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A Project report by, Vijay Aravind . A Vishnu D.S. Vishaal. G Under the guidance of MAHBOOB E. AFSHAN Senior Grade professor Department of Mechanical Engineering B. S. Abdur Rahman University. Heat Transfer Analysis by Stratification of HDPE encapsulated HS89(PCM)

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A Project report by,

Vijay Aravind . AVishnu D.S.Vishaal. G

Under the guidance of

MAHBOOB E. AFSHAN

Senior Grade professor Department of Mechanical Engineering

B. S. Abdur Rahman University.

Heat Transfer Analysis by Stratification of

HDPE encapsulated HS89(PCM)

• Solar energy is receiving a lot of sustainable energy and is used for power

generation and other applications. A major limitation is that it is available

only about 2000hrs a year in many places. Therefore it is critical in order to

store the thermal energy in off hours.

• Sensible heat have been storing energy but due to material properties this

type of storage have its limitations too.

• Using Encapsulated Phase change materials is potentially a better way to

store thermal energy with the associated reversible heat transfer.

• By storing the Latent heat energy into the Phase change materials by natural

heating and storing for a particular off hours, and releasing this heat energy

when required is the main objective of our project.

• Each site could be made as SMART GRID by this method of power storage.

• Greater power saving method by controlled heat emission by our requisites.

• Stand-By Capacity - in case the main machinery fails, the stored energy can

be utilized to handle the system loads, thereby providing a degree of back-up

facility.

• Flexible System - the overall machinery capacity and TES capacity can be

exactly matched to system loads.

• Reduced Machinery and reduced running cost - shifting some of the peak

load may enable designers to reduce the main machine size.

• Green Solution - reduced machinery size means reduced energy

consumption, giving lower direct and indirect CO2 emissions.

• The overall energy rate is heavily decreased considering the per annum

decrement of the energy consumption of the working machinery therby

reducing the cost.

There are several methods to store Thermal energy and are us follows :

Sensible Heat Storage Method

Latent Heat Storage Method

Chemical Heat Storage Method

Thermosyphon method- to achieve steam in the collectors

Stratification method

Cascading of the Phase Change Materials.

HTF from the solar heater

Cylindrical tank

Heat absorbed

by the pcm

HTF collected

at the bottom of the tank

HTF pumped

back

Choosing HS 89 as the Phase Change Material

HS 89 is an inorganic chemical based Phase Change Material with a

melting temperature of 89ᴼC. It stores thermal energy as latent heat in

its crystalline form. On changing its phase, this latent heat is released or

absorbed, allowing the ambient temp within the system to be

maintained. HS 89 is constituted to the right mix of various salts,

additives and nucleating agents allowing equilibrium between solid and

liquid phases to be attained at the melting point. While melting, it

continues to absorb heat from the environment without further increase

in temperature, thereby maintaining the system temperature.

It is non-flammable.

HS 89 is chemically and thermally stable.

HS 89 has a freezing temperature of 85ᴼC, a temperature that makes it

suitable for many storage applications.

The setup basically consists of four sections:

Heater setup

Thermal Energy Storage tank

Centrifugal Pump

Data Acquisition System

Heater setup :

The heater setup is a stainless steel tank of 360mm

diameter and 530mm height. Its capacity is 55lts. In the

bottom of this tank a 3000W immersion heater is attached

which will heat the HTF simulating the temperature of a

solar collector. To the immersion heater, a thermostat is

attached to the bottom which will control the temperature

ensuring that constant temperature is maintained in the

bath. The heater setup tank is insulated by glass wool to

prevent heat losses. The heater setup and TES tank are

connected by means of flexible steel hose and GI pipes.

Thermal Energy Storage tank :

The TES tank consists of PCM (HS 89) balls which are

packed in four layers. The bottom layer is left empty

to provide easy suction for the pump. Each layer in

the TES tank contains 11 balls each. The TES tank

contains 44 HS 89 balls in total.

Each of the layers is surrounded by a wire mesh. On

the top of the TES tank, a distributor plate of

circular cross section is placed to ensure that the

HTF falls uniformly on each ball in the different

layers. In each layer of the TES tank, a J-type

thermocouple is drilled into it to note the

temperature variation. The TES tank is insulated

using polyethylene foam to prevent heat losses.

Centrifugal pump :

The centrifugal pump is used to re-

circulate the HTF(heat transfer fluid)

leaving the TES tank back to the

heater setup tank. It is a mono-block

pump and it has a head of 15m.

Data Acquisition System :

The Data acquisition system consists of a NI-

9213(National instrument) for recording

temperatures from the thermocouples from

each layer of the TES tank. The temperatures

are measured using the LABVIEW software

and the data acquired is read onto the

computer from the NI-9213 instrument and

temperature readings are recorded for every

minute of the run.

Distributor plate

TES tank containing HS 89

balls

Drilling: Drilling is a cutting process that uses a drill bit to cut or enlarge a hole of

circular cross-section in solid materials. The drill bit is a rotary cutting tool, often multipoint. The bit is pressed against the workpiece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the workpiece, cutting off chips from what will become the hole being drilled

In the fabrication process,4mm holes were drilled in the nuts of the HS 89 balls so as to place the thermocouples inside and several holes were drilled in the distributor plate to enhance the flow rate of heat transfer fluid.

Brazing:Brazing is a metal-joining process whereby a filler metal is heated above melting

point and distributed between two or more close-fitting parts by capillary action. The filler metal is brought slightly above its melting (liquidus) temperature while protected by a suitable atmosphere, usually a flux. It then flows over the base metal (known as wetting) and is then cooled to join the workpieces together. It is similar to soldering, except the temperatures used to melt the filler metal are higher.

In the fabrication process, the thermocouples are brazed along with the nuts of the HS 89 balls to prevent HTF entering into the PCM.

Soldering:Soldering is a process in which two or more metal items are joined together by

melting and flowing a filler metal (solder) into the joint, the filler metal having a lower melting point than the work-piece. Soldering differs from welding in that soldering does not involve melting the work pieces. In brazing, the filler metal melts at a higher temperature, but the work-piece metal does not melt.

In the fabrication process, we have soldered the immersion heater in the stainless steel tank to prevent any leakages.

S.

NOBILL OF MATERIALS QUANTITIY AMOUNT

(In Rs)

1 HS-89 BALLS

2 THERMOFOAM

3 SHEET METAL

4 J-TYPE

THERMOCOUPLE

6 900

5 THERMOCOUPLE PIN 26 400

6 ROTOMETER 1

7 DAQ (NI-9213) 1

8 CENTRIFUGAL PUMP 1

9 ENERGY METER 1

10 DISTRIBUTOR PLATE 1

11 TES TANK(1:3) 1

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THANK YOU