MIET 2406 Cogeneration Assignment Due: 23:59pm Saturday, 27th May, 2017 – Online submission NOTE: (a) The assignment MUST be submitted through the Blackboard in learning hub on or before the due day (b) A penalty may apply for late submission unless appropriate approval for extension is granted before the due date. (c) Students are to use the excel template provided as the basis of their submission. Marking guidelines (marks per question etc) have been included in this file. General Questions: 1) In accordance with the first law of thermodynamics, a 950kW single effect absorption chiller with a COP of 0.81 will require a heat source of _______ kW and a heat rejection sink of _______ kW 2) If you were to change the absorption chiller specification to a double effect absorption chiller with a COP of 1.27, the heat source requirement would change to be ______ kW to power the cycle and a heat rejection sink of _______ kW would be needed. 3) Describe what the difference between single and double effect absorption chillers in terms of their heat source requirements. Reference should be made to difference in temperature requirements and a description on an installation that would be suitable for the deployment of each. 4) You have installed a large absorption chiller that provided a chilled water output of 4127kWh in the last 12 months. The electric chiller that this machine replaced operated at an average COP of 4.46. How much electricity did you save in the last 12 months? Technical and Commercial modeling Questions 5 & 6 The following section requires a detailed model to be completed using the template that has been provided. All formulas are to be dynamically referenced within the spreadsheet. There should be no hard coded values within your formulas to enable interrogation in line with modeling best practice. You have been contracted to conduct the technical and commercial analysis of a proposed Cogeneration facility to be installed at an industrial site that operates 24/7. You have mapped the average daily electrical and thermal use profiles over a number of days (supplied as Appendix 1) and note that the profile is consistent each operational day – therefore it can be assumed that the facility has the same electrical and thermal load profile for each day of operation for the purpose of this analysis. The planned cogeneration facility will operate on a 24/7 basis, will not export electricity from site and will provide Heating Hot Water (HHW) to the industrial process through recovery of wasteheat. At times when the thermal demand of the site exceeds the Cogen output, the existing conventional gas boiler will provide “top-up” thermal energy to supplement the site thermal requirements. Use the following assumptions when building your technical model: - The facility operates 360 days per year – 5 shut down days each year - The gas emissions factor is 55.3kg/GJ - The grid electricity emissions factor is 1.32kg/kWh - Required Investment rate: 12.5% - Maintenance costs should not be considered. The proposed facility details for analysis are as follows; Plant sizes to be considered Generator Size (kW) 1760 1195 925 Usable Thermal output (kW) 1840 1300 1085 Genset Heat Rate (HHV - GJ/MWh) 9.37 9.54 10.01 Top-up boiler Efficiency 86% 86% 86% Total facility cost ($/kW installed) $2,781 $3,203 $3,314 Question 5 Under each Scenario, you are to model and identify the following system parameters under operation: a) Total Electrical use of the facility each year (kWh) b) Total Cogen Electrical Generation each year (kWh) c) Total Gas use by the Cogen each year (GJ) d) Total Electricity provided by the grid (top-up) each year (kWh) e) Total Thermal HHW use by the facility each year (kWh) f) Total Cogen Thermal Generation each year (kWh) g) Total Thermal HHW that is provided by the top-up boiler (conventional boiler) (kWh) h) Total Additional Gas used by the top-up boiler each year (GJ) i) Total Gas saved through the use of Cogen thermal output at the facility (GJ) j) Total CO2 savings (electricity and gas) Question 6 Your clients are concerned about the possible increase in the cost of gas in the future. The concern is that gas cost increases will be much larger than any electricity cost increases that will be experienced which may erode the cogeneration business case. Accordingly you are to conduct a financial sensitivity analysis for the following possible pricing scenarios over a 5 year investment term (Note; all figures listed are $2017 and no further time based discounting is required): “Normal” Future pricing Scenario: NORMAL PRICING SCENARIO Year 1 Year 2 Year 3 Year 4 Year 5 Electricity 0.125 0.145 0.16 0.19 0.22 $/kWh Gas 9.76 10.14 10.75 11.43 12.50 $/GJ“High Gas” cost Future pricing Scenario: HIGH GAS PRICING SCENARIO Year 1 Year 2 Year 3 Year 4 Year 5 Electricity 0.125 0.145 0.16 0.19 0.22 $/kWh Gas 9.76 10.50 11.31 13.04 15.52 $/GJ For each of the 3 technical solutions (plant sizes), please identify the following: a) Net Present Value (NPV) under the “Normal” pricing scenario b) Net Present Value (NPV) under the “High Gas” pricing scenario Then considering the best commercial outcome, define: c) What is the best technical solution (system size) under the “Normal” pricing scenario? d) What is the best technical solution (system size) under the “High Gas” pricing scenario? e) Given the investment criteria your client has specified, is investment in the cogeneration facility justified in all, some or none of the technical and pricing scenarios? Please justify your response. SUBMISSION REQUIREMENTS You are required to submit the following items as part of this assessment: - An excel spreadsheet containing your detailed analysis o There should be no “hard coded” variables used within the formulas o The spreadsheet should be logically laid out so that any person reviewing your analysis can follow through the calculations you have used to solve / determine your stated answers and interrogate further if required. o You should have all information required to solve the problem, however, if you need to make any assumptions in your submission, ensure that these assumptions and your justification for their use are clearly defined. - A one page sheet summarizing the answers to all questions posed, this will be in the form of an “Answers” tab within the excel spreadsheet that you submit. All answers on this sheet should be dynamically linked to the answer cell on the worksheet tab that contains the relevant formula. Answers will be clearly labeled for ease of identification o HINT: If your answer is not able to be easily established or interrogated upon cursory review it is of little use to your manager/client REFERENCES (IF APPLICABLE) JAMES, T. and YING, A.C., (1988), “A new technique for producing stencils”, Proc. Int. Cong. on Stencils, ABCD, Melbourne, Australia, February 29-31. Use Harvard referencing styleAPPENDIX ONE – Average Daily electrical and thermal use profiles