We cannot deny that a single high-power air compressor is much better than multiple low-power screw compressors in terms of overall energy efficiency. This is a common feature of any type of air compressor. When you see this, don't think that a high-power air compressor is definitely better than a small one, and then only choose a large air compressor instead of a small one. Because the highest principle of choosing an air compressor based on energy efficiency is to choose a large one rather than a small one. Are all high-power air compressors better than small ones?
In fact, this is not the case. High-power screw compressors have both advantages and disadvantages. We consider from various aspects, and the selection of large air compressors is also affected by the following factors:
(I) Limitation of the power system
The first thing that must be considered is the application voltage. The low-voltage system (common 380~460 volts) is not suitable for using air compressors above 600HP. Secondly, it must be considered whether the large air compressor has sufficient shock resistance to the power grid when starting.
(ii) When the amount of compressed air of a screw compressor changes beyond a certain range (depending on the model) due to seasons, time differences or other factors, or when the actual air volume used is likely to be far lower than the estimated value before purchasing the compressor, a single compressor will inevitably cause emissions or unloading, resulting in energy waste. Multiple compressors have greater flexibility to accommodate changes in usage.
(iii) Abnormal machine tripping or necessary shutdown is a potential pressure for production suspension. In order to reduce the risk of production suspension, it is necessary to consider setting up a backup machine. The backup rate of a single machine will be as high as 50%, and the increase in investment cost may not be welcomed by the industry.
In fact, when you buy a complete set of screw compressors and accessories, whether the entire compressed air system can achieve the best energy efficiency. Therefore, when choosing the capacity of the air compressor, more than half of the key to success or failure is already in your hands. Having said that, how to choose the appropriate air compressor capacity is not something that can be covered in a few words, and it involves a wide range of aspects.
Let's take a look together! What exactly needs to be done!
(i) Require the manufacturer of pneumatic equipment to provide the gas consumption and gas consumption change as the basis for analyzing and selecting the capacity of the air compressor. Require the air compressor supplier to estimate the gas consumption of a certain pneumatic equipment.
(ii) If there are seasonal, time difference or other factors that affect the change of gas consumption, they should also be evaluated and listed in detail. If necessary, the air compressor supplier or professionals can be consulted for countermeasures.
(iii) Consider the overall development of the entire factory and make estimates of the air volume for short-term, medium-term and long-term investment plans.
(iv) Do not insist on the concept that the type, model and capacity of the air compressor must be consistent so that spare parts are interchangeable. In the case of a large range of changes in gas consumption, choosing a compressed air system that combines large, small and capacity air compressors can provide a more flexible response range, which will of course have unexpected energy-saving effects.
(V) Some people advocate configuring several large-capacity screw air compressors and small air compressors with half the capacity. Under the above premise, there are indeed many successful cases. This configuration method is not a universal principle. If the compressed air system uses 3 to 5 or more air compressors, as long as the appropriate control method and peripheral equipment are carefully selected, there is no need to consider the configuration method of combining large and small capacity air compressors to avoid the possibility of small capacity air compressors being idle.