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AbstractOne of the keys to make solar thermal system provide more efficient was the suitability of solar collector. Nowadays, solar thermal collectors have different methods to collect the thermal energy from sun radiation; however the choice depends on various issues but mainly location. In this paper we propose to determine the appropriated type of solar collector for low temperature hybrid solar- biomass thermal system (HSBTS). The efficiency, the value of investment, the patterns of use, net solar aperture and stagnation temperature are the actually the main criteria to considered. A review of solar collector types is presented. The most suitable collector type for Thailand’s low temperature hybrid solar-biomass thermal system (HSBTS) in Thailand is Fresnel due to highest value of investment and low of land used. KeywordsSolar thermal collector, Hybrid solar thermal system, solar collector type. I. INTRODUCTION OWADAYS, Thailand is increasing attention to the renewable energy source due to the energy problem. The department of alternative energy development and efficiency in Thailand is progressing the use of renewable energy source from 20% to 25% of final energy consumption in 2021 [1]. Especially in solar energy source, which producing average 5 kWh/m2 per day, the target was increased from 2,000 MW to 3,000 MW, but at present solar source used is only 554 MW. [1] The use of solar thermal systems is very interesting among the solar energy source applications. But the problem of solar energy source was the system stability because of day light period limitations. However, to improve the system stability is to grant ability that make its can operate during nighttime. The previous research result shown that this hybrid system can provide power all day operate [2][3][4]. The Hybrid Solar- Biomass Thermal System (HSBTS) is the most attractive Nattakorn Phetwiwat is with the Rattanakosin College for Sustainable Energy and Environment (RCSEE), Rajamangala University of Technology Rattanakosin, 96 moo 3 Puthamonthon Sai 5, Salaya, Puthamonthon, NakhonPathom, 73170 Thailand (corresponding author’s phone: +661 017 8412; e-mail:[email protected]). Narong Vatcharasathien, is with Research and Develop department, Electricity Generating Authority of Thailand, 53 Moo 2, Charan Sanitwong Road, Bangkruai, Nonthaburi 11130 Thailand (e-mail: [email protected]). Joseph Khedari is with the Faculty of architecture, Kasetsart University, Bangkok Thailand (e-mail: [email protected]). pattern among another hybrid solar thermal system, because the biomass are inexpensive sources and highly available in Thailand. However research result in Kenya [5], shown that we can increase the stability and efficiency for daytime by using the combination in different types of solar collector. So HSBTS in Thailand has not many extensive researches about suitable type of collectors that can improve outcome energy. This paper is to selecting of solar collector types which appropriate for low temperature HSBTS for Thailand. II. HYBRID SOLAR-BIOMASS SYSTEM The hybrid solar-biomass system that use for this experiment has been designed as Fig. 1. This system is designed by using simple Rankine cycle for a small scale hybrid solar-biomass system, with the capacity of 10 kW, maximum temperature 150-200 °C with different working fluid and use parabolic troughs solar collector type according to G.Pikra’s previous research work [6]. Fig. 1. Diagram of Solar Thermal power system (1.Solar Collector; 2.Fuel burner; 3.Thermal Storage; 4.Return Oil Pump; 5.Hot Oil Pump; 6.Evaporator; 7.Turbine;8.Generator; 9.Condenser; 10.Feeder Pump)[6] III. SOLAR COLLECTOR TYPES Types of solar collector for concentrated solar power (CSP) have different suitable working condition e.g. temperature ranks, land usage, cleaning water consumption, that can classifieds into 4 types. A. Figures and Tables Parabolic troughs type is a single-axis tracking solar collector that use reflect of parabolic curved glass mirrors for focusing the solar energy to receiver at focal axis (Fig 2). The Studies on Effect of Solar Collector types for Low Temperature Hybrid Solar-biomass Thermal Power Plant Nattakorn Phetwiwat, Narong Vatcharasathien, and Joseph Khedari N International conference on Innovative Engineering Technologies (ICIET’2014) Dec. 28-29, 2014 Bangkok (Thailand) http://dx.doi.org/10.15242/IIE.E1214063 119

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Abstract— One of the keys to make solar thermal system provide

more efficient was the suitability of solar collector. Nowadays, solar

thermal collectors have different methods to collect the thermal

energy from sun radiation; however the choice depends on various

issues but mainly location. In this paper we propose to determine the

appropriated type of solar collector for low temperature hybrid solar-

biomass thermal system (HSBTS). The efficiency, the value of

investment, the patterns of use, net solar aperture and stagnation

temperature are the actually the main criteria to considered. A review

of solar collector types is presented. The most suitable collector type

for Thailand’s low temperature hybrid solar-biomass thermal system

(HSBTS) in Thailand is Fresnel due to highest value of investment

and low of land used.

Keywords—Solar thermal collector, Hybrid solar thermal

system, solar collector type.

I. INTRODUCTION

OWADAYS, Thailand is increasing attention to the

renewable energy source due to the energy problem. The

department of alternative energy development and efficiency

in Thailand is progressing the use of renewable energy source

from 20% to 25% of final energy consumption in 2021 [1].

Especially in solar energy source, which producing average 5

kWh/m2 per day, the target was increased from 2,000 MW to

3,000 MW, but at present solar source used is only 554 MW.

[1]

The use of solar thermal systems is very interesting among

the solar energy source applications. But the problem of solar

energy source was the system stability because of day light

period limitations. However, to improve the system stability is

to grant ability that make its can operate during nighttime. The

previous research result shown that this hybrid system can

provide power all day operate [2][3][4]. The Hybrid Solar-

Biomass Thermal System (HSBTS) is the most attractive

Nattakorn Phetwiwat is with the Rattanakosin College for Sustainable

Energy and Environment (RCSEE), Rajamangala University of Technology

Rattanakosin, 96 moo 3 Puthamonthon Sai 5, Salaya, Puthamonthon,

NakhonPathom, 73170 Thailand (corresponding author’s phone: +661 017

8412; e-mail:[email protected]).

Narong Vatcharasathien, is with Research and Develop department,

Electricity Generating Authority of Thailand, 53 Moo 2, Charan Sanitwong

Road, Bangkruai, Nonthaburi 11130 Thailand (e-mail: [email protected]).

Joseph Khedari is with the Faculty of architecture, Kasetsart University,

Bangkok Thailand (e-mail: [email protected]).

pattern among another hybrid solar thermal system, because

the biomass are inexpensive sources and highly available in

Thailand.

However research result in Kenya [5], shown that we can

increase the stability and efficiency for daytime by using the

combination in different types of solar collector. So HSBTS in

Thailand has not many extensive researches about suitable

type of collectors that can improve outcome energy. This

paper is to selecting of solar collector types which appropriate

for low temperature HSBTS for Thailand.

II. HYBRID SOLAR-BIOMASS SYSTEM

The hybrid solar-biomass system that use for this

experiment has been designed as Fig. 1. This system is

designed by using simple Rankine cycle for a small scale

hybrid solar-biomass system, with the capacity of 10 kW,

maximum temperature 150-200 °C with different working

fluid and use parabolic troughs solar collector type according

to G.Pikra’s previous research work [6].

Fig. 1. Diagram of Solar Thermal power system (1.Solar

Collector; 2.Fuel burner; 3.Thermal Storage; 4.Return Oil Pump;

5.Hot Oil Pump; 6.Evaporator; 7.Turbine;8.Generator; 9.Condenser;

10.Feeder Pump)[6]

III. SOLAR COLLECTOR TYPES

Types of solar collector for concentrated solar power (CSP)

have different suitable working condition e.g. temperature

ranks, land usage, cleaning water consumption, that can

classifieds into 4 types.

A. Figures and Tables

Parabolic troughs type is a single-axis tracking solar

collector that use reflect of parabolic curved glass mirrors for

focusing the solar energy to receiver at focal axis (Fig 2). The

Studies on Effect of Solar Collector types for

Low Temperature Hybrid Solar-biomass

Thermal Power Plant

Nattakorn Phetwiwat, Narong Vatcharasathien, and Joseph Khedari

N

International conference on Innovative Engineering Technologies (ICIET’2014) Dec. 28-29, 2014 Bangkok (Thailand)

http://dx.doi.org/10.15242/IIE.E1214063 119

shape of a parabola would make solar rays will be reflected

toward the focus. Most losses in such collectors are due to

imperfections in the parabolic shape and imperfect reflection.

It can control temperature output by control receiver’s fluid

flow rate, lower flow rate more temperature output. This type

of collector has thermal limit about 380-450 °C [5] [8], with

different working fluid. This collector type is cheap to

construct, simple to operate and easy to maintenance.

However, this type of collector has low power output [5] [8].

It is good for desert areas or place where is clear sky and no

sunlight shortage.

Fig. 2 Diagram of parabolic trough

B. Solar Tower

Solar tower type is based on the use of very large

concentrating collector. The optical system consists of a field

of a large number of 2-axis sun-tracking mirrors, each

reflecting beam radiation onto a central receiver. The

difference of this collector type concept was the way to

receiver energy. All of the solar energy to be collected in the

entire field, is transmitted optically to a small central

collection region rather than being piped around a field as hot

fluid (Fig 3). This type of collector has highly efficient and

high thermal output (around 540 to 840°C) [7] [8]. However,

they really need a large space to place all reflectors, can’t

work efficiently without tracking system and can’t be used on

cloudy days.

Fig. 3 Diagram of solar tower

C. Linear Fresnel

Linear Fresnel is a collector that use flat mirrors which

concentrate solar beam in a fixed linear receiver placed at

focal point above these mirrors (Fig 4.), it’s quite similar to

the parabolic trough types. This type of collector has thermal

output about 200 to 400°C [10] [14]. Linear Fresnel type is a

really lower price than parabolic because it uses flat mirror

design to concentrate sun that simpler production and

installation, simple to operate and easy to maintenance.

However, it suitable for small plant size (2-200MW) and has

low thermal output when compare to another types.

Fig. 4 Diagram of linear Fresnel

D. Big Dish Technology

Big Dish Technology or Parabolic dish is a parabolic-

shaped reflector mirror that concentrates the solar radiation to

the receiver at a single focal point so it is really high reliable

collector type. With 2 axis tracking system, these type of

collector is a environmentally friendly alternative to acquire

sun energy that suitable for wide open area as deserts (Fig 5.).

This collector type could concentrate energy to provide steam

temperatures around 500 to 1,000 °C [11] [12].

International conference on Innovative Engineering Technologies (ICIET’2014) Dec. 28-29, 2014 Bangkok (Thailand)

http://dx.doi.org/10.15242/IIE.E1214063 120

Fig. 5 Diagram of big dish Technology

IV. COMPARISON AND SELECTION THE SUITABLE SOLAR

COLLECTOR TYPE

The main criteria to consider which collector type that the

most suitable for HSBTS, is efficiency, the value of

investment, the patterns of use, net solar aperture, stagnation

temperature and working fluids.

A. Total cost and land use

After reviewed the existing collector technologies, the

comparative data of total cost, construction and maintenance

cost, and land use are shown as Fig 6 [15] [16].

Fig. 6 Comparative data of solar collector types in total cost and land

use criteria

The Parabolic Dish is the highest of total cost when

compare to another types while solar tower is the highest of

land use and Linear Fresnel and Parabolic trough are no

different in total cost. To select a type for different area, land

use might less concern than total cost, parabolic trough and

linear Fresnel are attractive option. Giorgio Cau and Daniele

Cocco [14] also support this choice, they concern about

medium size solar concentrating power plant and found that

both linear Fresnel and parabolic trough are good choice for

medium plant, if the total cost is the main criteria then

parabolic trough is the best choice but if land use is main

criteria linear Fresnel is the best one. However to choose the

best one form both criteria they suggest that an economic

analysis is required to identify the one.

B. Efficiency and Reliability

The comparative data of efficiency of collectors is shown as

Fig 7.

Fig. 7 Comparative data of solar collector types in efficiency criteria

The solar tower is the highest efficiency and high reliability

type that should be the best choice for solar collector if both

efficiency and reliability are main criteria. However the other

types that got medium on reliability and lower efficiency are

best for other criteria too.

C. Temperature tolerance

After using simulating model from TRNSYS 15 for

different solar collectors in the same solar data and working

system. The tolerances for temperature are shown as Fig 8.

Fig.8 Comparative data of solar collector types in temperature

tolerance criteria

Energy output from simulating for different solar collectors

with a year solar data in Thailand are shown as Fig 9.

Fig 8 shown that solar tower has a wide working

temperature while linear Fresnel is really the lowest

temperature tolerance rank. But the suitable one for HSBTS in

Thailand should the one that got tolerance about 150-200 °C.

So it should be solar tower and linear Fresnel types for this

criteria. Fig 9 shown that solar tower has a highest energy

output but the lowest energy output is parabolic trough, even

it has high efficiency but it got low reliability. To selects type

of collector in energy output criteria, it was up to propose of

used.

International conference on Innovative Engineering Technologies (ICIET’2014) Dec. 28-29, 2014 Bangkok (Thailand)

http://dx.doi.org/10.15242/IIE.E1214063 121

0

5

10

15

20

25

30

35

5-6

6-7

7-8

8-9

9-10

10-1

1

11-1

2

12-1

3

13-1

4

14-1

5

15-1

6

16-1

7

17-1

8

18-1

9

Ener

gy o

utp

ut

(kW

h)

day-hour

Parabolic trough Solar Tower

Linear Fresnel Parabolic Dish

Fig. 9 Comparative data of collector types in energy output

All main criteria to make a decision, which one is suitable

for the selected solar power plant systems. For HSBTS in

Thailand, it’s design for remote area, low temperature and low

cost, the Fresnel types are more suitable than other types. The

critical criteria for remote area are temperature tolerance and

total cost because suitable temperature tolerance for HSBTS

mean longer lifetime of system and total cost is really

important for investment in remote area. Fresnel types can

produce suitable temperature for steam (100-300 °C), lowest

land use, for Linear Fresnel type, and low cost. With this all

criteria, the most suitable for hybrid HSBTS is turn to Linear

Fresnel type. J.D. Nixon investigated the best solar thermal

collection technology for electricity generation in north-west

India. This study shown that the linear Fresnel lens with CPC-

type secondary is the recommend solar collector type because

of their potential low cost and high reliability make Fresnel

worthy of further investigation [16].

V. CONCLUSIONS

HSBTS in Thailand was analyzed to find the main criteria

for select a suitable solar collector type for Thailand plant.

The plant characteristic for Thailand is work for lower

temperature steam (150-200 °C), low cost and easy to setup

and operate in remote area. With this temperature range

criteria, the solar tower and Linear Fresnel Reflector are a

good choice to choose. However, with total cost and land use

criteria, Linear Fresnel reflector system is the best one that

more suitable for Thailand plant. From all criteria, found that

the most attractive solar collector type is linear Fresnel

because of the critical criteria for remote area in Thailand is

total cost, with lowest total cost, medium efficiency, medium

energy output and suitable temperature tolerance make Linear

Fresnel is the most attractive solar collector for remote area in

Thailand.

ACKNOWLEDGMENT

The authors are grateful to Prof.Jongjit Hirunlabh for useful

advice and suggestion.

REFERENCES

[1] Department of Alternative Energy Development and Efficiency, 2013,

“Energy in Thailand: Facts & Figures. Thailand. Available from:

http://www.dede.go.th/dede/images/stories/stat_dede/factsFigures_2013

/q3_2013_re.pdf; [accessed 10.10.2013].

[2] S.H. Chowdhury, “Biomass supported solar thermal hybrid power

plant for continuous electricity generation from renewable sources”

Developments in Renewable Energy Technology (ICDRET), 5-7

Jan. 2012, Dhaka, pp. 1-4.

[3] J.Eakburanawat, “Solar-biomass thermoelectric power generation

simulation” 22nd international Conference on thermoelectric (2003),

pp. 582-584.

[4] Tai lv, “Study on the Continuous and Stable Running Mode of Solar

Thermal Power Plant”, Power and Energy Engineering Conference,

2009. APPEEC 2009. Asia-Pacific, pp.1-5.

[5] Kibaara S., “A thermal analysis of parabolic trough CSP and biomass

hybrid power system”, Transmission and Distribution Conference and

Exposition (T&D), 2012 IEEE PES, pp. 1-6.

[6] G. Pikra, “Development of small scale concentrated solar power plant

using organic Rankine cycle for isolated region in Indonesia”,

International Conference on Sustainable Energy Engineering and

Application [ICSEEA 2012], Energy Procedia 32 (2013), pp. 122 -

128.

[7] IRENA. Renewable energy technologies: cost analysis series

concentrating solar power. Abu Dhabi: International Renewable

Energy Agency; 2012.

[8] Daniel H., “Performance Simulation For Parabolic Trough

Concentrating Solar Power Plants And Export Scenario Analysis For

North Africa”, a thesis submitted to the Faculty of Engineering at Cairo

University in Partial Fulfillment of the Requirement for the Degree of

Master of Science in Mechanical Power Engineering, Faculty of

Engineering, Cairo University, Giza, Egypt 2012.

[9] SolarReserve LLC. Crescent dunes. Available from:

www.solarreserve.com/what-we- do/csp-projects/crescent-dunes; 2012

[accessed 07.08.2013].

[10] Mertins, M., M. Selig, and G. Morin, Supernova - Construction,

Control and Performance of Steam Superheating Linear Fresnel

Collector, in Solar PACES 2011. 2011: Granada, Spain.

[11] Siangsukone PL. Transient simulation and modeling of a dish solar

thermal power system. PhD, Faculty of Engineering and

Information Technology, The Australian National University,

Canberra, Australia; 2005.

[12] Juergen H. Peterseim, “Concentrated solar power hybrid plants, which

technologies for hybridization?”, Renewable Energy Volume 57,

September 2013, pp 520–532.

http://dx.doi.org/10.1016/j.renene.2013.02.014

[13] N. Jonathan (2012), “Solar thermal collector for use in hybrid solar-

biomass power plants in India”, PhD thesis, Aston University.

[14] G. Cau, “Comparison of medium-size concentrating solar power plants

based on parabolic trough and linear Fresnel collectors”, Energy

Procedia 45 (2014), pp. 101-110.

http://dx.doi.org/10.1016/j.egypro.2014.01.012

[15] D. Dovic, “Numerically assisted analysis of flat and corrugated plate

solar collectors thermal performances”, Solar Energy 86 (2012), pp.

2416-2431. http://dx.doi.org/10.1016/j.solener.2012.05.016

[16] J.D. Nixon, “The feasibility of hybrid solar-biomass power plants in

India”, Energy volume 46, Issue 1, October 2012, pp. 541-554.

http://dx.doi.org/10.1016/j.energy.2012.07.058

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