Babel Buster: It is how to connect things to BACnet.
Part three of a three part series on the business case for submetering, the measurements required to succeed, and a comparison of available submetering models. By the end you should know the right questions to ask when choosing a submeter supplier.
The Business Case for Submetering - Part 1-3 Submetering 101 - Part 2-3
While there is no question that submetering projects are one of the most effective ways to drive down facility operational costs, there are plenty of questions surrounding the best way to move forward with a solution that will provide a good return on your investment.
How should the project be financed? How do I get my energy readings? Is it easy enough for existing staff to use? Will it meet our future needs for more advanced monitoring and cost savings initiatives? These are some of the big questions you need to consider when choosing a meter supplier.
Know Your Primary Objective
Before you launch into any submetering program there is one fundamental question you need to ask yourself. What is the primary objective of the project?
At a very high level there are two reasons for installing a submetering system: fair billing and energy usage reduction.
• Fair Billing
Many submetering systems are put in place as a way to fairly and accurately allocate the existing utility bill between tenants. Revenue grade meters are generally required for this purpose and although total energy costs normally drop once a fair billing system is in place landlords are generally expected (and in a growing number of states legislated) to share the savings with their tenants. Buildings with tenant billing systems in place have a higher market value and fewer tenant disputes about utility bills.
• Energy Usage Reduction
The other type of submetering system is an Energy Management system. The primary objective of this type of system is to measure and report energy usage in such a way as to clearly identify opportunities for cost savings through energy usage reduction. These systems provide detailed information on when and where energy is being used, often down to the minute. They provide an ongoing detailed audit of energy usage that identifies high usage, or unusual usage immediately. Energy Management systems are designed primarily to drive down operating costs as opposed to just splitting up the bill more fairly.
There are two basic payment options available in the industry: product purchase and service subscription. The model you choose will depend largely on your budgetary processes and areas of influence. Capital expenditure budgets allow for large up front purchases and normally provide the best long term return on investment. Operational budgets on the other hand lend themselves to smaller, long term subscription based payments and are sometimes easier to get approved.
• Product Purchase Model
Using the product purchase model the customer makes a one-time purchase of equipment and installation. The system is then yours to use forever at no additional cost. On the plus side, fully purchased solutions provide the best return on investment in the long run. The down side is that depending on the size of your installation a large up-front capital expenditure can sometimes be difficult to get approved.
• Subscription Service Model
Using a service subscription based model the customer signs a contract for an energy usage reporting service rather than buying the monitoring system. In this model the metering company provides and maintains ownership of all submetering equipment. They read the meters and provide periodic reports to the customer for a monthly or annual fee. Since operational budgets are often easier to get approved than capital expenditures this is often the only way to get a submetering system in place. The down side is that over the long run you generally end up paying more.
Recent advances in technology have made getting energy readings out of your meter and in front of the right people on the computer easier than ever. For very reasonable prices you can now purchase meters that make meter reading effortless. Here are some things you should ask about when considering a submetering system.
• Spreadsheet Files
Meters can now produce reports in many different formats. Some are readable by people. Some are only readable using special software. One of the most flexible, and useful formats available is a simple spreadsheet. Spreadsheets are uniquely flexible in that they can be used by advanced building control and reporting systems to import very detailed data or given to a receptionist or accountant with basic PC skills to track energy usage manually.
• eMail Reporting
Advanced metering systems can be set up to send you an email every week or every day with graphs and spreadsheets of all your meter readings. To read your meter all you do is open your email. Sharing the data is as easy forwarding the email.
• Automatic File Transfer to Your PC
Once you get used to using your energy usage reports it can be very useful to just have them show up automatically in a directory on your PC. One of the most popular ways to do this is to set up an FTP (file transfer protocol) server on your PC and have your meters publish data to the FTP server on a regular basis. This is a good method if you have some IT staff to help you set things up and all of your meters have FTP push technology.
Another common method of getting data from the meter to your PC is to use a small application to grab data from the meters periodically. In some cases an application like this can be obtained from the meter supplier and eliminates the need to set up and maintain an FTP server. It also keeps all your communication settings in once place rather than distributed between each meter making it easier to make changes in the future.
• Real-Time Web Page Updates
Today's most advanced meters have built in web pages that let you see data in real time using your internet browser. This is an easy way to get data on an as needed basis or give visibility to a group. You should be able to download reports and go to detail pages for more information on a meter with good web page features.
• Remote Diagnostics & Updates
Even in the best designed systems sometimes you need a little help. The ability to grant access to your supplier for remote support and diagnostics can save thousands of dollars in unnecessary travel costs, and give you immediate answers. With remote web access you can get help changing settings, checking readings, and diagnosing problems. Some built in meter web pages can even tell you if you have the meter wired incorrectly from a PC on site, or from a thousand miles away.
• Data Analysis and Reporting Tools
Many advanced energy usage analysis and reporting software packages are available if you need more flexibility than spreadsheet files and email reports provide. These packages let you view your data graphically in multiple ways, group meters together, and create custom reports for detailed analysis or distribution to tenants or department heads. Make sure your submeters produce data in a format that is compatible with your chosen reporting systems.
• Ethernet Port
Many installed data collection systems today are based on 2-wire RS-485 connections or 9-pin RS-232 connections for communication. Although these systems still work well the world is rapidly moving towards Ethernet/Internet based solutions. Submeters without Ethernet ports do not integrate as smoothly into local networks or Internet based solutions, and lack the ease of use for remote diagnostics and support. As Ethernet communication is much faster than other methods and is quickly taking over way we connect things to each other it is definitely something to look for if you want to be able to smoothly integrate your meters into current and future versions of monitoring and automation systems.
Whether you are looking for a system to provide fair
billing or to drive down your operational costs the choices you make when
choosing a system will dictate your success and return on investment.
The ease of use and expandability of the system you choose will dictate your success for years to come. So ask questions about the usability of the system and determine which reporting methods are best for you.
If you need more information, talk to your local installers and don't be afraid to suggest suppliers and systems that sound good to you.
About the Author:
Daryl Cowie is business development manager at Wescon Technologies. For more information on how to justify and choose a system that fits your needs visit http://MultiCircuitMetering.com to get 2 free reports:" Show Me the Money - real life submetering cost savings examples" and "The Facilities Manager's Submetering System Checklist - basic requirements, options & standards"
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