What is the economic advantages of absorption chiller compared with electric chiller?

Answer 1

· Cost effective and more economical than electrical chillers. Use heat for compression while vapour compression chillers use mechanical compressor for compression purposes which consume a lot of electrical energy.

· Since the compression is caused by heat and does not include any moving mechanical parts, it is less noisy and vibration free.

· For a facility that demands high system reliability, the lower electricity demands of the absorption chiller will reduce emergency generator load requirements.

· Good for the environment as it eliminates the requirement of using CFC and HCFC refrigerants used in electrical chillers which have high global warming potential and instead use natural refrigerants such as water.

Answer 2

It depends. The absorption chiller uses primarily heat to drive its cycle. The electric chiller uses a vapor compression cycle that generally uses an electric motor as the driving force. So, if one has a source of heat at a sufficient temperature to drive the absorption cycle, and if this heat can be obtained in a cost effective manner, then it may be possible to generate chilled water more cost effectively as compared to the vapor compression system that uses electricity at a high rate.

A single effect absorption chiller generally requires a temperature of at least 180-220F. A double effect system generally requires much higher temperatures of at least 350-400F. The advantage of the latter is that it's more efficient at making use of the available heat (however, it tends to use slightly more electricity to drive its pumps due to the higher fluid pressures involved). A single effect system requires about 15,000-20,000 btu/hour of heat per refrigeration ton of cooling. A double effect system can achieve the same cooling with roughly 9,000-12,000 btu/hour of heat. Note that these values are very general and they vary widely depending on the design of the system. Typically, the electricity consumption rate of the absorption system is on the order of only 10-20% of the vapor compression counterpart (this includes chilled water pumps and air moving equipment). Again, these values vary broadly depending on the design.

Just to provide some examples, if one happened to have a source of fuel such as natural gas that is very inexpensive relative to electricity, and considering the long term costs of maintaining equipment, then the absorption chiller might be a cost effective alternative. Another example might be an off grid setting where electricity is very expensive to generate, yet where biomass fuel such as wood is plentiful. In that setting, the absorption chiller might be a practical means to provide air conditioning. One might have available process heat or heat that is otherwise wasted that might be of sufficient temperature to provide air conditioning. In that case the system is very cost effective as it can be powered by energy that is otherwise wasted. A common example here is the exhaust from engines. Finally, solar energy might be a viable candidate where this heat can be harvested in a cost effective manner (although there are many technical problems to overcome here to make it an economic proposition).