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In order to propagate the correct volume flow rates from the secondary side to the primary side, one should correctly choose the primary temperature regime. The software will calculate the secondary capacity, temperature regime, and flow using the design system components. Afterward, using this information and the filled-in supply and return temperature, the UA value can be calculated. If the UA-value is known, only the supply temperature should be filled in, as the return temperature will be calculated using this information.
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For the supply temperature, you can choose between
absolute temperature
relative temperature → this is an offset to the secondary supply emperature
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Common errors
Error message | Solution |
|---|---|
Override supply temperature and secondary supply temperature are too close together | The supply temperature before and after the heat exchanger can only become equal for an infinitely large HX. Make sure the primary supply temperature is higher than the secondary supply temperature. |
Override return temperature and secondary return temperature are too close together | The return temperature before and after the heat exchanger can only become equal for an infinitely large HX. Make sure the primary return temperature is higher than the secondary return temperature. |
Expected the override supply temperature to be higher than the secondary supply temperature | In order to transfer heat in the right direction. the primary supply temperature should always be higher than the secondary supply temperature. |
Expected the override return temperature to be higher than the secondary return temperature | In order to transfer heat in the right direction. the primary return temperature should always be higher than the secondary return temperature. |
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Heat exchanger flow type | ||||||
|---|---|---|---|---|---|---|
Counter flow |
|  Most commonly used type | ||||
Parallel flow |  |  Not often used due to low heat exchanger effectiveness | ||||
Cross flow |  | Often used for compactness. Heat exchanger effectiveness is somewhere in between counter and parallel flow. Not easy to visualize with a graph because the heat exchange is 2 dimensional in nature. |
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