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Material and Component SpecificationsNon Imaging Concentrator
Prepared by IT Power India
Under UNDP-GEF market development & promotion of solar concentrator based process
heat application in IndiaMinistry of New and Renewable Energy
Government of India December 2015
Preface
This booklet outlines the material and component specifications of Non Imaging Concentrators for process heat applications. The purpose of this booklet is to layout the material and component specifications of key components of the Non Imaging Concentrator system so as to serve as a reference document to maintain quality in the field by manufacturers supplying and installing the system.
The booklet is intended to serve as a guide for stakeholders interested in Con-centrated Solar Thermal (CST) system based on this technology for applications in process heat for industry and help them set up a durable system which meets the necessary safety and quality standards. It is one of a series of such booklets produced to cover the field of commercially available CST systems marketed for process heat applications in India.
The specifications for key components and subcomponents of the Non Imag-ing Concentrator system and their relevant parameters are outlined in an easy to understand tabular format. Wherever applicable, images of the components and schematic diagrams have also been presented for easy identification of the components.
The booklet has been compiled with technical inputs from the developers and manufacturers of this technology. Inputs and suggestions of experts in the do-main of concentrated solar thermal systems and users have also been taken in the compilation of this booklet.
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Background
India has a very good potential of solar energy, with average solar irradiation be-ing around 4-7 kWh/m2/day. This abundant solar radiation can be used to meet the demand of low to medium process heat as required by various industries and institutions. Concentration of solar radiation to produce the temperature in the range of 100 to 450˚C or more is called concentrated solar thermal (CST) technol-ogy. This technology offers sizeable potential across diverse range of industries and commercial establishments in India.
There are six CST technologies commercially available in India, namely,• Fixed focus automatically tracked elliptical dish (Scheffler)• Dual axis tracked paraboloid dish• Fresnel reflector based dish (ARUN dish)• Single axis tracked parabolic trough concentrator• Non-imaging concentrators• Linear Fresnel reflector
About Non Imaging Concentrator TechnologyNon Imaging Concentrator (NIC) is similar to flat plate collector with the excep-tion of a compound parabolic collector (CPC) fixed at a tilted base.
Underlying principle The CPC reflector mainly consists of two parabolic reflectors each with different focal points and this is the reason it is named as a non-imaging concentrator be-cause no image of the source is formed at the focal point. These parabolas con-centrate the incoming radiation onto the receiver tube which is placed between the focus of two parabolas. The acceptance angle of reflector is the maximum angle through which incoming radiation can enter the collector. The receiver tube is specially coated and enclosed within a glass tube to reduce convection losses. The space between the absorber and glass tube may be evacuated. Non-imaging concentrator does not require any tracking system however, the module has to be oriented properly in order to increase its output energy. The NIC panel is generally mounted in the East-West direction with the panel facing south in-clined from the ground at an inclination angle of (Latitude Angle + 10°).
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Key components of Non Imaging ConcentratorKey components of a Non Imaging Concentrator based system can be classified on the basis of their individual functions:
NON IMAGING CONCENTRATOR• Collector• Receiver • Module
BALANCE OF SYSTEM• Piping • Instrumentation and Safety Mechanism• Storage System (optional)
Key design variantsNon Imaging Concentrator is currently available in two primary designs, as given below [In brackets: Collector Size]
End-use applicationNon Imaging Concentrator is used for the low to medium process heat applica-tion. It can attain a maximum temperature up to 120°C as per requirement in industries, commercial & residential complexes, religious places, etc.
Some of the typical application areas of a Non Imaging Concentrator are namely;• Hot Water for Bathing• Component Washing• Community cooking• Solar-assisted comfort cooling• Laundry • Effluent Treatment
SolPac NI30 (3.4 m2) by Thermax NIC (20 m2) by Bergen Solar
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The configuration of an industrial process heat solar system depends on the spe-cific application. It may consist of one or more number of Non Imaging Concen-trators in a system. Non Imaging Concentrators have been installed in various thermal applications across industries including vehicle manufacturing for wash-ing of automobile parts, chemical plants, etc. There are 2 key manufacturers of this technology and around 6 case specific examples of Non Imaging Concentra-tor installed across India. The list is given as an Annexure.
Development of the Non Imaging Concentrator in the country requires compo-nent and material standards to be followed for maintaining the quality in the field by the manufacturer and thereby assurance of the quality by the end-user.The following section covers detailed specifications of various components and materials of a Non Imaging Concentrator.
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Schematic Diagram of CST based system with Non Imaging Concentrator (Courtesy: CSH India)
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Material and Component Specifications
CollectorThe Non-imaging concentrator uses a compound parabolic concentrator (CPC) reflector to capture the incident sun rays. The metal reflector of high reflectivity is generally used. The acceptance angle of the reflector determines the amount of sunlight that will enter and get reflected to the receiver placed at its focus.
SpecificationsReflector
Parameter Specification
Type Weather proof, scratch resistant Compound Para-bolic Concentrator
Material Pure Aluminium Sheet / Alloy Aluminium sheet
Shape Cylindrical with parabolic cross section
NON-IMAGING CONCENTRATOR
CPC Reflector
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Parameter Specification
Thickness 0.3 – 0.8 mm
Reflective Coating Aluminum with 7 layer coatings for weather proof-ing and reflectivity.
Reflectivity At least 90%
Protective Coating Anodizing / Epoxy, Polyester (PE), Polyurethane (PU), Fluorocarbon coating / Lacquer coating
Durability Minimum 10 years
ReceiverThe receiver of a Non-imaging concentrator is an evacuated type linear tube placed at the focus of CPC reflector. It transfers the heat reflected by CPC collec-tor to the heat transfer fluid flowing through the tube
Exploded View of Receiver (Source: Andy Schroder)
Receiver – CPC collector Schematic (Source: Andy Schroder)
Receiver
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International Organization for Standardization1
Specifications
Receiver
Sub components Specification
Absorber
Design U shaped tubing attached to metal fins. This unit is con-tained in an internal glass tubeMaterialU Tube – Copper, Stainless steel.Metal Fins – Aluminium sheetGlass – Borosilicate Glass 3.3 conforming to ISO1 3585
Absorber Coating
Type & MaterialOuter surface of Internal Glass tube is selectively coated with Aluminium Nitride based proprietary materialAbsorptivityAt least 92 % to 95% at AM2 1.5
Outer Glass Cover
DesignGlass tube with vacuum between Internal and outer glass tubeMaterialBorosilicate Glass 3.3 conforming to ISO 3585TransmittanceAt least 90 to 96 % at AM 1.5Outer Diameter47-70 mmThickness 1.6 – 2.0 mm
Absorber - Glass fixing
U shaped copper tube is connected to the header pipe with prior arrangement on header to fix the tubing.
Internal glass tube is closed at the base and seated in a steel strut. Other end of internal glass tube is thermally sealed with one end of outer glass tube.
The other end of outer glass tube is thermally sealed after ensuring the desired vacuum
Air Mass26
ModuleCPC reflector and receiver tube assembly are placed above the module with a proper fixing mechanism. A module can have a number of receiver tubes as per design with individual CPC reflector. Module can be connected in series or paral-lel to other module. Series connection is used for high temperature requirement whereas parallel for high flow rate.
The basic framework of the stand is a steel structure. The structure is designed to withstand wind speed under an operating condition as per the prevalent struc-tural design code. The overall system rests on a civil foundation.
Specifications
Module
Parameter Specification
Design & MaterialBack cover made of Aluminium sheet fixed on Aluminium or steel Frame
Fixing of Receivers
One end of receiver tube is fixed on to the module with the help of brackets and standard fasteners
Fixing of Reflectors
Reflectors are glued or attached to the frame by standard glue material
Back Sheet Frame Module Stand
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Module Stand
Sub components Specification
Structural Support
Foundation
DesignStructural steel support made of standard angles and sec-tions which are further fastened to the civil structure
MaterialCarbon Steel
Protection from corrosionCathode Electrode Deposition painting processStrength Designed as per IS3 875 and allied/applied codes
DurabilityMinimum 10 years
Civil Foundation
DesignDesigned to rest on soil of sufficient strength or to suit the prevalent soil condition
MaterialCement and concrete
Coating ProtectionCoating of paint on exterior surface (optional)
StrengthDesigned as per IS 456 and allied/applied codes
Balance of plant includes a number of components such as heat transfer pipes & support structure, instrumentation & safety mechanism and storage tank (op-tional) to control both the fluid flow and temperature. The heat transfer pipes carry fluid and transfer the heat received by it to the end use application. Fluid circulates in the system at a certain desired rate.
BALANCE OF SYSTEM
Indian Standards3 8
Heat Transfer Pipe
Parameter Specification
Design Electric Resistance Welded (ERW) pipe or seamless pipe or as per IS standards for hot water
Material Galvanized Iron/ Mild Steel/ Stainless Steel
Size Diameter of pipe depends on the flow rate of fluid Thickness is based on the pressure required in the system
Working Fluid Hot Water / Pressurized Hot water/Thermic Fluid
Strength & Durability As per IBR4/ASME5 and allied/ applied standards
Typical LRB Mattress Cladding
Type Thick insulation layer with cladding over the pipe
Material
Insulation Material - Mineral wool or Glass wool or Light Resin Bonded (LRB) mattresses Cladding Material – Aluminium/Stainless Steel/ Galva-nized Iron sheets
Indian Boiler Regulation4
American Society of Mechanical Engineers5
Insulation
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Circulation Pump
PumpAs per API6 674/ISO 5199 / DIN7 24255 / EN8 733 Standards
Instrumentation
Pressure Gauges As per IS 13947 / IS 3624 Standards
Temperature sensors
As per DIN 43760 / EN 60751 / IEC9 751 Standards
Valves As per API 598 / BS10 5352 Standards
Flow meters Standard Positive displacement / Turbine / Electromag-netic / DP / Vortex flow meters as suitable for application flow rate
DesignStructural steel support made of standard angles and sections which are further fastened to the civil structure
Material Carbon Steel
Coating Protection Cathode Electrode Deposition painting process
Strength & Durability
Designed as per IS 875 and allied/applied codesMinimum 10 years
American Petroleum Institute6
Deutsches Institut für Normung i.e. German Institute for Standardization7
British Standards
8 European Standards9 International Electro technical Commission
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Support Structure
Pressure gauge Temperature Sensor
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Heat Transfer Pipe
Insulation
Typical LRB Mattress Aluminium Cladding
Storage system (optional)The thermal storage subsystem is a part of the circulation system. It extracts heat from the circulating fluid when the temperature becomes too high. When the temperature is too low, it supplies stored heat to the fluid. Insulation should be provided on tank and supporting structure.
Specifications
Heat Storage Tank
Parameter Specification
Type Cylindrical tank
Material Generally MS, other material as per the application under consideration.
Size Depends on the application requirements
Storage medium Hot water / Pressurized hot water / Hot oil
Strength and Durability Designed as per ASME codes and allied/ applied codes
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Heat Transfer Pipe
Pressure Gauge Typical Pressure Valve Typical Flow Meter
Instrumentation
Annexure
List of Installations
User State System Size (sq. m.)
Application
ITC Limited, Tobacco Division, Bengaluru
Karnataka 680 Pre heating of boiler feed-water
Mahindra & Mahindra, Farm
Equipment Sector, Kandivli
Maharashtra 442 Pressurized hot water for cleaning and
degreasing application
ITC, Ranjangaon, Pune
Maharashtra 442 Preheating of boiler feed water
Mahindra Holidays & Resorts, Ooty
Tamil Nadu 82 Process Heat
Neel Metals Product Ltd., Gurgaon
Haryana 612 Process Heat application for the
paint shop
ManufacturersThere are four Non Imaging Concentrator manufacturers in India. Details of manufacturers can be found on MNRE website.
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Prepared by IT Power India
Contact:For more details on the manufacturers/suppliers, government sup-port, applications, technologies and successful installations please visit: www.mnre.gov.in OR www.cshindia.in OR contact Project Management Unit UNDP-GEF CSHP, Ministry of New and Renew-able Energy, Block 3, CGO Complex, Lodi Road, New Delhi-110003. Telefax: 011-32314365/24363638, Email: [email protected]
Toll Free Helpline No. 1800 2 33 44 77 could be accessed Mon-day through Friday between 9:30am to 6:30pm and on Saturday 9:30am to 1:30pm
Prepared for the Ministry of New and Renewable Energy, Govern-ment of India, under the UNDP-GEF project on Concentrated So-
lar Heat by IT Power Consulting Pvt. Ltd, New Delhi-110019 website: www.itpower.co.in
