March 4, 2016
Radu Petrescu
[Part 1] The 5 minute guide to an 'Open System' BMS, cost-effective & easy to implement. What we learned after 30+ years of trial and error...
Part 1/5: How to design a submetering solution that is both affordable and non-intrusive?
In all my professional career I have been involved in BMS design work and have had an amazing journey solving complex integration projects but also trying to get small repetitive cost-effective solutions designed.
I'm a problem solver myself and I'm sure you are too and I would like to share with you the solutions I found to some of the most challenging BMS design problems I had to solve.
Even though submetering is the key component in targeting energy efficiency, more often than not, businesses chose not to submeter their utilities. This is due to either the high cost of installation or the disruption involved in wiring the meters back to the BMS system over long distances.
When designing such a solution to deliver both cost effective and non-intrusive installation the answer had to be wireless. The question was then which wireless to use? To answer this we have tried all the available wireless solutions and the conclusion we reached was that there must be a specific set of criteria to be met in order to make this work.
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Long range Wireless.
Only using 868MHz Wireless one can achieve up to 300m in buildings without using repeaters.
Is true in general that using wireless reduces the wiring cost which in turn makes the installation affordable which is great. Most wireless providers promise this almost without exception.
The reality is that very few manufacturers achieve long range wireless so we always ended up installing many repeaters which added cost, which we have not budgeted, but also added delays the project which was not to the liking of either the client or the project manager.
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Open Protocol Wireless.
Maximum flexibility is achieved only using Wireless solutions that are able to talk an open protocol such as modbus.
We needed to have a wireless solution that was both secure and would work with any BMS manufacturer, this in turn gave us the flexibility to use the most appropriate BMS for the rest of the building.
Also we discovered that we wanted to pick up existing meters but also add new ones where required so we needed the flexibility to pick up both modbus and pulse counter meters.
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Keep it simple.
The only way to get the system installed and maintained effectively was to keep it simple for the BMS engineers.
Looking at the multitude of wireless solutions available the first problem was to navigate through a very complex set of part numbers and figure out which one was needed for each specific project. So too many part numbers was confusing the project engineer but also complicating life for the procurement team.
Too many part numbers also means that a lot of information needed to be captured in the site survey in order to determine how many repeaters are needed and where.
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Is this solution available today? Yes, we have the perfect answer to all the above and we are very proud to have been able to solve this. We are equally excited to share this with you... |
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