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ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, MARIAH ENERGY CORPORATION HEAT PLUS POWER SYSTEM
Citation:
GGTC. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, MARIAH ENERGY CORPORATION HEAT PLUS POWER SYSTEM. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-01/115, 2001.
Description:
The Greenhouse Gas Technology Center (GHG Center) has recently evaluated the performance of the Heat PlusPower(TM) System (Mariah CDP System), which integrates microturbine technology with a heat recovery system. Electric power is generated with a Capstone MicroTurbine(TM) Model 330 and line power unit having a nominal power output of 30 kWe alternating current at 430 VAC and selectable frequency of 50 or 60 hertz (Hz). The unit runs parallel with the local power utility and is designed to automatically disconnect from the grid when grid power fails, which isolates the system from grid faults. The standard turbine requires a natural gas supply pressure of 52 to 60 psig, but an optional booster compressor is available for sites without high pressure gas. The heat recovery system consists of a fin-and-tube heat exchanger with a circulating propylene glycol mixture. If the heat demand is significantly lower than the heat recovered, the heat recovery system will automatically shut off.
Verification of the system was conducted at Walker Court condominium in Calgary, Alberta, which is a live/work arrangement consisting of 12 units that combine street-level retail/office space with a two-level residence above. A single unit, connected in parallel with the Alberta grid, provided on-site electricity, hot water, and space heating. The test program consisted of a series of load tests at 100, 90, 75, and 50% of rated power followed by 38 days of 24 hours/day operation at maximum electrical power output and heat recovery rate. Performance evaluation includes power output, heat recovery rate, electrical efficiency, thermal efficiency, and total system efficiency. Emission of nitrogen oxides (NOx), carbon monoxide (CO), total hydrocarbons (THC), carbon dioxide (CO2), and methane (CH4) were measured in the turbine exhaust stack simultaneously with efficiency determination at the four load conditions cited.
All load tests occurred at ambient temperatures of 40.90 to 43.96 degrees F, barometric pressure of 12.90 to 13.11 psia, and a relative humidity of 44 to 54%. The system generated 28.39 +/- 0.01 kWe at full load, and maximum heat recovery rate was 186.9 +/- 5 Mbtu/hr. Full load efficiencies were 24.6% electrical, 47.2% thermal, and 71.7% total system. NOx concentrations were <5 ppmvd from full load down to 50% load, ay which point average NOx concentrations increased abruptly to 70.09 ppmvd, CO emissions ranged from <5 ppmvd at full power to 25.04 ppmvd at 50% load. THC concentration was 2.47 ppmvd at 50% load and lower than the 2 ppmvd sampling system detection limit at all other loads.