Phase Change Materials2.imimg.com/data2/MB/SB/MY-/pcm-brochure.pdf · This is the flexible mode of...

ALLTEC PROTECTION SYSTEMS (P) LTD.F-208/1, Lado SaraiOld M.B. Road, New Delhi - 110030, IndiaTel: +91 11 41665994 - 96Fax: +91 11 41665997Email: [email protected]

Phase Change Materials

®

®

Latent

Liquid

Sensi

ble

Sensible

Temperature T

Thermal Energy

T1

T2

Tmelt

PCM works on the principle of “Latent Heat Utilization” (i.e. itabsorbs heat while melting and releases it while solidifying). Inshort, the following sequences of operations happen everymelting and cooling cycles. Figure 1 presents the PCMbehaviour

PCM provides energy efficient solution for manyindustries including:

Telecommunications and Heat SinksBiopharmaceutical/Food/Poultry/MilkTransportation & Storage

Insulation for Building and Piping ProductsHot and Cold StorageBoilers / waste heat recoverySolar Water Heaters

However, there is no limit as to who can apply PCMtechnology to their operation to improve thermalmanagement, cost, and energy efficiencies, byexploiting off-peak electricity tariffs and thermal energystorage.

�

�

�

�

�

�

�

�

�

�

�

Solid PCM on heating, at melting point changesphase from solid to liquid

Material absorbs a certain amount of heatFusion - nthalpy

The temperature of the material stays constant, whenthe phase change is taking place

In the reverse process from liquid to solid, the storedlatent heat is released at a constant temperature

The whole process can be repeated number of times.

- Heat ofE

�

�

�

�

�

�

�

Can be tailor-made for specific temperature requirementLatent heat utilizationEasy handling and can be encapsulated in a variety of mediumsInexpensive and highly stable over long periods of timeStable performance over repeated phase change cyclesLow / No flammabilityNon toxic and Non combustible

Applications

Benefits of PCM

Solid

�

�

�

�

�

�

�

Heat transfer rate mainly depends upon convection (major source of heat removal) and some by radiation. Q

= h x A x T is the formula where ‘h’ is the Convective coefficient and depends upon the mass flow rate of fluid,

(i.e. air in the telecom shelter). ‘A’ is the area exposed for air to come in contact with the PCM profiles. ‘

�

�T’ is thetemperature difference which is of the user’s interest.

Since placement of profiles in a shelter is constrained by the placement of the BTS (Base TransreceiverStation) unit, batteries, power interface units and other telecom switching equipment, the profiles containingPCM are placed only in the free area available. Hence, not all the surface area is available for heat transfer.

Generally,

Locations

�

�

�

�

for good fluid flow in a shelter, 2-3 fans with the specifications of approx. 50W, 24V/48V DC, and3000 RPM are recommended. Lower RPM fans will reduce the air circulation and may hamper necessary heattransfer.

of the fans depend entirely on the position of the PCM profiles and other Electronic equipment.

For four hour back-up 3kW x 4 hrs (12kWh) an exposed (in direct contact with air) area with a minimum of 27 mof surface is required. The number of savE HS 29 profiles of 4 kgs (0.4 Sqm) mm is usually 70 profiles for thisexposed area (translating it to 280 kgs of HS 29). While using the 2.8kgs profiles (0.3 Sqm), the requirement ofboth area and salt quantity is met by using only 86 profiles (translating it to 240kgs only).

In general, the position & number of profiles and fans will vary from shelter to shelter. It is strongly advised thatindividual testing and experimentation be done by the Telecom Shelter manufacturer/installer to determine theoptimum:

number of profiles requiredplacement of profileslocation of fansRPM of fans for effective heat distribution/direction towards profiles

The PCM panels are mounted on-site approximately 30° from vertical. Three to four such racks can be put onone frame, having the facility of mounting 35-60 PCM panels. The upper three sections in each rack arenormally left empty for effective air circulation provided by a DC fan (24V/48V) placed on top of the frame. Twodifferent pattern of racks are available.

2

�

�

Theoretically, for one hour backup for 1kWh, 20 kg of savE HS29 is required, based on the latent heatof HS 29. This translates to 240 kgs of HS 29 for four hour backup with 3kWh heat source.

It may be noted that it is not only the quantity of salt essential for desired backup but also a minimum ofexposed surface for heat absorption. This may at times necessiate additional profiles.

Advantages of the design

Important points to be remembered

�

�

�

�

�

�

�

�

�

High exposed area of the profile surfaceProfiles occupy less spaceRack may be placed anywhere, preferably nearthe electronic (BTS) instrumentsFans mounted on the top ensure that the hot air flow from thesurroundings is directed to the PCM profile. Heat exchange occurs, andthe cold air is released towards the electronic equipment / BTS,maintaining low temperature inside the shelter.

PCM inside the profiles should be in 100% frozen condition before useGood airflow is required around the profiles for optimum thermal heattransferSufficient surface area of profiles should be available for heat transferCalculations of ambient heat transferred into the shelter at differenttimes of the year should be considered while evaluating the requirementof PCMTrials must be executed to confirm quantity of PCMCalcium Chloride

© 2007 Alltec Protection Systems (P) Ltd. 09/2007

PCM Working Principles

Phase Change Materials (PCM) are organic or inorganic compounds having a large amount of heatenergy stored in the form of Latent Heat, which is absorbed or released when the material changesphase from solid to liquid or liquid to solid. The PCM retains its latent heat without any change inphysical or chemical properties over thousands of cycles.

Various specific temperature PCMs are available varying between -30°C to + 90 These can be classifiedinto two categories:- Organic and Inorganic PCMs. The Organic PCM generally consists of various paraffins,waxes, and alcohols, while Inorganic PCMs are primarily hydrated salts.

°C .


Why?

Installation of PCM ( HS 29) for Shelter ApplicationssavE™

Encapsulation

HDPE profiles/panels

HDPE / PP Spherical Balls:

Multilayer Pouches & Pads:

Various PCM encapsulation techniques have been developed for different PCMs for use in numerousapplications.

have been exclusively designed in different dimensions and capacity for telecomapplications. These rigid profiles have cavities filled with PCM. The panels shall be installed in a horizontal planewith angular mounting to provide a high value energy saving supplement to proprietary thermal managementsystems.

By encapsulating PCM into small spherical rigid balls, the properties and benefits ofPCM can be gainfully utilized for applications like boilers, solar water heaters, room heaters etc.

This is the flexible mode of PCM packaging. The material used for these pouchesare multilayer films (PET/Aluminum/PET) used to impart good strength, durability and integrity. These PCMpouches may be utilized in material transportation containers for temperature sensitive goods, apparel and hotpads. This packing can also be utilized within central air conditioning ducts and false roofing of commercialcomplexes.

Given good thermal contact, the PCM begins to solidify at a specified temperature when the material is slowlycoooled. Correspondingly, it begins to melt at the specified melting temperature. In practice, a thin container ofgood thermal conductivity is not always possible. In such cases the following factors come into play:

Thickness of containerThermal conductivity of containerMovement of medium (air, water, oil, etc.) around the containerRate of heat transfer between inside / outsideTemperature differential between PCM and the environmentAmount of heat being generated in the environment.

Installation of PCM should take into account good air circulation to allow air above the surface of the PCMcontainer to be removed efficiently and sufficient air conditioning/free cooling to ensure recharging of PCMafter it has changed its phase to liquid state.

�

�

�

�

�

�

The following steps should be taken to ensure reliable, good quality back-up, particularly for installation inTelecom Shelters:

Heat transfer rate mainly depends upon convection (major source of heat removal) and some by radiation.

Q = h x A x T is the formula where ‘h’ is the Convective coefficient and depends upon the mass flow rate offluid, (i.e. air in the telecom shelter). ‘A’ is the area exposed for air to come in contact with the PCM profiles.

‘

�

�

�T’ is the temperature difference which is of the user’s interest.

When used in conjunction with conventional HVAC systems, PCM provides cost saving flexibility due to effectivethermal management through programmed temperature maintenance. ALLTEC has the capability to design andimplement systems for your cooling needs based on the heat loads inside any enclosure.

For cold storage applicationALLTEC has specially designed two materials - andHS23N HS7N

savE - Property Chartnergy HS 23N & HS 7N

Pharmaceutical transportation of vaccines, serums, blood tissues and cells etc.Cold storage backup against power failure and for refrigerated vehicles

Ice creams, MilkFrozen Foods, Beverages,Flowers and HorticulturePoultry, Meat & SeafoodFruits and Vegetables

Backup in Domestic & Commercial Refrigerators

Transport:

Ice Boxes:

�

�

�

�

�

�

�

�

�

�

�

�

No power complications during transportReplace Diesel GeneratorsEasy handlingCharge overnight and use during dayPrevent Food from spoiling during transportSaves waterReusable and durable

Dimension of profiles/pouches/balls & Capacity

DimensionsEmpty

Weight**PCM

Capacity

Profiles1000mmx160mmx16mm 480 gms

520 gms2.80 Kg4.00 kg

PP Spheres75mm O.D*, 1.2mm W.T**

35 gms 0.175 Kg

Pouches145mmx260mm

15 gms 0.400 Kg

* Outer Diameter,** Wall Thickness, ** Approximately

850mmx200mmx20mm

Properties HS 24 HS 29 HS 34 HS 58 HS 89

Appearance (color)Grey/Brown

liquid/crystalsGrey/Brown


liquid/crystalsWhite

crystals/powderWhite

crystals/powder

DescriptionProprietarymixture of

inorganic salts

Proprietarymixture of

inorganic salts


inorganic salts

Proprietarymixture of organic& inorganic salts


inorganic salts

Phase Change Temp. (°C) 23-25 28-30 32-34 57-59 88-91

Operating Temp. Range (°C) 21-27 26-32 29-39 55-61 86-92

Density (Kg/m3) (ASTM D891-95) 1480 1550 1500 1320 1550

Latent Heat (kJ/kg) (Calorimetry) 155 205 145 251 160

Congruent Melting Yes Yes Yes Yes Yes

Sub Cooling No No No No No

Flammability No No No No No

Stability (cycles) > 1000 3000 > 1100 > 1000 > 1000

Max. Operating Temp. °C ~ 60 ~ 60 ~ 80 ~ 90 ~105

Guidelines for Use of Phase Change Material (PCM)

Where ?


HDPE Profiles

PouchesPP Spheres

In India, PCM application picked up with a vast usage in the Telecom Sector. In the mobile telecom industry PCM

is used by encapsulating it in its uniquely designed High Density Polyethlene (HDPE) profiles. The telecom

switch, battery and the SMPS being the main source of heat in the telecom cabin, ACs are used to maintain the

desired temperatures around 23 - 24°C, allowing it to rise up to 34°C maximum. In the absence of power to AC

the temperature rises sharply and an alternate source of power backup to run the AC becomes mandatory. Upon

power failure, PCM panels lined along the wall provide backup to the temperature inside (with forced air

circulation). On changing phase, the latent heat is released or absorbed, allowing the ambient temperature within

the system to be maintained. This minimizes the use of diesel generators during power outages, saving on

maintenance and operation costs of the generator. A high rate of savings can also be achieved with the use of

complementary systems like heat exchanger/fan.

Time (B-A= T)�

Tem

pera

ture

(C

)0

With PCMWithout PCM

A BFigure 2

Figure 2 shows the effects of using PCM inside a telecom enclosure. It defines the durationwhen the air-conditioning is “switched off”. The rise in temperature is rapid without PCM. WithPCM installed, the rise in temperature is delayed, as much of the equipment heat energy getsabsorbed. Thus, the temperature inside the enclosure remains constant (rT) for a longerduration without the assistance of any conventional cooling system.

The heat energy absorbed can later be discharged by using active/passive cooling systemsduring off-peak hours, making the PCM available for another cycle.

savE™ HS 29 is a Calcium Chloride based PCM having a Phase

Change temperature of 28°C- 30°C, with the right mix of various salts,

additives and nucleating agents allowing equilibrium between solid and

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

continues to absorb heat from the environment without further increase

in temperature, maintaining the temperature in the instrument shelter

during power failures or programmed shut downs. 20 Kgs of HS

29 is used for countering 1 kWh of heat energy. Use of ACs or other

means of re-freezing the salts may be necessary for the next cycle of

operation.

savE™

Boilers and Power Plants:

,

These are systems typically operating at high

temperature.The energy below 100°C is normally wasted. If stored this energy

can be gainfully utilized for pre-heating the media essential for boiler and power

plants, heating swimming pool water, and domestic water. This saves energy for

future use in the same, or other purposes. HS 89 is the ideally suited

product for such energy storage. Encapsulated in the form of HDPE/PP spherical

balls and placed in a tank supported with heat pump, the PCM absorbs the low

temperature energy for other beneficial uses.

savE™

Cold Storage : PCM HS 23N & HS 7N is used to keep

Frozen Food, Beverages, Packed Foods, Ice Creams, Flowers, and

Food & Vegetables cold particularly as a backup for refrigerator and

cold storage power failure.

These PCM profiles can be put into a refrigerated vehicle to prevent

food from spoiling during transportation or extended storage without

power.

savE™

,

Solar Water Heaters

Hot Pads

work during the daytime raising the water

temperature with support of solar energy. Even in the insulated tanks

this temperature is not retained for long. PCM HS 89 or

HS 58 when used either as a supporting jacket lining around

the tank or in form of spherical balls placed in the tank can retain this

heat energy for a much longer duration, ensuring hot water

availability even after sunset

PCM supported creating a dry

warm compress for use by sportsmen or in

cases of injuries or discomfort, are available

with specific designs and sizes for use at

ankles, elbows and as general pads.

savE™

savE™ ,

,

.

Transportation of Biopharmaceutical/Food/Poultry/Milk

Products

Apparel and Fabrics

is done in controlled low temperature containers to prevent

damage or decay of the product. Since the transportation is a time

sensitive activity, the controlled temperature can easily be achieved

by low temperature PCMs (-4°C to +7°C) in appropriate quantity

instead of diesel operatedAC vans.

: PCM HS 24

micro encapsulated and coated to the fabrics or

used in soft pouch jackets can provide relief to

persons working in extreme weather conditions

such as snow mountain peaks or deserts. The

appropriate quantity related to the comfort

duration can be provided for gainful use by

soldiers, sportsmen, or field laborers. It can

savE™

y

Other Applications


Why?

Installation of PCM ( HS 29) for Shelter ApplicationssavE™

Encapsulation

HDPE profiles/panels

HDPE / PP Spherical Balls:

Multilayer Pouches & Pads:

Various PCM encapsulation techniques have been developed for different PCMs for use in numerousapplications.

have been exclusively designed in different dimensions and capacity for telecomapplications. These rigid profiles have cavities filled with PCM. The panels shall be installed in a horizontal planewith angular mounting to provide a high value energy saving supplement to proprietary thermal managementsystems.

By encapsulating PCM into small spherical rigid balls, the properties and benefits ofPCM can be gainfully utilized for applications like boilers, solar water heaters, room heaters etc.

This is the flexible mode of PCM packaging. The material used for these pouchesare multilayer films (PET/Aluminum/PET) used to impart good strength, durability and integrity. These PCMpouches may be utilized in material transportation containers for temperature sensitive goods, apparel and hotpads. This packing can also be utilized within central air conditioning ducts and false roofing of commercialcomplexes.

Given good thermal contact, the PCM begins to solidify at a specified temperature when the material is slowlycoooled. Correspondingly, it begins to melt at the specified melting temperature. In practice, a thin container ofgood thermal conductivity is not always possible. In such cases the following factors come into play:

Thickness of containerThermal conductivity of containerMovement of medium (air, water, oil, etc.) around the containerRate of heat transfer between inside / outsideTemperature differential between PCM and the environmentAmount of heat being generated in the environment.

Installation of PCM should take into account good air circulation to allow air above the surface of the PCMcontainer to be removed efficiently and sufficient air conditioning/free cooling to ensure recharging of PCMafter it has changed its phase to liquid state.

�

�

�

�

�

�

The following steps should be taken to ensure reliable, good quality back-up, particularly for installation inTelecom Shelters:

Heat transfer rate mainly depends upon convection (major source of heat removal) and some by radiation.

Q = h x A x T is the formula where ‘h’ is the Convective coefficient and depends upon the mass flow rate offluid, (i.e. air in the telecom shelter). ‘A’ is the area exposed for air to come in contact with the PCM profiles.

‘

�

�

�T’ is the temperature difference which is of the user’s interest.

When used in conjunction with conventional HVAC systems, PCM provides cost saving flexibility due to effectivethermal management through programmed temperature maintenance. ALLTEC has the capability to design andimplement systems for your cooling needs based on the heat loads inside any enclosure.

For cold storage applicationALLTEC has specially designed two materials - andHS23N HS7N

savE - Property Chartnergy HS 23N & HS 7N

Pharmaceutical transportation of vaccines, serums, blood tissues and cells etc.Cold storage backup against power failure and for refrigerated vehicles

Ice creams, MilkFrozen Foods, Beverages,Flowers and HorticulturePoultry, Meat & SeafoodFruits and Vegetables

Backup in Domestic & Commercial Refrigerators

Transport:

Ice Boxes:

�

�

�

�

�

�

�

�

�

�

�

�

No power complications during transportReplace Diesel GeneratorsEasy handlingCharge overnight and use during dayPrevent Food from spoiling during transportSaves waterReusable and durable

Dimension of profiles/pouches/balls & Capacity

DimensionsEmpty

Weight**PCM

Capacity

Profiles1000mmx160mmx16mm 480 gms

520 gms2.80 Kg4.00 kg

PP Spheres75mm O.D*, 1.2mm W.T**

35 gms 0.175 Kg

Pouches145mmx260mm

15 gms 0.400 Kg

* Outer Diameter,** Wall Thickness, ** Approximately

850mmx200mmx20mm

Properties HS 24 HS 29 HS 34 HS 58 HS 89

Appearance (color)Grey/Brown



liquid/crystalsWhite

crystals/powderWhite

crystals/powder

DescriptionProprietarymixture of

inorganic salts


inorganic salts


inorganic salts

Proprietarymixture of organic& inorganic salts


inorganic salts

Phase Change Temp. (°C) 23-25 28-30 32-34 57-59 88-91

Operating Temp. Range (°C) 21-27 26-32 29-39 55-61 86-92

Density (Kg/m3) (ASTM D891-95) 1480 1550 1500 1320 1550

Latent Heat (kJ/kg) (Calorimetry) 155 205 145 251 160

Congruent Melting Yes Yes Yes Yes Yes

Sub Cooling No No No No No

Flammability No No No No No

Stability (cycles) > 1000 3000 > 1100 > 1000 > 1000

Max. Operating Temp. °C ~ 60 ~ 60 ~ 80 ~ 90 ~105

Guidelines for Use of Phase Change Material (PCM)

Where ?


HDPE Profiles

PouchesPP Spheres

Latent

Liquid

Sensi

ble

Sensible

Temperature T

Thermal Energy

T1

T2

Tmelt

PCM works on the principle of “Latent Heat Utilization” (i.e. itabsorbs heat while melting and releases it while solidifying). Inshort, the following sequences of operations happen everymelting and cooling cycles. Figure 1 presents the PCMbehaviour

PCM provides energy efficient solution for manyindustries including:

Telecommunications and Heat SinksBiopharmaceutical/Food/Poultry/MilkTransportation & Storage

Insulation for Building and Piping ProductsHot and Cold StorageBoilers / waste heat recoverySolar Water Heaters

However, there is no limit as to who can apply PCMtechnology to their operation to improve thermalmanagement, cost, and energy efficiencies, byexploiting off-peak electricity tariffs and thermal energystorage.

�

�

�

�

�

�

�

�

�

�

�

Solid PCM on heating, at melting point changesphase from solid to liquid

Material absorbs a certain amount of heatFusion - nthalpy

The temperature of the material stays constant, whenthe phase change is taking place

In the reverse process from liquid to solid, the storedlatent heat is released at a constant temperature

The whole process can be repeated number of times.

- Heat ofE

�

�

�

�

�

�

�

Can be tailor-made for specific temperature requirementLatent heat utilizationEasy handling and can be encapsulated in a variety of mediumsInexpensive and highly stable over long periods of timeStable performance over repeated phase change cyclesLow / No flammabilityNon toxic and Non combustible

Applications

Benefits of PCM

Solid

�

�

�

�

�

�

�

Heat transfer rate mainly depends upon convection (major source of heat removal) and some by radiation. Q

= h x A x T is the formula where ‘h’ is the Convective coefficient and depends upon the mass flow rate of fluid,

(i.e. air in the telecom shelter). ‘A’ is the area exposed for air to come in contact with the PCM profiles. ‘

�

�T’ is thetemperature difference which is of the user’s interest.

Since placement of profiles in a shelter is constrained by the placement of the BTS (Base TransreceiverStation) unit, batteries, power interface units and other telecom switching equipment, the profiles containingPCM are placed only in the free area available. Hence, not all the surface area is available for heat transfer.

Generally,

Locations

�

�

�

�

for good fluid flow in a shelter, 2-3 fans with the specifications of approx. 50W, 24V/48V DC, and3000 RPM are recommended. Lower RPM fans will reduce the air circulation and may hamper necessary heattransfer.

of the fans depend entirely on the position of the PCM profiles and other Electronic equipment.

For four hour back-up 3kW x 4 hrs (12kWh) an exposed (in direct contact with air) area with a minimum of 27 mof surface is required. The number of savE HS 29 profiles of 4 kgs (0.4 Sqm) mm is usually 70 profiles for thisexposed area (translating it to 280 kgs of HS 29). While using the 2.8kgs profiles (0.3 Sqm), the requirement ofboth area and salt quantity is met by using only 86 profiles (translating it to 240kgs only).

In general, the position & number of profiles and fans will vary from shelter to shelter. It is strongly advised thatindividual testing and experimentation be done by the Telecom Shelter manufacturer/installer to determine theoptimum:

number of profiles requiredplacement of profileslocation of fansRPM of fans for effective heat distribution/direction towards profiles

The PCM panels are mounted on-site approximately 30° from vertical. Three to four such racks can be put onone frame, having the facility of mounting 35-60 PCM panels. The upper three sections in each rack arenormally left empty for effective air circulation provided by a DC fan (24V/48V) placed on top of the frame. Twodifferent pattern of racks are available.

2

�

�

Theoretically, for one hour backup for 1kWh, 20 kg of savE HS29 is required, based on the latent heatof HS 29. This translates to 240 kgs of HS 29 for four hour backup with 3kWh heat source.

It may be noted that it is not only the quantity of salt essential for desired backup but also a minimum ofexposed surface for heat absorption. This may at times necessiate additional profiles.

Advantages of the design

Important points to be remembered

�

�

�

�

�

�

�

�

�

High exposed area of the profile surfaceProfiles occupy less spaceRack may be placed anywhere, preferably nearthe electronic (BTS) instrumentsFans mounted on the top ensure that the hot air flow from thesurroundings is directed to the PCM profile. Heat exchange occurs, andthe cold air is released towards the electronic equipment / BTS,maintaining low temperature inside the shelter.

PCM inside the profiles should be in 100% frozen condition before useGood airflow is required around the profiles for optimum thermal heattransferSufficient surface area of profiles should be available for heat transferCalculations of ambient heat transferred into the shelter at differenttimes of the year should be considered while evaluating the requirementof PCMTrials must be executed to confirm quantity of PCMCalcium Chloride

© 2007 Alltec Protection Systems (P) Ltd. 09/2007

PCM Working Principles

Phase Change Materials (PCM) are organic or inorganic compounds having a large amount of heatenergy stored in the form of Latent Heat, which is absorbed or released when the material changesphase from solid to liquid or liquid to solid. The PCM retains its latent heat without any change inphysical or chemical properties over thousands of cycles.

Various specific temperature PCMs are available varying between -30°C to + 90 These can be classifiedinto two categories:- Organic and Inorganic PCMs. The Organic PCM generally consists of various paraffins,waxes, and alcohols, while Inorganic PCMs are primarily hydrated salts.

°C .


ALLTEC PROTECTION SYSTEMS (P) LTD.F-208/1, Lado SaraiOld M.B. Road, New Delhi - 110030, IndiaTel: +91 11 41665994 - 96Fax: +91 11 41665997Email: [email protected]


®

®

Phase Change Materials2.imimg.com/data2/MB/SB/MY-/pcm-brochure.pdf · This is the flexible mode of...

Documents

Transcript of Phase Change Materials2.imimg.com/data2/MB/SB/MY-/pcm-brochure.pdf · This is the flexible mode of...