1 / 80

Drive for Energy Efficiency

Drive for Energy Efficiency. Roger S H Lai 23.04.2007. Why need to pay attention to energy efficiency?.

annick
Download Presentation

Drive for Energy Efficiency

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Drive for Energy Efficiency Roger S H Lai 23.04.2007

  2. Why need to pay attention to energy efficiency? • 1. Try to arrest the runaway increase of carbon dioxide. If the world does not do anything now and let business as usual, then by 2050, there will be so much climate change that the situation would be irreversible. (El Gore, IEA study: Energy Technology Perspectives 2006 :Scenarios and Strategies to 2050) • 2. Fossil fuel is finite

  3. Reference Scenario:Implications for CO2 Emissions 50 40 Increase = 14.3 Gt (55%) 30 Gt of CO2 20 10 0 1980 1990 2004 2010 2015 2030 Coal Oil Gas Half of the projected increase in emissions comes from new power stations, mainly using coal & mainly located in China & India

  4. Alternative Policy Scenario:Global Savings in Energy-Related CO2 Emissions 42 Increased nuclear (10%) Increased renewables (12%) Power sector efficiency & fuel (13%) 38 Electricity end-use efficiency (29%) Reference Scenario Fossil-fuel end-use efficiency (36%) 34 Gt of CO2 Alternative Policy Scenario 30 26 2004 2010 2015 2020 2025 2030 Improved end-use efficiency of electricity & fossil fuels is accounts for two-thirds of avoided emissions in 2030

  5. Ways to save energy and reduce emission (1) • Use a different way of energy generation rather than fossil fuel: e.g. by 2030, contributions of reduction from: Renewable energy (12%), nuclear (10%) • Improve the fuel to energy conversion of fossil fuel. • Improve the loss of energy transmission to end use: • Improve energy efficiency at end-use: potential of contributing up to 65% of the projected growth reduction • CO2 sequestration (probably not mature enough to be significant)

  6. Compounding losses…or savings—so start saving at the downstream end

  7. What other countries are doing? (1) Advanced countries have set ambitious goals. One scenario studied in Germany is: a) maintain current level of total energy consumption while maintaining economic growth, build no more fossil fuel power stations; b) phase out existing nuclear stations c) build renewables to replace (b) d) improve energy efficiency by 50% by 2050 to meet new energy needs

  8. What other countries are doing? (2) UK: similar consideration. Carbon tax introduced. Aim to reduce carbon dioxide by 50% by 2050. USA: e.g. Government buildings to save energy of 2% per year from 2005 to 2015: that is 20% in ten years. China: Laws for RE and for EE established in recent years.

  9. Are these energy efficiency targets realistic? • With innovative approaches, and changes in conventional installation practices, such targets are realistic. • Cases quoted by Rocky Mountain Institute: over 50% energy eff. improvement achieved • Case quoted by Scientific America in 9/2006 issue: factory in Germany 43% improvement. • Our studies : A simple novel project at BATCX achieved 16% improvement • Let’s see some examples

  10. Lighting • T5 tubes much more energy efficient • “Plug and enhance” devices now available • Electronics ballasts incur less loss • Use of reflective luminaires • Much of the existing lighting systems could be retrofitted • Suitable de-lamping

  11. Fluorescent Tubes Lighting (1) • Power (lamp only)

  12. Fluorescent Tubes Lighting (2) • Coating • Halo-phosphate (standard T8) • Tri-phosphate (standard provision for T5)

  13. Electronics ballasts • Potential Energy Saving • Take 1200mm system as an example

  14. Plug and Enhance (7) • PnE not using QEB • It use tri-phosphors T8 tube with shorter than standard length and lamp power together with an additional EMB • 11% reduction in energy consumption

  15. Use of LED Exit Signs • Conventional Exit Sign • 18W • 2-year service life • LED Exit Sign • 3W • 5-year service life • Estimated savings: 24,800 kWh/annum

  16. Replacement of Incandescent Lamps Incandescent lamps CFLs

  17. A/C system (1) Design • Water-cooled a/c system more energy efficient than air-cooled a/c system (more than 15%, up to 30% possible). Use of fresh water cooling towers. • Improved piping and ductwork design, minimize bends, use larger size pipes and ducts. • Do not excessively oversize the pumps and motors.

  18. A/C systems (2) New design and retrofit • Automatic tube cleaning device • Use of PROA to reduce scaling on the refrigerant side of the heat exchanger • VSD for the air flow control and liquid flow • CO2 sensing and control • Operational control: water temperature reset, air temperature reset, air duct static pressure reset

  19. Typical areas for big savings • Thermal integration • Power systems • Designing friction out of fluid-handling systems • Water/energy integration • Superefficient and heat-driven refrigeration • Superefficient drivesystems • Advanced controls Let’s look at one example: pumping systems (information from Rocky Mountain Institute www.rmi.org)

  20. Why focus on pumping? examples • Pumping is the world’s biggest use of motors • Motors use 3/5 of all electricity • A big motor running constantly uses its capital cost in electricity every few weeks • RMI (1989) and EPRI (1990) found ~1/2 of typical industrial motor-system energy could be saved by retrofits costing <US$0.005 (1986 $) per saved kWh—a ~16-month payback at a US$0.05/kWh tariff. Why so cheap? Buy 7 savings, get 28 more for free! • Downstream savings are often bigger and cheaper—so minimize flow and friction first

  21. EXAMPLE optional vs. 1% 99% hydraulic pipe layout Then minimize piping friction 1% 99% Boolean pipe layout

  22. New design mentality • • Redesigning a standard (supposedly optimized)industrial pumping loop cut power from 70.8 to 5.3 kW (–92%), cost less to build, and worked better • Just two changes in design mentality

  23. New design mentality, an example 1. Big pipes, small pumps (not the opposite)

  24. No new technologies, just two design changes 2. Lay out the pipes first, then the equipment (not the reverse)

  25. No new technologies, just two design changes • Fat, short, straight pipes — not skinny, long, crooked pipes! • Benefits counted • 92% less pumping energy • Lower capital cost • “Bonus” benefit also captured • 70 kW lower heat loss from pipes • Additional benefits not counted • Less space, weight, and noise • Clean layout for easy maintenance access • But needs little maintenance—more reliable • Longer equipment life • Count these and save…~98%?

  26. This case is archetypical • Most technical systems are designed to optimize isolated components for single benefits • Designing them instead to optimize the whole system for multiple benefits typically yields ~3–10x energy/ resource savings, and usually costs less to build, yet improves performance • We need a pedagogic casebook of diverse examples…for the nonviolent overthrow of bad engineering (RMI’s 10XE (“Factor Ten Engineering” project—partners welcome)

  27. …or how about this? return from tower to chiller return from tower Which of these layouts has less capex & energy use? Condenser water plant: traditional design return from tower to chiller return from tower to chiller return from tower to chiller • Less space, weight, friction, energy • Fewer parts, smaller pumps and motors, less installation labor • Less O&M, higher uptime

  28. Summary of improved piping and ductwork • Reduce bends to minimize obstructions to flow • Use larger diameter pipes and smaller pumps/motors • Power proportional to v3 • Layout the pipe and duct first before laying out the components

  29. Trial of the concept at BATCX • BATCX as the trial site for “big pipe small pump’concept • BATCX was commissioned in 1999 • 2 x 330kW sea water-cooled ammonia chiller • 1/F sea water pump room pumping cooling water to 4/F chiller plant room

  30. BATCX – Sea Water Flow Schematic Diagram

  31. Proposed Modification

  32. Existing Configuration

  33. Proposed Design

  34. Proposed Modification - 1/F Pump Roomsome bends eliminated Before After

  35. Proposed Modification - 4/F Chiller Plant with one section of pipe enlarged After Before

  36. Impeller Trimming (1) • The operating point is shifted to the right after the pipe work modification as frictional loss is reduced and the flow is increased

  37. Impeller Trimming (2) The impeller should be trimmed down as to reduce the flow back to the point before the pipe work modification

  38. Impeller Trimming (3) The distance between the original pump curve and the one extrapolated from the new operating point dictates how much the impeller should be trimmed down

  39. Impeller Trimming (4) The impeller was trimmed down from 228.6mm to 221.6mm (7mm) in diameter Improvement recorded ~8%

  40. High Efficiency Motor EFFI of ECMEMP

  41. Power Consumption of Sea Water Pump #2 at Different Stages 4.00 3.50 3.00 2.50 Power Consumption (kW) 2.00 1.50 1.00 0.50 0.00 Before Pipe Work Modification After Pipe Work Modification After Impeller Trimming After Installation of High Efficiency Motor

  42. Conclusion from the trial project in BATCX • Energy saving from the modified changes in reducing pipe bends, and enlarging one section of the pipe gives about 8% improvement in energy efficiency. • Use of high-efficiency motor gives another 8% • More energy reductions could be achievable if the pipework is designed from scratch.

  43. Water-cooled a/c system • Government conducted a study in 1999, water-cooled a/c much more efficient than air-cooled a/c • Launched the pilot scheme for using fresh water cooling towers for water-cooled a/c systems • Some installed systems have achieved good results

  44. Development

  45. Private Sector Participation • November 2005 figures • 46 Applications from New Development 1,489,556 m2 (51% of newly constructed buildings) • 107 Applications from Existing Development 3,538,083 m2 (5% of existing buildings)

  46. Achievement (1)

  47. Achievement (2) • Completed cooling capacities: 362,533 kW • Annual energy saving: 35,120,000 kWh/yr • Annual emission reduction: • CO2 24,584 tonnes/yr • NOX 63 tonnes/yr • SO2 49 tonnes/yr • Particulate 3 tonnes/yr

  48. Benefits of Pilot Cases • Lower heat rejection system energy cost for replacing air-cooled dry radiators by cooling towers : 88% • Lower condenser water temperature : 8oC in summer • Improve chiller plant efficiency : 23%

  49. A shopping mall • 12 x 2,333kW cooling towers (total heat rejection: 27,996kW) • Annual energy saving: 4,870,000 kWh/yr

  50. A commercial complex • 9 x 3,336kW cooling towers (total heat rejection: 30,024kW) • Annual energy saving: 4,650,000 kWh/yr

More Related