A device submitted to the Pa- tent Office is shown schemati- cally in the figure to the right. Its inventor claims that it can generate 10 kW of electrical power continuously, using only 0.03 kg/s of low-pressure (2 bar) saturated steam, which exits as a mixture of liquid and gas also at 2 bar. A stream of cooling water (0.3 kg/s, liquid at 1 bar) is used in the device; the patent application lists its entrance and exit temperatures as 20 °C and 40 °C, respectively. The de- vice does not have any other heat or material exchanges with the environ- ment. You are asked to give your fully justified opinion as to whether steady-state operation of this device is (or is not) thermodynamically per- missible. If it is not possible to obtain the electrical power stated, what is the maximum power than can be generated? 0.03 kg/s sat. steam, P = 2 bar 0.3 kg/s liq. water, 8= 20 °C Device liq. + vap. P = 2 bar 8 = 40 °C

A device submitted to the Pa- tent Office is shown schemati- cally in the figure to the right. Its inventor claims that it can generate 10 kW of electrical power continuously, using only 0.03 kg/s of low-pressure (2 bar) saturated steam, which exits as a mixture of liquid and gas also at 2 bar. A stream of cooling water (0.3 kg/s, liquid at 1 bar) is used in the device; the patent application lists its entrance and exit temperatures as 20 °C and 40 °C, respectively. The de- vice does not have any other heat or material exchanges with the environ- ment. You are asked to give your fully justified opinion as to whether steady-state operation of this device is (or is not) thermodynamically per- missible. If it is not possible to obtain the electrical power stated, what is the maximum power than can be generated? 0.03 kg/s sat. steam, P = 2 bar 0.3 kg/s liq. water, 8= 20 °C Device liq. + vap. P = 2 bar 8 = 40 °C

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter2: Matter And Energy

Section: Chapter Questions

Problem 27RQ: How many Btu/h would be produced in a 12-kW electricheater?

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