Method for determining Heat Removal Requirements
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| Step1: |
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Collect information and data about a product to be cooled
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Specific heat (J/kg・ ) |
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Weight (kg) |
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Temperature difference ( t)
( actual temperature minus desired temperature ) |
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Cooling time (sec) |
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| Step2: |
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Determine the amount of heat ( per second )to be removed to cool the product
(Heat Removal Requirements ) by applying the following formula to the above
information.
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| Heat Removal Requirements (W) = |
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Weight (kg)x Specific heat (J/kg・)x Temperature difference (t) |
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| Cooling time (sec) |
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| Step3: |
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Safety ratio and selection of the adequate UCAG model
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| 1) |
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Determine heat removal requirements including various losses (Heat Removal
Requirements Including Losses ) based on Heat Removal Requirements obtained
in the above Step 2.
In selection of the adequate UCAG model, take into consideration losses
( efficiency 60-80%) derived from shape of the product, distance between
the cold end of the UCAG and the product, etc. In case of cooling the product
down below the ambient temperature, take into consideration heat which
the product absorbs from ambient surrounding.
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| * |
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All the heat (cold air) from the UCAG cannot be absorbed by the product.
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Heat Removal Requirements Including Losses = (Heat Removal Requirements
of Step 2) / (efficiency (0.6∼0.8))
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| 2) |
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Confirm the available compressed- air pressure and select the adequate
model of the UCAG.
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The available compressed- air pressure at the inlet of the UCAG should
be confirmed.
( not the compressed- air pressure at the outlet of compressor )
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Confirm the air consumption of each model of the UCAG under the each available
compressed- air pressure.
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Example of determining Heat Removal Requirements
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| Step1: |
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Taking an iron product as an example,
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Specific heat of the product = 460 J/kg・ |
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Weight = 1kg |
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Temperature difference (t) = Temperature of the product 50 - Desired temperature 30 = 20 |
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Cooling time = 40sec |
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| Step2: |
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| Heat Removal Requirements (W) = |
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1Kg x 460(J/kg・) x 20 |
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| 40(sec) |
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230(W) |
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| Step3: |
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| 1) |
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Determine Heat Removal Requirements Including Losses based on the above
Heat Removal Requirements of Step2, supposing efficiency is 0.7.
Heat Removal Requirements Including Losses =230 (W) / 0.7 = 329 ( W )
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| 2) |
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Select the adequate UCAG model confirming available compressed-air pressure.
For example, with available compressed -air pressure at 0.7Mpa, the UCAG
model 190-75SV has a cooling capacity of 343(W).
And, at this time, air consumption is approximately 650 l/m.
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Above Heat Removal Requirements is just a calculated figure. Actually,
as various factors including radiation heat have an intricate affect, above
calculated figure should be considered only as an index. And there are
losses which vary depending on a number of factors, such as distance between
the UCAG and the product, size and shape of the product, etc.
Sanwa’s staffs are, based on vast experiences and actual results, always
ready to give you advices that help you determine adequate model under
your specific conditions.
If you have any question or request, fill up the REQUEST FORM and send to us.
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