Achieving Net Zero CO2 Emissions with Single Pair Ethernet

summary

To achieve net zero CO2 emissions, the building industry needs to modernize its communication infrastructure. This article will show how buildings using traditional links such as RS-485 can be easily retrofitted with single-pair Ethernet (specifically 10BASE-T1L) to increase digitalization, enable automation, improve safety, and significantly reduce energy consumption for greater sustainability.

Introduction

In order to combat climate change and achieve sustainable development, more than 90 countries are actively developing CO2 net zero emission policies. In short, net zero emissions can be achieved when human CO2 emissions can be reduced and offset by other activities.

An essential element of achieving net zero emissions is reducing CO2 emissions across all sectors. However, according to the International Energy Association (IEA), the building sector remains on track to achieve the global net zero CO2 emissions target for 2050. Specifically, the 2030 target is to reduce energy consumption per square meter by 35% compared to 2021. 1 Currently, buildings account for 30% of global energy consumption, leading to concerns that emissions targets will not be met unless the building industry takes concrete actions to digitally transform and automate systems. The challenge is further exacerbated by the need for more real-time data collection for effective automation, which exceeds the current throughput and responsiveness of traditional RS-485-based infrastructure. In addition, connecting devices and building systems to the network poses the risk of cyberattack, requiring advanced security capabilities that exceed the current capabilities of these traditional networks.

This article will explore how single-pair Ethernet can help the building industry achieve net zero goals while supporting AI-based automation in a secure and cost-effective manner. Single-pair Ethernet can provide long-distance connectivity to the edge for new and retrofit facilities, making it an important tool for seamlessly transmitting data between IT and OT domains.

Energy savings through digital transformation

The IEA 2030 Net Zero Plan3 calls for reducing emissions by around 15% through demand reduction through technologies such as behavioural change and digitalisation. While teaching people how to save energy can be effective, an IEA case study4 suggests that automation, rather than behavioural change, is more likely to reduce energy consumption.

As commercial buildings become increasingly digital, operators can not only measure operational performance improvements, but also lay the foundation for operational automation. With sensor data and control functions, building operations can be optimized, energy consumption can be reduced, and people in the building can receive better services.

For example, improving indoor air quality places additional demands on building operations. New regulations such as ANSI/ASHRAE 62.1 require more outdoor air to be drawn in and may require increased ventilation2 to ensure compliance with health and hygiene standards. These ventilation standards will result in increased energy consumption, which means that energy demand must be further reduced. To optimize operation, the many HVAC systems within a building must be able to work together without conflicts between systems.

In order for different HVAC, lighting, fire and access control systems to operate in fusion, the right data and access control functions need to be obtained. Fusion operations can optimize AI and machine learning (ML) to determine the ideal lighting, heating or cooling settings based on people's current and planned activities. Fusion operations can also control airflow to help ensure proper indoor air quality while balancing energy consumption.

However, it is difficult to fuse data from multiple systems because different vendors maintain different databases, resulting in data silos. According to the IEA group responsible for the Building and HVAC System Data Sharing Guide5, the next challenge is how to bring different data sources together into a single console so that trends can be compared and analytics can be applied to generate new insights, as shown in Figure 1.

Modernizing communications infrastructure

The key to integrating the many different data sources within a building lies in the measurement and connectivity infrastructure used. Traditionally, sensors and control functions in commercial buildings have been connected via wired serial communication links using RS-485 transceivers and protocols such as BACnet™, Modbus, and LonWorks.

However, RS-485 is a legacy interface that is limited in both throughput and security. For example, BACnet MS/TP, a common building automation protocol, which runs on the RS-485 physical layer, has a maximum baud rate of 115.2 kbps. 10 In addition, legacy communication protocols such as BACnet and Modbus are designed for closed networks and lack built-in encryption and authentication capabilities. Because these devices are connected to the internet through IT infrastructure gateways, they are exposed to extreme cybersecurity threats.

Single-pair Ethernet (specifically 10BASE-T1L) is an exciting new communications method that was approved by IEEE 802.3cg in November 2019 and is now being deployed in buildings. 9 Wired serial link cables that support RS-485 can be reused and 10BASE-T1L Ethernet data can be transmitted over these cables. Therefore, existing infrastructure can be adapted for single-pair Ethernet. This has many advantages:

• Nodes can now support higher bandwidth (up to 10 Mbps).

• Nodes are IP addressable, simplifying device management.

• It can reach up to 1 km, more than enough to support the maximum length of existing RS-485 cabling. This is a significant improvement over the limitation of standard 10 Mbps/100 Mbps Ethernet, which is only 100 meters. 11

• IEEE 802.3cg specifies Category 15 requirements, allowing up to 52 W of power to be transmitted along with 10BASE-T1L data over a single twisted pair cable. Using the recently introduced LTC4296-1 Power over Ethernet (PoE) controller, the system can power a wide range of end devices. Note that due to differences in cable quality, it is recommended to power only new installations.

The first step in the digital transformation journey is to communicate over Ethernet-based versions of these legacy protocols, called BACnet/IP and Modbus TCP/IP, with building controllers deployed using standard 10 Mbps/100 Mbps Ethernet. 6 BACnet/IP devices use the same data objects as BACnet MS/TP legacy devices, so it is easy to implement a system with both devices. Ethernet-connected facilities that use IP-based protocols such as BACnet/IP and Modbus TCP/IP that support modern cybersecurity measures are increasing. 12 BACnet has approximately 60% market share worldwide7, and approximately 80% of new installations use wired serial communications based on RS-485. The Building Services Research and Information Association (BSRIA) estimates that 5% of HVAC sensors in 2019 were wireless sensors, which have limited their application due to their lower connection reliability and the need for batteries. 8

Improved communications

Heating and cooling systems have multiple components, including thermostats, controllers, air handling units, and variable air volume units, that need to exchange information to achieve temperature set points. Increasing the communication frequency from the common serial baud rate of 9.6 kbps to 115.2 kbps to the Ethernet bandwidth of 10 Mbps means that the data throughput of the system will increase significantly. This high-speed IP-based communication has several major advantages.

Figure 1. Convergence of multiple systems enables data visualization through a single console and saves energy when used with automation and AI/ML.

Analyze, not sample: Traditional communications have slow data transfer rates, so building managers must prioritize and then sample the data they collect. With single-pair Ethernet, managers no longer have to worry about serial communications sampling rates and can now focus on developing advanced analytics that leverage more of the data collected from the system. 14

Energy savings: This additional data can lead to greater energy savings through faster control loops or computationally intensive energy optimization using models and real-time sensor input.

Converge Data/Eliminate Data Silos: Traditional wired serial communications require gateways to convert data from edge devices into Ethernet-based packets that are then transmitted to the cloud. If the wired serial communication link is upgraded to single-pair Ethernet 10BASE-T1L, the existing cabling can be reused while eliminating these gateways. This avoids data silos, reduces points of failure, eliminates gateway costs, and reduces overall latency.

Real-time responsiveness: Communication protocols and software running on the gateway slow response times to seconds, while building automation applications such as IO monitoring may require latency of 100 milliseconds or less. 13 Single-pair Ethernet has higher throughput and without the need for a gateway, throughput is faster so the system can respond in real time.

Secure Communications

Memoori12, a leader in smart building research, points out that lack of effective network coverage is rapidly becoming a major obstacle to the advancement of smart building applications.

One of the biggest challenges in achieving digital transformation is the convergence of IT and OT. Traditional fieldbus OT networks based on RS-485 can be retrofitted with security by upgrading to protocols such as BACnet/SC, but this is costly, time-consuming, and can easily miss vulnerabilities in existing systems. A 2020 study by Kaspersky showed that among all industrial control systems, building automation systems were subject to the most cyberattacks, surpassing the oil and gas, energy, and automotive manufacturing industries, so effective security protection is essential. 15