Why does the freezing point matter when picking cooler ice packs?












3












$begingroup$


I'm looking at buying some ice packs for my cooler. Looking a specific brand they have several "models", each with a different freezing temperature. Why does this matter?



Let's say I have one pack that freezes at 5 °F (-15 °C) and another that freezes at 34 °F (1 °C). Let's also assume they are the same mass. Let's say I put both of these in my freezer that is at 0 °F (-18 °C) and leave them long enough that they both reach 0 °F (-18 °C). If I then put each of them in identical coolers, won't they have the same cooling capacity? One may cool faster than the other, but on a long enough timeline they'll both cool the cooler to the same temperature (assuming that the cooler is insulated enough that heat into the cooler is slower than heat into the ice pack.










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New contributor




tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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$endgroup$








  • 1




    $begingroup$
    The freezing point is useful, but I'd also want to know the heat capacity and latent heat of fusion.
    $endgroup$
    – PM 2Ring
    11 hours ago












  • $begingroup$
    Isn't 34 °F a typo? That temperature is above the freezing point of water at the common pressures.
    $endgroup$
    – Peter Mortensen
    3 hours ago


















3












$begingroup$


I'm looking at buying some ice packs for my cooler. Looking a specific brand they have several "models", each with a different freezing temperature. Why does this matter?



Let's say I have one pack that freezes at 5 °F (-15 °C) and another that freezes at 34 °F (1 °C). Let's also assume they are the same mass. Let's say I put both of these in my freezer that is at 0 °F (-18 °C) and leave them long enough that they both reach 0 °F (-18 °C). If I then put each of them in identical coolers, won't they have the same cooling capacity? One may cool faster than the other, but on a long enough timeline they'll both cool the cooler to the same temperature (assuming that the cooler is insulated enough that heat into the cooler is slower than heat into the ice pack.










share|cite|improve this question









New contributor




tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$








  • 1




    $begingroup$
    The freezing point is useful, but I'd also want to know the heat capacity and latent heat of fusion.
    $endgroup$
    – PM 2Ring
    11 hours ago












  • $begingroup$
    Isn't 34 °F a typo? That temperature is above the freezing point of water at the common pressures.
    $endgroup$
    – Peter Mortensen
    3 hours ago
















3












3








3





$begingroup$


I'm looking at buying some ice packs for my cooler. Looking a specific brand they have several "models", each with a different freezing temperature. Why does this matter?



Let's say I have one pack that freezes at 5 °F (-15 °C) and another that freezes at 34 °F (1 °C). Let's also assume they are the same mass. Let's say I put both of these in my freezer that is at 0 °F (-18 °C) and leave them long enough that they both reach 0 °F (-18 °C). If I then put each of them in identical coolers, won't they have the same cooling capacity? One may cool faster than the other, but on a long enough timeline they'll both cool the cooler to the same temperature (assuming that the cooler is insulated enough that heat into the cooler is slower than heat into the ice pack.










share|cite|improve this question









New contributor




tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




I'm looking at buying some ice packs for my cooler. Looking a specific brand they have several "models", each with a different freezing temperature. Why does this matter?



Let's say I have one pack that freezes at 5 °F (-15 °C) and another that freezes at 34 °F (1 °C). Let's also assume they are the same mass. Let's say I put both of these in my freezer that is at 0 °F (-18 °C) and leave them long enough that they both reach 0 °F (-18 °C). If I then put each of them in identical coolers, won't they have the same cooling capacity? One may cool faster than the other, but on a long enough timeline they'll both cool the cooler to the same temperature (assuming that the cooler is insulated enough that heat into the cooler is slower than heat into the ice pack.







freezing






share|cite|improve this question









New contributor




tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|cite|improve this question









New contributor




tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|cite|improve this question




share|cite|improve this question








edited 23 mins ago









Peter Mortensen

1,95311323




1,95311323






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Check out our Code of Conduct.









asked 11 hours ago









tir38tir38

1183




1183




New contributor




tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






tir38 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 1




    $begingroup$
    The freezing point is useful, but I'd also want to know the heat capacity and latent heat of fusion.
    $endgroup$
    – PM 2Ring
    11 hours ago












  • $begingroup$
    Isn't 34 °F a typo? That temperature is above the freezing point of water at the common pressures.
    $endgroup$
    – Peter Mortensen
    3 hours ago
















  • 1




    $begingroup$
    The freezing point is useful, but I'd also want to know the heat capacity and latent heat of fusion.
    $endgroup$
    – PM 2Ring
    11 hours ago












  • $begingroup$
    Isn't 34 °F a typo? That temperature is above the freezing point of water at the common pressures.
    $endgroup$
    – Peter Mortensen
    3 hours ago










1




1




$begingroup$
The freezing point is useful, but I'd also want to know the heat capacity and latent heat of fusion.
$endgroup$
– PM 2Ring
11 hours ago






$begingroup$
The freezing point is useful, but I'd also want to know the heat capacity and latent heat of fusion.
$endgroup$
– PM 2Ring
11 hours ago














$begingroup$
Isn't 34 °F a typo? That temperature is above the freezing point of water at the common pressures.
$endgroup$
– Peter Mortensen
3 hours ago






$begingroup$
Isn't 34 °F a typo? That temperature is above the freezing point of water at the common pressures.
$endgroup$
– Peter Mortensen
3 hours ago












2 Answers
2






active

oldest

votes


















8












$begingroup$

The properties of the cooling material are quite important to how it will interact with it's surroundings and exchange heat.



First, I'm going to address a misconception with the cooling capacity that you have brought up. Just because the two ice packs are brought to the same temperature, does not mean they will supply the same net cooling to the system. The thermal properties of the cooling packs is also very important.



For one, different substances will have a different heat capacity per unit mass (i.e. it takes more energy to cool 1 gram of water 1°C than it does to cool 1 gram of glass 1°C, all other factors equal). You also have to account for the latent heat of fusion; which is the amount of thermal energy required to melt the ice at the phase change.



Obviously this still doesn't explain why the melting point is important. That has to do with the latent heat of fusion, along with the desired behaviour of the ice pack. When the ice pack melts, it is taking more energy from the system without increasing temperature. This means that having the ice pack melt while keeping your cooler chilled is actually a relatively good thing, since it's extra heat capacity of the ice pack.



So for your examples of a 5°F melting point vs a 34°F melting point shows a good difference. If you wanted to keep the cooler below 34°F, you would want the ice pack that melts at 5°F, not at 34°F. That's because the ice pack that melts at 34°F is not able to take away the heat of fusion from the system, and only takes away heat due to the heat capacity. The heat of fusion represents a substantial amount of cooling capacity, so the melting temperature of your ice pack should be lower than your maximum acceptable temperature; if you want to get the most use out of the ice pack.



Other factors that might be important when selecting an ice pack are if you can have it frozen, or if you need a malleable gel bag to fit around whatever you are trying to cool. Sometimes efficiency takes a back seat to utility.






share|cite|improve this answer









$endgroup$





















    4












    $begingroup$

    The freezing point is useful because while a substance is melting, its temperature doesn't change: the heat goes into causing the phase change from solid to liquid. The temperature won't rise until the substance has melted. So if you need the temperature in your cooler to stay at or below 5° F, then choose the pack rated at 5° F.



    However, to choose a freezer pack I'd also want to know the heat capacity and latent heat of fusion. That information lets you calculate how much heat in total that the freezer pack can absorb.






    share|cite|improve this answer









    $endgroup$













    • $begingroup$
      Beat you by 4 seconds!
      $endgroup$
      – JMac
      10 hours ago










    • $begingroup$
      @JMac Oh well. :) Adding links is a little painful on the phone...
      $endgroup$
      – PM 2Ring
      10 hours ago










    • $begingroup$
      If I wrote my answer on the phone it would have looked a lot closer to yours. I get... carried away when it's easy to type.
      $endgroup$
      – JMac
      10 hours ago










    • $begingroup$
      Both very good answers!
      $endgroup$
      – tir38
      10 hours ago












    Your Answer





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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    8












    $begingroup$

    The properties of the cooling material are quite important to how it will interact with it's surroundings and exchange heat.



    First, I'm going to address a misconception with the cooling capacity that you have brought up. Just because the two ice packs are brought to the same temperature, does not mean they will supply the same net cooling to the system. The thermal properties of the cooling packs is also very important.



    For one, different substances will have a different heat capacity per unit mass (i.e. it takes more energy to cool 1 gram of water 1°C than it does to cool 1 gram of glass 1°C, all other factors equal). You also have to account for the latent heat of fusion; which is the amount of thermal energy required to melt the ice at the phase change.



    Obviously this still doesn't explain why the melting point is important. That has to do with the latent heat of fusion, along with the desired behaviour of the ice pack. When the ice pack melts, it is taking more energy from the system without increasing temperature. This means that having the ice pack melt while keeping your cooler chilled is actually a relatively good thing, since it's extra heat capacity of the ice pack.



    So for your examples of a 5°F melting point vs a 34°F melting point shows a good difference. If you wanted to keep the cooler below 34°F, you would want the ice pack that melts at 5°F, not at 34°F. That's because the ice pack that melts at 34°F is not able to take away the heat of fusion from the system, and only takes away heat due to the heat capacity. The heat of fusion represents a substantial amount of cooling capacity, so the melting temperature of your ice pack should be lower than your maximum acceptable temperature; if you want to get the most use out of the ice pack.



    Other factors that might be important when selecting an ice pack are if you can have it frozen, or if you need a malleable gel bag to fit around whatever you are trying to cool. Sometimes efficiency takes a back seat to utility.






    share|cite|improve this answer









    $endgroup$


















      8












      $begingroup$

      The properties of the cooling material are quite important to how it will interact with it's surroundings and exchange heat.



      First, I'm going to address a misconception with the cooling capacity that you have brought up. Just because the two ice packs are brought to the same temperature, does not mean they will supply the same net cooling to the system. The thermal properties of the cooling packs is also very important.



      For one, different substances will have a different heat capacity per unit mass (i.e. it takes more energy to cool 1 gram of water 1°C than it does to cool 1 gram of glass 1°C, all other factors equal). You also have to account for the latent heat of fusion; which is the amount of thermal energy required to melt the ice at the phase change.



      Obviously this still doesn't explain why the melting point is important. That has to do with the latent heat of fusion, along with the desired behaviour of the ice pack. When the ice pack melts, it is taking more energy from the system without increasing temperature. This means that having the ice pack melt while keeping your cooler chilled is actually a relatively good thing, since it's extra heat capacity of the ice pack.



      So for your examples of a 5°F melting point vs a 34°F melting point shows a good difference. If you wanted to keep the cooler below 34°F, you would want the ice pack that melts at 5°F, not at 34°F. That's because the ice pack that melts at 34°F is not able to take away the heat of fusion from the system, and only takes away heat due to the heat capacity. The heat of fusion represents a substantial amount of cooling capacity, so the melting temperature of your ice pack should be lower than your maximum acceptable temperature; if you want to get the most use out of the ice pack.



      Other factors that might be important when selecting an ice pack are if you can have it frozen, or if you need a malleable gel bag to fit around whatever you are trying to cool. Sometimes efficiency takes a back seat to utility.






      share|cite|improve this answer









      $endgroup$
















        8












        8








        8





        $begingroup$

        The properties of the cooling material are quite important to how it will interact with it's surroundings and exchange heat.



        First, I'm going to address a misconception with the cooling capacity that you have brought up. Just because the two ice packs are brought to the same temperature, does not mean they will supply the same net cooling to the system. The thermal properties of the cooling packs is also very important.



        For one, different substances will have a different heat capacity per unit mass (i.e. it takes more energy to cool 1 gram of water 1°C than it does to cool 1 gram of glass 1°C, all other factors equal). You also have to account for the latent heat of fusion; which is the amount of thermal energy required to melt the ice at the phase change.



        Obviously this still doesn't explain why the melting point is important. That has to do with the latent heat of fusion, along with the desired behaviour of the ice pack. When the ice pack melts, it is taking more energy from the system without increasing temperature. This means that having the ice pack melt while keeping your cooler chilled is actually a relatively good thing, since it's extra heat capacity of the ice pack.



        So for your examples of a 5°F melting point vs a 34°F melting point shows a good difference. If you wanted to keep the cooler below 34°F, you would want the ice pack that melts at 5°F, not at 34°F. That's because the ice pack that melts at 34°F is not able to take away the heat of fusion from the system, and only takes away heat due to the heat capacity. The heat of fusion represents a substantial amount of cooling capacity, so the melting temperature of your ice pack should be lower than your maximum acceptable temperature; if you want to get the most use out of the ice pack.



        Other factors that might be important when selecting an ice pack are if you can have it frozen, or if you need a malleable gel bag to fit around whatever you are trying to cool. Sometimes efficiency takes a back seat to utility.






        share|cite|improve this answer









        $endgroup$



        The properties of the cooling material are quite important to how it will interact with it's surroundings and exchange heat.



        First, I'm going to address a misconception with the cooling capacity that you have brought up. Just because the two ice packs are brought to the same temperature, does not mean they will supply the same net cooling to the system. The thermal properties of the cooling packs is also very important.



        For one, different substances will have a different heat capacity per unit mass (i.e. it takes more energy to cool 1 gram of water 1°C than it does to cool 1 gram of glass 1°C, all other factors equal). You also have to account for the latent heat of fusion; which is the amount of thermal energy required to melt the ice at the phase change.



        Obviously this still doesn't explain why the melting point is important. That has to do with the latent heat of fusion, along with the desired behaviour of the ice pack. When the ice pack melts, it is taking more energy from the system without increasing temperature. This means that having the ice pack melt while keeping your cooler chilled is actually a relatively good thing, since it's extra heat capacity of the ice pack.



        So for your examples of a 5°F melting point vs a 34°F melting point shows a good difference. If you wanted to keep the cooler below 34°F, you would want the ice pack that melts at 5°F, not at 34°F. That's because the ice pack that melts at 34°F is not able to take away the heat of fusion from the system, and only takes away heat due to the heat capacity. The heat of fusion represents a substantial amount of cooling capacity, so the melting temperature of your ice pack should be lower than your maximum acceptable temperature; if you want to get the most use out of the ice pack.



        Other factors that might be important when selecting an ice pack are if you can have it frozen, or if you need a malleable gel bag to fit around whatever you are trying to cool. Sometimes efficiency takes a back seat to utility.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered 10 hours ago









        JMacJMac

        8,87621833




        8,87621833























            4












            $begingroup$

            The freezing point is useful because while a substance is melting, its temperature doesn't change: the heat goes into causing the phase change from solid to liquid. The temperature won't rise until the substance has melted. So if you need the temperature in your cooler to stay at or below 5° F, then choose the pack rated at 5° F.



            However, to choose a freezer pack I'd also want to know the heat capacity and latent heat of fusion. That information lets you calculate how much heat in total that the freezer pack can absorb.






            share|cite|improve this answer









            $endgroup$













            • $begingroup$
              Beat you by 4 seconds!
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              @JMac Oh well. :) Adding links is a little painful on the phone...
              $endgroup$
              – PM 2Ring
              10 hours ago










            • $begingroup$
              If I wrote my answer on the phone it would have looked a lot closer to yours. I get... carried away when it's easy to type.
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              Both very good answers!
              $endgroup$
              – tir38
              10 hours ago
















            4












            $begingroup$

            The freezing point is useful because while a substance is melting, its temperature doesn't change: the heat goes into causing the phase change from solid to liquid. The temperature won't rise until the substance has melted. So if you need the temperature in your cooler to stay at or below 5° F, then choose the pack rated at 5° F.



            However, to choose a freezer pack I'd also want to know the heat capacity and latent heat of fusion. That information lets you calculate how much heat in total that the freezer pack can absorb.






            share|cite|improve this answer









            $endgroup$













            • $begingroup$
              Beat you by 4 seconds!
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              @JMac Oh well. :) Adding links is a little painful on the phone...
              $endgroup$
              – PM 2Ring
              10 hours ago










            • $begingroup$
              If I wrote my answer on the phone it would have looked a lot closer to yours. I get... carried away when it's easy to type.
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              Both very good answers!
              $endgroup$
              – tir38
              10 hours ago














            4












            4








            4





            $begingroup$

            The freezing point is useful because while a substance is melting, its temperature doesn't change: the heat goes into causing the phase change from solid to liquid. The temperature won't rise until the substance has melted. So if you need the temperature in your cooler to stay at or below 5° F, then choose the pack rated at 5° F.



            However, to choose a freezer pack I'd also want to know the heat capacity and latent heat of fusion. That information lets you calculate how much heat in total that the freezer pack can absorb.






            share|cite|improve this answer









            $endgroup$



            The freezing point is useful because while a substance is melting, its temperature doesn't change: the heat goes into causing the phase change from solid to liquid. The temperature won't rise until the substance has melted. So if you need the temperature in your cooler to stay at or below 5° F, then choose the pack rated at 5° F.



            However, to choose a freezer pack I'd also want to know the heat capacity and latent heat of fusion. That information lets you calculate how much heat in total that the freezer pack can absorb.







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered 10 hours ago









            PM 2RingPM 2Ring

            3,40321023




            3,40321023












            • $begingroup$
              Beat you by 4 seconds!
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              @JMac Oh well. :) Adding links is a little painful on the phone...
              $endgroup$
              – PM 2Ring
              10 hours ago










            • $begingroup$
              If I wrote my answer on the phone it would have looked a lot closer to yours. I get... carried away when it's easy to type.
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              Both very good answers!
              $endgroup$
              – tir38
              10 hours ago


















            • $begingroup$
              Beat you by 4 seconds!
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              @JMac Oh well. :) Adding links is a little painful on the phone...
              $endgroup$
              – PM 2Ring
              10 hours ago










            • $begingroup$
              If I wrote my answer on the phone it would have looked a lot closer to yours. I get... carried away when it's easy to type.
              $endgroup$
              – JMac
              10 hours ago










            • $begingroup$
              Both very good answers!
              $endgroup$
              – tir38
              10 hours ago
















            $begingroup$
            Beat you by 4 seconds!
            $endgroup$
            – JMac
            10 hours ago




            $begingroup$
            Beat you by 4 seconds!
            $endgroup$
            – JMac
            10 hours ago












            $begingroup$
            @JMac Oh well. :) Adding links is a little painful on the phone...
            $endgroup$
            – PM 2Ring
            10 hours ago




            $begingroup$
            @JMac Oh well. :) Adding links is a little painful on the phone...
            $endgroup$
            – PM 2Ring
            10 hours ago












            $begingroup$
            If I wrote my answer on the phone it would have looked a lot closer to yours. I get... carried away when it's easy to type.
            $endgroup$
            – JMac
            10 hours ago




            $begingroup$
            If I wrote my answer on the phone it would have looked a lot closer to yours. I get... carried away when it's easy to type.
            $endgroup$
            – JMac
            10 hours ago












            $begingroup$
            Both very good answers!
            $endgroup$
            – tir38
            10 hours ago




            $begingroup$
            Both very good answers!
            $endgroup$
            – tir38
            10 hours ago










            tir38 is a new contributor. Be nice, and check out our Code of Conduct.










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