Low-Cost Microscale Distributed Generation and Combined Heat and Power for Use in Laundry Facilities

This project successfully developed a 49 horsepower combined heat and power system using a laundry facility as an example application. To accomplish this, the research team modified an automotive rotary engine to operate on natural gas and mated it to a generator. The system was packaged into a unit containing all necessary connections and balance of plant. Emission testing indicated good performance when operated on natural gas, but required the use of a catalytic converter to achieve the desired emissions levels. Hundreds of hours of operational experience were accumulated on two engines. One engine was retained at the laboratory of the Advanced Power and Energy Program at University of California, Irvine, while the second was used at a commercial laundry facility. The testing indicated some challenges remain with integrity of the heat exchanger system and the generator. One concern, the integrity of the seals of the rotary engine, was removed as analysis of wear suggested adequate life. Emission levels below those required by the California Air Resources Board could be attained for oxides of nitrogen and carbon monoxide with appropriate engine tuning. Regarding demonstration testing, the original demonstration site was unable to support the test due to changes in management. Deployment at the alternative site was straightforward, although the heat demand at the alternate site was significantly less than that of the original. This precluded desired long-term testing at the alternate site. The engine at the laboratory, however, was operated for long periods and proved reliable aside from the heat exchanger and generator issues mentioned. Analysis projected for the original site with the larger thermal load indicated possible total savings of about $1,300 per month in the winter and $2,080 per month in the summer, based on relevant utility rates.