Types |
Ammonia Absorption |
Ammonia water/ hydrogen |
Lithium Bromide Absorption |
Lithium bromide water |
- Ammonia Absorption: Is not used in commercial building applications due to the quantities of ammonia gas. There for normally used where hazards are very slight
- Lithium Bromide: Is commonly used for chilled water systems in commercial + industrial applications
- Major Components:
-Absorber
-Condenser
-Evaporator
-Generator or Concentrator
-Pumps
Major liquids Used:
-Water: Used as the refrigerant located in the evaporator
-Lithium Bromide: Used as an absorbent for water vapor found in the absorber
Terminology:
Absorbent: Is the liquid that has the ability to absorb large amounts of water vapor (Lithium bromide)
Absorber: Component where the vapor is absorbed by the absorbent
Condenser: Component used to condense the water vapor returning from the generator
Evaporator: Component used to absorb heat from the area to be cooled or the chilled water circuit
Strong Bromide Solution: A solution of lithium bromide and water (Which has a relatively low concentration of water vapors). The solution which leaves the generator back to the absorber
Weak Bromide Solution: A solution of lithium bromide and water (which has a relatively high concentration of water vapors). The solution which leaves the absorber and enters the generator
Solution Pumps: Used to move system fluids
-Between absorber + Generator
-Circulate water with in the evaporator
High Side: Contains the condenser + Generator - 1.47 PSIA
Low Side: Contains the evaporator + absorber – 0.12 PSIA
Heat Exchanger: Used to cool strong solution from the generator before entering absorber as well as heating up weak solution from absorber before entering the generator
Crystallization: Is when the salt crystals precipitate out of the solution. This is normally with in the heat exchanger because the strong bromide solution has been dropped below 110°F at 65% concentration
Purge Units: Non condensables are always present in absorption machines. If allowed to accumulate they can have the following affects
-Reduction in capacity (Higher leaving chilled water temp.)
-Crystallization (Because of a reduction in load)
-Corrosion = oxygen + salt solution
Methods of Removal:
-Mechanical vacuum pump
-Non-mechanical continuous purge units
*Note: Crystallization starts at a higher temperature
|
