A US Department of Energy “Building America Case Study” found that Greffen Systems’ M2G boiler control produced significant savings for heating buildings using hydronic boilers.
The DOE installed and monitored Greffen Systems M2G Advanced Load Monitoring (ALM) aftermarket controllers at two Chicago multifamily buildings and reported fuel savings up to 14 percent over a heating season.
• Are compatible with hydronic boilers only.
• Monitor loads and continuously measure supply and (in some cases) return water temperatures.
• Derive energy savings by dynamically managing the boiler differential, where a microprocessor with memory of past boiler cycles prevents the boiler from firing for a period of time, to limit cycling losses during perceived low-load conditions.
• Differ from OTR controllers, which vary boiler set points with ambient conditions while maintaining a fixed differential.
Results show that energy savings depend on:
• How much boilers are oversized for their load (cycling rates).
• Time of year (savings vary with cycling rates and greater savings are observed in shoulder months).
Over the monitoring period, oversized boilers at one site showed reductions in cycling and energy consumption in line with previous laboratory studies. Less oversized boilers at the second site showed muted savings.