Combined heat and power (CHP) or cogeneration technologies that utilize natural gas are emerging as an economic and efficient method of heat and electricity production. There are many examples worldwide of large ( > 150kW) CHP systems that are part of district heating systems or incorporated into refineries to offset their electrical use and provide required process heating. On the other hand, very few small (50-150kW) or micro ( < 50kW) CHP systems are installed in Canada, even though some regions have an abundant supply of natural gas, greenhouse gasintensive electrical production, and cold climate, all of which make CHP a good potential choice for space heating and distributed electrical production. This paper presents results of the long term (3,800 hours) operation of a micro CHP (mCHP) system that was retrofitted to a manufacturing plant located in Regina, Saskatchewan, in order to provide the building with base load space heating and on-site electrical energy production. The prototype mCHP system was developed to SRC's specifications for this project, by a third party, using commercially available component technologies, and it is the first mCHP system to offer a 5.6 kW electric + 13 kW thermal output rating with on-grid / off-grid functionality. It was commissioned in March 2010.

The mCHP system was integrated into the existing heating system through the addition of hydronic heating coils installed in the forced air heating ductwork served by the existing natural gas furnaces and a heat recovery ventilator. The heat recovered from the mCHP unit was buffered by a hot water storage tank. Results and key findings up to March 2011 showed that the system achieved a long term average combined electrical and thermal efficiency of 69.6 % (higher heating value basis). Parasitic loads equated to 15% of total generation of electrical energy over the year, most of which were attributable to pumps required to move heat from the unit to the hydronic coils.

The monitoring results show that nearly 185 GJ of useable heating energy and nearly 19,000 kWh of electrical energy were produced by the mCHP system over its 3,800 hours of operation. The heat and power production on site showed a 34% reduction in greenhouse gas emissions when compared to using existing natural gas heating systems and electricity purchased from the grid.