TEST BANK FOR Energy Management 7th Edition By Pawlik, Klaus-Dieter E. and Capehart, Barney L (Solutions Manual)

Exam (elaborations) TEST BANK FOR Energy Management 7th Edition By Pawlik, Klaus-Dieter E. and Capehart, Barney L (Solutions Manual) Solutions Manual for Guide to Energy Management, Seventh Edition Klaus-Dieter E. Pawlik v Table of Contents Chapter 1: Introduction to Energy Management............... ....................1 Chapter 2: The Energy Audit Process: An Overview.........................15 Chapter 3: Understanding Energy Bill...................................................21 Chapter 4: Economic Analysis and Life Cycle Costing......................37 Chapter 5: Lighting....................................................................................53 Chapter 6: Heating, Ventilating, and Air Conditioning.....................69 Chapter 7: Combustion Processes and the Use of Industrial Wastes.......................................................83 Chapter 8: Steam Generation and Distribution..................................103 Chapter 9: Control Systems and Computers.......................................111 Chapter 10: Maintenance..........................................................................119 Chapter 11: Insulation...............................................................................127 Chapter 12: Process Energy Management.............................................141 Chapter 13: Renewable Energy Sources and Water............................149 Management Supplemental..........................................................................158 1 Chapter 1 Introduction to Energy Management Problem: For your university or organization, list some energy management projects that might be good “first ones,” or early selections. Solution: Early projects should have a rapid payback, a high probability of success, and few negative consequences (increasing/decreasing the air-conditioning/heat, or reducing lighting levels). Examples: Switching to a more efficient light source (especially in conditioned areas where one not only saves with the reduced power consumption of the lamps but also from reduced refrigeration or air-conditioning load). Repairing steam leaks. Small steam leaks become large leaks over time. Insulating hot fluid pipes and tanks. Install high efficiency motors. And many more 2 Solutions Manual for Guide to Energy Management Problem: Again for your university or organization, assume you are starting a program and are defining goals. What are some potential first-year goals? Solution: Goals should be tough but achievable, measurable, and specific. Examples: Total energy per unit of production will drop by 10 percent for the first and an additional 5 percent the second. Within 2 years all energy consumers of 5 million British thermal units per hour (Btuh) or larger will be separately metered for monitoring purposes. Each plant in the division will have an active energy management program by the end of the first year. All plants will have contingency plans for gas curtailments of varying duration by the end of the first year. All boilers of 50,000 lbm/hour or larger will be examined for waste heat recovery potential the first year. Introduction to Energy Management 3 Problem: Perform the following energy conversions and calculations: a) A spherical balloon with a diameter of ten feet is filled with natural gas. How much energy is contained in that quantity of natural gas? b) How many Btu are in 200 therms of natural gas? How many Btu in 500 gallons of 92 fuel oil? c) An oil tanker is carrying 20,000 barrels of #2 fuel oil. If each gallon of fuel oil will generate 550 kWh of electric energy in a power plant, how many kWh can be generated from the oil in the tanker? d) How much coal is required at a power plant with a heat rate of 10,000 Btu/kWh to run a 6 kW electric resistance heater constantly for 1 week (16 8 hours)? e) A large city has a population which is served by a single electric utility which burns coal to generate electrical energy. If there are 500,000 utility customers using an average of 12,000 kWh per year, how many tons of coal must be burned in the power plants if the heat rate is 10,500 Btu/kWh? f) Consider an electric heater with a 4,500 watt heating element. Assuming that the water heater is 98% efficient, how long will it take to heat 50 gallons of water from 70 degree F to 140 degree F? 4 Solutions Manual for Guide to Energy Management Solution: a) V = 4/3 (PI) P = 4/3 × 3.14 × 53 523.33 ft3 E = V × 1,000 Btu/cubic foot of natural gas = 523.33 ft3 X 1,000 Btu/ft3 = 523,333 Btu b) E = 200 therms × 100, 000 Btu/therm of natural gas = 20,000,000 Btu E = 500 gallons × 140,000 Btu/gallon of #2 fuel oil 70,000,000 Btu c) E = 20,000 barrels × 42 gal./barrel × 550 kWh/gal. 4.6E+08 kWh d) V = 10,000 Btu/kWh × 6 kW × 168 h/25,000,000 Btu/ton coal = 0.40 tons of coal e) V = 500,000 cus. × 12,000 kWh/cus. × 10,500 Btu/kWh × I ton/25,000,000 Btu = 2,520,000 tons of coal f) E = 50 gal. × 8.34 lbm/gal. × (140F - 70F) × 1 Btu/F/lbm = 29,190 Btu = 29,190 Btu/3,412 Btu/kWh = 8.56 kWh = 8.56 kWh/4.5 kW/0.98 = 1.94 h Introduction to Energy Management 5 Problem: If you were a member of the upper level management in charge of implementing an energy management program at your university or organization, what actions would you take to reward participating individuals and to reinforce commitment to energy management? Solution: The following actions should be taken to reward individuals and reinforce commitment to energy management: Develop goals and a way of tracking their progress. Develop an energy accounting system with a performance measure such as Btu/sq. ft or Btu/unit. Assign energy costs to a cost center, profit center, an investment center or some other department that has an individual responsibility for cost or profit. Reward (with a monetary bonus) all employees who control cost or profit relative to the level of cost or profit. At the risk of being repetitive, note that the level of cost or profit should include energy costs. 6 Solutions Manual for Guide to Energy Management Problem: A person takes a shower for ten minutes. The water flow rate is three gallons per minute, the temperature of the shower water is 110 degrees E Assuming that cold water is at 65 degrees F, and that hot water from a 70% efficient gas water heater is at 140 degrees F, how many cubic feet of natural gas does it take to provide the hot water for the shower? Solution: E = 10 min × 3 gal./min × 8.34 lbm/gal × (110 F - 65 F) × 1 Btu/lbm/F = 11,259 Btu V = 11,259 Btu × 1 cubic foot/1,000 Btu/0.70 = 16.08 cubic feet of natural gas Introduction to Energy Management 7 Problem: An office building uses 1 Million kWh of electric energy and 3,000 gallons of #2 fuel oil per year. The building has 45,000 square feet of conditioned space. Determine the Energy Use Index (EUI) and compare it to the average EUI of an office building. Solution: E(elect.) = 1,000,000 kWh/yr. × 3,412 Btu/kWh = 3,412,000,000 Btu/yr. E(#2 fuel) = 3,000 gal./yr. × 140,000 Btu/gal. = 420,000,000 Btu/yr. E = 3,832,000,000 Btu/yr. EUI = 3,832,000,000 Btu/yr./45,000 sq. ft = 85,156 Btu/sq. ft/yr. which is less than the average office building 8 Solutions Manual for Guide to Energy Management Problem: The office building in Problem 1.6 pays $65,000 a year for electric energy and $3,300 a year for fuel oil. Determine the Energy Cost Index (ECI) for the building and compare it to the ECI for an average building. Solution: ECI = ($65,000 + $3,300)/45,000 sq. ft = $1.52/sq. ft/yr. which is greater than the average building Introduction to Energy Management 9 Problem: As a new energy manager, you have been asked to predict the energy consumption for electricity for next month (February). Assuming consumption is dependent on units produced, that 1,000 units will be produced in February, and that the following data are representative, determine your estimate for February. ————————————————————— Units Consumption Average Given: Month produced (kWh) (kWh/unit) ————————————————————— January 600 600 1.00 February 1,500 1,200 0.80 March 1,000 800 0.80 April 800 1,000 1.25 May 2,000 1,100 0.55 June 100 700 7.00 Vacation month July 1,300 1,000 0.77 August 1,700 1,100 0.65 September 300 800 2.67 October 1,400 900 0.64 November 1,100 900 0.82 December 200 650 3.25 1-week shutdown January 1,900 1,200 0.63 Solution: First, since June and December have special circumstances, we ignore these months. We then run a regression to find the slope and intercept of the process model. We assume that with the exception of the vacation and the shutdown that nothing other then the number of units produced affects the energy used. Another method of solving this problem may assume that the weather and temperature changes also affects the energy use. 10 Solutions Manual for Guide to Energy Management ————————————————————————— Units Consumption Average Month produced (kWh) (kWh/unit) ————————————————————————— January 600 600 1.00 February 1,500 1,200 0.80 March 1,000 800 0.80 April 800 1,000 1.25 May 2,000 1,100 0.55 July 1,300 1,000 0.77 August 1,700 1,100 0.65 September 300 800 2.67 October 1,400 900 0.64 November 1,100 900 0.82 January 1,900 1,200 0.63 From the ANOVA table, we see that if this process is modeled linearly the equation describing this is as follows: kWh (1,000 units) = 623 + 0.28 × kWh/unit produced = 899 kWh 2,500 2,000 1,500 1,000 500 January Febuary March April May June July August September October November December Units produced Comsumption (kWh) Introduction to Energy Management 11 —————————————————————————————————— Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Lower 95. 0% Upper 95.0% —————————————————————————————————— Intercept 623. 93. 6. 9.19E-05 411. 834. 411. 834. X Variable 1 0, 0. 3. 0. 0, 0. 0. 0. —————————————————————————————————— SUMMARY OUTPUT ———————————— Regression Statistics ———————————— Multiple R 0. R Square 0. Adjusted R Square 0. Standard Effort 118. Observations 11 ———————————— ANOVA —————————————————————————— df SS MS F Significance F —————————————————————————— Regression 1 .9788 .9 15.54545 0. Residual 9 ..07 Total 10 .5455 —————————————————————————— 500 1,000 1,500 2,000 2,500 • • • • • • • • • • • 1,400 1,200 1, Units produced Energy Used (kWh) 12 Solutions Manual for Guide to Energy Management Problem: For the same data as given in Problem 1.8, what is the fixed energy consumption (at zero production, how much energy is consumed and for what is that energy used)? Solution: By looking at the regression run for problem 1.8 (see ANOVA table), we can see the intercept for the process in question. This intercept is probably the best estimate of the fixed energy consumption: 623 kWh. This energy is probably used for space conditioning and security lights. Introduction to Energy Management 13 Problem: Determine the cost of fuel switching, assuming there were 2,000 cooling degree days (CDD) and 1,000 units produced in each year. Given: At the Gator Products Company, fuel switching caused an increase in electric consumption as follows: —————————————————————————— Actual energy Expected consumption energy after consumption switching fuel —————————————————————————— Electric/CDD 75 million Btu 80 million Btu —————————————————————————— Electric/units of production 100 million Btu 115 million Btu —————————————————————————— The base year cost of electricity is $15 per million Btu, while this year’s cost is $18 per million Btu. Solution: Cost variance = $18/million Btu - $15/million Btu = $3/million Btu Increase cost due to cost variance = Cost variance × Total Actual Energy Use = ($3/million Btu) × ((80 million Btu/CDD) × (2,000 CDDs) + (115 million Btu/unit) × (1,000 units)) = $825,000 CDD electric variance = 2,000 CDD × (80 - 75) million Btu/CDD = 10,000 million Btu Units electric variance = 1,000 units × (115 - 100) million Btu/unit = 15,000 million Btu 14 Solutions Manual for Guide to Energy Management Increase in energy use = CDD electric variance + Units electric variance = 10,000 million Btu + 15,000 million Btu = 25,000 million Btu Increase cost due to increased energy use = (Increase in energy use) × (Base cost of electricity) = 25,000 billion Btu × $15/million Btu = $375,000 Total cost of fuel switching = Increase cost due to increased energy use + Increased cost due to cost variance = $375,000 + $825,000 = $1,200,000 15 Chapter 2 The Energy Audit Process: An Overview Problem: Compute the number of heating degree days (HDD) associated with the following weather data. Tempera- 65F -Tem- ture Number perature Hours Given: Time Period (degrees F) of hours (degrees F) × dT Midnight - 4:00 AM :00 AM - 7:00 AM :00 AM - 10:00 AM :00 AM - Noon 22 2 43 86 Noon - 5:00 PM :00 PM - 8:00 PM :00 PM - Midnight ——— 1,028 Solution: From the added columns in the given table, we see that the number of hours times the temperature difference from 65 degrees F is 1,028 F-hours. Therefore, the number of HDD can be calculated as follows: HDD = 1,028 F-hours/24 h/day = 42.83 degree-days 16 Solutions Manual for Guide to Energy Management Problem: Select a specific type of manufacturing plant and describe the kinds of equipment that would likely be found in such a plant. List the audit data that would need to be collected for each piece of equipment. What particular safety aspects should be considered when touring the plant? Would any special safety equipment or protection be required? Solution: The following equipment could be found in a wide variety of manufacturing facilities: Equipment Audit data Heaters Power rating Use characteristics (annual use, used in conjunction with what other equipment, how is the equipment used?) Boilers Power rating Use characteristics Fuel used Air-to-fuel ratio Percent excess air Air-conditioners Power rating Chillers Efficiency Refrigeration Cooling capacity Use characteristics Motors Power rating Efficiency Use characteristics Lighting Power rating Use characteristics Air-compressors Power rating Use characteristics Efficiency Various air pressures An assessment of leaks The Energy Audit Process: An Overview 17 Specific process equipment for example for a metal furniture plant one may find some sort of electric arc welders for which one would collect its power rating and use characteristics. The following include a basic list of some of the safety precautions that may be required and any safety equipment needed: Safety precaution Safety equipment As a general rule of thumb the auditor should never touch anything: just collect data. If a measurement needs to be taken or equipment manipulated ask the operator. Beware of rotating machinery Beware of hot machinery/pipes Asbestos gloves Beware of live circuits Electrical gloves Have a trained electrician take any electrical measurements Avoid working on live circuits, if possible Securely lock and tag circuits and switches in the off/open position before working on a piece of equipment Always keep one hand in your pocket while making measurements on live circuits to help prevent accidental electrical shocks. When necessary, wear a full face respirator mask with adequate filtration particle size. Use activated carbon cartridges in the mask when working around low concentrations of noxious gases. Change cartridges on a regular basis. Use a self-contained breathing apparatus for work in toxic environments. Use foam insert plugs while working around loud machinery to reduce sound levels by nearly 30 decibels (in louder environments hearing protection rated at higher noise levels may be required) Always ask the facility contact about special safety precautions or equipment needed. Additional information can be found in OSHA literature. For our metal furniture plant: Avoid looking directly Tinted safety goggles at the arc of the welders 18 Solutions Manual for Guide to Energy Management Problem: Section 2.1.2 of the Guide to Energy Management provided a list of energy audit equipment that should be used. However, this list only specified the major items that might be needed. In addition, there are a number of smaller items such as hand tools that should also be carried. Make a list of these other items, and give an example of the need for each item. How can these smaller items be conveniently carried to the audit? Will any of these items require periodic maintenance or repair? If so, how would you recommend that an audit team keep track of the need for this attention to the operating condition of the audit equipment? Solution: Smaller useful audit equipment may include: A flashlight Extra batteries A hand-held tachometer A clamp-on ammeter Recording devices These smaller items can be conveniently be carried in a tool box. As with most equipment, these items will require periodic maintenance. For example, the flashlight batteries and light bulbs will have to be changed. For these smaller items, one could probably just include the periodic maintenance as part of a pre-audit checklist. For items that require more than just cursory maintenance, one could include the item in their periodic maintenance system. The Energy Audit Process: An Overview 19 Problem: Section 2.2 of the Guide to Energy Management discussed the point of making an inspection visit to a facility at several different times to get information on when certain pieces of equipment need to be turned on and when they are unneeded. Using your school classroom or office building as a specific example, list some of the unnecessary uses of lights, air conditioners, and other pieces of equipment. How would you recommend that some of these uses that are not necessary