ES4E0 Renewable Energy Re-sit assignment 2020 GSFS PDF

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ES4E0 Renewable Energy (Re-sit) assessmentSummary All questions should be answered and the method/ calculations shown for each answer in order for all marks to be obtained.  The completed assessment (submission) must be no more than 8 pages.  Completion of this assessment should take no more than...

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ES4E0 Renewable Energy (Re-sit) assessment Summary   

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All questions should be answered and the method/ calculations shown for each answer in order for all marks to be obtained. The completed assessment (submission) must be no more than 8 pages. Completion of this assessment should take no more than 1 week (~40h) for the average student, having already invested the requisite time in self-guided study in support of this subject. The assessment carries a weighting of 70% of the module mark as the re-sit for the “exam” component of this module.

Assessment submissions The assessment should be submitted via Tabula. 

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Submissions: 1st September 10am BST. All submissions that miss this deadline will be subject to the normal 5 marks per day penalty, starting at 10:01 on 1st September. IT/Technology issues experienced in the hour before submission will not warrant mitigating circumstances and late penalties will be applied. We recognise that some students will have deferred their summer assessments because they do not have an appropriate environment and or access to the right equipment to complete those assessments. When informed about their September assessments, students in these situations will be able to request an on-campus sitting by exception, and we will consider these on a case-by-case basis. You must notify Dave Britnell by email ([email protected]) within 24 hours of receipt of the September assignment brief, and no later than 3rd August, if you wish to be considered as an on-campus sitting by exception.

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Q1. The figure below shows water in a lake flowing down a pipe and powering a Pelton Wheel through a single nozzle. The elevation of the highest point in the lake (point 1) is 550 m above the point where the jet leaves the nozzle (point 2).

The length of the pipe connecting the lake and the Pelton Wheel is 1000 m, its diameter is 0.8 m and it has a friction factor, 𝑓, of 0.025. The jet diameter is 0.25 m. a) Calculate the maximum theoretical power output in kW (assume β is set for maximum theoretical power). You should account for friction losses, and as such Bernoulli’s energy conservation relation (as seen in Problem Set 2, Q1) simplifies to 𝑧1 =

𝑣2 2 2𝑔

𝑙 𝑉2

+ ℎ𝑙 , where ℎ𝑙 = 𝑓 𝐷 2𝑔.

Use ρwater = 1000 kg·m-3 and a ϕ value for theoretical maximum power. Assume k = 1 and mass flow conservation such that flow in the pipe equals flow out of the nozzle (i.e. AV = A2V2). b) If the pipe were smooth (therefore no frictional losses, meaning Vj and Q would be larger), what value of β would be required to achieve the same power output as found in part a)? [25 marks total]

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Q2. Technical data specifying the performance of solar thermal collector: value units 0.95  0.07  0.88  F’ 0.9 W m-2 K-1 UL 4.18 m2 Ac 1.8 The manufacturer of solar thermal collectors detailed above claims that its collectors are 95% efficient. It further claims that the earth receives more than 1 300 W m-2 of energy from the sun, even at high latitudes. a) Making use of your own knowledge and the data provided explain: i.

Where the manufacturer’s claims have come from?

ii.

Why are these claims potentially misleading?

iii.

What is the likely maximum efficiency?

iv.

What is the likely insolation received for such a collector in the UK (ie at a latitude of 51° North) in mid-summer (22 June) when the clearness index is 0.6? Show your calculations based on the data provided.

In the summer, water is heated at 60°C whilst the average ambient temperature is 20°C. Radiation data for summer day: Time Insolation W m-2

0700-0900 200

0900-1100 400

1100-1300 800

1300-1500 800

1500-1700 400

1700-1900 200

b) Sketch a plot with collector efficiency on the y-axis. i.

Mark the values of the intercepts.

ii.

Calculate the efficiency of the collector through the day (assuming the Insolation provided is equal to Gt).

iii.

How much energy is collected during the course of this day? [25 marks total]

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Q3. It is proposed that a house for a family of two adults and two children be built in a remote mountainous area of the UK. The site for this home is not connected to the electricity grid and provision of such a connection would be expensive. The occupants will require hot water, space heating and electricity. The owner is an enthusiast for renewable energy but has no technical knowledge. You are asked to make some recommendations for a system using solar and/or wind and/or hydropower but do not need to restrict your response to these.

a) Describe the basic requirements and components, including ancillaries, for: i.

a solar thermal system,

ii.

a solar photovoltaic system,

iii.

a wind energy system,

iv.

a small hydropower system

b) Which of the technologies listed above should be the lowest priority? Justify your answer. c) What additional information about the house, its occupants and the location would you need to specify and size the systems if you were asked to produce a more detailed proposal? d) Identify any other energy technologies that should be considered and describe their requirements.

Your response should provide enough guidance to enable the homeowner to make an informed decision and make their plans accordingly. This task is rather open ended so you will be able to demonstrate your understanding of the technologies and the subject in general. [50 marks total]

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