. What is the speed at which water must flow through the pipe if the water temperature is increasing?
A sensor Solar consists of a flat plate that absorbs heat from the sun. A water pipe attached to the back of the plate carries the heat absorbed (Figure 20.19). Suppose that the collector has an area of 4.0 m2 facing the Sun and the power per unit area delivered by the sun is 1.0 X 103 W/m2. What is the speed at which water must flow through the pipe if the water temperature is increased to 40 ° C as it passes through the collector:? Image http://curricula2.mit.edu/pivot/book/showgfx.html?images/ch20/lrgimg/ph20fig014.gif
Q_dot * A * = c * m_dot deltaT Solve for m_dot: m_dot Q_dot * = A / (c * DeltaT) Data: c: = 4184 J / kg-C; Q_dot: = 1000 / ^ W m 2 A: 4 = m ^ 2; deltaT: C = 40; Result: m_dot = 0.0239 kg / S
