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Energy Efficiency in Office Buildings

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This is my Masters Thesis. The climatic model is of New Delhi. Software used is called IES-VE.

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Energy Efficiency in Office Buildings

  1. 1. “ Modelling and Parametric Study of a Typical Office Segment for Thermal Comfort and Energy Consumption in New Delhi” By Abhinav Dhaka Internal Guide:Dr.S.Ghosh (VIT University) External Guide:Dr.ir.E.L.C. (Emilia) van Egmond – de Wilde De Ligny(Eindhoven University of Technology)
  2. 2. Climatic Zone Map of India
  3. 3. New Delhi <ul><li>New Delhi is placed at an elevation of 215 meters </li></ul><ul><li>Latitude 28.38 N and Longitude 77.12 E </li></ul><ul><li>Warm weather;Summer:45degC </li></ul><ul><li>Cold Weather;Winter:5degC </li></ul>
  4. 4. Example of an Office Building in New Delhi
  5. 5. Climate Chart
  6. 6. IES-VE <ul><li>Integrated Environmental Solutions-Virtual Environment </li></ul><ul><li>Building energy usage and carbon dioxide emission assessment </li></ul><ul><li>Integrates with other Architectural design softwares e.g., Revit, Google Sketchup, etc. </li></ul>
  7. 7. Tools of IES-VE <ul><li>Thermal </li></ul><ul><ul><li>Thermal </li></ul></ul><ul><ul><li>HVAC </li></ul></ul><ul><ul><li>Macro-Flo-Multi Zone Air Movement </li></ul></ul><ul><li>Lighting </li></ul><ul><li>Solar </li></ul><ul><li>Value </li></ul><ul><li>Cost </li></ul><ul><li>Evacuation </li></ul><ul><li>Mechanical </li></ul><ul><li>Electrical </li></ul><ul><li>CFD </li></ul>
  8. 8. Objective : Bi-directional Functionality <ul><li>To design an indoor thermal environment that satisfies more people and is energy efficient as well; </li></ul><ul><li>To define and quantify the sensitivity of various parameters that would have an impact on the human thermal comfort levels. </li></ul>
  9. 9. Interface
  10. 10. Modelling of an Office Floor North_Zone North_Corridor East_Zone East_Corridor South_Zone South_Corridor West_Zone West_Corridor
  11. 11. Selected Zones <ul><li>North_Zone-N_Z </li></ul><ul><li>West_Zone-W_Z </li></ul><ul><li>South_Zone-S_Z </li></ul><ul><li>East_Zone-E_Z </li></ul><ul><li>North_Corridor-N_Z_C </li></ul><ul><li>West_Corridor-W_Z_C </li></ul><ul><li>South_Corridor-S_Z_C </li></ul><ul><li>East_Corridor-E_Z_C </li></ul>
  12. 12. 3D-Model(Base)
  13. 13. Interior Design
  14. 14. Interior Design
  15. 15. PMV <ul><li>Predicted Mean Vote PMV ..an index that predicts the mean value of the votes of a large group of persons on the following 7-point thermal sensation scale. </li></ul><ul><li>+3 +2 +1 0 -1 -2 -3 </li></ul><ul><li>Hot Warm Slightly Warm Neutral Slightly Cool Cool Cold </li></ul>
  16. 16. PPD <ul><li>Predicted Percentage of Dissatisfied PPD ..an index that predicts the percentage of thermally dissatisfied people.The percentage of a large group of people voting hot,warm,cool or cold on the following 7-point thermal sensation scale. </li></ul>
  17. 17. Heat, Ventilation, Air Conditioning and Thermal Comfort <ul><li>Major Aim:To provide an acceptable indoor climate </li></ul><ul><li>International Standard: ISO 7730 - Moderate Thermal Environments-Determination of PMV and PPD Indices and Specification of the Condition for Thermal Comfort </li></ul><ul><li>Indian Standard: Energy Conservation Building Code of India (2006) </li></ul>
  18. 18. Thermal Comfort <ul><li>Condition of mind which expresses satisfaction with the thermal environment </li></ul><ul><li>Discomfort measure-PMV and PPD (Fanger,1982) </li></ul><ul><li>Local Discomfort </li></ul><ul><li>Individual perceptions and preferences </li></ul>
  19. 19. Thermal Comfort(contd.) <ul><li>According to the new standard – Comfort requirements are specified to be acceptable by at least 80% of the occupants </li></ul><ul><li>Thermal sensation influenced by: </li></ul><ul><ul><li>Clothing </li></ul></ul><ul><ul><li>Physical Activity </li></ul></ul><ul><li>ISO standard for PMV [-0.5<PMV<+0.5] </li></ul>
  20. 20. Humphrey’s Equation <ul><li>T C = 0.534T M + 11.9 </li></ul><ul><li>Where T C = Predicted Indoor Comfort Temperature </li></ul><ul><li>T M = Monthly Mean Outdoor Temperature </li></ul><ul><li>For New Delhi, June :(T M = 38.33 deg C) </li></ul><ul><li>T C = 0.534x38.33 + 11.9 </li></ul><ul><li>= 32.36 deg C </li></ul>
  21. 21. Definitions <ul><li>Parametric Analysis - An experiment designed to discover the differential effects of a range of values of an independent variable. </li></ul><ul><li>Sensitivity Analysis - is the study of how the variation (uncertainty) in the output of a mathematical model can be apportioned, qualitatively or quantitatively, to different sources of variation in the input of a model </li></ul>
  22. 22. Parameters <ul><li>Orientation </li></ul><ul><li>Glazing Area </li></ul><ul><li>Glazing Type </li></ul><ul><li>Thermal Mass(Insulation and Materials) </li></ul><ul><li>Shading(External and Internal) </li></ul>
  23. 23. Base Case <ul><li>External Walls: 20cm thick Concrete, Plaster(Both sides)(0.5cm) </li></ul><ul><li>Internal Walls: 10cm thick Brickwork, Plaster(Both sides)(0.5cm) </li></ul><ul><li>Roof: Clay Tile(5cm) + Felt/Bitumen Layer(0.12cm) + Concrete(10cm)+ Plaster(0.5cm) </li></ul>
  24. 24. Base Case(contd.) <ul><li>Floor: Synthetic Carpet(1cm) + Concrete(10cm) </li></ul><ul><li>Vertical Fenestration(External): 8mm Single Clear Glass + Metal Frame </li></ul><ul><li>Vertical Fenestration(Internal):4mm single Clear Glass </li></ul><ul><li>No Vertical shading, no Interior shading </li></ul><ul><li>Door: Wooden </li></ul>
  25. 25. Base Case(External Wall)
  26. 26. Base Case (Internal Wall)
  27. 27. Base Case (External Glazing)
  28. 28. Base Case (Roof)
  29. 29. U-Value <ul><li>The U-factor measures how well a product prevents heat from escaping. The rate of heat loss is indicated in terms of the U-factor of a window assembly </li></ul><ul><li>U-factor ratings generally fall between 0.20 and 1.20 </li></ul><ul><li>Unit is W/m² K </li></ul>
  30. 30. SHGC(Specific Heat Gain Coefficient) <ul><li>is the fraction of incident solar radiation which enters a building as heat </li></ul><ul><li>Based on solar energy transmittance + inwardly flowing fraction of absorbed solar energy on the entire window </li></ul>
  31. 31. Shading Coeffcient(SC) <ul><li>is defined as the ratio of solar heat gain through a particular glazing to the solar heat gain through a single lite of 1/8&quot; clear glass </li></ul>
  32. 32. Emissivity <ul><li>The ability of a surface to reflect long-wave radiation </li></ul><ul><li>Measured by its emissivity. Emissivity vanes from 1 (100% of long-wave radiation emitted) to 0 (0% emitted). For glass, </li></ul><ul><li>The lower the emissivity, the lower the U-factor </li></ul>
  33. 33. U-Values of Base Case(W/m 2 .K) <ul><li>External Walls = 1.97 </li></ul><ul><li>Internal Walls = 2.11 </li></ul><ul><li>Roofs = 2.76 </li></ul><ul><li>Floors = 2.93 </li></ul><ul><li>Glazing(External) = 4.174 </li></ul><ul><li>Glazing(Internal) = 4.08 </li></ul><ul><li>Door = 2.16 </li></ul>
  34. 34. U-Values recommended by Energy Conservation building Code of India(2006) <ul><li>Roof = Max 0.409 </li></ul><ul><li>Walls = Max 0.352 </li></ul><ul><li>Windows = Max 3.177 </li></ul><ul><li>All Units are W/m 2 K </li></ul>
  35. 35. Internal Gain <ul><li>The heat produced by sources of heat in a building (occupants, appliances, lighting, etc) </li></ul><ul><li>Equipments that contribute to internal gain: </li></ul><ul><ul><li>PC </li></ul></ul><ul><ul><li>Monitor </li></ul></ul><ul><ul><li>Printer </li></ul></ul><ul><ul><li>Photo Copier </li></ul></ul><ul><ul><li>Fax </li></ul></ul><ul><ul><li>Scanner </li></ul></ul><ul><ul><li>Vending Machines </li></ul></ul>
  36. 36. Base Case Model <ul><li>Occupancy: </li></ul><ul><li>Each 5X5 room has an occupancy of 2 </li></ul><ul><li>Equipment: </li></ul><ul><li>2PC’s = 2x160W = 320W </li></ul><ul><li>Lighting: </li></ul><ul><li>Rooms - Power = 13W/m 2 x0.84 = 10.92W/m 2 </li></ul><ul><li>Corridor – Power = 0.92W/m 2 </li></ul><ul><li>There are no internal gains from Equipment in the corridors </li></ul>
  37. 37. Density of Occupancy <ul><li>Room = 10m 2 /person </li></ul><ul><li>Corridor = 20m 2 /person </li></ul>
  38. 38. Profiles <ul><li>Occupancy profile: Weekly Profile follows the 8:00 – 18:00 schedule </li></ul><ul><li>Equipment profile = Weekly Profile follows the 8:00 – 18:00 schedule </li></ul><ul><li>Lighting Schedule = Weekly Profile follows the 8:00 – 18:00 schedule </li></ul>
  39. 39. Sample Weekly Profile
  40. 40. Base Case Simulation
  41. 41. Base Case(Summer Season)
  42. 42. Glazing Area
  43. 43. Glazing Area – 100% - HVAC & Internal Gain-North Zone
  44. 44. Glazing Area – 90% - HVAC & Internal Gain-North Zone
  45. 45. Glazing Area – 80% - HVAC & Internal Gain-North Zone
  46. 46. Glazing Area – 70% - HVAC & Internal Gain-North Zone
  47. 47. Glazing Area – 60% - HVAC & Internal Gain-North Zone
  48. 48. Glazing Area – 50% - HVAC & Internal Gain-North Zone
  49. 49. Glazing Area – 40% - HVAC & Internal Gain-North Zone
  50. 50. Base Peak Hourly Load for North Zone at 100% Glazing
  51. 51. Base Peak Hourly Load West Zone
  52. 52. Base Peak Hourly Load South Zone
  53. 53. Base Peak Hourly Loads East Zone
  54. 54. Variation in Predicted Mean Vote(North Zone)
  55. 55. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor
  56. 56. Glazing Area –90% - HVAC & Internal Gain-North Zone Corridor
  57. 57. Glazing Area – 80% - HVAC & Internal Gain-North Zone Corridor
  58. 58. Glazing Area – 70% - HVAC & Internal Gain-North Zone Corridor
  59. 59. Glazing Area – 60% - HVAC & Internal Gain-North Zone Corridor
  60. 60. Glazing Area –50% - HVAC & Internal Gain-North Zone Corridor
  61. 61. Glazing Area – 40% - HVAC & Internal Gain-North Zone Corridor
  62. 62. Thermal Mass
  63. 63. Glazing Area – 100% - HVAC & Internal Gain-North Zone - Brickwork
  64. 64. Glazing Area – 100% - HVAC & Internal Gain-North Zone – Brickwork-cav-12
  65. 65. Glazing Area – 100% - HVAC & Internal Gain-North Zone – Brickwork-cav-12-ins-eps
  66. 66. Glazing Area – 100% - HVAC & Internal Gain-North Zone – Brickwork-cav-12-ins-polst
  67. 67. Glazing Area – 100% - HVAC & Internal Gain-North Zone – Brickwork-cav-12-ins-polu
  68. 68. Base Peak Hourly Loads (North Zone)
  69. 69. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork
  70. 70. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-cav-12
  71. 71. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-cav-12-ins-polst
  72. 72. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-cav-12-ins-polu
  73. 73. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-cav-12-ins-eps
  74. 74. Base Peak Hourly Loads
  75. 75. Glazing Type
  76. 76. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 6mm-Double-Cav12-North Zone
  77. 77. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 12mm-Double-Cav12-North Zone
  78. 78. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type-Low-e– 12mm-Double-Cav12-North Zone
  79. 79. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type-Low-e – 12mm-Double-Cav12-Argon-North Zone
  80. 80. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 6mm-Double-Cav12-North Zone Corridor
  81. 81. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 12mm-Double-Cav12-North Zone Corridor
  82. 82. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type-Low-e– 12mm-Double-Cav12-North Zone Corridor
  83. 83. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type-Low-e – 12mm-Double-Cav12-Argon-North Zone
  84. 84. Base Peak Hourly Loads (North Zone)
  85. 85. Roof
  86. 86. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 6mm-Double-Cav12-roof-eps-Ins-North Zone
  87. 87. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 6mm-Double-Cav12-roof-eps-Ins-North Zone Corridor
  88. 88. Shading
  89. 89. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 6mm-Double-Cav12-roof-eps-Ins-Int_shading_North Zone
  90. 90. Glazing Area – 100% - HVAC & Internal Gain-North Zone Corridor – Brickwork-Ins-EPS-Glazing Type – 6mm-Double-Cav12-roof-eps-Ins-Int_shading_Ext_shading_North Zone
  91. 91. Base Peak Hourly Loads (North Zone)
  92. 92. Final Model
  93. 93. Final_Model_June
  94. 94. Base Case Model
  95. 95. Final_Glazing_100_Mar_Sept
  96. 96. Final_Glazing_50_Mar_Sept
  97. 97. Decline in Total Energy Consumption Glazing Area(%) TEC(MWh) 100 1.76 90 1.72 80 1.61 70 1.591 60 1.567 50 1.542 40 1.517
  98. 98. Decline in Total Energy Consumption Brickwork and Insulation TEC(MWh) B20 1.754 B20+12mmCav 1.751 EPS 1.742 Polystyrene 1.743 Polurethane 1.742
  99. 99. Decline in Total Energy Consumption Glazing Type TEC(MWh) 6mmDoub+12mmCav 1.712 12mmDoub+12mmCav 1.711 6mmDoub+12mmCav+Argon 1.705 6mmDoub+12mmCav+Low-e 1.707
  100. 100. Decline in Total Energy Consumption Roof Insulation TEC(MWh) EPS 1.533
  101. 101. Decline in Total Energy Consumption Shading TEC(MWh) Internal(Blinds) 1.386 Internal+External(Louvres) 1.226 Final+Glaze50 1.131 (36.8% decline from the base case)
  102. 102. Decline of Total Energy Consumption with respect to Parametric Variation
  103. 103. Final Model
  104. 104. Conclusion <ul><li>Sensitivity in Descending Order: </li></ul><ul><ul><li>Shading Devices </li></ul></ul><ul><ul><li>Insulation(Roof Slab)(Only in Cases where the model is considered to be on the top floor) </li></ul></ul><ul><ul><li>Glazing Area </li></ul></ul><ul><ul><li>Glazing Type </li></ul></ul><ul><ul><li>Insulation(Walls) </li></ul></ul>
  105. 105. Conclusion <ul><li>It was concluded that internal and external shading devices had the most significant effect on thermal comfort in terms of PMV. This was followed by the effect of adding EPS insulation to the roof slab </li></ul><ul><li>A steady decline of Total Energy Consumption after reducing the glazing area was observed which was closely matched by the decline of Total Energy Consumption by adding insulation to the roof slab and by adding internal and external shading devices </li></ul>
  106. 106. Conclusions <ul><li>It was concluded that reducing the glazing area, caused the Peak Hourly Load for the rooms facing East and West direction to drop by a greater extent when compared to rooms facing North and South direction. Therefore orientation of the building would be the determining factor in the case of energy consumption. </li></ul>
  107. 107. Conclusions <ul><li>The prospect of adding brickwork and insulation to the external walls had bought down the Peak Hourly Room Load (North Zone) from 7.786 kW to 7.281 kW </li></ul><ul><li>Orientation follows the rule that buildings facing North-South should be properly insulated with double glazed façade on the East-West and the glazing needs to be reduced or completely eliminated for this orientation. Further studies need to be initiated in order to mark the influence of the change of slightest of orientations on the building energy consumptions. </li></ul>
  108. 108. Recommendations <ul><li>Internal Gains need to be controlled and checked for excessive heat generation and the environment plays a pivotal role in determining the internal gain exuberated from presence of people. </li></ul><ul><li>Remote sensors that bring in the dimming effect in areas that receive plenty of sunlight for major part of the day need to be monitored and managed for effective usage of light sources. </li></ul>
  109. 109. Recommendations <ul><li>Insulation falls short in contributing towards a greener path when it comes to summer season in the composite climate of New Delhi. However the insulation of roof is vital to the transmittance of shortwave radiation which is absorbed by the thermal mass of the room. The thickness and properties need to be verified before usage of such materials before they are installed and a cost benefit analysis needs to be done prior to the usage of the same. </li></ul>
  110. 110. Recommendations <ul><li>Area required for fenestration needs to be hardlined for performance when it comes to a building that orients itself in an East-West Direction. Glazing material with low-e coating filled with argon gas suffers from a shortcoming that makes it a hassle to refill the argon gas from time to time. Once again a proper analysis is required to assess the criteria, location and purpose of the building before determining the amount of fenestration that the building would require. </li></ul>
  111. 111. Recommendations <ul><li>Unnecessary leakage or infiltration could be avoided to a greater extent if the joints around windows and external doors are sealed properly, so as to allow the least amount of infiltration through openings. </li></ul>
  112. 112. Recommendations <ul><li>Studies that take the winter season into account with the addition of night time or day time ventilation need to be taken up so as to get a hindsight on the annual performance of a building with the right choice of active and passive systems. </li></ul>
  113. 113. Final Note <ul><li>Thermal Comfort or Comfortability is completely subjective in nature and the results are an indication not a guideline towards the design of buildings that utilize the power consumption they are offered to the maximum which can be reduced by various design strategies. However it should be kept in mind that perceptions of a group of people is always accurate in first hand encounters and are subject to have a degree of eccentricity in case of a simulation software like IES. </li></ul>
  114. 114. References <ul><li>M.C. Singh, S.N. Garg, Ranjna Jha (2008), “Different glazing systems and their impact on human thermal comfort—Indian scenario”, Building and Environment,Vol. 43, pp 1596 – 1602. </li></ul><ul><li>Elisabeth Gratia and Andre De Herde (2003), “Design of low energy office buildings”, Energy and Buildings, Vol. 35, pp 473 - 491. </li></ul><ul><li>Krishan Kant and S.C. Mullick (2003), “Thermal comfort in a room with exposed roof using evaporative cooling in Delhi”, Building and Environment, Vol.38, pp 185 – 193. </li></ul><ul><li>Vinod Gupta (1992), “Energy Conservation in Office Buildings”, Architecture and Design, pp 57 – 61. </li></ul><ul><li>Marie – Claude Dubois (2001), “Impact of Shading Devices on Daylight Quality in Offices” Department of Construction and Architecture, Lund University, Lund, Sweden. </li></ul>
  115. 115. References <ul><li>Anamika Prasad and Robert W Jones (2001), “A Methodology for Thermal Comfort Enhancement in Housing Design, New Delhi, India”, Seventh International IBPSA Conference, pp 521 -528. </li></ul><ul><li>Charlie Huiezenga, Hui Zhang, Pieter Mattelaer, Tiefeng Yu and Edward Arens and Peter Lyons (2005), “Window Performance for Human Thermal Comfort”, Centre for Built Environment. </li></ul><ul><li>R.J. de Dear and K.G. Leow and S.C. Foo (1991), “Thermal Comfort in Humid Tropics: field Experiments in air conditioned and naturally ventilated buildings in Singapore”, International Journal of Bio-meteorology, Vol.34, pp 259 - 265. </li></ul><ul><li>Simon G. Hodder and Ken Parsons (2007), “The effects of solar radiation on thermal comfort”, International Journal of Bio-meteorology, Vol.51, pp 233 – 250. </li></ul>

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