Simulation of Two Pass Solar Air Heater using Matlab

By,

Avinash v Dharwadkar

USN:2BV10MES04

Contents

• Problem definition

• Objectives

• Introduction

• Classification of FPC

• The majority of flat plate collector main component

• Insulation and casing

• SAH classification

Contents

• Application of solar air heaters

• Advantages of solar air heaters

• Disadvantages of solar air heaters• Literature Survey

• Specification

• Packed Bed

• Steel mesh as a packing material

• Porous solar air heaters

Contents

• Nonporous solar air heaters

• V groove nonporous solar air heaters

• V groove porous solar air heaters

• Results

• Conclusion

• References

Akoweldement

1)K. Sopian , M.A. Alghoul , Ebrahim M. Alfegi , M.Y. Sulaiman , E.A. Musa

2)Suppramaniam satcunanathan

and Stanley deonarine

3) N. E. Wijeysundera, Lee ah and Lim Ek Tjioe

4) Bashria A. A. Yousef and Adam N. M,Analysis of Single and Double Passes With and Without Porous Media for V-groove absorber

• The study involves the predicting the better solar air heaters and high performance air heaters for the purpose of crop drying, space heating etc.

• Efficiency involved with the losses. Considering losses predicting efficiency for different conditions like nonporous,porous,Vgroove porous,Vgroove nonporous solar air heaters.

• Among the above mentioned types of solar air heaters checking their performances for different variable parameters like pressure drope, flow depth variations,outlet tempreture, and mass flow rate.

Problem definition

Objectives

• To show the performance of two pass solar air heaters using MATLAB.

• Comparing the results of nonporous and porous media used in the second channel of the air heaters.

• Effect of porous media on Nussult number and Reynolds number by results obtained from the Matlab.

Classification of FPC

• Based on the type of the heat transfer fluid used can be divided into two main classifications;

• Liquid heating collector

• Air or Gas heating collector

Introduction

• It is solar collector device for collecting solar radiation and transfer the energy to a fluid passing in contact with it.

• Where temperature below 900 C are adequate, flat plat collector are convenient.

• They are made in about 1.7 to 2.9 sq.m in area and are relatively simple to construct and erect.

• They can absorb both direct and diffused radiation.

• They are consequently effective even on cloudy days when there is no direct radiation.

Construction of FPC

• When temperature is below about 900C is adequate they are for space heating and service water heating flat plate collector

Which are non concentrating type. are particularly convienient.They are made in rectangular panels, from about 1.5 to 2.9square meter in area.

The majority of flat plate collectorhave main components as follows

• A transparent cover which may be one or more sheets of glass or radiation transmitting plastic film or sheets.

• Tubes,fins,passages or channels are integral with the collector absorber plate pr connected to it which carry the water, air or other fluid.

• The absorber plate, normally metallic or with a black surface although a wide variety of other materials can be used with air heaters

Insulation and casing

• Insulating materials, which should be provided at back and sides to minimize the heat losses. Standard insulating materials like glass wool ,styro foam are used for this purpose.

• The casing or container which enclose the other components and protect from weather.

• Heat is transferred from the absorber plate to the point of use by circulation of fluids across the solar heated surface. Thermal insulation of 5 to 10 cm thickness is usually placed behind the rear surface. insulation materials is generally mineral wool, glass wool .

Continued…

• The front covers are generally glass that is transparent to in coming solar radiation and opaque to the infrared re-radiation from the absorber. The glass cover acts as a convection shield to reduce losses from the absorber plate .Glass is most favorable materials.Its thickness is 3 to 4mm.

SAH classification

• Air heaters are classified into two categories

Nonporous: In this kind air passes directly on the absorber plat

Porous absorber : in this kind air passes through the porous materials

Application of solar air heaters

The solar air heaters which supply hot air could be mainly used for the following purposes:

• Heating buildings

• Drying agricultural products.

• Heating green house.

• Space heating.

• Seasoning of timber

• Curing of industrial products

Advantages of solar air heaters

• The use of air as heat transport fluid eliminates both freezing and corrosion problems

• Small air leakage are less concern than the water leaks

• The heated air can directly used for space heating while in water heating it can not be used directly for the same purpose.

Disadvantages of solar air heaters

• Need to handling larger volume of air.

• Thermal capacity of air is low.

• They have relatively high fluid circulation costs.

• Relatively larger volume of storage.

• They have higher noise level.

• Space is required for ducting.

Literature Survey

• K. Sopian, M.A. Alghoul

Evaluation of thermal efficiency of double-pass solar collector with porous–nonporous media

Introducing porous media in the second channel increases the heat transfer area. This type of collector has a higher thermal performance compared to the conventional single- pass solar collector. Typical thermal efficiency of the double pass solar collector with porous media is about 60–70%.

Literature Survey

• K. Sopian etall

Analysis of Single and Double Pass Solar Collector With and Without Porous Media

• It is found that increasing the mass flow rate through the air heaters results in higher efficiency but also there is increased pressure drop.

Literature Survey

Elradi A. Musa Et all.

• In the double-pass solar collector, the mass flow rate has more effect on the temperature rise. The solar radiation has more effect on temperature rises at low porosity. In addition, the Reynolds number has more effect than the Nussult number at low porosity. Heat transfer coefficient increases by using more porous media in the lower channel of the double-pass solar collector

Literature Survey

• The double flow is more efficient than the single flow made and the using of porous media increase the system efficiency and the outlet temperature. This increment will result in the increase of the pressure drop thus increasing the pumping power expanded in the collector.

• Higher porosities in the porous media improved the thermal efficiency. Pressure drop study indicated that lower pressure losses are encountered with low porosity than with high porosity of the saturated porous media.

Introduction of Matlab

• The name MATLAB stands for matrix laboratory. MATLAB was originally written to provide easy access to matrix

software developed by the LINPACK and EISPACK projects.• In university environments, it is the standard instructional tool

for introductory and advanced courses in mathematics, engineering, and science.

• In industry, MATLAB is the tool of choice for high-productivity research, development, and analysis. MATLAB features a family of add-on application-specific solutions called toolboxes.

Introduction of Matlab

• Very important to most users of MATLAB, toolboxes allow you to learn and apply specialized technology. Toolboxes are comprehensive collections of MATLAB functions (M-files) that extend the MATLAB environment to solve particular classes of problems. Areas in which toolboxes are available include signal processing, control systems, neural networks, fuzzy logic, wavelets, simulation, and many others.

Porous flat plate solar air heaters

Specification• L = 2.4m• W = 1.2m• d = 0.02 to 0.07m• Glass martial emissivity = 0.95• Plate emissivity = 0.95• Plate absorbtvity = 0.92• Reflectivity of plate = 0.15• Plate thickness = 2mm• Glass thickness = 3mm• Insulation thickness on side and back = 0.05m• Density = 1.29Kg/m3

• Absolute viscosity = 19*10-6 kg/ms• Specific heat of air = 1.005 kJ/kgK• Thermal conductivity of the insulation = 0.045kw/mk

Packed Bed

• The packed bed solar air heaters means filling the porous materials in the channels of solar air heaters

• Materials are used are steel mesh, crushed glass,glass wool ect.

• Pressure drop is more in the packed bed than the usual solar air heaters.

• Hence pumping power required is more.

Nonporous solar air heaters

Pressure drop vsflow depth

Efficiency vs flow depth

Outlet temp,efficiency vs mass flow rate

Reynolds number

Heat transfer coefficient

Porous solar air heaters

Pressure drop vs flow depth

Efficiency vs flow depth

Outlet temp,efficiency vs massflow rate

Heat transfer coeffiicent

Reynolds number

V-groove nonporous solar air heaters

Pressure drop vs flow depth

Efficiency vs flow depth

Outlet temp,efficiency vs mass flow rate

Heat transfer coefficient

Reynolds number

V-groove porous solar air heaters

Pressure drop vs. flow depth

Efficiency vs. flow depth

Outlet temp,efficiency vs. mass flow rate

Heat tansfer coefficient

Reynolds number

Results

Types of solar

air heaters

Efficiency

considering

mass flow

rate,m

η considering

Flow depth,m

Pressure drop

(pa)considering

Flow depth

Outlet

temperature (c)

Reynolds

Number

Nussult

number

Nonporous 64 64 4 45 16000 10

porous 73 73 5 50 10000 25

V-groove

nonporous65 65 8.5 45.5 3000 12

V-groove

porous66 65.5 9 50 2500 20

Percentage differencesTypes of solar air

heaters

% in increase in

efficiency considering

mass flow rate

% increase in the

efficiency considering

flow depth

% increase in the

pressure drop

% increase in the outlet

temperture,c

Porous solar air heaters 14% 14% .25% 11.23%

V-groove nonporous

Solar air heaters1.5% 1.56% 1.125% 13.3%.

V- groove porous Solar

air heaters2.34% 2.34% 1.25% 0.111%

Conclusion

• The Nussult number values are less in the nonporous than in the porous because the heat transfer reduces in nonporous media.

• The Nussult number values are more in the porous than in the nonporous because the heat transfer increases in porous media.

• The Reynolds number is more in the nonporous due to higher velocity of air due to free flow through the ducts.

• The Reynolds number is less in the porous due to lower velocity of air due to flow through the packed ducts.

• Efficiency is increases with increase in mass flow rate.

Conclusion• Outlet temperature decreases with the increase in mass flow

rate.• Efficiency decreases with increase in the channel depth.• In two pass solar air heaters variables like efficiencies,

pressure drop ,outlet tempreture,friction factors ,collector efficiency factors ,collector flow factor in flat plate porous and nonporous ,V groove porous and non porous obtained through Matlab programming is almost equal.

• Efficiencies of four types of collectors are between 60% to 73%.

• Pressure drop for four types of collectors varied between 2 to 17 Pascal’s.

• Reynolds number varied between 600 to 16000.

Conclusion

• Nussult number varied between 3 to 40.

• The highest efficiency obtained from the flate plate porous kind of solar air heaters.

• The outlet temperature is maximum in flat plate with porous solar air heaters.

• The outlet temperature is minimum in V groove plate with porous solar air heater.

• Pressure drop is directly proportional to length of the collector more length is leads more pressure drop and more pumping power is requared.

References

[1] K. Sopian a, M.A. Alghoul , Ebrahim M. Alfegi b, M.Y. Sulaiman , E.A. Musa, Evaluation of thermal efficiency of double-pass solar collector with porous–nonporous media.

[2] B. A. A. Yousef and N. M. Adam, Thermal Performance and Economic Effectiveness for Solar Air Heaters: Analysis and Expert System Developments

[3] Bashria A. A. Yousef and Adam N. M,Analysis of Single and Double Passes With and Without Porous Media for V-groove absorber.

[4] A. A. Shabaneh, P. Gandhidasan, M. A. Antar and H. Baig,Simulation of hdh desalination system using tilted, two-pass solar air heater.

[5] Adisu Bekele , Manish Mishra, Sushanta Dutta,Effects of delta shaped obstacles on the thermal performance of solar air heater.

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factor correlations for packed bed solar air heaters for a low porosity system

[9] M K Lalji et al, Solar Air Heater.[10] F.L.Lansing and R.Reynolds,High performance solar air

heaters.[11] Suppramaniam Satcunanathan and Stanley Deonarine,A

two-pass solar air heater[12] N. E. Wijeysundera,Lee lee ah and Lim Ek Tjioe,Thermal

performance study of two-pass solar air heaters.

References

[13] Ahmad Fudholi, Kamaruzzaman Sopian, Mohd Hafidz Ruslan, Mohd. Yusof Othman and Muhammad Yahya, Analytical and Experimental Studies on the Thermal Efficiency of the Double-Pass Solar Air Collector with Finned Absorber

[14] A. Fudholi, M,H. Ruslan, M.Y. Othman, mM. Yahya, Supranto, Experimental Study of the Double-Pass Solar Air Collector With Staggered Fins.

[15] Amrita Agrawal, Nalin Deshpande, Aakanksha Dubey, Design, Fabrication & Performance Analysis of Solar air heater.

[16] Rai.G.D, Solar Energy Utilization

[17]S.P.Sukahtme,Solar Energy

References[[18]Rudra Pratap, Getting Started with Matlab[19]H.P.Garg,J.Prakash,Solar energy Fundamentals and

Applications[20] www.sciencedirect.com[21] www.mathworks.com

[22] C. Choudhuryp, . M. Chauhana and H. P. Garg,Performance and cost analysis of two-pass solar air heaters.

[23] Bashria A, A. Yousef and Adam N. M, K Sopian, A. Zaharim and M. Alghoul,Analysis of Single and Double Passes V-Grooves Solar Collector With and Without Porous Media.

Thank you