Delta T (ΔT)

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Delta (Δ) is the fourth let­ter of the Greek al­pha­bet and is used as a math­e­mat­i­cal sym­bol. Here, the delta Δ de­scribes the dif­fer­ence of any vari­able quantity.

Ex­am­ples of vari­ables are:

  • Tem­per­a­ture
  • Amount of substance
  • Light in­ten­si­ty

T is the for­mu­la sym­bol for the phys­i­cal tem­per­a­ture. With the des­ig­na­tion of the tem­per­a­ture we de­scribe the ther­mal con­di­tion of an ob­ject or a sys­tem. With it we ex­press whether some­thing is “cold” or “hot”. It is ex­pressed in de­grees Cel­sius (°C), de­grees Kelvin (°K) or de­grees Fahren­heit (°F). When these two pieces of in­for­ma­tion are com­bined, it is un­der­stood that Delta T (ΔT) stands for tem­per­a­ture difference.

Use of delta T (∆T)

In a ther­mal process, delta T (or ΔT) is the val­ue that in­di­cates the dif­fer­ence be­tween two mea­sured tem­per­a­tures. These val­ues can be mea­sured at dif­fer­ent lo­ca­tions or at dif­fer­ent mo­ments in a sys­tem. Three sit­u­a­tions can be recorded:

  • The tem­per­a­ture has not changed, it has re­mained the same
  • The first val­ue is small­er than the sec­ond val­ue — tem­per­a­ture increase 
  • The first val­ue is greater than the sec­ond val­ue — tem­per­a­ture loss

Calculation of delta T (∆T)

∆T = T2 – T1

Practical examples of delta T (∆T)

Tem­per­a­ture dif­fer­ences can be de­ter­mined in many ap­pli­ca­tions. A typ­i­cal ex­am­ple is the tem­per­a­ture pro­file in a cool­ing tow­er where the wa­ter is test­ed on the sup­ply and return. 

Unintended differences in temperature

Delta T (∆T) is an im­por­tant mea­sure­ment for mon­i­tor­ing tem­per­a­ture de­vi­a­tions and loss­es. Un­in­ten­tion­al changes in tem­per­a­ture quick­ly have a neg­a­tive im­pact on the func­tions in the sys­tem and should be iden­ti­fied and elim­i­nat­ed as soon as pos­si­ble. For quick ver­i­fi­ca­tion of tem­per­a­ture dif­fer­ences, da­ta log­gers can be used to record changes in the cir­cuit and pro­vide con­clu­sions about the problem.

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