Phase Change Material; Electronics, Air Conditioning..

Phase Change Materials (PCM) is a relatively new subject. You can say it is as new as computers but a little less awareness is there about it. Phase change material can be linked to Solar Energy or alternate source of energy. Very little was said about it in 1970s as the concept of renewable energy was not a focus of any community. With the growth of electronics, and the rising prices of fuel the focus on the subject has increased.

Phase Change Materials (PCMs) or Thermal Salts are "latent" energy storage materials. They use chemical bonds to store and release heat. The thermal energy transfer occurs when a material changes from a solid to a liquid, or from a liquid to a solid. This is called a change in state, or "phase." Ice is an excellent Phase Change Material - PCM. Ice changes phase when heated at 0 deg C and is converted to water.

It absorbs a large amount of heat in the process of changing from solid to liquid phase and this results in cooling of the surroundings.

If you are not versed with the subject, you will have to think hard before you give an example of another Phase Change Material. Well, you will say that your breakfast butter is also a Phase Change Material - PCM. This too happens with a lot of heat absorption or release when it changes phase at about 40-45^oC.

Phase Change Materials (PCM) or Thermal Salts are "latent" thermal storage materials. They use chemical bonds to store and release heat. The thermal energy transfer occurs when a material changes from a solid to a liquid or from a liquid to a solid. This is called a change in state or "phase." Initially, these solid-liquid Thermal Salts perform like conventional storage materials; their temperature rises as they absorb solar heat. Unlike conventional heat storage materials, when PCMs reach the temperature at which they change phase (their melting point), they absorb large amounts of heat without getting hotter. When the ambient temperature in the space around the PCM material drops, it solidifies, releasing its stored latent heat. PCMs absorb and emit heat while maintaining a nearly constant temperature. Within the human comfort and electronic-equipment tolerance range of 20°C to 36°C, latent thermal storage materials are very effective. The main applications for Thermal Salts are when space restrictions limit larger thermal storage units in direct gain or sunspace passive solar systems. PCMs may be used in Thermal Enclosures like Telecom Chambers BTS or BT Shelters or solar domestic hot water heating or passive solar space heating/cooling systems.

Glauber's salt, Soda Ash, Sodium acetate, Calcium Chloride and paraffin wax are the most commonly used PCMs or Thermal Salts in solar heating systems. Although these compounds are fairly inexpensive, the packaging and processing necessary to get acceptable performance from them is complicated and costly. They are not offering a reliable pattern of releasing heat as the chemicals in these Thermal Salts separate and stratify when in their liquid state. These PCMs have not always re-solidified properly. When temperatures dropped, they did not completely solidify, reducing their capacity to store latent heat. These problems have been addressed by packaging phase change materials in thin or shallow containers, and by adding thickening and clumping agents. Many salt hydrate PCMs have the disadvantage that during extraction of stored heat the material super-cools before freezing. This reduces the utility of the materials and if too severe, it can completely prevent heat recovery. They lose their heat storage property after some cycles. These types of PCMs, however, compare unfavorably with the newer generation of low-cost, highly efficient PCMs. Researchers now label these older compounds as "limited utility" PCMs. Phase Change Materials perform best in containers that have a depth of one inch (25.4 millimeters). However, our T-Series Latest™ PCMs have defied this restriction. The packaging material should conduct heat well; and it should be durable enough to withstand frequent changes in the storage material's volume as phase changes occur. It should also restrict the passage of water through the walls, so the materials will not dry out. Packaging must also resist leakage and corrosion. Aluminum, steel and polyethylene are common packaging materials.

Phase Change Materials PCMs can be broadly classed as Organic and Inorganic.

Organic PCMs:
Organic Thermal Salt can be Aliphatic or Other Organics. Users rarely specify the use of Organic PCMs. Latest^TM can offer Organic PCMs in low temperature range. Organic items are expensive and they have average Latent Heat per unit volume and low density. Most items in organic range are combustible in nature. They also have a wider range of Melting Point. Some customers specify organic PCM and we offer them as per their requirement. You need specify the desired Melting Point only.

Inorganic PCMs:
Inorganic Thermal Salt are generally Hydrated Salt based materials. Academicians are likely to misguide you into using pure hydrated salts like Sodium Sulphate Decahydrate and so on. Hydrated salts have a number of hydrates and an anhydrous form leading to stratification of material and loss of Latent Heat recovery with time. Hydrated salts also have a sub-cooling tendency. Old generation Thermal Salt manufacturers managed to add performance-enhancing agents. These additives do help in delaying the degradation of the thermal salt for say 100 cycles or thereabout. However, they do not address the basic reasons due to which sub-cooling and degradation happens. Earlier researchers emphasized that it is beneficial to use impure grades of base material as it promotes the nucleation and prevents sub-cooling. However, impurities also promoted nucleation of undesirable hydrates leading to stratification. Experts on crystallography have managed to identify the “Preferred Crystal Nucleation” method. It consists of a “Cold Finger” that nucleates and promotes the growth of desired crystals and “Detoxification” or “Selective Elimination” whereby any impurity that promotes the growth of undesirable crystals is removed. The current methods of Thermal Salt manufacturing are like the new generation “Combination Drugs”.

Selected List of Hydrated Salt/Eutectic Phase Change Materials (PCMs) by Melting Point Temperature.

Melting Point^oC	Grade of PCM	Useful Range	Latent Heat (L.H.) KJ/Kg	L.H. in Useful Range KJ/Kg	Specific Gravity	Remarks
-50^oC	Freezer Salt	-60 to -40^oC	325	395	1.3
-23^oC	Freezer Salt	-30 to -15^oC	330	380	1.2
-16^oC	Freezer Salt	-25 to -05^oC	330	380	1.02
00^oC	Precision	-10 to -00^oC	335	380	1
04^oC	Preservation	00 to 10^oC	105	135	1.4
07^oC	Preservation	02 to 12^oC	135	170	1.4
07^oC	Preservation	02 to12^oC	300	330	1.4	Premium Grade. Know-How Offered.
10^oC	Preservation	05 to 15^oC	170	200	1.4
15^oC	Preservation	10 to 20^oC	175	210	1.4
18^oC	Solar	15 to 21^oC	175	210	1.5	Free Day-Night Cooling & Heating. Cool Furniture, Cool Vests etc.
21^oC	Solar	18 to 24^oC	175	210	1.5
24^oC	Solar	18 to 30^oC	175	210	1.5
27^oC	Solar	22 to 32^oC	175	210	1.5
29^oC	AC-Backup	22 to 36^oC	>175	>210	1.5	To Give Back-up to AC & Comfort Telecom Shelter


32^oC	AC-Backup	22 to 36^oC	210	250	1.4
36^oC	Electronic	30to 50^oC	260	300	1.4	Electronic Comfort Telecom Shelter
40^oC	Electronic	30 to 50^oC	220	260	1.4	Electronic Comfort Telecom Shelter
45^oC	Heating	40 to 55^oC	220	260	1.4	Solar Heater Hot Pads. Heat Sinks
48^oC	Heating	40 to 58^oC	220	260	1.4
58^oC	Heating	40 to 58^oC	220	260	1.4
68^oC	Electronics	40 to 70^oC	220	280	1.8	Electronic Sinks
70^oC	Electronics	40 to 75^oC	230	290	1.8
78^oC	Electronics	40 to 80^oC	240	300	1.8
89^oC		50 to 100^oC	145	185	1.5-1.6
We have Phase Change Materials (PCMs) & Heat-Treatment Salts upto 1100^oC
The Yellow Marked Products are running items and extensively used world wide.

For a detailed write up on Thermal Salt visit our page Phase Change Material PCM Products. It gives general information on all the products like T-series Salts18-29^oC; S-series Salts 32-48^oC. Hot & Cold Packs, Freezer Salts, “Your Choice PCM”, and Encapsulation are also addressed.

For a write up on Thermal Salt for general purpose like Green house Electronics, Electronics visit our page Phase Change Material - General Products like Green House & Electronic cooling. It covers most items with a little more details.

For a write up on Thermal Salt Free Air Conditioning & Heating by Day-Night equalization at a target of 23-24^oC, visit Natural Cooling Phase Change Material - PCM, Aircondition AC

For a write up on Thermal Salt for Air Conditioning Back-up & Free-Cooling by Day-Night equalization in Telecom Shelter along with a Live-Site Trial, Elimination of Diesel Generator visit our page Telecom Shelters PCM

For Encapsulation of PCMs visit our page PCM - Encapsulation

For Testing Methods, Conversion to BTU/^oF/lb etc. and Frequently Asked Questions visit our page FAQ

PCM Energy P. Ltd
Nesbit Road, Mumbai 400 010, INDIA
TEL: 91-22-23770100, 23774610, 23726950, 23723564. FAX: 91-22-23728264.

Muby Chemicals Old Spice: Manufacturing since more than Three Decades:
Ammonium Chloride	Calcium Chloride	Magnesium Chloride	Potassium Cloride - KCl
Sodium Acetate	Sodium Diacetate Manufacturers	Sodium Thiosulfate Manufacturers	Zinc Chloride
Best Selling IP BP USP FCC ACS Grades of Chemicals by Anmol Chemicals
Ammonium Chloride	Benzyl Alcohol	Boric Acid	Borax; Sodium Borate
Calcium Chloride	Calcium Hydroxide	Calcium Oxide	Calcium Sulfate
Chromic Chloride	Gentian Violet	Magnesium Chloride	Magnesium Sulfate
Manganese Chloride	Manganese Sulfate	Methylene Blue	Potassium Chloride
Sodium Acetate	Sodium Bicarbonate	Sodium Hydroxide	Sodium Thiosulfate
Zinc Chloride

Phase Change Material - PCM for Air Conditioning, Electronics ...