The WHAT, WHY and HOW of Phase Change Cooling Garments - All in One Place

After compiling a series of articles on Phase Change Cooling as a heat stress solution, I thought it wise to put all of the articles together in one place. I hope that this makes it easier. Enjoy.

What is a PCM … and How Does It Work?

In a recent discussion with a customer, I was asked to provide additional information and training on our KFS PCM product line similar to my 4 part series “How to Know A Quality Evaporative Cooling Fabric From…Well the Other Stuff.” While a different cooling technology, Phase Change Materials (PCM) are a crucial component in any effective personal cooling product line and do deserve their own overview.  So, here comes my best shot at it, and I hope that those PCM experts in my LinkedIn group chime in to help fill in any details that I may have missed.

PCM stands for Phase Change Material, which is a pretty unhelpful term in that it does not tell you what the material is, but it does tell you what the material does, it changes.  Since there are a variety of materials that can act as PCMs, right now we start with what it stands for and what a PCM does.  A Google search will give you the below.

A "phase change material" (PCM) is a substance that can absorb or release a large amount of heat energy during a phase transition, like changing from a solid to a liquid state, while maintaining a relatively constant temperature within a specific range, essentially acting as a thermal energy storage mechanism; it essentially stores heat by changing its physical state, not just by increasing temperature. 

Key points about phase change materials:

• Function: They absorb heat when transitioning from solid to liquid and release heat when transitioning back to solid. 

• Applications: Used in various applications like temperature regulation in buildings, thermal protection in electronics, cooling garments, and energy storage systems. 

• Examples: Common PCMs include paraffin wax, salt hydrates, and fatty acids. 

So, if you are using a PCM in something like a cooling vest, these phase change materials cool the user by absorbing heat away from the body and storing it.  This helps to keep a constant temperature around the body and does not rely on airflow to keep the user cool.  This last point is crucial to remember, “and does not rely on airflow to keep the user cool.”  This characteristic means that a PCM Cooling vest can be used in hazmat suits, heavy PPE and enclosed areas or high humidity areas, where evaporative cooling does not work.  Hence, no personal cooling product line is complete without a PCM cooling vest solution.

There are several different types of materials that can be used as a PCM.  When using PCMs for making our KewlFabric Cooling Vests we utilize organic PCMs based on paraffin oil.  These types of PCMs give you the best options for temperature ranges, cost and availability, but we also offer other types of organic PCMs and inorganic PCMs, if required by the customer.  These options provide our customers with a full range of solutions depending on temperature, duration and weight considerations etc.

What is a PCM … A Deep Dive into PCMs and Variables to Consider When Selecting Your PCM Cooling Solution

As a quick reminder, a PCM is "phase change material" (PCM) that is a substance that can absorb or release a large amount of heat energy during a phase transition, like changing from a solid to a liquid state, while maintaining a relatively constant temperature within a specific range, essentially acting as a thermal energy storage mechanism; it essentially stores heat by changing its physical state, not just by increasing temperature

What makes a PCM a key part of any personal #activecooling product line is that it does not rely on airflow to work, so it is one of a few cost effective solutions for keeping someone cool in enclosed areas or in heavy PPE such as a hazmat suit, or in high humidity areas.

When considering whether or not to use a PCM solution versus an evaporative cooling solution consider these variables.

1. The environment.  If you can expect humidity at greater than 80-85% evaporative cooling will not be effective and it is probably best to go with a PCM solution.

2. If the work area has little to no airflow such as in the belly of an airplane or when wearing a hazmat suit, it is probably best to go with a PCM solution

3. If one of the two above situations is in play and the user can wear a bulkier cooling vest it is probably best to go with a PCM solution.

These three questions are the essential ones to ask yourself whenever you are trying to find the right personal cooling solution, whether working indoors or outdoors, to maximize #performance and productivity.  These questions are the right ones to ask when trying to find a solution for #heatfatigue and #heatstress risks in the workplace.  As a result, they also present  a convincing explanation as to why any complete heat stress line of #workwear products needs a PCM solution as part of the product line.

So now that you know you need a PCM #coolingsolution, how do you decide which PCM is right for you?  Of course, it starts with understanding your target market, in this case, I will focus on the Industrial Safety market.  You need to consider durability, duration, modularity, cost and weight when selecting your PCM solution.

What Is A PCM … How to Pick the Right Phase Change Cooling Material Solution for Your Product Line

Once you (and your customer) recognize that you need a PCM solution as part of your PPE #workwear you need to decide what kind of PCM solution fits your need.  You can start to address this question by considering 5 variables, Duration, Cost, Weight, Durability, Modularity.  Each variable will carry a different value or weight for you, but think through each and its implications on your customer.

1. Duration

What is the minimum amount of time you need your PCM #coolingvest to operate to generate productivity gains and address safety concerns that make the expense worthwhile? How long do you need to be cool?  I specifically ask about minimum cooling duration because cooling duration is tied to cost and weight.  The longer you want the cooling vest to last in one activation, the costlier it can be.  Most PCM solutions will last 2-4hrs and will re-charge in one hour.  These seem to balance duration with weight and cost considerations.  The best selling and best known option below (and our main offering) is in the chart in blue and bold.

Different PCMs offer different durations tied to the amount of PCM needed (weight) and cost.  Our current offering provides the above choices with our Solid-Solid Gel options standing out as a rather unique PCM option.

There is alot to think about, but we are here to help when you are ready.

2. Cost

Cost will always be a consideration for any business.  There has to be an ROI measured in improved safety (heat fatigue and heat stress avoidance), and/or improved productivity and/or improved performance etc.

The various combinations above all come at different price points based on cost to produce, volume considerations and raw materials costs.  Paraffin oil based PCMs are the most commonly used, and are produced in the largest quantities making them a cost effective option that can be delivered in high volumes quickly.  When amount of PCM used is a factor in cooling duration, the lower the cost of the PCM, the longer cooling duration you can get per dollar spent.

What Is A PCM … How to Pick the Right PCM Solution for Your Product Line, Weight, Modularity & Durability

Now lets look at Weight, Durability and Modularity when selecting your PCM solution.

3. Weight

Weight plays a role in how the actual buyer may feel about the #coolingvest or #activecooling solution you are trying to sell them, before even trying it.  PCM vests tend to weigh more than evaporative cooling vests but work where evaporative cooling vests do not. A PCM vest can weigh 4-5lbs (or less) and last 2-3hrs at a fixed temperature.  More often than not, the user, when comparing working say in a furnace room without a PCM vest and being impacted by heat fatigue vs with a PCM vest and avoiding heat fatigue, does not notice the 4-5lbs, but not always.  The weight of a PCM vest is made up by the carrier and the PCM inserts, so you need to play with both to keep the weight down as a selling feature but keep the cooling temperature and duration up as a selling feature.  It is a balancing act to get it right and avoid any sales obstacles.

4. Modularity

Modularity, or design options for materials used and PCM variations from your supplier is a key consideration.  We offer different temperature options, different encapsulation options and different phase change material options.  We even throw in color options, but would prefer that you do not choose yellow as a color option for your PCM.

Modularity does not just end with the above options, it also includes the ability to make PCM inserts into a variety of sizes and shapes that meet the particular needs of your product line.

There are a variety of vest inserts that can be made, a variety of stand-alone PCM vests (no carrier needed), crown coolers for hard hats and bump caps, neckbands, brow pads etc. all can be shaped into PCM inserts.  Don’t restrict your PCM offering by selecting the wrong PCM partner who does not have the skills to create the insert shape you want and the know how to provide the various material options.

5. Durability

Durability … and quality are important considerations when selecting your PCM and PCM supplier.  Durability does relate to and can be impacted by the encapsulation material you choose but any of the three above (Nylon, TPU or Aluminium) work very well.  Durability and quality also relate to the expertise of the maker.  Whether using TPU, Nylon or Aluminium, do they have the expertise to create properly sealed inserts so that there are no leaks?  You cannot afford to have your inserts leak due to poor seals.

These five key variables to consider when selecting your PCM solution will play a key part in the success of your PCM product offering.  We at KewlFabric Solutions can help guide you through the process.

Series summation

Q: Why do you need a PCM solutions as part of your product line?

Ans: When we work or play outside in the heat, we often talk about a dry heat or a humid heat.  Evaporative cooling products that use KewlFabric 7101 (or any evaporative cooling fabric)  work best in a dry heat.  See our series “How to Know A Quality Evaporative Cooling Fabric from … Well the Other Stuff.”  When you have high humidity (80% or higher), or no airflow, such as in a hazmat suit, the most cost effective and effective solution (in my opinion) is a PCM solution for all of the reasons we discussed.  If you have customers that work or play in high humidity areas, or who are wearing equipment that does not allow airflow, the right solution is a PCM solution.

1. What key variables should you consider when selecting your PCM solution

a. Duration, what is the minimum cooling duration you need.

b. Cost, what cost keeps you competitive and what cost allows your customers justify the purchase with the right ROI, whether that be safety or productivity.

c. Weight, what weight is workable for your customers when at work or play

d. Modularity, what supplier can offer you all of the right options to satisfy your customer base.

e. Durability/Quality

2. What are some standard PCM products

a. PCM at 14C

b. PCM vests that last 2-3 hrs and some up to 4hrs

c. PCM vests with a TPU encapsulation method

d. 4 cell and 8 cell PCM inserts for vests

Contact us at www.KewlFabric.com to help you define your PCM need and solution.

The Technology of Kewl!  Beat the Heat!  Get It Done!