Rayteq's new Fleet Commander™ Interactive Demand Management System (IDMS™) is new, next-generation technology that enhances the many benefits of electric resistance melting by dramatically reducing electric utility demand charges of a group or fleet of electric melting furnaces by interacting with and synchronizing each furnace's power demand.
All Rayteq electric furnaces include Furnace Director™' custom designed programmable logic controller (PLC) that operates the furnace, tracks critical production variables such as metal bath temperature and furnace power consumption, and networks with the central IDMS™ computer. This central computer, equipped with Rayteq's Fleet Commander™ software, can coordinate an unlimited number of electric furnaces equipped with Furnace Director™ PLCs to effectively hold total fleet kW demand to the minimum required to meet production melting needs without adversely impacting metalcasting performance.
Fleet Commander™ IDMS™ is several times more effective than first-generation open-loop, non-interactive demand management systems (DMS) yet it does not impair production rates or casting quality.
How Rayteq IDMS™ Works
Rayteq's Fleet Commander™ IDMS™ custom programmed software is loaded into an industrial-grade computer that communicates with a fleet of electric resistance furnaces equipped with Rayteq's Furnace Director™ PLCs via standard Ethernet cables or industrial-grade wi-fi radio bridges. A furnace participant may be a Rayteq designed and built furnace or it can be a compatible conventional furnace such as a Dynarad* or StrikoDynarad* electric melter equipped with the Rayteq IDMS™ retrofit control panel which contains the required Furnace Director™ PLC.
Regardless of fleet makeup, the IDMS™ mission is interactive kW demand management to minimize the total kW electrical demand of the entire furnace fleet supplied from a single metered electrical service without compromising the user's production and quality control requirements.
In operation, the Rayteq IDMS™ software gathers all relevant information about the fleet and periodically provides each Furnace Director™ PLC with recommended actions which may include kW reductions in the form of heating element brownouts for each furnace. Each Furnace Director™ PLC considers the impact of these recommendations on the user's preset production and quality control requirements before deciding to what extent it will implement them. In addition, the Furnace Director™ PLC can elect to shed a previously accepted brownouts recommendation that is still in effect should it later become incompatible with the user's production requirements. Giving each Furnace Director™ PLC local decision-making authority ensures that the user's production and quality control needs for each furnace are always properly maintained.
Fleet Commander™ continuously tracks kW demand of all electric furnaces in its fleet, making it an effective sub-metering system. It is also a comprehensive data logger, storing nearly all of the information it gathers for later examination. Should strange things happen in the night they can be tracked down and examined at a later time, making Fleet Commander™ valuable as an analytical tool.
Demand Management Theory
Electric utility monthly demand charges are determined by the highest (peak) average kW demand over a 15 to 30 minute period, typically during a calendar month, as recorded on the utility's demand meter. The theory behind both Rayteq's new IDMS™ and the more conventional DMS is that unsynchronized electrical equipment, including electric melting furnaces, will randomly but inevitably draw maximum power simultaneously a number of times during the utility's month-long demand metering cycle. Just one such incident will drive the utility demand charge up to the maximum possible cost for that month. Because most metalcasters do not operate their equipment including furnaces at maximum red-line output there will always be room to reduce the total fleet kW demand. Demand management systems work to reduce utility demand charges through synchronized restriction of the total kW demand of an electric equipment group, and the manner in which they accomplish this has a major impact on (a) demand reduction effectiveness and (b) production output and quality control.
Comparing Rayteq IDMS™ with Conventional DMS
Fleet Commander's highly effective control method spreads a large demand reduction across the entire furnace fleet in an orderly and efficient manner instead of applying harsh rolling 100% blackouts to one or more furnaces, whether they are meeting production needs or not, as do conventional first-generation on/off, non-interactive demand management systems (DMS). Because these early systems have no awareness of the state of each furnace, they attempt to hold total plant demand to supervisor adjusted, arbitrary set-point limits with no special attention given to any individual furnaces which may be falling short of the user's required melting rates. In many cases this set-point limit is set unnecessarily high due to the supervisor's hesitancy, possibly because of previous bad experience with production disruptions, and setting a higher than needed maximum power limit results in lower cost savings. By contrast, Rayteq's interactive approach considers the conditions in each furnace before taking action, thus maximizing overall demand reduction while maintaining quality control and full production without interruption.
Every night after the last production shift the Fleet Commander™ IDMS™ automatically begins recalculating the furnace fleet's daily kW demand requirements based on adjustments to production rates as well as changes in furnace status (on-line, off-line, etc.) without requiring a supervisor to input any demand set-points or continually tweak the furnace fleet kW demand target. As a result, Rayteq's IDMS™ continuously adapts and squeezes every last drop of demand out of its furnace fleet without any human interaction or guesswork. The results are impressive - net IDMS™ kW demand savings can exceed conventional demand management systems by 100% to 500%!