A European food manufacturer recently contacted Energy Technology & Control seeking to improve the efficiency of its boiler set-up. The food manufacturer utilises six boilers to provide enough heat to cook and process its raw produce, which is also packaged and distributed from the same location. In this case study we analyse how the innovative Plant Master mode on the ETC6000 can be used to analyse boiler results and improve efficiency.
Boiler efficiency v’s factory demand
When multiple boilers utilise a common steam header, each boiler will be working separately to meet the overall demands of the business. Without a sequencing system this can result in one or two boilers working flat out while others idle. By incorporating the Plant Master capability, it allows the system to ascertain the capacity of the entire boiler set-up. By comparing this with the most efficient operating point for the individual boilers, it can then ensure that each boiler is run at its highest level of efficiency to meet the factory’s current power requirement.
Plant Master mode allows engineers to view all boilers as one system, providing input into the steam generation process. A CANBus sensor, connected to a local ETC6000 controller (The CANBus sensor is connected directly to the plant master), is used to measure the steam pressure. The Plant Master interface allows the CANBus sensor to be designated as the sensor input (to monitor the header pressure or temperature for the entire system) The engineer will enter details regarding high fire, low fire and the best modulation, the Plant Master will then deduct the most efficient range for each boiler.
This facility can be provided by bespoke external systems which are plugged into the boiler set-up, however Plant Master mode utilises the existing Ethernet to connect up to 10 ETC6000 series controllers to the user interface, making it easier than ever before to analyse boiler results without the need for dedicated bespoke systems which can be costly.
The costs of inefficiency
Typically, boiler efficiency peaks at around 75% modulation but all boilers are different. Once correctly set up the system will try to keep each boiler at its most efficient modulation rate but will modulate them past this point if demand requires. A well-modulated sequencing system enables the overall system to better match its output to the demand, meaning that the processes that rely on this are better served.
A factory with an inefficient boiler set-up can suffer in several ways. If the boilers are working too hard, they will produce extra heat which if not used ends up going to waste, conversely if the heat produced doesn’t meet demand the cooking process is slower, this adversely affects the bottom line.
A decrease in efficiency at full output typically occurs because of the increased heat losses accrued. Conversely boiler losses can also increase at lower modulation rates, this occurs for a variety of reasons, not least because whilst modulation rates can be reduced the physical size of the equipment remains constant. Improving the on/off strategy with intelligent sequencing will lead to less boiler cycling, increasing the overall efficiency of the setup and reducing the wear on the boiler and system components.
Less boiler cycling also increases efficiency of the overall system because boiler purging at start-up leads to heat losses. If you would like to discuss how innovations from Energy Technology & Control could help your business save energy and reduce costs get in touch.