The Heat Rejector

What does the condenser do?

The condenser’s function in a refrigeration system is to transfer heat from the refrigerant to another medium, air or water. The gaseous refrigerant condenses to a liquid inside the condenser by rejecting heat.


Background of droplets on window during rain


How does the condenser reject heat? 

Let us imagine; It’s 3 pm on a British heatwave afternoon’… imagine.

After a day of arm curling the office phone, you are covered in sweat. You pull up your t-shirt by your collar and blow some air; that feels relieving. 


But wait, why do you feel that the air is cooler than your body temperature? Especially considering the air is coming from the hottest part of your body… 


Alright, sweat might have done the trick to some extent – yes.


Now keep your wrist in front of your mouth. Gently blow some air as if you are cooling down that first sip of tea. Now in step 2, again on your wrist, open your mouth and exhale air from your mouth as if you’ve just burned it from impatiently refusing to let your tea cool enough. 


*Ah Chah Chah.* 

Photography of Blue Ceramic Coffee Cup


Feel the difference?

In the first case, you are blowing pressurised air from your mouth, so it’s cooled (when a gas expands, it loses its temperature). In the second case, you blow warm air from your mouth without any change in pressure.


Most of the heat transfer occurs when the refrigerant changes state.


The liquid refrigerant in the evaporator absorbs its latent heat of vaporisation. In the process, it changes from a liquid to a vapour.


The opposite happens here; the gas refrigerant within the condenser rejects its latent heat of vaporisation, thus changing from a gas to a liquid. This cycle change moves the removed heat from one place to another.


Dirty Condenser Coils Are the Culprits That Cause Many HVACR Problems | 2018-11-05 | ACHR News


This subcooled liquid feeds into the metering device… 


Which you can learn about here! When the blog is released.

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