MP4709: Apply principles of computational thermodynamics to modern energy systems: Energy Systems Coursework, UCLan, UK

Learning outcomes
This formative assignment should produce sufficient evidence for partial fulfillment of the following module learning outcomes:

• Apply principles of computational thermodynamics to modern energy   systems.
• Critically evaluate integrated power systems and different sources of energy.
• Analyze performance of different energy conversion technologies.
• Design, integrate and analyze energy systems for specific uses.

 Background

To prevent power cuts at peak times, different sources of electricity production must adequately respond to the flexible demands on national grids That is, electrical supply and demand dictates a balance between power production methods.

As a consequence of the Energy Act [6], the UK has begun to lead internationally in achieving an electrical power production balance. Currently, traditional fossil fuels and renewable energy account for 34% each of the overall power production in the UK, with 17% being sourced from nuclear and biomass (at 6.3%) accounting for the majority of the rest2 This being compared with the rest of Europe, which on average produces over 50% of its electricity from fossil fuels and only 15% from renewable energy sources [7]. On the other hand, North Africa, with its vast natural and renewable recourses, relies on fossil fuels for a massive 80% (67% Gas, 13% Oil and gas) of its electricity, with only 19% being from renewable sources.

In previous years, especially in Europe, the drive toward so-called carbon-neutral energy production has been to increase the nuclear contribution. However, this source is relatively expensive when compared with more traditional ones [9] resulting in higher strike rates. This probably being the principal reason for the current stall in nuclear new-build programmed across the UK. Moreover, nuclear power has become less popular with governments in the wake of the Fukushima Daiichi disaster. Indeed almost overnight, in March 2011 Germany reduced its nuclear power production from 25% to 12%.

Furthermore, public opinion there remains broadly opposed to nuclear power with virtually no support in the Bundestag for new-build. Given this, together with current international impetuous for carbon-neutral power production and the natural depletion of global fossil resources the need for other commercial power-plant designs, perhaps based on renewable technology becomes more provocative [10]. One avenue of exploration is the implementation of Concentrating Solar Power (CSP) trough-plants [2].

This assignment is therefore designed to enable candidates to compare and contrast each of the integrated power production systems as shown in Figure 1 [2]. Applying the fundamental laws of thermodynamics to this modern system via the consideration of technological merits in terms of energy sustainability and any environment impacts.

Tasks

Candidates are advised to refer to relevant literature [2] and class/lecture material to focus of the module aims being explored [11], ergo the Learning outcomes identified on the title page of this document. It is the purpose of the final submitted report to demonstrate what learning has taken place throughout to assessment process and what module learning outcomes have been achieved [12].

1. Use the Engineering Equation Solver (EES) or otherwise to design and analyze the CSP trough-plant a detailed in the references [2], using water as a working fluid. Here a boiler is supplied heat from the solar collector field and
plant rejects heat to a temperature reservoir. Fluid is then extracted from a high pressure turbine with a faction of this used to feed the Closed Feed-Water Heater (CFWH).

The remaining fluid is passed though a lower temperature turbine which is then subsequently reheated using heat transferred from the collector array, then expanded through third turbine. A fraction of the exhaust fluid is then directed to an Open Feed-Water Heater (OFWH), with the remainder passing through the final low pressure turbine and then condensed.

Saturated fluid leaving the condenser is pumped to the Open Feed-Water Heater (OFWH). The liquid is pulled from the OFWH and pumped up to the CFWH. The flow through the CFWH being controlled so that the extracted fluid leaving is a saturated liquid. With a third pump being exploited to ensure isobaric conditions in a mixing chamber. The pinch points for both of these heat exchangers occur at their warm end.

(a) Describe the principle of operation the CSP trough-plant detailed in the reference and compare and contrast this with the alternative shown in Figure Discuss the capital and operational costs when compared with an equivalent nuclear power plant.

(b) Use salient values evident in the literature for each of the cogent device isentropic efficiencies and heat exchanger approach temperatures throughout your model. Utilize a standard procedure  to facilitate each of the turbines and another procedure  for each of the pumps in the system, thereby evaluate salient plant operational parameters.

2. Hence critically evaluate the alternative design suggested by Ekremet
(a) Produce the pressure-volume, entropy-temperature and Mollier diagrams for each of cycles.
(b) Find three plant design criteria.
(c) Assuming that all of the radiation is absorbed by the collector pipe. For each of the designs Determine the total rate of solar energy incident on the solar-trough field for a sensible collector size, obtaining an appropriate solar flux value from literature [2]pp424

3. Use LyX3, LATEX(or otherwise) to produce a report detailing most important findings from your modelling work. It
is suggested that the final submitted document pays attention to the following details.

(a) Introduction and scope 
• Principle of operation and costing analysis, e.g. Task 1 part(a)
• Scope: How are the Learning Outcomes to be demonstrated?

(b) Methods 
• Definitions, including the standard Rankine cycle.
• Justification of assumptions e.g. isentropic efficiency, approach temperatures, etc.
• Benchmarking: Turbine and pump procedures.
• Complete description of the modelling process used. You may find it useful        to  use the EES automated LyX/LATEXreport command to generate any required equations and formulae.

(c) Results
• Tabulated state arrays
• Pressure-volume, temperature-entropy and Mollier diagram comparisons, together with appropriate description of them.
• Plant design criteria values together with suitable explanations.

(d) Discussion 
• Consideration of the merits or otherwise of the designs detailed in Figure 1.
• Suitable cost and/or size comparisons made with similar plants evident in the literature [2, 3] and/or
nuclear power equivalents.

(e) Conclusions
• Reflection on Learning Outcomes, stating when and were they have been demonstrated in the previous sections.
• Main scientific conclusions (possibly bullet point list) based on 5-10 key results.

(f) Salient language 
• Freedom of spelling, grammatical and cross-referencing errors.
• Use of appropriate scientific and academic language.

Answer

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