Innovation through Design

Compression

Ammonia Absorption

Lithium Bromide

Electrical energy

Runs fully on electrical power. Varies from 1KW/TR at 0^oC to 2KW/RT at -25^oC

Typically uses about 7%-10% of compressor electric energy for pump.

Typically uses about 5% of compressor electric energy for pump.

Refrigerant used

Varies with application.

Ammonia, with water as absorbent.  Environment friendly, and low cost refrigerant.

Water, with Lithium Bromide as absorbent.  Absorbent charging / disposal is expensive.  

Temperature limitation

Depends on refrigerant.  

Up to -33^oC and lower.

Only up to +7^oC

Thermal energy required.

None

Low pressure steam, hot water or equivalent waste heat sources.

Low pressure steam (single stage units) and high pressure steam (two stage units)

Thermal energy quantity (as steam)

None

Varies from about 9kg/TR (at 0^oC operation) to 11kg/TR (-25^oC operation)

About 8kg/TR (single stage.  About 5kg/TR (two stage) for +7^oC operation.

Installation.

Indoor installations. 

Skid-mounted outdoor installations.  No building cost. 

Skid-mounted indoor / outdoor installation.

Remarks.

Requires standby for critical service.  Vulnerable to fluctuations in cooling water temperature.  Moving parts wear and tear means low operating life.

Low maintenance, industrial standard heat-exchangers as per TEMA.  Stand-by pump for reliability.  Flexible operation.  Higher steam temperatures can offset cooling water temperature fluctuation.

Operation is easily understood and picked up by ammonia compressor operators.

Pungent, characteristic  ammonia smell acts as a natural alarm in event of leakage.

Vulnerable to fluctuations in cooling water temperature.  Vacuum service leakages are difficult to identify.  Refrigerant may need to be changed if exposed to air during maintenance.

Exotic material construction.  Site repair and maintenance is difficult.