Air Compressors Info

An air compression is a means by which one type of energy is converted to another. During this conversion certain losses occur because of the rise in temperature of the air as it compressed. In general practice, the air is stored in a receiver and heat is lost both in the receiver and pipe lines running to equipment. Since the rise in temperature of the air is a direct loss of energy. We want to keep it down to a minimum. The ideal method is to compress air isothermally but this is impossible in practice owing to lack of time necessary to affect transfer. Water jackets and inter-cooling can be used to keep the temperature down. These have the effect of reducing the compression index (n) to something less than 1.4. When air is compressed to a pressure to exceeding about 4 bar it is usual to compress it in stages, with intercooling between each stage. This considerably reduces the total amount of work required on the air. For two stages compressing, the air is compressed in the first...

To understand how to save the energy in compressed air system , it is useful to start with theory background of how the air compressors work and how the energy is consumed. As we know from Thermodynamic principle that the compressor work is, where: rev = reversible in = input Our objective is to minimize the air compressor work that means to approach the reversible process i.e. minimize the friction, and turbulence Practical way to do this is to make v (specific volume) small by maintaining T (temperature) at low temperature during compression because v a T. In other words, to reduce the work input to a compressor, air should be cooled as it is compressed. Effect of Cooling Isentropic process: No cooling during compression Polytropic process: Involve some cooling Isothermal process: Involve maximum cooling Which process yields the minimum required compressor work? Let's consider the following equations of each process. Assumptions: All three processes are executed between the same...