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zaharov [31]
4 years ago
9

A promising method of power generation involves collecting and storing solar energy in large artificial lakes a few meters deep,

called solar ponds. Solar energy is absorbed by all parts of the pond, and the water temperature rises everywhere. The top part of the pond, however, loses to the atmosphere much of the heat it absorbs, and as a result, its temperature drops. This cool water serves as insulation for the bottom part of the pond and helps trap the energy there. Usually, salt is planted at the bottom of the pond to prevent the rise of this hot water to the top. A power plant that uses an organic fluid, such as alcohol, as the working fluid can be operated between the top and the bottom portions of the pond. If the water temperature is 35°C near the surface and 80°C near the bottom of the pond, determine the maximum thermal efficiency that this power plant can have. Is it realistic to use 35°C and 80°C for temperatures in the calculations? Explain

Engineering
2 answers:
frosja888 [35]4 years ago
8 0

Answer:

The maximum thermal efficiency is 12.7%

Explanation:

The efficiency in the Carnot cycle can be calculated using the following equation

n=1-\frac{T_{L} }{T_{H} }

where n is the efficiency

TL = cold tank temperature = 35°C = 308 K

TH = hot tank temperature = 80°C = 353 K

Replacing

n = 1 - (308/353) = 0.127 = 12.7%

Mademuasel [1]4 years ago
4 0

Answer:

The calculation is on the attached diagram

Explanation:

This value is an idealised value. In the true sense the temperature of the working fluid must be above 35 in the condenser and below 80 in the boiler. This will give room for the heat transfer to be effective.

So therefore the max efficiency will be lower than what I calculated vin my attached diagram

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A pump is used to deliver water from a lake to an elevated storage tank. The pipe network consists of 1,800 ft (equivalent lengt
Nataly_w [17]

Answer:

h_f = 15 ft, so option A is correct

Explanation:

The formula for head loss is given by;

h_f = [10.44•L•Q^(1.85)]/(C^(1.85))•D^(4.8655))

Where;

h_f is head loss due to friction in ft

L is length of pipe in ft

Q is flow rate of water in gpm

C is hazen Williams constant

D is diameter of pipe in inches

We are given;

L = 1,800 ft

Q = 600 gpm

C = 120

D = 8 inches

So, plugging in these values into the equation, we have;

h_f = [10.44*1800*600^(1.85)]/(120^(1.85))*8^(4.8655))

h_f = 14.896 ft.

So, h_f is approximately 15 ft

7 0
3 years ago
A gear box’s shaft is made of a hollow circular steel tube with allowable yield stress equal to σa????????o???? . The shaft is l
Leni [432]

Answer:

See explaination

Explanation:

The failure theory asserts that Material failure theory is the science of predicting the conditions under which solid materials fail under the action of external loads. The failure of a material is usually classified into brittle failure or ductile failure.

See attachment for the step by step solution.

3 0
4 years ago
g Part 2: The features arrived the grammar Splitting categories and non-terminals gets out of hand fast. An alternative to the p
koban [17]

Answer:

The split is given by including spaces in both tabs

Explanation:

The bracket notation can be used to indicate the split. Here is an example:

String [ ] parts = s. split ( "[/]")

3 0
3 years ago
A 2 m3 insulated rigid tank contains 3 kg of nitrogen at 90 kPa. Now work is done on the system until the pressure in the tank r
Nutka1998 [239]

Answer: \Delta S = 1.47kJ/K

Explanation: <u>Entropy</u> is the measure of a system's molecular disorder, i.e, the unuseful work a system does.

The nitrogen gas in the insulated tank can be described as an ideal gas, so it can be used the related formulas.

For the entropy, the ratio of initial and final temperatures is needed and as volume is constant, we use:

\frac{P_{1}}{T_{1}} =\frac{P_{2}}{T_{2}}

\frac{P_{2}}{P_{1}} =\frac{T_{2}}{T_{1}}

\frac{T_{2}}{T_{1}} =\frac{175}{90}

\frac{T_{2}}{T_{1}} =1.94

<u>Specific</u> <u>Heat</u> is the quantity of heat required to increase the temperature 1 degree of a unit mass of a substance. Specific heat of nitrogen at constant volume is c_{v}= 0.743kJ/kg.K

The change in entropy is calculated by

\Delta S= m[c_{v}ln(\frac{T_{2}}{T_{1}})-Rln(\frac{V_{2}}{V_{1}} )]

For the nitrogen insulated in a rigid tank:

\Delta S= m[c_{v}ln(\frac{T_{2}}{T_{1}})]

Substituing:

\Delta S= 3[0.743ln(1.94)]

\Delta S= 1.47

The entropy change of nitrogen in an insulated rigid tank is 1.47kJ/K

6 0
3 years ago
What is professional engineering?
Nina [5.8K]

Answer:

professionl engineering means and individual who has fufilled academic and experience requirements and permitted by government to offer engineering services directly to the public

plz mark brainliest✌️✌️

7 0
3 years ago
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