Ashrae Journal - November 2008 - (Page 47)

of entire country), using higher utility rates.‡ Assuming a 1 kW (electric) Stirling engine operating at 15% (LHV) electricity generation efficiency and using a thermal and electric load following strategy,§ the system would reduce annual energy costs by about 12%. With net metering, the energy cost savings increased to about 17%. This study also estimated an installed system cost (when produced at significant volume) of around $7,000, with two important changes: it does not serve service water heating loads and provides back-up power via lead-acid batteries.4 Assuming that the backup power capability adds $1,000 to the cost, the RCHP system has a cost premium of around $2,250 relative to an EnERgy STAR® boiler.8 Based on the utility cost structure noted earlier, it would realize annual cost savings of around $280,4 yielding a payback of about eight years. Of course, energy cost savings will decrease—and SPP will increase—as heating demand decreases, e.g., for more efficient homes.2,3 Both analyses reinforce how greater availability of net metering would improve the economics of RCHP; in essence, net metering allows the system to always follow the thermal load because any excess electricity will always be used. Although the Energy Policy Act of 2005 requires public utility commissions to consider net metering, it is not clear that this legislation will increase net metering availability for nonrenewable generation technologies.4 Achieving the long lifetimes characteristic of furnaces and boilers, e.g., on the order of 20,000 to 40,000 hours, is another challenge for Stirling engine-based RCHP. Because the engines are sealed, the internals of Stirling engines cannot be lubricated, which makes achieving such long lifetimes very challenging. Although both KSE and FPSE configurations have demonstrated operation in excess of 5,000 hours,1 it is not clear is that they have demonstrated the longevity required for RCHP. Finally, European and Japanese RCHP products typically use IC engines, Stirling engines, or fuel cells, but these products are not compatible with the forced hot-air heating systems that dominate the U.S. housing stock. Furthermore, these products cannot provide backup power.3 Litho 300DPI 4. TIAX. 2006. “Research, Development, and Demonstration of Micro-CHP Systems for Residential Applications—Phase I.” Final Report by TIAX LLC to the U.S. Department of Energy, Office of Electric Delivery and Energy Reliability, Report no. DOE/ nT/4221401. http://tinyurl.com/tiax2006 (or www.propanecouncil.org/ uploadedFiles/11538_TIAX_MicroCHP_Report_FInAL.pdf). 5. Bell, M., et al. 2004. “Testing residential combined heat and power systems at the Canadian centre for housing technology.” Proceedings of the ACEEE Summer Study for Energy Efἀciency in Buildings. http:// tinyurl.com/bell2004 (or www.eceee.org/conference_proceedings/ ACEEE_buildings/2004/Panel_11/p11_1/). 6. DOE. 2008. Buildings Energy Data Book. U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. http:// buildingsdatabook.eren.doe.gov/. 7. goldstein, L., et al. 2003. “gas-Fired Distributed Energy Resource Technology Characterizations.” national Renewable Energy Laboratory Final Report. nREL/TP-620-34783. http://tinyurl.com/ goldstein2003 (or www.nrel.gov/docs/fy04osti/34783.pdf). 8. navigant Consulting. 2007. “EIA Technology Forecast Updates— Residential and Commercial Building Technologies—Reference Case Second Edition (Revised).” Presented to the U.S. Department of Energy, Energy Information Administration. 1 1 8.1875” X 10.875” 8.5” X 11 4 CLR HiRES Kurt Roth, Ph.D., is a principal, and Jason Targoff is an associate principal with TIAX LLC, Cambridge, Mass. James Brodrick, Ph.D., is a project manager with the Building Technologies Program, U.S. Department of Ener gy, Washington, D.C. 13732 03/27/08 MIT ELECTRC 2008 JANUARY Mesca Trade Ad_Ashrae_H2i_E FO SM MG DG References 1. EPRI. 2005. “Technology Review and Assessment of Distributed Energy Resources.” Final Report prepared by TIAX LLC for the Electric Power Research Institute Inc. no. 053828. http://tinyurl.com/epri2005 (or http://mydocs.epri.com/docs/public/000000000001012983.pdf). 2. Carbon Trust. 2007. “Micro-CHP Accelerator—Interim Report.” The Carbon Trust. http://tinyurl.com/carbontrust2007 (or www. c a r b o n t r u s t . c o . u k / p u bl i c a t i o n s / p u bl i c a t i o n d e t a i l . h t m ? productid=CTC727). 3. Zogg, R.A., et al. 2005. “Micro-generation appliances for the U.S. Market.” Proceedings of the 56th International Appliance Technical Conference and Exhibition. ‡ Those typical of New York State circa 2003, i.e., $11.44/MMBtu and $0.1431/kWh. § The RCHP system output is modulated so that both its entire electric and thermal outputs can be used by the household. That is, sometimes electric loads will limit CHP system operation and thermal loads will limit operation at others.4 www.info.hotims.com/16019-4 November 2008 ASHRAE Journal 47 http://tinyurl.com/tiax2006 http://www.propanecouncil.org/uploadedFiles/11538_TIAX_MicroCHP_Report_FINAL.pdf http://www.propanecouncil.org/uploadedFiles/11538_TIAX_MicroCHP_Report_FINAL.pdf http://www.tinyurl.com/bell2004 http://www.tinyurl.com/bell2004 http://www.eceee.org/conference_proceedings/ACEEE_buildings/2004/Panel_11/p11_1/ http://www.eceee.org/conference_proceedings/ACEEE_buildings/2004/Panel_11/p11_1/ http://buildingsdatabook.eren.doe.gov/ http://buildingsdatabook.eren.doe.gov/ http://tinyurl.com/goldstein2003 http://tinyurl.com/goldstein2003 http://www.nrel.gov/docs/fy04osti/34783.pdf http://tinyurl.com/epri2005 http://mydocs.epri.com/docs/public/000000000001012983.pdf http://tinyurl.com/carbontrust2007 http://www.carbontrust.co.uk/publications/publicationdetail.htm?productid=CTC727 http://www.carbontrust.co.uk/publications/publicationdetail.htm?productid=CTC727 http://www.carbontrust.co.uk/publications/publicationdetail.htm?productid=CTC727 http://www.ajmfg.com http://www.info.hotims.com/16019-4

Table of Contents Feed for the Digital Edition of Ashrae Journal - November 2008

Ashrae Journal - November 2008 Contents Commentary Industry News Meetings and Shows Feature Articles Reducing Data Center Energy Consumption Building Sciences Feature Articles Sustainable Nature Center Emerging Technologies Special Products Washington Report Special Supplement: BACnet® Today BACnet® Goes Green Seeing the Light with BACnet® BACnet® on Campus BACnet® for Net Zero Analyzing BACnet® BACnet® at Xerox Campus BACnet® in Europe BACnet® for Green Library BACnet® at the University of Minnesota: Flexibility, Interoperability InfoCenter Product Showplace Classified Advertising Advertising Index

Ashrae Journal - November 2008

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