Building Overview:

• 6 storey large commercial/retail tower (approximately 60,000 square metres)
• Domestic steam heating system with seamless ERW steel pipe. The heat source is a central steam plant located off-site from the building (80% efficiency). The steam is delivered at low pressures and the peak demand is approximately 4,000 kg/hr.
• Chilled water system with ductile iron piping. 600 tonnes of cooling mounted in roof level mechanical room. Chilled water leaving temperature = 10ºC; Chilled water entering temperature = 16ºC
• Both the steam and chilled water piping was originally insulated however over time the insulation has been removed by contractors and has deteriorated over time.
• Limited domestic water piping, which was excluded from the analysis since a majority of the domestic hot water piping is less than 1 inch (25 mm) in diameter.
• Remaining service life: 30 years for the both the steam and chilled water piping
• Both systems operate for approximately 4,000 hours per year
• Indoor design temperature: 23ºC
• Gas cost: $9.846/GJ
• Electricity Cost: $0.0691/kwh

Modeled Scenarios:

1. Deteriorated or missing insulation on steam and chilled water pipes

2. 50mm thick insulation on steam pipes; 25mm thick insulation on chilled water pipes

Results

Over the course of one year the following savings would result from the use of insulation.

ANNUAL ENERGY AND GREENHOUSE GAS SAVINGS

The following table summarizes the impact on overall building energy consumption.

The estimated payback for the investment in insulation would be less than 6 months for the steam system and over 5 years for the chilled water system.