solar-hydrogen stand-alone power system design and simulations a thesis submitted to the ...

124 Pages·2010·3.88 MB·English

SOLAR-HYDROGEN
STAND-ALONE POWER SYSTEM
DESIGN AND SIMULATIONS

A THESIS SUBMITTED TO
THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES
OF
MIDDLE EAST TECHNICAL UNIVERSITY

BY

ARMAN ULUOĞLU

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR
THE DEGREE OF MASTER OF SCIENCE
IN
MECHANICAL ENGINEERING

MAY 2010
Approval of the thesis:

SOLAR-HYDROGEN STAND-ALONE POWER SYSTEM DESIGN AND
SIMULATIONS

submitted by ARMAN ULUOĞLU in partial fulfillment of the requirements for the
degree of Master of Science in Mechanical Engineering, Middle East
Technical University by,

Prof. Dr. Canan Özgen _______________
Dean, Graduate School of Natural and Applied Sciences

Prof. Dr. Suha Oral _______________
Head of Department, Mechanical Engineering Dept., METU

Asst. Prof. Dr. İlker Tarı _______________
Supervisor, Mechanical Engineering Dept., METU

Examining Committee Members:

Assoc. Prof. Dr. Cemil Yamalı _____________________
Mechanical Engineering Dept., METU

Asst. Prof. Dr. İlker Tarı _____________________
Mechanical Engineering Dept., METU

Assoc. Prof. Dr. Derek K. Baker _____________________
Mechanical Engineering Dept., METU

Asst. Prof. Dr. Tuba Okutucu Özyurt _____________________
Mechanical Engineering Dept., METU

Assoc. Prof. Dr. Yüksel Kaplan _____________________
Mechanical Engineering Dept., Niğde University

Date: ______________
I hereby declare that all information in this document has been obtained
and presented in accordance with academic rules and ethical conduct. I
also declare that, as required by these rules and conduct, I have fully
cited and referenced all material and results that are not original to this
work.

Name, Last name: Arman Uluoğlu

Signature:

iii
ABSTRACT

SOLAR-HYDROGEN STAND-ALONE POWER SYSTEM DESIGN AND
SIMULATIONS

Uluoğlu, Arman
M.Sc., Department of Mechanical Engineering
Supervisor: Asst. Prof. Dr. İlker Tarı

May 2010, 107 pages

In this thesis, solar-hydrogen Stand-Alone Power System (SAPS) which is planned
to be built for the emergency room of a hospital is designed. The system provides
continuous, off-grid electricity during the whole period of a year without any
external electrical power supply. The system consists of Photovoltaic (PV) panels,
Proton Exchange Membrane (PEM) based electrolyzers, PEM based fuel cells,
hydrogen tanks, batteries, a control mechanism and auxiliary equipments such as
DC/AC converters, water pump, pipes and hydrogen dryers. The aim of this work is
to investigate the optimal system configuration and component sizing which yield
to high performance and low cost for different user needs and control strategies.
TRNSYS commercial software is used for the overall system design and
simulations.

Numerical models of the PV panels, the control mechanism and the PEM
electrolyzers are developed by using theoretical and experimental data and the
models are integrated into TRNSYS. Overall system models include user-defined
components as well as the default software components. The electricity need of
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the emergency room without any shortage is supplied directly from the PV panels
or by the help of the batteries and the fuel cells when the solar energy is not
enough. The pressure level in the hydrogen tanks and the overall system efficiency
are selected as the key design parameters. The major component parameters and
various control strategies affecting the hydrogen tank pressure and the system
efficiency are analyzed and the results are presented.

Keywords: Stand-Alone Power Systems, TRNSYS, Photovoltaic cells, PEM
electrolyzers, fuel cells, hydrogen.
v
ÖZ

GÜNEŞ ENERJİSİ VE HİDROJENLİ ŞEBEKEDEN BAĞIMSIZ ENERJİ SİSTEMİ
TASARIMI VE SAYISAL ANALİZİ

Uluoğlu, Arman
Yüksek Lisans, Makina Mühendisliği Bölümü
Tez Yöneticisi: Y. Doç. Dr. İlker Tarı

Mayıs 2010, 107 Sayfa

Bu tezde, bir hastanenin acil servisine kurulması planlanan güneş enerji sistemi
tasarlanmıştır. Bu sistemin tek enerji kaynağı güneş enerjisidir. Sistem tüm yıl
boyunca şebeke elektriğinden yararlanmadan acil servise kesintisiz elektrik enerjisi
sağlar. Güneş enerji sistemi, Fotovoltaik (PV) paneller, PEM bazlı elektrolizörler,
PEM yakıt hücreleri, hidrojen tankı, piller, control mekanizması ve DC/AC
dönüştürücüler, su pompası, borular ve hidrojen kurutucular gibi yan
ekipmanlardan oluşmaktadır. Bu çalışmanın amacı, değişik kullanıcı ihtiyaçlarına ve
control stratejilere göre yüksek performansta ve düşük maliyette çalışacak sistem
konfigürasyonlarını ve ekipman seçimlerini araştırmaktır. Sistemi tümüyle
tasarlamak ve analiz etmek için TRNSYS ticari yazılımı kullanılmıştır. PV
panellerinin, kontrol mekanizmasının ve PEM elektrolizörün sayısal modelleri,
deneysel ve teorik bilgilerden yararlanılarak oluşturulmuş ve TRNSYS yazılımına
eklenmiştir. Tümüyle tasarlanmış system modelleri bu kullanıcı tanımlı elemanlar ve
yazılım içerisinde yer alan varsayılan elemanlar kullanılarak oluşturulmuştur. Acil
servise ihtiyacı olan enerji doğrudan PV panellerinden ya da güneş enerjisi yeterli
olmadığı zamanlar piller ve yakıt hücreleri yardımıyla sürekli ve eksiksiz biçimde
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sağlanmaktadır. Hidrojen tankındaki basınç seviyesi ve sistemin toplam verimi
anahtar parametreler olarak seçilmiştir. Bu anahtar parametreleri etkileyen
ekipman seçimleri ve boyutlandırmaları ile control stratejileri incelenmiş ve
sonuçları sunulmuştur.

Anahtar Sözcükler: Şebekeden bağımsız enerji sistemleri, TRNSYS, fotovoltaik
piller, PEM elektrolizörler, yakıt pilleri, hidrojen.

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To My Family
viii
ACKNOWLEDGEMENTS

The author wishes to express his deepest gratitude to his supervisor Asst. Prof. Dr.
İlker Tarı for his close guidance, invaluable supervision, encouragements and
insight throughout the study.

I wish to express my sincere appreciation to Prof. Dr. Haluk Aksel for his
understanding and help about using CFD laboratory.

The author would like to thank TUBITAK (project no: Tübitak 106G130) for
supporting this research.

The author would also like to thank his colleague Mr. Ender Özden, for his help and
support throughout the study.

The author gratefully thanks to his family for their continuous encouragement,
understanding and support.

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TABLE OF CONTENTS

ABSTRACT ………………………………………………………………………………………………… iv
ÖZ …………………………………………………………………………………………………………… vi
ACKNOWLEDGEMENTS ……………………………………………………………………………… ix
TABLE OF CONTENTS ………………………………………………………………………………… x
LIST OF TABLES ………………………………………………………………………………………… xii
LIST OF FIGURES ……………………………………………………………………………………… xiii
LIST OF SYMBOLS ……………………………………………………………………………………… xv
LIST OF ABBREVIATIONS …………………………………………………………………………… xvii
CHAPTERS
1. INTRODUCTION................................................................................1 
1.1 Renewable Energy........................................................................1 
1.2 Stand Alone Power Systems..........................................................2 
1.3 TRNSYS.......................................................................................4 
1.4 Literature Survey..........................................................................5 
1.4.1 Experimental Works............................................................5 
1.4.2 Component and System Modeling........................................8 
1.5 Brief Outline...............................................................................11 
2. COMPONENT MODELING..................................................................12 
2.1 Photovoltaic Panel......................................................................12 
2.1.1 Electrical Model................................................................13 
2.1.2 Thermal Model.................................................................19 
2.1.3 Maximum Power Point Tracking Model...............................21 
2.1.4 PV Pane Model Results and Discussion...............................22 
2.2 Proton Exchange Membrane (PEM) Electrolyzer............................27 
2.2.1 Electrolyzer Description.....................................................30 
2.2.2 Electrolyzer Modeling........................................................31 
3. SYSTEM SIMULATIONS....................................................................34 
3.1 System Description.....................................................................34 
3.2 Results and Discussions..............................................................39 
x