Energy efficiency measures - Residential - Building envelope - Apartment building

Template assignment

Base case

• A six storey rectangular apartment building has a floor area of 750 m² and an interior volume of 19,500 m³
• The building is oriented with the short side facing 10° east of north
• The building is heated by a natural gas fired mid-efficiency boiler and is air conditioned with a central reciprocating compressor chiller
• The 450 m² north wall has 10 m² windows
• The south wall has 20 m² windows
• The 1,500 m² west wall has 200 m² windows and 10 m² doors
• The east wall has 100 m² windows and 10 m² doors
• The U value of all windows and doors is 5 (W/m²)/°C
• The only solar shading is 20% during the summer on the east and south windows
• Solar heat gain of windows is 0.65
• Walls are insulated to 2.3 m²-°C/W, floor to 0.7 m²-°C/W and roof to 2.2 m²-°C/W
• Air change rate is 1 per hour
• Set point temperature for space heating and cooling is 23 °C
• Fuel rates are: electricity $0.10/kWh, natural gas $0.40/m³

Proposed case

• New set point temperature for heating is 21 °C, for cooling is 24 °C
• Assume 75% occupancy rate on a daily basis and that set back temperature is 3 °C during non occupied periods
• Insulate roof to 5 m²-°C/W for $30,000
• Reduce air changes to 0.5 per hour by comprehensive caulking and other air leakage prevention, cost is $30,000

Solution

The worked-out solution is the data file selected from within the RETScreen Project Database. The user automatically downloads the Project Database file while downloading the RETScreen software.