Adopting Low-cost Alternative for Energy Saving
Energy Saving Potential

This section showcases the energy conservation measures in a building with ECBC envelope and efficient lighting case. The Energy Conservation Measures considered here are ECBC compliant wall, roof & window, and efficient lighting with Daylight integration and optimum Window Wall Ratio (WWR). The strategies are mentioned here under.

  • 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 Density*

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 ECBC envelope:

Energy Performance Index of an ECBC envelope and efficient lighting with daylight integration & 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: 78 (kWh/m2/annum)
EPI of the building (including lighting & HVAC
consumption only): 95 (kWh/m2/annum)

Lighting: 46 (kWh/m2/annum)
HVAC: 184 (kWh/m2/annum)
EPI of the building (including lighting & HVAC
consumption only):231 (kWh/m2/annum)

   
ENERGY SAVING POTENTIAL: 51%** (IN COMPARISON TO CONVENTONAL BUILDING CASE)
ENERGY SAVING POTENTIAL: 52%** (IN COMPARISON TO CONVENTONAL BUILDING CASE)

It is also observed in air-conditioned buildings for both day use and 24 hour-use, ECBC compliant envelope + LPD 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 envelope and efficient lighting measures, the energy saving potential in a day use building is less than that in a 24 hour use building. 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 36.2% reduction in the EPI for day use buildings and 41.5% for 24-hr 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 and efficient lighting with daylight integration and optimum WWR of 0.30 was carried out under this project. The LCC of this case in day-use building considering 25yrs is 766 Million Rs and the Pay back is found out to be as 2 yrs. The LCC of this case in 24-hr use building considering 25yrs is 1976Million Rs and the Pay back for is found out to be as 1 yr.


     
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