Vapor Absorption Refrigeration
Vapor Absorption Refrigeration
Ammonia Absorption Refrigeration Plants
AARP V/s LiBr Chillers
The following table gives comparison of AARP V/s LiBr Chillers (Single Effect Lithium Bromide Absorption Refrigeration Chillers) for Chilled Water Application. Hot water driven AARP is a more reliable Absorption System than Single Effect LiBr Chiller for production of chilled water using hot water of temperatures less than 100°C.
| AARP | Single Effect LiBr Chiller |
|---|---|
| Application Range | |
| Operating Temp. Range: +5 to -60°C | Operating Temp Range: +7 & above |
| Driving Heat Source Temp Range: 85°C & above. | Driving Heat Source Temp Range: 85°C & above |
| Cooling water Temp: 35°C or below. | Cooling water Temp: 35°C or below |
| Construction | |
| Refrigerant - Ammonia (NH3) | Refrigerant - Water |
| Absorbent - Water | Absorbent - Lithium Bromide (LiBr) |
| Material of Construction | Material of Construction |
| Plates - Carbon Steel | Plates - Carbon Steel |
| Tubes - Carbon Steel | Tubes - Copper Nickel Tubes |
| All welded construction | Tubes to tube sheet are expanded joint rest is welded construction |
| Operating System pressure is above atmosphere upto (-30°C) | System is under vacuum |
| Functioning | |
| Fully automatic continuous Modulation | Fully automatic continuous Modulation |
| Part load efficiency is good | Part load efficiency is good |
| Maintenance & Spares | Maintenance & Spares |
| No Maintenance | Vacuum maintenance is critical functions and system life |
| Tubes are carbon steel & solution pumps are standard centrifugal pumps. | Copper Nickel tubes & Hermetic pumps are very costly |
| Copper Nickel tubes need replacement periodically & hence repair cost is high. | |
| Life | |
| Long life of 25 years or more | Entire equipment life is not more than 15 years. |
| Corrosion | |
| Corrosion is negligible | Corrosion is high Highly susceptible to corrosion and therefore life can be limited if vacuum is not maintained properly. Expanded tube-to-tube sheet joints have tendency to leak periodically. |
| Due to low corrosion repairs maintenance costs are very low | Due to corrosion tube repairs and replacement is frequent. All tubes are Copper or Copper Nickle Tubes. Therefore tube replacement is very costly. |
| Due to pressurized system; No special care is needed | Due to vacuum System; special care is needed otherwise plant stops frequently. Also due to thousand of expanded tube to tube sheet joints, the vacuum loss is frequent with passage of time. Fault finding is very time consuming. |
| Chilled water application | |
| Chilled water temperature | Chilled water temperature |
| 7oC outlet | 7oC outlet |
| 12oC return | 12oC return |
| Cooling water temperature : 30°C | Cooling water temperature : 30°C |
| Driving Heat Sources temperature 85°C to 140°C | Driving Heat Sources temperature 85°C to 140°C |
| C.O.P.: 0.6 to 0.65 | C.O.P.: 0.6 to 0.65 |
