Transient simulation and modeling of photovoltaic-PEM water electrolysis

ABSTRACT

This work aims at analyzing the transient behavior of a photovoltaic-Polymer Electrolyte Membrane (PV-PEM) water electrolyser system based on regional weather data. The goal of a dynamic modeling is to check how the system works against the load variations. In this study, the PV array is used for power supply then, a controller and power conditioning to provide clean energy for electrolyser. The electrolyser model is developed in MATLAB and it is used in a TRNSYS environment. The performance of a PEM electrolyser can be illustrated by the polarization curve which is voltage–load current (V–I) characteristics. Moreover, a mathematical modeling for computing dynamic voltage based on current and all operation parameters in electrolyser stacks have been developed. Then the transient behavior of the PV-PEM system is analyzed over the seasonal condition base on Vienna average weather information.

KEYWORDS:

• PEM electrolyser
• TRNSYS
• hydrogen
• photovoltaic
• simulation

Nomenclature

Cp	=	standard specific heat, J/K mol
ΔH	=	change in enthalpy, J/mol
ΔHf°	=	standard enthalpy of formation, J/mol
P	=	pressure, bar
R	=	universal constant of gases, J/K mol
T	=	temperature, K
Sf°	=	standard entropy of formation, J/mol
ΔS	=	change in entropy, J/mol
α	=	charge transfer coefficient
i0	=	exchange current density, A/cm2
i	=	exchange current density, A/cm2
φm	=	membrane thickness (μm)
σm	=	membrane conductivity (Scmˉ1)
F	=	faraday’s constant, 96,485 C
n	=	molar flow rate of species, mol/s
I	=	current, A
ne	=	number of electron exchange in the reaction
nc	=	cell numbers in series
Ta	=	ambient temperature, ºC
Rt	=	thermal resistance, KWˉ1
Ct	=	eletrolyte heat capacity, JKˉ1
Q	=	heat, W
Η	=	energy efficiency
Utn	=	Thermoneutral Potential, Volt
η	=	Energy or thermal efficiency

Subscripts

i	=	component index
w	=	water index
an	=	referring to anode
cat	=	referring to cathode
a	=	ambient
0	=	reference condition
cons	=	consumed
gen	=	generated
rev	=	reversible

Acknowledgments

I would like to express my special thanks of gratitude to all of our company partners.

Additional information

Funding

The project is funded by the program Research Studios Austria (RSA) within the “Energieforschungsinitiative” at the Federal Ministry of Science, Research and Economy (BMWFJ). Additional financial contributions received by OMV . I would like to express my special thanks of gratitude to all of our company partners.