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Publisher: Earthscan, UK Homepage: www.earthscan.co.uk/?tabid=101807

Energy and the New Reality, Volume 1: Energy Efficiency and the Demand for Energy Services Chapter 8: Municipal Services L. D. Danny Harvey harvey@geog.utoronto.ca.

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Publisher: Earthscan, UK Homepage: www.earthscan.co.uk/?tabid=101807

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  1. Energy and the New Reality, Volume 1:Energy Efficiency and the Demand for Energy ServicesChapter 8: Municipal Services L. D. Danny Harveyharvey@geog.utoronto.ca This material is intended for use in lectures, presentations and as handouts to students, and is provided in Powerpoint format so as to allow customization for the individual needs of course instructors. Permission of the author and publisher is required for any other usage. Please see www.earthscan.co.uk for contact details. Publisher: Earthscan, UKHomepage: www.earthscan.co.uk/?tabid=101807

  2. This chapter discusses • Water supply • Waste water treatment • Solid wastes • Recreational facilities

  3. Energy used to supply water to southern California • Pumping of groundwater, 1.4-2.2 MJ/m3, or • Diversion, 9 MJ/m3, or • Desalination of seawater, 13-14 MJ/m3, or • Treatment 0.1-0.2 MJ/m3 • Local distribution 0.5-2.7 MJ/m3 • Provision of bottled water 5600-10,200 MJ/m3

  4. Measures to reduce energy use in supplying water • Reduce leakage (30-50% of the water that enters the supply system in developing country cities is typically lost) • Improve pumping system (can reduce electricity use by 20-40%) • Reduce waste by end users • Improve desalination (where applicable) • Discourage use of bottled water

  5. Wastewater treatment • The biggest energy savings is through recovery and use of all of the biogas that is produced from the anaerobic digestion of sewage sludge • The pending shortage of P will require eventual recovery of P from sewage for use as a fertilizer. Normal procedures are energy-intensive (150 MJ/kgN); extraction from minimally diluted urine would require much less energy (65 MJ/kgN)

  6. Solid wastes • Landfilling • Incineration (or pyrolysis or gasification) • Anaerobic digestion • Composting • Mechanical biological treatment (MBT) - separate recyclable materials (metals, glass, plastic) - digest or compost organic materials

  7. Items to consider in assessing the lifecycle energy balance of different waste management options • Energy required to collect, clean and sort materials that are used by secondary production facilities • Energy used for primary and secondary production facilities • Energy value of co-products produced at primary or secondary production facilities • Energy costs of disposal of wastes associated with primary and secondary production • Electrical or useful thermal energy produced through incineration

  8. Items (continued) • Efficiency of methods that would produce the heat and electricity that are otherwise produced through incineration • The efficiency with which wood that is saved through the recycling of paper could be used to generate heat or electricity • The ratio with which recycled fibres can substitute for virgin fibres in the production of paper • Capture and emission of methane from landfills

  9. Figure 8.1a,b: Material flows for cases without and with recycling but without losses Source: Boustead (2008, Plastics Recycling – An Overview, Plastics Europe, www.plasticseurope.org)

  10. Figure 8.1c: Recycling (m x f) with losses (F x mf) Source: Boustead (2008, Plastics Recycling – An Overview, Plastics Europe, www.plasticseurope.org)

  11. Figure 8.2: Recycling of two materials with downcycling Source: Boustead (2008, Plastics Recycling – An Overview, Plastics Europe, www.plasticseurope.org)

  12. General results • Recycling of paper and cardboard is clearly and consistently superior to any alternative option from an energy point of view • Recycling of steel and aluminium is strongly superior to any alternative • Recycling of glass is preferable to incineration or landfilling • Recycling of plastics is preferable to incineration when cleaning is not necessary, but incineration with electricity generation can otherwise be better from an energy point of view

  13. Incineration tends to provide very little energy because • Some materials yield little or no energy • Water that is vaporized subtracts from the net energy supplied • The efficiency of generating electricity is low (20-30%) because of the need to limit the temperature and pressure of combustion due to impurities and irregularities in the waste stream

  14. Figure 8.3 Efficiency in generating electricity from waste in comparison to generation of electricity from fossil fuels or biomass

  15. Figure 8.4a Organic carbon flow with landfilling Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  16. Figure 8.4b: Organic carbon flow with composting Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  17. Figure 8.4c: Organic carbon flow with anaerobic digestion Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  18. Figure 8.4d: Organic carbon flow with mechanical-biological treatment (MBT) Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  19. Figure 8.4e: Organic carbon flow with incineration Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  20. Figure 8.5a Fossil fuel carbon flow with landfilling Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  21. Figure 8.5b Fossil fuel carbon flow with MBT Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  22. Figure 8.5c Fossil fuel carbon flow with incineration Source: EC (2001b) Source: EC (2001, Integrated Pollution Prevention and Control (IPPC), Reference Document on Best Available Techniques in the Glass Manufacturing Industry, www.eippcb.jrc.es/pages/FActivities.htm)

  23. Figure 8.6CO2-equivalent CH4 emission from landfill when some fraction of the generated CH4 is captured and used to produce electricity, and the rest is emitted to the atmosphere. A credit for displaced coal-generated electricity is given here.

  24. Recreational Facilities • Indoor skating rinks • Indoor swimming pools, gymnasia and recreation complexes

  25. Figure 8.7 Breakdown of energy use in a typical Canadian indoor skating arena

  26. Energy saving opportunities for indoor skating rinks • Supply required heat from the condenser of the chiller • Increase (for new rinks) the thickness of insulation beneath the concrete floor slab • Increase insulation of the building and install enthalpy exchangers • Install low-emissivity ceiling (to reduce infrared heat flow to the ice surface) • Place variable speed drives on brine pumps in the refrigeration system

  27. Net result • Easily a 50% reduction in energy use compared to conventional designs in Canada • Energy load reduced to the point where a significant fraction of the remaining load could be met with rooftop PV

  28. Indoor swimming pools • Higher relative humidity (RH) will reduce evaporation from (and evaporative cooling of) the pool • However, without high-performance glazing, condensation problems will occur • Normally, high rates of air exchange are created so as to maintain the RH low enough to avoid condensation problems, which further increases the energy requirements

  29. A high-performance envelope • Directly reduces heat loss through the envelope • Permits maintenance of a higher indoor RH because inner surface temperatures will be warmer, thereby reducing evaporative cooling of the pool • Permits lower rates of air exchange with the outside, because RH does not need to be kept as low A pool in Germany built to the Passive House standard is expected to achieve a savings of 60-70% in total energy use compared to pools meeting the current German building code

  30. Gymnasia:Construction to the Passive House standard results in ventilation airflow alone providing enough heat to the gym, and allows a single ventilation system with air flowing from the gym to the changing rooms (with additional heating due to the different thermal requirements of the gym and changing rooms) and then to the outside

  31. Recreation complexes: • Lend themselves to the use of heat exchangers and heat pumps to match heat sources and heat requirements • Use of just 4 heat exchangers in a complex in Mexico (involving a hospital, laundry centre, sports centre with a swimming pool and a family health centre) would save almost 40% of total heating requirements

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