Thermal energy storage system

Thermal Energy Storage system By

Abhinav Bhaskar

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Content Layout

� Introduction To TESS

� Classification

� Latent Heat Storage

� Phase change materials and application

� Case study application

� References

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Thermal energy storage –Why do we need it ?

� Energy demands vary on daily, weekly and seasonal bases. TES is helpful for balancingbetween the supply and demand of energy

� Thermal energy storage (TES) is defined as the temporary holding of thermal energy inthe form of hot or cold substances for later utilization.

� TES systems deal with the storage of energy by cooling, heating, melting, solidifying orvaporizing a material and the thermal energy becomes available when the process isreversed.

� TES system for a particular application depends on storage duration, economics, supplyand utilization temperature requirements, storage capacity, heat losses and availablespace

� Peak Shaving

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Demand Supply mismatch during peak hours

State Demand Supply Surplus/Deficit Percentage

Chandigarh 367 367 0 0.00

Delhi 6006 5925 81 1.35

Haryana 9152 9152 0 0.00

Himachal Pradesh 1422 1422 0 0.00

Jammu and Kashmir 2554 2043 511 20.01

Punjab 11534 10023 1511 13.10

Rajasthan 10642 10642 0 0.00

Uttar Pradesh 15670 13003 2667 17.02

Uttrakhand 1930 1930 0 0.004

Regional Supply Demand Mismatch-Year 2014

Region

Energy Peak

Requirem

ent

Availabilit

y

Surplus/Def

icit % Demand Met

Surplus/D

eficit %

Northern 332453 311589 20864 6.2757743 51977 47642 4335 8.340227

Western 317637 314923 2714 0.8544345 44166 43145 1021 2.311733

Southern 285797 274316 11481 4.017187 39094 37047 2047 5.236098

Eastern 119082 117155 1927 1.6182127 17040 16932 108 0.633803

North-Eastern 14224 12982 1242 8.731721 2528 2202 326 12.89557

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Thermal Energy storage projects –World Wide

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TES : Thermal Energy Storage

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0

10

20

30

40

50

60

70

0 5 10 15 20 25

Te

mp

era

ture

Heat added Q

Solid -Solid

Solid-liquid

liquid-vapour

Latent Heat

Latent Heat

B

CD

E

O

A

Process flow in a TES

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Charging Storing DischargingExcess

Heat/Cold

Thermal Energy Storage types

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Thermal energy storage

Cryogenic heat

storage

Latent heat storage

Sensible heat

storage

Thermo-chemical

heat storage

Combination of

LHES and SHES

Sensible Heat Storage

� Thermal energy is stored by raising the temperature of a solid orliquid. SHS

system utilizes the heat capacity and the change in temperature of the material

during the process of charging and discharging.

� Amount of heat stored depends on the specific heat of the medium, the

temperature change and the amount of storage material.

� Ti = Initial Temperature

� Tf= Final Temperature

� Q= Heat stored Cp =Specific Heat m= mass of the material

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LHES

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The earliest Latent Heat energy storage system

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Phase change material-Classification

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Phase change materials

Organic

Paraffin compounds

Non-paraffin compounds

Inorganic Salt Hydrates

Metallics

Eutectics

Organic-Organic

Inorganic-Inorganic

Inorganic-organic

Selection Criteria for PCM material

� Melting temperature

� latent and sensible heat capacities

� Thermal stability, mechanical stability

� Cyclic property degradation

� Heat transfer characteristics

� Cost

� Corrosiveness

� Ozone depleting potential

� Fire hazard

� Ease of encapsulation

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Melting Enthalpy and Temperature of PCM materials

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Melting temperatures help in

choosing the correct material

for an application

Organic PCM materials

� Paraffins, fatty acids and sugar alcohols can be used as PCM . These material classes cover the temperature range between 0 ºC and about 200 ºC.

� Due to the covalent bonds in organic materials, most of them are not stable to higher temperatures.

� The most commonly used organic PCM are paraffins. Paraffin is a technical name for an alkane, but often it is specifically used for linear alkanes with the general formula CnH2n+2

� Paraffins show good storage density with respect to mass, and melt and solidify congruently with little or no subcooling.

� Thermal conductivity is comparatively low.

� vapor pressure is usually not significant. Their volume increase upon melting is in the order of 10 vol.%; this is similar to that of many inorganic materials, but less critical as paraffins are softer and therefore build up smaller forces upon expansion.

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Alkanes as PCM materials

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-Pure Alkanes are

expensive

-Produced from

fractional distillation

of petroleum

-A mixture of alkanes

can be used

-This provides better

flexibility in terms of

temperature ranges

A3

A4

Slide 17

A3 Author, 9/2/2015

A4 Tetra Decane is the smallest alkane which has a melting point higher than zeroAuthor, 9/2/2015

Fatty acids as PCM

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A5

Slide 18

A5 Author, 9/2/2015

Inorganic Phase change materials

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Material Melting

Point ©

Density

(kg/m3)

Latent

Heat(kJ/kg)

Heat

stored(kJ/k

g)

Heat

stored(MJ/

m3)

NaNO3 310 2260 172 354 800

KNO3 330 2110 266 388 819

NaOH 318 2100 165 373 783

KOH 380 2044 150 297 607

MgCl2/KCl/

NaCl

380 1800 400 496 893

FeCl2 304 2800 266 336 941

KNO3/4.5%

KCl

320 2100 150 271 569

Salt hydrates as PCM material

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Eutectic Mixtures as PCM

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Technical Data for a RT-25 , Rubitherm GMBH

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Commercially Available Phase change material

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Solar thermal-Single tank schematic

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Source:research.fit.edu/nhc/documents/TES_NAI_Journal_Final.pdf

Solar thermal -Two tank molten salt storage

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Source:research.fit.edu/nhc/documents/TES_NAI_Journal_Final.pdf

Transportation-Cold chain

• PCM materials are used for stabilizing temperatures duringtransportation of goods

• They have replaced water as the temperature stabilization agentin medicine transportation. Due to the fact that PCM’s have highermelting point then water the medicine will not be subjected tolower temperatures then necessary and the risk of crystallizationin the product has been eliminated.

• PCM can revolutionize the frozen goods transportation market.• Replaced Dry ice is the most common used freeze agent in thistype of transportations today. It is

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PCM performance in cold chain application

Generic Name Pros (Cold chain application) Cons(Cold chain application)

n-Alkanes: CH3(CH2)nCH3 High latent heat; inert,

non-toxic, non- corrosive

Limited availability,

limited biodegradability

Fatty Acid Methyl Esters:

CH3(CH2)nCOOCH

Biodegradable, non-toxic, non-

corrosive

Limited availability, strong odor,

solvent for EPS, latent heat

below alkanes

Fatty Alcohols:

CH3(CH2)nCH2OH

Biodegradable, non-toxic Limited availability, odor,

flammable, easily oxidized,

latent heat below alkanes

Fatty Acids: CH3(CH2)nCOOH Biodegradable, good cycling

stability, limited super-cooling

Limited availability, causes

burns, corrosive, latent heat

below alkanes

Salt Hydrates

(inorganic): Salt∙nH2O

Water based systems, packaging

compatible, good latent heat

Very limited availability, poor

cycling stability, may be

corrosive27

Green Buildings

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PCM materials are used for creating temperature

control in Green buildings.

• Commercial projects in Australia and Canada are

showing good performance .

• Encapsulated PCM materials can be mixed with

the building construction material according to the

requirement.

• Lot of research is being done on embedding PCM

material in the glasses used in buildings these days

.

• Both cold and hot climates can benefit from the

use of PCM in building applications .

• Increases the “thermal inertia” of the buildings by

300%.

• Organic PCM materials are being used

commercially.

PCM Encapsulation

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Solid PCM Liquid PCM Solid PCM

Heating Cooling

Shell

thickness

Case studies and application

Project NameTechnology Type

Technology Type Category 1

Technology Type Category 2

Rated Power in kW

Duration at Rated Power HH:MM

Status Web Link

India One Solar Thermal Plant

Heat Thermal Storage

Heat Thermal Storage

Thermal Storage

100016:0.00Under Construction

Renewables Capacity Firming

http://india-one.net

Clique Solar Solar Thermal HVAC System

Chilled Water Thermal Storage

Chilled Water Thermal Storage

Thermal Storage

17548:0.00 OperationalElectric Bill Management with Renewables

http://www.cliquesolar.com/latest.a

spx#

KVK Energy Solar Project

Molten Salt Thermal Storage


Thermal Storage


Renewables Energy Time Shift

http://www.nrel.gov/csp/solarpaces

/project_detail.cfm/projectID=260

Gujarat Solar One



Thermal Storage





Diwikar CSP Plant



Thermal Storage





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Major companies in India

� TESSOL

� CoolElectrica- Promthean Power systems

� Cristopia Energy

� Clique Solar

� Pluss (Research , Development and Manufacturing)

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TESSOL

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TESSOL Launches PLUGnCHILL Freezebox for grocery e-

commerceTESSOL has developed a single and dual temperature freezer

box for chilled and frozen transport of food / pharma products

in the last mile. The box that comes in 100-200 liter capacity

can transport goods in a desired temperature range for 6-8

hours while maintaining the desired temperatures. Some key

features of the system:

1. Compressor less system on board (no power connection or

additional load required)

2. Contains chargeable cartridges that can be added and

removed in a couple of minutes

3. Thermal cartridges charged in an outside chiller and inserted

in the vehicle 30 mins before leaving for a delivery

Freezebox Fits inside the delivery

truck

Promethean Power Systems

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Feature Benefits

Cooling Farm

Produce at the

Source

• First cool and then transport principle enables longer

shelf life and higher margins on premium quality

produce.

• Capture more % of farmers in the catchment area.

• Eliminates post harvest losses

Cold storage back

up

• Eliminates Diesel generator sets.

• Low maintenance and operation costs.

• Unlike electro-chemical batteries , thermal batteries

don’t require replacement every 3-5 years.

Simple Flexible

design

• Single phase connection at farms

• Easy to operate.

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Technical Specifications

Challenges with Phase change materials

� Material Compatibility

� Material Properties and Thermal Performance

� Packaging for Use

� Conditioning for Use

� Cost and Availability

� Health, Safety and Disposal

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Comparison of water based and PCM based packaging

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Thermo Chemical Energy Storage (Brief)

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• Storage by means of chemical

reactions

• Using reversible

endothermic/exothermic

reactions.

• Drawbacks may include

complexity, cyclability,

uncertainties in the

thermodynamic properties of the

reaction components and of the

reaction kinetics under a wide

range of operating conditions,

high cost, toxicity, and

flammability

References

� http://www.coldchaintech.com/assets/Cold-Chain-Technologies-PCM-White-Paper.pdf

� http://www.pluss.co.in/consulting.html

� https://beopt.nrel.gov/sites/beopt.nrel.gov/files/Sharma%20et%20al,%202009%20-

%20Review%20on%20thermal%20energy%20storage%20with%20phase%20change.pdf

� http://www.tessol.in/wp-content/uploads/2013/03/PLUGnCHILL-Brochure.pdf

� http://www.rgees.com/technology.php

� For more comprehensive lists of materials the reader should look at the early publications of Steiner et al. 1980, Abhat 1983, Lane 1983 and 1986,

Schröder 1985, and more recent publications like Kakiuchi et al. 1998, Hiebler and Mehling 2001, Zalba et al. 2003, Sharma et al. 2004, Farid et al.

2004, and Kenisarin andMahkamov 2007.

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Engineering

Thermal energy storage system