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Hypograph of a function. In mathematics, the hypograph or subgraph of a function: is the set of points lying on or below its graph. A related definition is that of such a function's epigraph, which is the set of points on or above the function's graph.
Epigraph of a function A function (in black) is convex if and only if the region above its graph (in green) is a convex set.This region is the function's epigraph. In mathematics, the epigraph or supergraph [1] of a function: [,] valued in the extended real numbers [,] = {} is the set = {(,) : ()} consisting of all points in the Cartesian product lying on or above the function's graph. [2]
Hypograph may refer to: Hypograph (mathematics) , the set of points lying below the graph of a function Hypograph, or hypogram, something written at the end of a document (for example, a postscript )
An oil heater, also known as an oil-filled heater, oil-filled radiator, or column heater, is a common form of convection heater used in domestic heating. Although filled with oil , it is electrically heated and does not involve burning any oil fuel ; the oil is used as a heat reservoir (buffer).
A thermic fluid heater (TFH), [1] also known as a thermal oil heater, is a device used for indirect heat transfer through a thermic fluid. It heats the fluid to a desired temperature and then transfers that heat to various processes without any direct contact between the heating source and the product.
The energy factor metric only applies to residential water heaters, which are currently defined by fuel, type, and input capacity. [5] Generally, the EF number represents the thermal efficiency of the water heater as a percentage, since it is an average of the ratio of the theoretical heat required to raise the temperature of water drawn to the amount of energy actually consumed by the water ...
Solar heat is clean and renewable. This is the most modern system. Increasingly, solar powered water heaters are being used. Their solar thermal collectors are installed outside dwellings, typically on the roof or walls or nearby, and the potable hot water storage tank is typically a pre-existing or new conventional water heater, or a water heater specifically designed for solar thermal.
For larger buildings with intermittent or occasional hot water use, multiple POU water heaters may be a better choice, since they can reduce long waits for hot water to arrive from a remote heater. The decision where to locate the water heater(s) is only partially independent of the decision of a tanked vs. tankless water heater , or the choice ...