CSE Pure Power - Fall 2008 - (Page 19)

cover story 19 ❮❮ PURE POWER // FALL 2008 The protectors’ purpose is to prevent the ﬂow of electrical energy from one feeder back onto another feeder. The protectors are set to instantaneously detect the reversal and open the contactor, but that opening takes 5 to 25 sec and requires a manual reset. When on-site power generation is installed at a site with a network supply, it may be possible for the site load to momentarily drop below the generator output, resulting in an export of electricity unless other preventive devices are used. This possibility is minimized by requiring a buffer between the generator and the normal load. However, this measure does not guarantee that an export will never occur. If an export does occur, the network protector senses a reverse current and instantaneously begins to open. PG&E expressed concern that all network detectors might sense the reversal and begin to open, rendering the site without any grid-supplied electrical power and requiring time and cost to reset them. To avoid this situation, signiﬁcant interconnection upgrades were required on this site (see Figure 2). The cost of the interconnect upgrades required by the utility totaled approximately $140,000. Monthly CHP system operating proﬁle Max Hr January February March April May June July August September October November December Total 744 672 744 720 744 720 744 744 720 744 720 744 8,760 Operating Hr % 718 633 601 510 648 717 742 744 717 741 718 742 8,231 96.5% 94.3% 80.8% 70.8% 87.0% 99.6% 99.7% 100.0% 99.6% 99.6% 99.7% 99.8% 94.0% Nonoperating Hr % 26 25 113 109 0 0 0 0 3 0 2 0 277 3.5% 3.8% 15.2% 15.1% 0.0% 0.0% 0.1% 0.0% 0.4% 0.0% 0.2% 0.0% 3.2% Data gap Hr 0 11 30 101 92 3 1 0 0 3 0 2 243 % 0.0% 1.7% 4.0% 14.1% 12.3% 0.4% 0.1% 0.0% 0.0% 0.4% 0.0% 0.2% 2.8% Table 2: This table provides monthly operating hours for the CHP system, non-operating hours, and missing data segments. This early generation CHP system demonstrated high system operation (94%) during its ﬁrst year. COMMISSIONING Commissioning of the CHP system was completed by Carrier under contract to UTC Power. The commissioning was performed according to a written protocol that provided guidelines for startup of both the microturbines and the absorption chiller. Following the protocol, a safety inspection, site evaluation, mechanical inspection, electrical inspection, and communications inspection were completed prior to startup. The effectiveness of the grid protection circuitry was conﬁrmed. The microturbines were started and performance was veriﬁed. The chiller was evacuated of the nitrogen blanket that had been applied for shipping. The chiller was then started and the charge level was veriﬁed. Once commissioning was completed, the system was put into service. No formal report was generated with respect to the exact extent of the commissioning process. Overall, the CHP system achieved an extremely high level of utility with EMISSIONS Each microturbine uses advanced natural gas combustion technology to constrain NOx emissions <9 ppm at 15% exhaust oxygen; it is CARB 2003 certiﬁed. The exhaust from each microturbine is manifolded together and delivered as the input energy to a double-effect absorption chiller. On Nov. 15, 2001, the California Air Resources Board adopted a regulation that established a distributed generation (DG) certiﬁcation program as required by Senate Bill 1298 (chaptered September 2000). The DG certiﬁcation program requires manufacturers of electrical generation technologies that are exempt from district permit requirements to certify their technologies to speciﬁc emission standards before they can be sold in California. minimal outages. The system produced at least 60 kW of net electrical power for 8,231 hours, or 94% of the year. Table 2 presents the monthly breakdown of operating, nonoperating, and data gap hours. For the year, data gaps represented 2.8% of the available run hours. POST-COMMISSIONING OPERATION The CHP system was installed with the chiller in the hotel chilled water loop and parallel to existing electric chillers as described previously. Engineers observed that the output from the absorption chiller was very interactive with the electric chiller, particularly from May through mid-November. This interaction resulted in a shift between the CHP cooling-only mode (see Figure 1A) and the simultaneous cooling mode (Figure 1B) for approximately half of the days during this period, as evidenced by a high absorber chilled water ﬂow rate for CHP cooling only mode and a lower ﬂow rate for simultaneous mode. This binary situation www.purepowermagazine.com http://www.purepowermagazine.com

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CSE Pure Power - Fall 2008 In the News Commissioning CHP Enhancing Emergency Lighting Data Centers for Uncle Sam Handling a Nuisance Trip Sustainable Projects and Partnerships New Products Ad Index

CSE Pure Power - Fall 2008

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