1.
A NEW COGENERATION RESIDENTIAL
SYSTEM BASED ON SOLID OXIDE FUEL
CELLS FOR A NORTHERN EUROPEAN
CLIMATE
Giulio Vialetto and Masoud Rokni
Global Conference on Global Warming 2015, Athens (Greek)

2.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
FUEL
ELECTRICITY
GRID
HEAT

3.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
1
0.42
0.52 1.9
1 0.9
HEATING
2.32
0.9
HEAT
PRODUCED
+ 158 %
(All energy fluxes are in kWh, COP of heat pump is assumed as 3.66, efficiency of the boiler 0.9)
Innovative
system
Traditional
system

4.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
SOFC - Simulation of the fuel cell and fuel reformer
was made in DNA
- Simulation of an inverter for DC/AC
conversion with 92% of efficiency
- Energy consumption of auxiliaries is
considered with a lower overall efficiency
SOFC Performances
H/P 0.8262
ηSOFC 0.53
(SOFC of 1 kW at full load)

5.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
HEAT PUMP (GSHP)
- Ground source heat pump (GSHP) with
closed loop ground-coupled heat exchangers
- Simulation using as reference a real heat
pump according to UNI/TS 11300-3 and EN
14825Performance
COP 5.1
(Performance at full load, W10/W55)
- It covers heating demand (both space
heating and DHW demand) when waste heat
from SOFC is not enough
Regarding simulation of GSHP with UNI/TS 11300-3 see also
Energy and economic analysis of different heat pump systems for
space heating (Busato F., Lazzarin R. and Noro M., 2012)

6.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
EQUIVALENT ELECTRIC LOAD (EEL)
SOFC is driven by electricity demand related not only to the electrical
demand of the user but also to the energy consumption of the heat pump
in order to cover heating demand considering that waste heat of SOFC
covers a part of it.
EEL=f(ηSOFC, H/P, COPHEATINGELEDEMAND,HEATDEMAND)
Regarding EEL see also Design of a combined heating, cooling and power system: Sizing,
operation strategy and parametric analysis (Kavvadias K.C., Tosion A.P. and Maroulis Z.B.
2010)

7.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES

8.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
EQUIVALENT ELECTRIC LOAD (EEL)
ADVANTAGES
- EEL is more constant than only
electrical demand during the day
- It is required a smaller water tank
than the other strategies
- A paper (K.C. Kavvadias et al.,
2010) shows that this strategy is
more profitable than other ones
DISADVANTAGES
- It is necessary to know exactly
the performances of the SOFC
and heat pump in order to
calculate the correct EEL

9.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
EQUIVALENT ELECTRIC LOAD (EEL)
- following EEL with a maximum of 1 kW of SOFC electricity
production ELF=min(EEL, 1 kW) (called ELF 1 kW)
EEL is used to define ELF (Electric Load Following). The aim of the
strategy is to follow the electric equivalent load and it is done in three
different ways:
- following EEL with a maximum of 2 kW of SOFC electricity
production ELF=min(EEL, 2 kW) (called ELF 2 kW)
- EEL monthly average is calculated and used as set point so SOFC
works all the hour at constant power (called CO)

10.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
EEL(kWh)
EEL ELF 2 kW

11.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
EEL(kWh)
EEL CO

12.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES

13.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
11150
5472
212
198
3028
2458
4765
8986
13695
56
0 2000 4000 6000 8000 10000 12000 14000
Fuel in
SOFC El. Prod.
Grid in
Grid out
User ele. dem.
GSHP ele. cons.
SOFC heat prod.
GSHP heat prod.
User heat dem.
Heat losses
Energy (kWh)
Energy fluxes with system under ELF 2 kW strategy

14.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
8928
4340
1486
97
3028
2701
3854
9876
13695
35
0 2000 4000 6000 8000 10000 12000 14000
Fuel in
SOFC El. Prod.
Grid in
Grid out
User ele. dem.
GSHP ele. cons.
SOFC heat prod.
GSHP heat prod.
User heat dem.
Heat losses
Energy (kWh)
Energy fluxes with system under ELF 1 kW strategy

15.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
11673
5671
1802
2025
3028
2420
5044
8850
13695
199
0 2000 4000 6000 8000 10000 12000 14000
Fuel in
SOFC El. Prod.
Grid in
Grid out
User ele. dem.
GSHP ele. cons.
SOFC heat prod.
GSHP heat prod.
User heat dem.
Heat losses
Energy (kWh)
Energy fluxes with system under CO strategy

16.
A new cogeneration residential system based on Solid Oxide Fuel Cell for a Northern European climate (Vialetto G., Rokni M.)
OVERVIEW MODEL ANALYSIS CONCLUSIONSTRATEGIES
CONCLUSION
- System proposed has high primary energy saving ratio and efficiency
of the fuel cell
- Heat demand is mainly convered by GSHP
- ELF 2 kW strategy shows that the system could be used for stand-
alone user
- CO strategy shows that a SOFC with a nominal power of 1 kW could
be used only if net metering is possible

17.
THANK YOU FOR YOUR
ATTENTION
ANY QUESTION?
CONTACT
E-Mail: giulio@giuliovialetto.it
Site: www.giuliovialetto.it