The M2G from Greffen Systems is an intelligent boiler control unit designed to optimize the heating efficiency of hot water boilers. A unit attached to each boiler monitors the temperature of the water in the flow and return every 10 seconds, and the information is recorded along with the heat transfer rates at both the first and second stage firings.
When a loading demand is made, the M2G system checks the latest data it has stored and determines whether it is more economical to retain first stage firing or to introduce a second stage firing. The result is substantial fuel reduction during less demanding situations while ensuring maximum capacity during heavy load periods.
Differing from a time delay unite, the M2G uses self learning intelligence when deciding if and when a boiler should fire and for how long it should fire. Time delay units will stop the burner from firing even when there is a real demand from the building for heat.
Weighing 3.6 pounds, the M2G unit is designed for a variety of commercial applications that consume natural gas, LP gas, Class C oil, or Class D oil. Although designed for multiple boilers, it can also be used singly and can be fitted to many types of boiler including forced draft and atmospheric systems. Verified documented installations illustrate a reduction in energy consumption of up to 30%. Payback periods normally run between six and 24 months.
In 2009, a facility energy manager working in a federal government building in metro Atlanta installed an M2G unit as part of a pilot program in a 328,000 sf, 1963 era single story facility. He shared with TFM that 12 months later, a year over year, weather normalized analysis of gas usage showed an 18.7% reduction in fuel use, with a return on investment (ROI) of six months. He explains, “We are required to meet the EPACT 2005 and EISA 2007 mandates along with Executive Orders 13423 and 13514 for energy and water reductions. We had funds available to try for additional energy reductions. It was a local decision to go for natural gas reductions. After extensive research, we found the M2G, which seemed to fit our criteria. Greffen agreed to do a pilot test for our 6.6 MmBTU/hr dual fuel Weil-McLain hydronic boiler, and they installed the M2G along with a day on/day off timer to control the running of the unit and Dent data loggers to monitor the firing cycles.”
“After approximately 32 days, we saw a 40% reduction of our firing (dry cycling) and Greffen’s calculations suggested we would see about 11% reduction in fuel use and an ROI of about 12 months. I was naturally skeptical even with the hard numbers in hand. The following February while doing our first quarterly energy report. I saw the natural gas reduction was only 8%. So I started looking very hard at all the data and variables (e.g., population, weather). After reviewing the weather data, I came to realize we had seen an 11% increase in heating degree days, while at the same time an 8% reduction in fuel use, with no adverse impact on occupants. This equated to a 19% reduction.”