A thermal energy storage unit consists of a large rectangular channel, which is well insulated on its outer surface and encloses alternating layers of the storage material and the flow passage. Storage material Hot gas Th Each layer of the storage material is an aluminum slab of width W=0.05 m, which is at an initial temperature of 25°C. Consider conditions for which the storage unit is charged by passing a hot gas through the passages, with the gas temperature and the convection coefficient assumed to have constant values of T = 600°C and h = 100 W/m²- K throughout the channel. How long will it take to achieve 75% of the maximum possible energy storage? What is the temperature of the aluminum at this time?

A thermal energy storage unit consists of a large rectangular channel, which is well insulated on its outer surface and encloses alternating layers of the storage material and the flow passage. Storage material Hot gas Th Each layer of the storage material is an aluminum slab of width W=0.05 m, which is at an initial temperature of 25°C. Consider conditions for which the storage unit is charged by passing a hot gas through the passages, with the gas temperature and the convection coefficient assumed to have constant values of T = 600°C and h = 100 W/m²- K throughout the channel. How long will it take to achieve 75% of the maximum possible energy storage? What is the temperature of the aluminum at this time?

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.18P

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Question

A thermal energy storage unit consists of a large rectangular channel, which is well
insulated on its outer surface and encloses alternating layers of the storage material and
the flow passage.
Each layer of the storage material is an aluminum slab of width ? = 0.05 m, which is at an
initial temperature of 25°C. Consider conditions for which the storage unit is charged by
passing a hot gas through the passages, with the gas temperature and the convection
coefficient assumed to have constant values of ?∞ = 600°C and ℎ = 100 W/m2– K
throughout the channel. How long will it take to achieve 75% of the maximum possible
energy storage? What is the temperature of the aluminum at this time?

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