[This is Part#4 of the Energy Management Series. You may access Part#1 here, Part#2 here, Part#3 here and Part#4 here.
Data collection is the key part of any Energy Management System. In absence of systematically and periodically collected data, most of the decision makers fail in defining the most optimum and practical system for Energy Management. Energy Management Policy can only be derived once decision maker has proper data to chart.
So, what is data collection?
In Part#1, Energy Management – the Traditional Practices; we say how traditionally energy management was handled. Manual data collection, compilation, and analysis leads to not only improper but also misleading analysis. Thus, when the globe is chasing for utmost energy efficiency by optimum asset utilization and prudential engineering practices, the way one collects, compiles and analyzes the data – matters a lot. Essentially nothing but sensors are the ground-force elements which collect data such as electricity, temperature, pressure, flow, energy, production, etc. For each of these, we have a different set of hardware/sensor. These sensors do read data. Generally, from energy management perspective, the user prefers to have various data over and above electricity related data, as they – one or the other ways – are associated with the energy consumption.
- Electricity – Current Transformer + Energy Meter (for HT side, one would also require Potential Transformer)
- Temperature sensor
- Pressure Sensors
- Flow Meters
- Btu meters
Data read by the Energy Meters can easily be communicated over protocols such as Modbus/Profibus/DLMS/etc. However, other sensors do read and communicate the data in the form of electrical signals (0-20 mA or 0-10 V DC). Thus, received analog signals are converted to digital form, which in turn can be used for recording and analysis. To convert the analog signals into digital form, we use Analogue to Digital Converter (ADC). ADCs may be a single-channel or multi-channel, depending upon the requirement. A channel of ADC can convert one analog signal to its digital form. e.g. if we have one temperature sensor and we want to read the data, we follow below mechanism:
- RTD (Resistance Temperature Detector) à Single Channel ADC
- Similarly, if we have two temperature sensors and one pressure sensor, we need multi-channel ADC.
From this point, an onwards industry has two technologically different solutions for data management, viz. Local Energy Management System and Wireless Energy Management System.
Local Energy Management System
ADCs give standard digital output over RS-485 or RS-232, and do support Modbus protocol for communication. Data is communicated by ADC (1/4/16/32 channel) or Data Logger (64/128 channel) are comparatively small in size. But one Data Logger cannot process data of multiple Data Loggers, nor can it handle multiple protocols and ports. To handle such massive and varied data or data formats, it requires typical hardware, called Gateways or Switches.
Data from Energy Meters, ADCs, etc. do flow to Gateways/Switches. These Gateways or Switches are kind of hardware that can collect data from multiple streams of small size, and can further send the same over different protocols/hardware / etc. Also, these Gateways / Switches are can also be used in sync with the servers such as Windows 2000, Windows XP, Server 2003, Vista, Server 2008 (x86/x64), Windows Server 2008 R2, Windows 7/8/8.1 (x86/x64), Windows Server 2012 (x64), Windows 2012 R2. Such support creates ease of further data handling and further management. Below are examples of typical network gateways.
Data from Gateways are fed to the server. Typically, these servers hold configuration of a normal desktop (1.9 GHz processor, 500 GB Hard Disk, & 2 GB RAM), that houses the EMS software. EMS supplier configures such software that can read, analyze & display the collected data. One can do various functions over the data collected, as per the defined software function.
One can visualize a typical wired energy management system as below:
- Data does not go out of the client premise
- Client has full control over the data for what to do with the data
- No dependency on GPRS or Wi-Fi network
- No operational cost in the form of GPRS charges
- Software up-gradation is a big cost
- Scalability of the system is extremely small
- Report / Alert / Notification customization is not possible
- User does not remain in sync with the globally accepted practices
- Since data storage is on local server, user needs to take manual back up periodically
- Limited users have access to the data; one needs to go to the designated work-station to see the data
Wireless Energy Management System
This form of EMS has wireless data collection and cloud hosted servers manage the software applications, data storage, and processing. Essentially data from the Energy Meters or ADCs are read by the Modem and thus communicated to the Cloud Hosted Server over GPRS. The Modem can read data from up to 25 No of meters simultaneously. This saves not only the cost of the additional modems but also that of GPRS (data charges). You may read more about data communication over GPRS Modem here.
Data thus sent by the Modem to the cloud-hosted server is processed by various applications and software modules. Data being on the cloud server, a user can easily access the data over the web-portal, using secured authentication process.
- User does not require to maintain any server related infrastructure
- User gets the most updated software version automatically
- Customization on display, reports and alerts/notifications are easy to do
- Progressive development by the service provider becomes easily available to the user
- User can access the data from anywhere using secure authentications provided
- Data does not remain in control of the user
- Data communication has dependency on GPRS / Wi-Fi network, failure of which may cause data loss
Undoubtedly, wireless energy management system is the most preferred system, over the local system. On the way Industry 4.0 and digitization of processes, energy management plays the very vital role. Surely, wireless energy management is the front-runner component of Industrial Internet of Things (IIoT).
Depending upon the requirement, the users may have configured screen for data visualization. But all of them have a common objective of optimization upon energy cost, though best utilization of data is a subjective matter. Below are few sample screens for reference.
Much discussed on what’s there in the market and how industries are making the best use of the available technology for Energy Management. In the subsequent post, we shall talk about the policies, i.e. how one should approach for energy management from policy perspectives.