TXV or Thermostatic Expansion Valve | Refrigeration for HVAC

by | Refrigeration | 8 comments

TXV or Thermostatic Expansion Valve are used in air conditioners and heat pumps to meter refrigerant.

TXV or Thermostatic Expansion Valve

The TXV or Thermostatic Expansion Valve is preferred over other refrigeration metering devices because it only allows a specified amount of refrigerant to flow based on demand. Any type of refrigeration metering device creates a pressure drop in the refrigerant and with a pressure drop of the refrigerant a temperature drop also occurs.

This temperature is necessary to drop the refrigerant down to temperature lower than ambient temperatures inside the structure being cooled. This allows the refrigerant to absorb the heat contained in the air passing over the evaporator coil. (more…)

Superheat and Sub-Cooling Refrigeration HVAC

by | Refrigeration | 4 comments

Refrigeration HVAC - Superheat and Sub-cooling
Superheat and Sub-cooling - In HVAC refrigeration coils and fans are used for air conditioners and heat pumps to transfer heat in one direction or another. A good HVAC technician is well versed in refrigeration. Refrigeration is defined as moving heat from one place to another. Modern air conditioners and heat pumps use a chemical refrigerant used in vapor compression refrigeration.

This chemical refrigerant has great properties for absorbing heat. What makes these chemicals so efficient is the temperature at which they change state or change from a liquid to a vapor and condense back to a liquid again. This is key to understanding superheat and subcooling. (more…)