ENVIRONMENTAL ENGINEERING WATER DISINFECTING PLEASE HELP?

Posted on 2015-09-21 06:09:00 in Engineering by NICHOLAS

Solar cookers can be used in developing countries for cooking and also for thermal disinfection of water. To disinfect water, the water must be heated to about 60oC. It takes time to raise the temperature of the water up to 60oC. A hemispherical hole 0.4 m in diameter is dug into the ground, lined, and filled with water (no inflow or outflow of water) for heating. Assume the hole is insulated by soil so that no heat escapes. The solar intensity is 800 W/m2.

A. Write the energy balance for this system in words.
B. What hydrodynamic model would you use for this system (batch, CSTR, or plug flow) and why?
C. If the water is heated for time t (in seconds), what is the value of the “energy in” term in joules?
D. How long will it take in hours to raise the water temperature from 20oC to 60oC? Use the model you have been developing in Parts A, B, and C.

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