3.3 Phase 3
As already mentioned, economic considerations have recently led to a preference for increased turbine exhaust specific loadings and, hence, relatively smaller condensers. This allows a relaxation in the structural inter-relationship between condenser and turbine.
Other factors have also promoted a move away from the side-mounted condenser towards an arrangement in which each low pressure turbine is combined with its own transversely-tubed underslung condenser. This has the advantage that it allows the development of a modular LP turbine/condenser design so that one, two or three modules can be combined to cover a large range of possible ratings, for example, 200 MW with one module, and 600 MW or more with three modules. This modular concept has a strong attraction for turbine manufacturers, particularly where they are competing in world markets. One or two highly developed basic designs can then meet all practical requirements.
In these few remarks, it is clear that the choice of condenser for future large turbine-generator plant appears to favour the transversely-tubed underslung condenser: this seems unlikely to be reversed in the foreseeable future.