Refrigerant inside the condenser coil

[Cheetos]

I recently worked with a HVAC personnel. He told me that, if you have a lot of refrigerant inside the condenser coil, you can reject the refrigerant inside the condenser coil by covering up the condenser coil with cloth while the fan is running or shut the fan off. (basically heating up the condenser). I'm fairly new at this HVAC stuff, so I'm not sure how does that work. When you "heat up" the condenser, the gas inside expands and pushes out the liquid? Maybe I just misunderstood him.

 

[Compositepro]

This is true for only some systems. I'm not sure where you would actually need to do this because because a back-up of liquid refrigerant in the condenser does essentially the same thing. The heat transfer area exposed to hot vapor decreases and therefore the temperature and pressure in the condenser increases. The increase in pressure results in more liquid flow through the expansion orifice.

 

[Cheetos]

cool. thx for the quick explanation.

 

[Cheetos]

Hmm.. I was thinking last night. So, in the winter, you may need to flood the condenser to maintain the refrigerant temp/pressure. When you do that, you're heating up the condenser, but, at the same time, pushing the refrigerant out of the condenser. How does that work since you want to keep the refrigerant inside the condenser to heat it up, but heating up the condenser pushes the refrigerant out of the condenser? I'm assuming a HVAC system has a regulator or a bypass to control how much refrigerant is inside the condenser based on pressure/temp.

 

[EnergyProfessional]

Condensers for low ambient will modulate the condenser fan to keep the refrigerant warm enough. Very low ambient condensers also have shrouds to "protect" them from air flow induced by wind.
I guess manually covering the condenser would do the same things, but wouldn't be automatic. so yo may overheat the condenser at higher ambient or when load is higher.