Solar Heaters Final

8/11/2019 Solar Heaters Final

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SOLAR AIR HEATERS

JYOTI JAIN

2011CH10159

Department of Chemical EngineeringIIT Delhi

Indian Institute of Technology, Delhi


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Motivation

Solar power if harnessed properly can save a lot of

non-renewable sources which can then last longer.

I would like to make this idea of solar air heaters

popular in industries and so would like to work on

increasing its efficiency which can make thistechnology more favorable for use.

Indian Institute of Technology, Delhi 2/18


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Overview

Types of Solar air heating system

Design of Solar Air heating system

Applications and related design Energy saving and Cost analysis

Current Research-Chemical Engineering

Perspective Conclusion



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Types Of Solar Air Heaters

Unglazed Air Collectors or Transpired Solar

a metal absorber without any glass or glazingover top that heats ambient air.

used primarily to heat ambient air incommercial, industrial, agriculture and processapplications.

Glazed Solar Collectorsrecirculating types that are usually used for

space heating.



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DesignGlazed Air Heater



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DesignGlazed Air Heater


Governing equations of heat

transfer


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DesignUnglazed Air Heater



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DesignUnglazed Air Heater



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Industrial SAH Systems


For ventilation air

in factories,

warehouses, etc.

Perforated fabric

ducting distributes

air at ceiling level.

Temperature control: mix fresh and re-circulated air,add heat if necessary.


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SAH System for Process Heat


Collector mounted on

any convenient surface.

Output of collector

ducted to process.

Temperature can beregulated by

Conventional heater

Bypass damper

Crop (coffee& tea) drying- low T

Preheat air for industrial processes


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Industrial SAH Systems


For ventilation air

in factories,

warehouses, etc.

Perforated fabric

ducting distributes

air at ceiling level.

Temperature control: mix fresh and re-circulated air,add heat if necessary.


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S H Efficiency


Collector thermal efficiency:

Efficiency decreases with air temp gain as the driving

force decreases.

Maximum efficiency reported is 80% with atemperature difference of 60 degree Celcius. with a

solar radiation flux of 800 W/m2.

Solar air heater 40 -80

Solar water heater 30-40

Solar power generation 7-15


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Cost Analysis


1 m2of collector

Energy Collected:

1 to 3 MJ/year

Installed costs:

Collector: Rs.6000 to Rs15000/m2

Ventilation system: Rs.0 to Rs.6000/m2

Total: Rs6000 to Rs.2100/m2

minus cost of conventionalcladding

Energy Savings for a 800m3/h system = Rs. 10000-15000

Payback Period in industrial systems around 2-3 years


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Ventilation Air Heating Systems Improved air quality at low cost

Ducts should be located near south wall

Paybacks of 2 to 5 years typical

Industrial systems often have quickest

payback

Apartment Building,Ontario, Canada

Portable Classroom, Ontario, Canada


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Current Research

Chemical Engineering Perspective


Absorber plate material : corrugated absorber material,

using a wire mesh over the absorber plate

Design using multiple glazing, forcing air through jets to

create turbulence. Problems with metal absorber and glass glazing: Corrosion

and fouling.

Collector efficiency of 70% was obtained by placing a

packing material over the heating surface. But packing comes at the cost of pressure drop.


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Current Research-


Double glazing and packing

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Current Research


impinging fins to increase heat transfer area.



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Conclusions

Solar Air Heating is more effective than Solar

power generation or water heatingless cost and

no leakage.

Efficiency is good but with more of research can

be made better.

Due to initial high cost and high area

requirements, industries reluctant to use.

Need to spread the idea among industries andmore research to make it more cheap and

effective area wise.



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THANK YOU

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Solar Heaters Final

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