Photovoltaic thermal hybrid solar collector Photovoltaic thermal hybrid solar collector Photovoltaic thermal hybrid solar collectors, also known as hybrid PV/T (PVT) or solar cogeneration systems, are power generation technologies that convert solar radiation into usable thermal and electrical energy. Such systems combine a solar cell, which converts sunlight into electricity, with a solar thermal collector, which captures the remaining energy and removes waste heat from the PV module. These technologies can be more energy efficient overall than solar photovoltaic (PV) or solar thermal alone. Significant research has gone into developing a diverse range of PV/T technologies since the 1970s.. While many collector types have been
Length of a module formal algebraic geometry. Let "M" be a (left or right) module over some ring "R". Given a chain of submodules of "M" of the form we say that "n" is the "length" of the chain. The length of "M" is defined to be the largest length of any of its chains. If no such largest length exists, we say that "M" has infinite length. A ring "R" is said to have finite length as a ring if it has finite length as left "R" module. The zero module is the only one with length 0. Modules with length 1 are