Adopting Low-cost Alternative for Energy Saving
Energy Saving Potential

This section showcases the energy conservation measures in a building with ECBC envelope with efficient lighting design case. The Energy Conservation Measures considered here are ECBC compliant wall, roof, and window, efficient lighting with Daylight integration, and optimum Window Wall Ratio (WWR). Although there is an energy saving potential from individual ECBC wall, roof, and window, efficient lighting; the overall energy saving potential from the ECBC envelope + efficient as a whole strategies are mentioned below.

  • ECBC wall
  • ECBC roof
  • ECBC window
  • Efficient lighting
  • Daylight integration and optimum WWR

For more information on the ECBC envelope, refer Technical Information Section.

           
Wall
Window
Roof

Lighting Power

Daylight integration

Window Wall Ratio

U-value : 0.391 W/m2°C

U-value : 2.22 W/m2°C

U-value : 0.385 W/m2°C

L.P.D = 6 W/m2

Daylight integration

(20- 30)%

           
   

Impact of Energy Conservation Measures-3 design Strategies:

Energy Performance Index of an ECBC envelope+ efficient lighting with daylight integration and optimum WWR in a day use and 24 hour use building with above mentioned energy conservation measures is in the following range:

Dayuse Building

24 Hour use Building

Lighting: 17 (kWh/m2/annum)
HVAC: 69 (kWh/m2/annum)
EPI of the building (including lighting & HVAC
consumption only): 86 (kWh/m2/annum)

Lighting: 46 (kWh/m2/annum)
HVAC: 163 (kWh/m2/annum)
EPI of the building (including lighting & HVAC
consumption only): 209(kWh/m2/annum)

   
ENERGY SAVING POTENTIAL: 53.8%** (IN COMPARISON TO CONVENTONAL BUILDING CASE)
ENERGY SAVING POTENTIAL: 55%** (IN COMPARISON TO CONVENTONAL BUILDING CASE)

It is observed in air-conditioned buildings for both day use and 24 hour-use, ECBC compliant envelope and efficient lighting with daylight integration & optimum WWR has high energy saving potential. Energy simulation engine was used to quantify energy saving potential in a daytime office and 24 hour buildings. The below graphs shows the reduction in energy consumption in a day time and 24 hour-use buildings by adopting low energy strategies;

Fig 1: Energy saving potential due to ECBC compliant envelope (ECBC envelope + Daylight integration and optimum WWR) in a day use building Fig 2: Energy saving potential due to ECBC compliant envelope (ECBC envelope + Daylight integration and optimum WWR) in a 24hour use building
   

**Note: The energy saving potential of Energy Conservation Measures (ECM2), is calculated with Building Envelope against Base case (conventional building). Low energy design strategies, lighting and HVAC systems in ECM2 are same as in Base case/Conventional Building

It is noted that adopting ECBC measures, the energy saving potential in a day use building is less than that in a 24 hour use building. From the graph below it is also observed that by just using efficient lighting (lower LPD) there is 38.6% reduction in the EPI for day use buildings and 47.6% for 24-hour use buildings.
   
Fig 3: Impact of using efficient lighting on EPI
   

Life Cycle Cost Analysis:

The Life Cycle Cost Analysis (LCC) of this ECBC envelope + efficient lighting with daylight integration and 0.3WWR was carried out under this project. The LCC for a day-use building of this case considering 25 years is 747 Million rupees. The Pay back for incorporating the above strategies is found out to be less than three years. The LCC for a 24 hour-use building of this case, considering 25 years is 2141 Million rupees. The Pay back for incorporating the solar passive design strategies is found out to be one year.


     
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