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Research Papers

# Studying a Hybrid System Based on Solid Oxide Fuel Cell Combined With an Air Source Heat Pump and With a Novel Heat Recovery

[+] Author and Article Information
Giulio Vialetto

Department of Management and Engineering,
Vicenza 36100, Italy
e-mail: giulio@giuliovialetto.it

Marco Noro

Department of Management and Engineering,
Vicenza 36100, Italy
e-mail: marco.noro@unipd.it

Masoud Rokni

Department of Mechanical Engineering,
Technical University of Denmark,
Copenhagen 2800, Denmark
e-mail: mr@mek.dtu.dk

1Corresponding author.

Manuscript received June 20, 2018; final manuscript received October 22, 2018; published online December 6, 2018. Assoc. Editor: Robert J. Braun.

J. Electrochem. En. Conv. Stor. 16(2), 021005 (Dec 06, 2018) (13 pages) Paper No: JEECS-18-1064; doi: 10.1115/1.4041864 History: Received June 20, 2018; Revised October 22, 2018

## Abstract

In this paper, a new heat recovery for a microcogeneration system based on solid oxide fuel cell and air source heat pump (HP) is presented with the main goal of improving efficiency on energy conversion for a residential building. The novelty of the research work is that exhaust gases after the fuel cell are first used to heat water for heating/domestic water and then mixed with the external air to feed the evaporator of the HP with the aim of increasing energy efficiency of the latter. This system configuration decreases the possibility of freezing of the evaporator as well, which is one of the drawbacks for air source HP in Nordic climates. A parametric analysis of the system is developed by performing simulations varying the external air temperature, air humidity, and fuel cell nominal power. Coefficient of performance (COP) can increase more than 100% when fuel cell electric power is close to its nominal (50 kW), and/or inlet air has a high relative humidity (RH) (close to 100%). Instead, the effect of mixing the exhausted gases with air may be negative (up to −25%) when fuel cell electric power is 20 kW and inlet air has 25% RH. Thermodynamic analysis is carried out to prove energy advantage of such a solution with respect to a traditional one, resulting to be between 39% and 44% in terms of primary energy. The results show that the performance of the air source HP increases considerably during cold season for climates with high RH and for users with high electric power demand.

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## References

Marrasso, E. , Roselli, C. , Sasso, M. , Picallo-Perez, A. , and Sala Lizarrag, J. M. , 2018, “ Dynamic Simulation of a Microcogeneration System in a Spanish Cold Climate,” Energy Convers. Manage., 165, pp. 206–218.
Lazzarin, R. , 2012, “ Dual Source Heat Pump Systems: Operation and Performance,” Energy Build., 52, pp. 77–85.
Rokni, M. , 2010, “ Thermodynamic Analysis of an Integrated Solid Oxide Fuel Cell Cycle With a Rankine Cycle,” Energy Convers. Manage., 51(12), pp. 2724–2732.
Pierobon, L. , Rokni, M. , Larsen, U. , and Haglind, F. , 2013, “ Thermodynamic Analysis of an Integrated Gasification Solid Oxide Fuel Cell Plant Combined With an Organic Rankine Cycle,” Renewable Energy, 60, pp. 226–234.
Rokni, M. , 2014, “ Thermodynamic and Thermoeconomic Analysis of a System With Biomass Gasification, Solid Oxide Fuel Cell (SOFC) and Stirling Engine,” Energy, 76, pp. 19–31.
Rokni, M. , 2013, “ Thermodynamic Analysis of SOFC (Solid Oxide Fuel Cell)—Stirling Hybrid Plants Using Alternative Fuels,” Energy, 61, pp. 87–97.
Hosseinpour, J. , Sadeghi, M. , Chitsaz, A. , Ranjbar, F. , and Rosen, M. A. , 2017, “ Exergy Assessment and Optimization of a Cogeneration System Based on a Solid Oxide Fuel Cell Integrated With a Stirling Engine,” Energy Convers. Manage., 143, pp. 448–458.
Zhang, H. , Xu, H. , Chen, B. , Dong, F. , and Ni, M. , 2017, “ Two-Stage Thermoelectric Generators for Waste Heat Recovery From Solid Oxide Fuel Cells,” Energy, 132, pp. 280–288.
Mortazaei, M. , and Rahimi, M. , 2016, “ A Comparison Between Two Methods of Generating Power, Heat and Refrigeration Via Biomass Based Solid Oxide Fuel Cell: A Thermodynamic and Environmental Analysis,” Energy Convers. Manage., 126, pp. 132–141.
Liso, V. , Zhao, Y. , Brandon, N. , Nielsen, M. P. , and Kær, S. K. , 2011, “ Analysis of the Impact of Heat-to-Power Ratio for a SOFC-Based mCHP System for Residential Application Under Different Climate Regions in Europe,” Int. J. Hydrogen Energy, 36(21), pp. 13715–13726.
Bompard, E. , Napoli, R. , Wan, B. , and Orsello, G. , 2008, “ Economics Evaluation of a 5 kW SOFC Power System for Residential Use,” Int. J. Hydrogen Energy, 33(12), pp. 3243–3247.
Elmer, T. , Worall, M. , Wu, S. , and Riffat, S. , 2016, “ Assessment of a Novel Solid Oxide Fuel Cell Tri-Generation System for Building Applications,” Energy Convers. Manage., 124, pp. 29–41.
Ho Lee, K. , and Strand, R. K. , 2009, “ SOFC Cogeneration System for Building Applications—Part 2: System Configuration and Operating Condition Design,” Renewable Energy, 34(12), pp. 2839–2846.
Sorace, M. , Gandiglio, M. , and Santarelli, M. , 2017, “ Modeling and Techno-Economic Analysis of the Integration of a FC-Based Micro-CHP System for Residential Application With a Heat Pump,” Energy, 120, pp. 262–275.
Al Moussawi, H. , Fardoun, F. , and Louahlia, H. , 2017, “ 4-E Based Optimal Management of a SOFC-CCHP System Model for Residential Applications,” Energy Convers. Manage., 151, pp. 607–629.
Fong, K. F. , and Lee, C. K. , 2016, “ System Analysis and Appraisal of SOFC-Primed Micro Cogeneration for Residential Application in Subtropical Region,” Energy Build., 128, pp. 819–826.
Shimoda, Y. , Taniguchi-Matsuoka, A. , Inoue, T. , Otsuki, M. , and Yamaguchi, Y. , 2017, “ Residential Energy End-Use Model as Evaluation Tool for Residential Micro-Generation,” Appl. Therm. Eng., 114, pp. 1433–1442.
Ramadhani, F. , Hussain, M. A. , Mokhlis, H. , and Hajimolana, S. , 2017, “ Optimization Strategies for Solid Oxide Fuel Cell (SOFC) Application: A Literature Survey,” Renewable Sustainable Energy Rev., 76, pp. 460–484.
Wakui, T. , Wada, N. , and Yokoyama, R. , 2012, “ Feasibility Study on Combined Use of Residential SOFC Cogeneration System and Plug-In Hybrid Electric Vehicle From Energy-Saving Viewpoint,” Energy Convers. Manage., 60, pp. 170–179.
Vialetto, G. , Noro, M. , and Rokni, M. , 2017, “ Combined Micro-Cogeneration and Electric Vehicle System for Household Application: An Energy and Economic Analysis in a Northern European Climate,” Int. J. Hydrogen Energy, 42(15), pp. 10285–10297.
Vialetto, G. , Noro, M. , and Rokni, M. , 2017, “ Thermodynamic Investigation of a Shared Cogeneration System With Electrical Cars for Northern Europe Climate,” J. Sustainable Dev. Energy, Water Environ. Syst., 5(4), pp. 590–607.
Frazzica, A. , Briguglio, N. , Sapienza, A. , Freni, A. , Brunaccini, G. , Antonucci, V. , and Ferraro, M. , 2015, “ Analysis of Different Heat Pumping Technologies Integrating Small Scale Solid Oxide Fuel Cell System for More Efficient Building Heating Systems,” Int. J. Hydrogen Energy, 40(42), pp. 14746–14756.
Klein, S. A. , 2004, “ TRNSYS: A Transient System Simulation Program,” TRNSYS Manual, Version 16, University of Wisconsin, Madison, WI.
Busato, F. , Lazzarin, R. , and Noro, M. , 2013, “ Two Years of Recorded Data for a Multisource Heat Pump System: A Performance Analysis,” Appl. Therm. Eng., 57(1–2), pp. 39–47.
Busato, F. , Lazzarin, R. , and Noro, M. , 2015, “ Ground or Solar Source Heat Pump Systems for Space Heating: Which Is Better? Energetic Assessment Based on a Case History,” Energy Build., 102, pp. 347–356.
Busato, F. , Lazzarin, R. , and Noro, M. , 2011, “ Ten Years History of a Real Gas Driven Heat Pump Plant: Energetic, Economic and Maintenance Issues,” Appl. Therm. Eng., 31(10), pp. 1648–1654.
Busato, F. , Lazzarin, R. , and Noro, M. , 2012, “ Energy and Economic Analysis of Different Heat Pump Systems for Space Heating,” Int. J. Low Carbon Technol., 7(2), pp. 104–112.
Vialetto, G. , and Rokni, M. , 2015, “ Innovative Household Systems Based on Solid Oxide Fuel Cells for a Northern European Climate,” Renewable Energy, 78, pp. 146–156.
Vialetto, G. , Noro, M. , and Rokni, M. , 2015, “ Innovative Household Systems Based on Solid Oxide Fuel Cells for the Mediterranean Climate,” Int. J. Hydrogen Energy, 40(41), pp. 14378–14391.
Kavvadias, K. C. , Tosios, A. P. , and Maroulis, Z. B. , 2010, “ Design of a Combined Heating, Cooling and Power System: Sizing, Operation Strategy Selection and Parametric Analysis,” Energy Convers. Manage., 51(4), pp. 833–845.
Wang, K. , Li, N. , Peng, J. , Wang, X. , Wang, C. , and Wang, M. , 2017, “ A Highly Efficient Solution for Thermal Compensation of Ground-Coupled Heat Pump Systems and Waste Heat Recovery of Kitchen Exhaust Air,” Energy Build., 138, pp. 499–513.
Oluleye, G. , Smith, R. , and Jobson, M. , 2016, “ Modeling and Screening Heat Pump Options for the Exploration of Low Grade Waste Heat in Process Sites,” Appl. Energy, 169, pp. 267–286.
Zink, F. , Lu, Y. , and Schaefer, L. , 2007, “ A Solid Oxide Fuel Cell System for Buildings,” Energy Convers. Manage., 48(3), pp. 809–818.
Lazzarin, R. , and Noro, M. , 2006, “ District Heating and Gas Engine Heat Pump: Economic Analysis Based on a Case Study,” Appl. Therm. Eng., 26(2–3), pp. 193–199.
Petersen, T. F. , Houbak, N. , and Elmegaard, B. , 2006, “ A Zero-Dimensional Model of a 2nd Generation Planar SOFC With Calibrated Parameters,” Int J Thermodyn., 9(4), pp. 147–159.
Braun, R. J. , 2010, “ Techno-Economic Optimal Design of Solid Oxide Fuel Cell System for Micro-Combined Heat and Power Application in U.S,” ASME J. Fuel Cell Sci. Technol., 7(3), p. 031018.
Italian Standards, 2010, “ Renewable Energy and Other Generation Systems for Space Heating and Domestic Hot Water Production,” Ente Nazionale Italiano di Unificazione, Milan, Italy, Standard No. UNI/TS 11300-4:2010.
European Committee for Standardisation, 2008, “ Air Conditioners, Liquid Chilling Packages and Heat Pumps, With Electrically Driven Compressors, for Space Heating and Cooling—Testing and Rating at Part Load Conditions and Calculation of Seasonal Performance,” European Committee for Standardisation, Brussels, Belgium, Standard No. EN 14825:2008.
Viessmann S.r.l. , 2016, “ Technical Datasheet From ViessmannâVitocal 200-A,” Viessmann, Balconi di Pescantina, Italy, accessed Feb. 2, 2018,
Busato, F. , Lazzarin, R. , Minchio, F. , and Noro, M. , 2012, Sorgenti Termiche Delle Pompe di Calore. Aspetti Tecnici, Economici e Normativi (Heat Sources of Heat Pumps. Technical, Economic and Standard Aspects), Editoriale Delfino, Milano, Italy (in Italian).
Rokni, M. , 2010, “ Plant Characteristics of an Integrated Solid Oxide Fuel Cell Cycle and a Steam Cycle,” Energy, 35(12), pp. 4691–4699.
ASHRAE, 2009, “ Fundamentals,” ASHRAE Handbook—Chapter 1: Psychometrics, ASHRAE, Atlanta, GA.
Lazzarin, R. , 2011, Pompe di Calore. Parte Teorica, Parte Applicativa (Heat Pumps. Theoretic Part, Application Part, in Italian), SGE, Padova, Italy.
European Parliament, 2012, “ Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 on Energy Efficiency,” European Parliament, Brussels, Belgium, accessed Mar. 3, 2018,
European Parliament, 2004, “ Directive 2004/8/EC of the European Parliament and of the Council of 11 February 2004 on Promotion of Cogeneration Based on a Useful Heat Demand in the Internal Energy Market,” European Parliament, Brussels, Belgium, accessed Mar. 3, 2018,
Ministero dello Sviluppo Economico, 2015, Applicazione delle metodologie di calcolo delle prestazioni energetiche e definizione delle prescrizioni e dei requisiti minimi degli edifici (Italian Economic Development Ministry, 2015, Application of Energy Performance Calculus Methods and Definition of Regulations and Minimum Requirements for Buildings), Italian Economic Development Ministry, Rome, Italy (in Italian).

## Figures

Fig. 1

(a) Representation of SOFC system [28,29] and (b) schematics of the entire system. The air adiabatic mixer to partly recover heat from the exhausted gases of the SOFC is connected after the heat recovery by state 1 (see Fig. 3).

Fig. 2

The cell voltage (V) versus current density (A cm−2) and comparison between the model and experimental data with 97% hydrogen and 3% water vapor

Fig. 3

Air mixing system: curves pointing down represent possible water condensation after the air heat exchange, respectively, in the mixer (state 31) and the evaporator (state 41)

Fig. 4

Technical datasheet, relation between nominal heating power and COP and external air temperature [39]

Fig. 5

Evaporator outlet air temperature (T4) in function of external air temperature (T2) in the two cases (air RH—SOFC nominal electric power), 25%—20 kW; 100%—50 kW

Fig. 6

COP in function of external air temperature (T2) in the two cases (air RH—SOFC nominal electric power), 25%—20 kW; 100%—50 kW

Fig. 7

COPvariation varying the external inlet air temperature for four different cases in terms of SOFC nominal power, air RH = 25%

Fig. 8

COPvariation varying the external inlet air temperature for four different cases in terms of SOFC nominal power, air RH = 100%

Fig. 9

Primary energy saving varying the external inlet air temperature for four very different cases in terms of SOFC nominal power and air relative humidity

Fig. 10

Sensitivity of the %PES with the grid electrical efficiency (T2 = 0 °C)

Fig. 11

Flowchart of SOFC system (the system is the same of Fig. 1)

Fig. 12

Air mixing system (the system is the same of Fig. 3)

## Errata

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