If you are like most organizations you are interested in gaining better control of your energy consumption. Maybe you have implemented an Energy Conservation Measure and want to better measure the Return on Investment. Or maybe you have multiple buildings being fed off of one utility service. Whatever your reasons may be, chances are you have looked into energy metering.
If you have reached this point and you have a building automation system (BAS) (LINK) than you probably have spoken to a controls technician or your building operator and have considered adding energy meters to your facility and have been advised that it would be easier to use your BAS as the backbone. After all, it is existing already, why wouldn’t you use it?
Many companies and organizations have gone through this same exercise a number of ways. We have helped a number of those companies that have learned the hard way why this is may be a bad idea. In our experience, here are 4 reasons why you should never add an energy meter (LINK) to a building automation system.
1. Data Usage
The biggest risk we see is the data. Simply put, building automation systems were not designed to manage the amount of data that energy meters can provide.
Building automation systems were designed to do controls and most of these systems do a fantastic job at this. Because of this, they were initially designed to handle smaller amounts of data for shorter amounts of time. For example, a control system may need to turn a fan on or off but not necessarily track how long that fan was on or the energy the fan consumed.
For the most part, devices on a building control systems give less than ten data points per device, where energy meters can give over 1,000 data points.
Most power meters alone can track over 1,000 meter points as often as every second. If you program your energy meters to track your energy data at the industry standard 15 minute interval then you could be getting 96,000 records every day! That is just for one meter!
This amount of data can start to slow down your building automation systems. We have worked with a number of universities who have implemented energy meters into their building automation only to find that their system was slowing down or becoming completely unresponsive at times.
2. Communications protocols
The amount of data that energy meters can produce can begin to slow down your network or other communication protocols.
Most building automation systems use proprietary communication protocols that the automation company themselves only have access too. If they are not using a proprietary protocol, chances are they are using what is becoming the industry standard protocol, BACNET.
BACNET is great at sharing data in a network and feeding back to a head end but it is an older
technology. The biggest problem we see with BACNET is the reliability of data with the number of devices on networks today. For example, if you have a standard 100,000 square foot building using BACNET you could have over 100 devices on your network.
Having so many devices on your network creates issues in finding the exact device you want as well as connecting reliably to the device. When you add energy meters to a BACNET system you are not only adding more devices but you are also adding more data points to an already crowded system. When this happens data loss can occur.
3. Ease of Expansion
If you are using a proprietary building automation system protocol then expansion can become a nightmare. Many automation companies are going away from proprietary networks due to this issue, however, many buildings still have these protocols in use. When you connect an energy meter to a proprietary network system, you limit your ability for future expansion.
Due to the nature of energy management systems, future expandability is very important. For example, you may want to start by metering only main energy feeds such as a main electrical panel but over time you start needing more granular data and decide to install sub-meters. If you have tied your main into a proprietary network then adding a sub-meter could end up costing you more money.
Most building automation systems and even some energy management systems, charge using a “point system”. This is where you are charged for every point that you wish to have connected. This could drive the cost of your energy information system high if you connect energy meters. As I mentioned earlier, power meters alone can have over 1,000 points. The more you connect the more points you need to purchase.
4. Data Integrity Issues
When it comes to energy metering, data integrity is key. We have all heard the old saying, “Garbage in, garbage out” this is extremely important when it comes to energy metering. How can you properly maintain an energy management program if the data you are getting is questionable? It becomes very difficult to measure ROI, do sub-billing or even gain control of energy if the data you are getting is questionable.
Due to the other three issues we have already discussed, data integrity becomes very important. When you connect your energy meters to a building automation system you are adding them to a system designed for control and automation, therefore the data could be compromised. We have seen cases where energy data was tweaked or altered by the building automation system. This causes issues in data integrity.
Also due to the nature of building automation systems, data storage becomes harder to manage. To properly maintain an energy information system you need to collect data representing long periods of time to enable the ability to do deep analytics. Simply put, building automation systems were not designed for data warehousing.
A SIMPLER APPROACH
We have solved these issues by creating a completely separate infrastructure that can run along side your building automation system. In some cases, it is important to have energy meter information inside a building automation system but not all of the data. In these cases we can create a bridge between the energy information system and the building automation system.
This allows both systems to work in harmony with each other without compromising data or raising the cost of energy management. Our approach allows our customers to have all of the data they need for energy management without compromise.