of efficiency.

 Additionally, tools such as the Smart Readiness Indicator (SRI) which is part of EPBD will provide a method of assessing a buildings ability to adapt to new technologies in terms of performance and energy flexibility.

 All of the above are excellent, however they tend to be a snapshot as they are used at the planning stage to assess a buildings “Green” credentials and then often overlooked in operation. The same could be said of any green initiative it will only be green if its maintained and the information provided acted upon to fine tune the system.

 We obviously need these systems, and I am a great advocate for green and smart initiatives as they set a framework which we can build upon and this is why it’s imperative we don’t rely on a design tool to characterize our buildings once they are in operation.

 The Smart Readiness Indicator (SRI) is an interesting concept that takes into consideration the life of the project and how the building needs to adapt to reflect the changes both in technology and use.

 We all know the most efficient form of lighting is that which is turned off. If you have sufficient daylight, then dimming or turning the lighting off makes perfect sense and optimises the use of energy to ensure we only use what we need.

 There are two important issues to raise here and that is firstly can the system allow you to regulate and switch the lighting in a sensible and safe manner to optimise daylight and secondly is the system truly fit for purpose technically.

If we tackle the first point, then we need to understand whether the controls system has been designed to meet the needs of the occupants. If spaces are partitioned and glazing is limited does the control system provide sufficient granularity to allow the user to control different zones within the building. So often the lighting controls scheme will be based on a generic solution of switching and sensing based on a standard grid pattern without consideration as to the final use of the building.

 If you don’t know the final use of the building, or the layout hasn’t been finalised then it imperative that we build in flexibility to the lighting controls system to allow for future upgrade or change of use.

 Secondly with smart technologies this has become simpler with the launch of DALI Wireless.

Wired systems based on DALI-2 can now be extended with a range of Wireless sensors, switches and drivers based on IEC 62386 Part 104. Initially Part 104 devices will be based on Thread with Bluetooth to follow later in the year.

In both instances these are interoperable solutions based on an international standard and not proprietary so mixing hardware from different manufactures is perfectly acceptable.

 You can of course design systems with wireless from the off and this will be the route that many companies may take, however we need to really look at the efficiency of the devices connected to the system and consider their operation both as individual devices and as part of a system.

The standardised approach works for a number of reasons as it takes out the guess work and removed dependency on a particular manufacturer.

If we consider wired DALI, then we understand the limitations of the systems and with both Part 102 and Part 103 we understand how much energy each device will consume so can design a system that optimises the number of drivers/ emergency devices along with switches and sensors. Efficiency is built into the system and the sum of the connected devices as well as power consumed in standby is known.

Wireless is slightly different and this why standards really do come into their own when we talk about new technologies. A regulated approach provides a simple method of evaluating the properties and efficiency of a Part 104 device. A proprietary solution however will be working to a different agenda and as such will be manufacturer defined and can be as efficient or inefficient as the system allows.

 I remember debating with an old colleague and friend about the term parasitic losses as I believe this is a very negative term but one that we all tend to ignore. I prefer the term standby losses and if you put this into context it’s the power a device uses whilst off.

 DALI drivers do consume a small amount of power and with smart controls this can be minimised and reduced to zero by switching off a circuit by the use of smart relays so whole circuits can be isolated.

Wireless on the other hand is continually working in the background and depending on how the system is configured may well be consuming a significant amount of energy whilst in its off state. Obviously, this will vary between manufacturers, so it’s worthwhile understanding how efficient your wireless solution really is. This all impacts on energy in use and really how best to optimise your system to reduce waste and minimise your energy footprint.

In reality most buildings will be a mix of disparate systems and providing you work within a solid framework as defined by IEC 62386 then you can mix wired and wireless on the same network and create hybrid smart systems that exploit the best of both worlds. 

 Crucial to all of this is analytics and this has been a prime focus for DALI to create a suite of commands that allow the system and ultimately the user to understand what their connected devices are doing. Power measurement is an example of a command set under DT51 that provides energy in use date for individual drivers which provides a level of granularity never before experienced within lighting. This is actual usage as opposed to data extrapolated from the system based on dimmed value and switching frequency.

It’s worth mentioning that IEC 62386 Part 104 supports analytics so information can be shared over both wired and wireless solutions therefore dashboards can be created to allow users fine tune their building and at a glance see the impact of the changes they make to their system.

 Power is nothing without control and this is exactly the case with a smart building. Knowing how your power is being managed allows you to optimise whilst considering the occupants as well as the use of the space.

Ultimately saving in energy in use has the greatest impact and this should a focus for all control systems. Continuous commissioning is a concept that has been promoted for many years, however, in reality systems are often left as the day they were initially commissioned and rather rapidly become inefficient and, in some cases, redundant

 At zencontrol we have created a software platform that is focused on the user experience and as such provides a seamless interface to all of the critical features of the lighting control system. Changing set points, profiles and zone/ group associations is simply the click of a mouse. Keeping it straightforward and open, removes the need for proprietary tools and the need for engineers to visit site so costs are reduced, and system support becomes a bureau service rather than just a maintenance contract.

 Tools such as SRI will change how we value our spaces, and part of this has to be a focus on open technologies as this manages risk whilst optimising opportunities.

 zencontrol the smart solution for even smarter buildings

 author: Stewart Langdown FSLL

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