Lighting the Way to Sustainability with PoE

According to the U.S. Department of Energy, commercial buildings are responsible

According to the U.S. Department of Energy, commercial buildings are responsible for roughly 18 percent of the total energy consumed in this country. So, reducing energy consumption, building by building, could have a big impact.

It's a safe assumption that a lot of that power is needlessly wasted. For example, during the pandemic shut-down the reduction in energy used in commercial buildings in New York City was significantly less than the drop in occupancy for those buildings.

That fact supports my opinion that intelligent control of building systems could go a long way toward improving energy efficiency.

To check out the possibilities, I had a discussion with Akram Khalis, CTO of MHT Lighting, Inc., Staten Island, NY, about their lighting control system, which is built on Power over Ethernet (PoE). The unique feature of a PoE network is that with a single low voltage cable, you can power the lighting, control it, and harvest detailed information about patterns of use. And you can also use it to coordinate with other building systems, like HVAC and powered window coverings.

PoE allows a single twisted pair Ethernet cable to provide both data and electrical power. Sensors, cameras, and access points have been using PoE power for some time now, but lighting has been largely overlooked. The switch to low-power LEDs for general lighting, however, has made it reasonable to use PoE as a power source for lighting.

With lighting, you already have a network in place throughout the entire building. So, if the lighting is powered by PoE, you can add sensors to the lighting fixtures and capture an extremely granular and detailed picture of the living building. By exporting data from those sensors over Ethernet, you could accumulate information like average temperature, average humidity, average light level per area, and room occupancy rates.

"I can't find an access point that's not PoE, but we never pay attention to the very high-density equipment in the building, which is lighting — it's in every office, in every room, in every square foot. It's the way to illuminate the building," said Khalis.

The MHT system can source up to 90 watts, the biggest portion of which can power the LEDs — at typically 10 watts per lamp. The remaining power can be used for sensors. And that's where the utility of PoE lighting systems shines.

There are two main ways an automated building system can reduce energy usage:

Different systems can be coordinated to automatically reduce energy, for example lighting and HVAC.

Distributed sensors can gather information about building conditions and by means of a dashboard, generate reports of kWh versus time, as the conditions vary. This can provide critical information indicating what contributes to increased energy consumption.

With MHT's Inspextor® software platform, you can plan coordinated actions to reduce a building's energy usage. The platform can track kWh usage and correlate that with events in the building, such as which rooms are occupied at certain times. So, for example, meetings could be rescheduled to reduce peak energy demand.

MHT's AI engine can convert raw data into meaningful information and send it back to a human being via a dashboard reporting mechanism.

You can use the platform to create goals for energy savings and then guide you to implementing them, rather than working backwards by shutting lights and turning down HVAC to measure their effects.

With Inspextor, you can predefine your goal, say to reduce consumption by 5-10%, save that goal and with the dashboard feature, see the numbers change statistically.

The dashboard can display actual consumption; project what would happen over time to consumption if you didn't do anything; and what could be achieved by following a suggested plan.

The information can be used in two different ways.

A building manager can gain insights into space utilization and peak occupancy over day, week, month, year, and then adjust the lighting policies programmed into the platform as well as policies for other building systems. An added benefit is that the policies can also be used to improve employees’ work environment.

The artificial intelligence can learn habits and frequent operations of the building and make small incremental adjustments on its own. It can recognize patterns, and adjust lumen output based on forecasts of occupancy or measurements of ambient light level.

Lighting-mounted sensors can detect whether a conference room is occupied — and with a thermal occupancy sensor in each corner of the room, it can even anonymously detect the number of occupants.

If the room is unoccupied, the most obvious action will be to turn off lights.

If the room is unoccupied, that information can direct networked motorized window shades to darken the room to reduce the load on the HVAC system.

With the addition of light level sensors, the LEDs can be automatically dimmed from 100 percent all the way down to one percent to take advantage of ambient daylight, while maintaining a constant light level in the room — daylight harvesting.

HVAC can be adjusted based on the number of occupants.

It's certainly doable, and extremely wise, to build a PoE network based on lighting control if you’re erecting a new building.

It also makes sense if you’re doing a deep retrofit, where you’re renovating and replacing building systems with the goal of reducing energy consumption.

if you’re a brand-new building owner you should look to future-proof the building. You are going to be locked into whatever systems you install now for at least 10-12 years.

There are some really good reasons to install PoE lighting systems.

It reduces the time and expense of having electrical power cabling installed. Network cables do not require a qualified electrician to fit them and can be located anywhere.

Without being tethered to an electrical outlet, devices such as IP cameras and wireless access points can be located wherever they are needed most and repositioned easily if required.

PoE delivery is intelligent and designed to protect network equipment from overload, underpowering, or incorrect installation.

PoE power comes from a central and universally compatible source rather than a collection of distributed wall adapters. It can be backed up by an uninterruptible power supply or controlled to easily disable or reset devices.

Having power available on the network means that installation and distribution of network connections is simple and effective.

Once the network is in place it is relatively easy to add new systems — to incorporate future technologies that become available.

Use of PoE will ease the way to participating in utility demand response (DR) programs.

We are seeing more and more laws and government regulations aimed at reducing energy in buildings. For example, New York City Local law 97 would penalize building owners based on the profile of the building. It characterizes every building based on its size and use case and allows it to use a specific amount of energy. "I would say over 80% of the buildings in New York are not in that profile, which means they’re getting penalized, or they will get penalized if they don't make a decision," said Khalis. "So, I think that's a very big driver now. The customers see big fines coming.

There is actually more than one bottom line.

First and foremost is the payoff in reduced energy consumption — something we need on a global scale.

For the building owner, less energy means lower utility bills.

An improved work environment, which leads to increased productivity.

The reduced cost of low voltage wiring compared to standard AC wiring and fixtures.

Simplifying installation of future technologies.

Avoiding fines and qualifying for government incentives.

This article was written by Ed Brown, editor of Sensor Technology. For more information go here .

This article first appeared in the February, 2023 issue of Sensor Technology Magazine.

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Lighting the Way to Sustainability with PoE