Why M2G is installed with BMS
Overview of Building Management Systems (BMS)
Most BMS systems control the various heating / cooling zones etc. by well tested and established methods, such as “weather compensation”, controlling 3 port mixing valves (Variable Temperature circuits). The building dynamics can also be taken into account by specifically controlling “optimisation” of comfort levels in the various zones etc. In the above cases, the boiler/burner plant may be simply enabled/ disabled according to the required room temperatures or occupancy times.
During these control functions, the burners/boilers are turned on or off irrespective of whether the burners are fully modulating, high/ low or at the correct operating temperature for the best thermal efficiency of the boiler plant.
In some cases the BMS may sequence the boilers according to load requirements. This is normally done via a common system flow or return temperature sensor determining a set point and P.I action to ”cascade” the boilers as and when required. The disadvantage of this type of sequencing is that unless you isolate the boiler hydraulics that are not currently firing, this will cause system hysteresis and temperature dilution of the required flow temperature set point.
How the M2G integrates with BMS
The M2G is fully compatible and complementary to all types of BMS/BEMS systems. The M2G is interlocked by fail safe relays, that are connected in series to the burner/boiler control or stat circuit, the BMS is also connected into this circuit via volt free contacts.
The BMS system will give a “call for heat” or enable signal, the M2G will in turn check for boiler demand and the boiler memorised flow and return profile. The M2G’s adaptive algorithms will ensure that the best firing stage is established for the current load conditions and invoke a “save mode”. The M2G has been designed specifically to overcome and avoid unnecessary “dry cycling” of the boiler operation under low load conditions, such as for “standing losses” etc.
To further complement the operation of BMS with M2G, it is possible to interface the inputs/outputs of the unit, to volt free relays and in this way it would be possible for the BMS system to directly monitor the M2G operations if required.
Building Management Systems typically controls the boilers' operation from a blended system temperature and does not control the individual boilers.