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Designing a hot water 'element' to melt honey-calculating flow rate and surface area

  1. Jan 30, 2012 #1
    Hi there,
    I am not an engineer but i do have scientific background. It is just a long time since i did any calculations!
    I am trying to design myself a new way of melting barrels of honey. I have 200L, 300kg barrels of crystalized honey that I need to melt. One method I envisage is to make an 'element' type coil of pipe with hot water flowing though it that would melt the honey in the barrel from the inside out.
    How would I calculate the surface area that the element would need to be to melt a barrel of honey in say 24 hours?
    That is from 10C to 50C. with say the water at 60C.
    Ah yes the specific heat capacity of honey is 0.73cal/g/C.

    Could i also work out how much hot water i needed? and how fast i would need to pump it around the coil?
    How do you think this would compare to just sitting the barrels in a big vat of hot water?

    Thanks for your help. It is much appreciated.
     
  2. jcsd
  3. Jan 30, 2012 #2
    Re: Designing a hot water 'element' to melt honey-calculating flow rate and surface a

    As a very rough guide to get you started I would say that the energy required to warm 300kg of honey from 10C to 50C would be 300 x 10^3 x (50-10) x 0.73 = 8.76 million calories
    or 36.8 Mjoules. (I am used to using Joules !!!)(1cal = 4.2J)
    To get this amount of energy from water cooling from 60C to 50C would need
    36.8x10^6/(10C x 4200) = 876kg
    So if you had a flow rate of water of 10kg/min it would take 87.6minutes
    These are very rough and ready figures which I hope make sense.
    I do not know whether honey has a LATENT HEAT (needed to convert solid to liquid)....
    I suspect it does not but...... I don't know
    good luck
     
  4. Feb 3, 2012 #3
    Re: Designing a hot water 'element' to melt honey-calculating flow rate and surface a

    Thanks for that technician. My calculations were only out by 2 decimal places!

    I have another question now... I have an idea for setting up a flow inside the drum. If the solid honey was melted from the outside and the bottom simultaneously would the warm honey flow to the top and push the solid core down to the bottom where it would be melted faster?

    Ta
     
  5. Feb 4, 2012 #4

    Danger

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    Re: Designing a hot water 'element' to melt honey-calculating flow rate and surface a

    This is just my opinion, Lukeluke, but your drum idea seems upside-down to me. I think that it would make more sense to heat it from all directions, or even just the bottom and sides that you suggest, and drain it straight out from the bottom. The cooler stuff will then naturally drop and be liquified in turn. I don't know the chemical properties of honey (unless "tastes great" counts), but I assume that you chose 60° because it will eliminate crystalization without adversely altering any other aspects.
     
  6. Feb 5, 2012 #5

    wolram

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    Re: Designing a hot water 'element' to melt honey-calculating flow rate and surface a

    What you need is an industrial kettle, these are double skinned with water flowing between the skins, the water is heated by elements in the bottom.
    They can be picked cheaply secondhand.

    http://www.specialprojects.com/search/kettle/

    They come in all sizes and shapes, some have stirrers.
     
    Last edited: Feb 5, 2012
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