8. Emission analysis

Emission savings could be a significant decisive factor to implement the CCHP system over traditional heating and cooling system separately. Government agencies or ecofriendly industries are always inclined toward installing energy systems (i.e., CCHP) with better emission characteristics even with non-attractive economic benefit. In recent years, various federal, state or local government agencies offered carbon credit as an emission incentive to promote energy efficient technology like CCHP systems to industries and residential consumers. The CCHP system could be economically feasible with carbon credit even when SPP, IRR, and EUAS show negative economic return for the CCHP system over a traditional building air conditioning unit.

Figure 7. Sample of variation of carbon dioxide with load [34].

CCHP reduces CO2 emissions significantly across a varying range of loads typical of microscale systems. Figure 7 shows that CO2 emissions per unit (kWh) of useful energy output results in a 61% reduction of CO2 when a trigeneration system operates at full load compared to a single generation system [34].

A case study conducted a detailed emission analysis for a CCHP system to compare it to emissions of a reference system, which is presented in [30]. Figures 8–10 summarize

8. Emission analysis

52 Energy Systems and Environment

building air conditioning unit.

Figure 7. Sample of variation of carbon dioxide with load [34].

Emission savings could be a significant decisive factor to implement the CCHP system over traditional heating and cooling system separately. Government agencies or ecofriendly industries are always inclined toward installing energy systems (i.e., CCHP) with better emission characteristics even with non-attractive economic benefit. In recent years, various federal, state or local government agencies offered carbon credit as an emission incentive to promote energy efficient technology like CCHP systems to industries and residential consumers. The CCHP system could be economically feasible with carbon credit even when SPP, IRR, and EUAS show negative economic return for the CCHP system over a traditional

Figure 6. PEC comparison of CCHP installed building types with the reference building in Minneapolis, MN [32].

Figure 8. CO2 emissions of reference building compared with CCHP installed different building types in Minneapolis, MN [32].

Figure 9. NOx emissions of reference building compared with CCHP installed different building types in Minneapolis, MN [32].

Author details

United States

References

1099-1106

Cambridge, MA; Jan. 1997

Kibria K. Roman1,2\*, Mahmudul Hasan3 and Hossain Azam<sup>4</sup>

1 Department of Mechanical and Energy Systems, SUNY, Canton, United States

3 Department of Civil and Environmental Engineering, The George Washington University,

CCHP System Performance Based on Economic Analysis, Energy Conservation, and Emission Analysis

http://dx.doi.org/10.5772/intechopen.77000

55

4 Department of Civil and Environmental Engineering, Manhattan College, United States

[1] Mago PJ, Chamra LM. Analysis and optimization of CCHP systems based on energy, economical, and environmental considerations. Energy and Buildings. Oct. 2009;41(10):

[2] Hart SL. Beyond Greening: Strategies for a Sustainable World. Harvard Business Review.

[3] How much energy is consumed in U.S. residential and commercial buildings?—FAQ—U. S. Energy Information Administration (EIA). U.S. Energy Information Administration

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[5] Chicco G, Mancarella P. From cogeneration to Trigeneration: Profitable alternatives in a competitive market. IEEE Transactions on Energy Conversion. Mar. 2006;21(1):265-272

[6] Wu DW, Wang RZ. Combined cooling, heating and power: A review. Progress in Energy

[7] Yang R, Qin Y, Li C, Zhu G, Wang ZL. Converting biomechanical energy into electricity by a muscle-movement-driven Nanogenerator. Nano Letters. Mar. 2009;9(3):1201-1205

[8] Smith AD, Mago PJ. Effects of load-following operational methods on combined heat and

[9] A. to S. Energy et al. Report to Congress on Server and Data Center Energy Efficiency:

[10] Bollen MHJ. Integration of Distributed Generation in the Power System. Wiley; 2011

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power system efficiency. Applied Energy. Feb. 2014;115:337-351

2 Department of Mechanical Science and Engineering, University of Illinois,

\*Address all correspondence to: romank@canton.edu

Urbana-Champaign, United States

Figure 10. CH4 emission of reference office building compared with CCHP installed building in Minneapolis, MN [32].

those emission results for the three gases analyzed. All three prime movers reduced emissions significantly and the microturbine provided the greatest reduction. For different building types, carbon dioxide emission savings show the highest savings occurred for the small hotel and small office. The reduction in carbon dioxide in the small hotel from the reciprocating ICE, microturbine, and fuel cell were 73.7, 82.0, and 74.9%, respectively. Overall, all building types experienced a reduction in emission from the implementation of CCHP systems. All three prime movers provided significant reduction in emissions; however the microturbine provided the most.

#### 9. Summary

Buildings are major energy sink comprising 40% of total U.S. energy consumption. Energy savings in buildings often do not come with economic and/or environmental benefit. Additionally, the optimum use of energy and prevention of energy loss in buildings can entail additional challenges. This chapter on CCHP shows significant promise of CCHP being adopted in buildings widely not only because of its superior capacity for optimum energy use/savings but also for its additional economic and environmental benefit. It is evident that the evolution of the CHP system to CCHP system makes it more beneficial for its wide scale use in buildings. Appropriate performance parameters relevant for buildings' energy, economic and environmental benefit were determined and applied to assess the different prime movers use in CCHP for buildings. A CCHP system either with ICE or microturbine prime mover shows significant benefit in terms of energy, economic and environmental consideration for buildings. Thus, CCHP has significant role to play for overall energy independence of buildings in twenty-first century.
