5123 Recuperators

Prime surface metallic recuperators that recover exhaust heat for combustion air preheating are most common, although ceramics hold considerable promise (McDonald, 2000), since seal deterioration on non-metallic regenerators can precipitate inordinately high leakage. Since recuperators are basically air-to-air heat exchangers, rather significant surface areas are needed because air to surface heat transfer coefficients are modest at best.

Both recuperator weight and costs typical of prime surface configurations with moderate pressure drops of 4 to 5% cycle pressure ratio are related to the recuperator effectiveness parameter (e). Recuperator weight and cost are proportional to key drivers as follows:

Recuperator effectiveness values exceeding 0.90, therefore, have very large weight and high cost. These can only be justified when thermal efficiency and the value of power produced dominates operating costs.

A more detailed survey of low cost MT recuperators is addressed by McDonald (2000). Clean burning combustion is the key to both low emissions and highly durable recuperator designs, even though gas bypass may be used for surface periodic cleaning. Recuperator bypass can also be used for higher exhaust heat generation for cogeneration systems, but this essentially confines the MT flowpath to the add-on recuperator design.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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