FREEZING AND MELTING PROCESS

Each ClimSel product has a unique phase change process and specific thermodynamic properties that make them suitable for customer applications in different temperature ranges. The products’ unique phase change characteristics are illustrated by the graphs on each product sheet. Here we explain the phase change process, using ClimSel C7 as an example.

The red line indicates the so-called melting curve where the ambient heat load is greater than the required temperature. The blue line indicates the so-called freezing curve where the ambient heat load is lower than the required temperature.

 

Climsel-C7

ClimSel C7 is a standard material in transport. For example, ClimSel C7 can be used
to create a microclimate in the temperature range 2-8°C/35-46°F.

r1

For shipments where the ambient temperature in the cargo space is higher than the required temperature, ClimSel C7 is charged at a temperature below 3°C/37°F. The cargo is then placed in a transport box with ClimSel and the transport begins.

r2

ClimSel C7 is now in a frozen (solid) state and the unique ClimSel's unique characteristics become evident. That is, the ambient temperature load (the heat) does not result in the PCM significantly increasing in temperature. Instead, the energy is consumed by the phase change and the melting process begins. Thus, the climate in the transport box is maintained within the pre-determined range and there is no significant increase in temperature.

r3

Only when the PCM has completely melted – and the phase change completed – does the temperature start to rise.

b1

For shipments where the cargo must be protected from the cold, the reverse takes place. ClimSel C7 is charged at a temperature exceeding 9°C/48°F. The freight is then placed in a transport box with ClimSel and the transport begins.

b2

ClimSel C7 is now in a liquid state. The ambient temperature load (the cold) causes the freezing process to begin. Instead, the energy is consumed by the phase change and the melting process begins. Thus, the climate in the transport box is maintained, within the pre-determined range and there is no significant reduction in temperature.

b3

Only when the PCM has completely solidified does the temperature begin to fall.

climsel-4

The phase change graph presented on each product sheet shows both the freezing and melting curves, as well as the typical range for temperature stabilisation. For the ClimSel C7 example, this is 2-8°C/35–46°F.