Renewable Energy Systems Assessment 1 - 1 - Renewable Energy Systems Assessment 1: Problems on energy systems analysis DUE DATE: Friday 16:00 hrs Week 5 This assignment consists of FOUR problems. Please attempt ALL questions and show your working clearly in each case. Solutions to the quantitative problems will be assessed on: (1) methodology (2) assumptions stated (3) clarity of solution presented (4) correct answers (up to 3 decimal points) and (5) correct units. Marking: each question is worth 25 marks. Use the appropriate data provided for solving these problems. Problem 1: Renewable Energy and Australia's Electricity Generation In 2012/2013 Australia's electricity generation was 249.1 TWh of which 13.1% was generated from renewable energy resources [BREE 2014, Table 4.1, p. 45]. Suppose Australia has a renewable energy target that requires 20% of its electricity supply to be generated from renewable energy resources by 2020/21. If the annual growth rate in electricity demand is 1.4 % from 2012/2013 to 2020/2021: (1) What amount of electricity must be generated from renewable resources in 2020/21? (2) Suggest a mix of renewable energy resources to meet this demand, and identify the contribution from each renewable energy resource. [Use the categories listed in Table 5.1 of the Energy in Australia 2014 report (BREE 2014). You may not need to include all categories in your mix of resources.] (3) Estimate the installed capacity required for each of the renewable electricity generation classes. Clearly state and explain any assumptions you make in your analysis. Reference Energy in Australia 2014 is available from the Australian Government, Department of industry and Science website Website:http://www.industry.gov.au/Office-of-the-ChiefEconomist/Publications/Pages/Energy-in-Australia.aspx Document:http://www.industry.gov.au/Office-of-the-ChiefEconomist/Publications/Documents/energy-in-aust/bree-energyinaustralia-2014.pdfRenewable Energy Systems Assessment 1 - 2 - Problem 2: Solar Hot Water Tests were carried out on a glazed flat-plate solar collector for a solar hot water system. The results are given in Table Question 2. In these tests, the efficiency of the solar flat-plate was measured over a range of water inlet temperature (Ti), ambient temperature (TA) and solar irradiance (G). The transmittance (or transmissivity), , of the glass cover is 0.97 and the absorbance (absorptivity), , of the collector surface is 0.92. The collector has a gross area of 3.96 m2. For this solar collector calculate the following: (1) The collector heat removal factor, FR. (2) The overall heat transfer coefficient, UL (express your answer in W/m2K). (3) The rate at which the collector can deliver useful energy (that is, the power output from the collector) when the solar irradiance incident of the collector is 750 W/m2, the ambient temperature is 15 oC and the water inlet temperature is 28 oC. (4) The stagnation temperature for this collector under the conditions of part (3). Table Question 2: Test results for a solar collector Efficiency, (Ti – TA)/G, m2.K/W 72.0 0.014 71.0 0.0175 67.9 0.02 61.5 0.0275 58.0 0.035 51.2 0.0425 45.5 0.0485 41.5 0.055 40.0 0.065 31.2 0.07 27.5 0.075 22.0 0.0825 Ti = water inlet temperature, oC TA = ambient temperature, oC G = solar irradiance, W/m2.Renewable Energy Systems Assessment 1 - 3 - Problem 3: Shading on a solar collector A resident is considering installing a 4.2 m2 solar collector on the rooftop of her house. The house is located at a latitude 30o 18' South and longitude 153o 8' East. These coordinates correspond to the location of Coffs Harbour in New South Wales. There are buildings and tall trees nearby which may cast a shadow on the collector for some days in the year. Measurements are made of the positions of these objects from the site where it is planned to locate the collector. The solar azimuth and solar height (altitude) angles of the outline of the objects are recorded in the table below (Table Question 3). (1). Use appropriate software to draw a sun path diagram for the specified location. (2). Construct a shading diagram on your sun path diagram. (You may do this manually or with the software used to draw the sun path diagram.) (3). Estimate the hours of sunlight and the times of the day when sunlight will reach the collector on the following days: (i) The equinoxes (ii) The winter solstice (iii) The summer solstice. Ensure you clearly identify if the times you give are solar time or local time. Table Question 3: Objects in the surroundings Point # Solar Azimuth, degrees Solar Height (altitude), degrees OBJECT 1 1 0 0 2 0 26 3 15 26 4 15 35 5 30 40 6 63 42 7 75 30 8 82 0 OBJECT 2 9 95 0 10 95 5 11 90 10 12 90 22 13 115 22 14 115 8 15 110 6 16 110 0 OBJECT 3 17 -150 0 18 -135 23 19 - 90 23 20 -75 20 21 -50 0Renewable Energy Systems Assessment 1 - 4 - SIGN CONVENTION: In Table Question 3, solar azimuth is measured with the convention 0 to +180 East and 0 to -180 West from true North. Problem 4: With reference to the data in Table below, extracted from the BREE publication, Energy in Australia 2014, answer the following questions: (1). What is Australia's major renewable energy resource currently being utilised in our energy supply systems? (2). Which renewable energy resources had the largest increase in production over the period from 2006/07 to 2012/13? Answer this question in absolute terms as well as percentage changes. (3). Which renewable energy resource has had the fastest growth rate in utilisation? (4). Which renewable energy resource has had the largest decline in absolute amount? Why has this occurred? Table Question 4 Australian renewable energy production (Source: BREE 2014, Australian Energy Statistics, Tables F and O.) 2006–07 2007–08 2008–09 2009–10 2010–11 2011-12 2012-13 PJ PJ PJ PJ PJ PJ PJ Bagasse 110.8 110.8 81.4 101.7 83.3 84.9 95.3 Biogas and biofuels 10.7 15.2 20.0 23.1 27.2 27.7 26.5 Hydro 52.3 43.4 42.7 48.8 60.5 50.7 65.8 Solar hot water 6.0 6.7 8.2 10.5 11.6 12.3 12.8 Solar electricity 0.4 0.4 0.6 1.5 5.5 9.2 13.7 Wind 9.4 11.1 13.8 18.2 20.9 22.0 26.4 Wood and woodwaste 98.7 98.7 94.5 93.3 90.0 88.7 89.1 Total 288.3 286.4 261.2 297.0 299.1 295.6 329.6 Energy in Australia 2014 is available from the Australian Government, Department of industry and Science website http://www.industry.gov.au/Office-of-the-Chief-Economist/Publications/Pages/Energy-inAustralia.aspx