The heat is on - commercial imperative for building owners and managers
With HVAC now accounting for around 40% of total building energy consumption, owners are looking for more efficient HVAC systems and solutions to improve their energy efficiency ratings and reduce maintenance costs. Such upgrades give a new lease of life to existing and ageing properties in order to attract new long-term tenants and add value to their asset.
While there are a number of ways to save energy and cut costs on an individual basis, the most effective way to reduce demand on the grid and operating systems is to have an efficient HVAC strategy in place which takes an integrated approach to the building’s design.
The combination of high efficiency equipment with smart design principles such as building orientation, selection of materials and natural cooling and heating features, can significantly optimise a buildings energy performance.
HVAC solutions can be low cost or extend to major upgrades and capital expenditure depending on what level of innovation is possible within existing systems and the age, design and layout of the building. Keys strategies include:
- Reducing demand on mechanical heating and cooling systems through improved building insulation, high performance window glazing, external window shading and minimising air leakage
- Optimising existing HVAC systems by checking control systems and thermostats to ensure the right amount of heat and air is provided when and where it is needed. Modifying distribution and ventilation system layouts is another way to reduce the demand for fan power
- Upgrading HVAC systems in favour of options that use passive heat transfer or low airflow rates, which can potentially halve mechanical HVAC energy use. Three of the most efficient technologies in this area are radiant chilled beams, displacement ventilation and climate/humidity controls which can track occupancy levels, and the time, season and outdoor temperature
A number of properties have successfully used innovative HVAC systems and building design to deliver on their environmental and commercial objectives including 30 the Bond, which remains a leading example of environmental sustainability through its use of passive chilled beam cooling and natural ventilation systems.
Currently home to Lend Lease in Millers Point Sydney, 30 The Bond was the first commercial building in Australia to commit to and achieve a five green star rating. It was also the first building in Australia to use chilled beam technology on a commercial scale, which has delivered a 30 to 40% reduction in energy use compared to typical office building and a 30% reduction in greenhouse gas emissions.Using environmentally sustainable design principles, the building delivered innovative heating and cooling solutions by adopting:
- a natural convection process through its chilled beam system which cools down heat generated by occupants and office equipment
- naturally ventilated sunrooms on each floor which operate comfortably for 60% of the year
- conference rooms designed as winter gardens on the west side the building, with windows that can be opened and shielded from the sun by automatically controlled external shades
- smart design using the building’s four-story stone wall (which is also Sydney’s longest and oldest convict-hewn sandstone cutting) to provide natural cooling to the building’s atrium
- fresh air which is continually provided to the workplace and exhausted out of the building without being recirculated, resulting in increased air quality and a reduced risk of sick building syndrome
- low energy lighting with single tube T5 light fittings and daylight responsive lighting control
- a comprehensive electrical sub metering and monitoring program.
Overall, energy use has been reduced to 1243 MWh per year and emissions to 162 300kg CO2 per year (59kg CO2/m2), and has also generated $157,000 in savings each year with no additional payback costs. Staff are also active participants in reducing energy use and can track their energy efficiency progress online each month. Regular post occupancy studies conducted to date show that since the retrofit, 84% of people feel more comfortable in their workplace environment and 51% say they are more productive.
What are the successful strategies in reducing HVAC energy?
Companies that have implemented successful HVAC strategies have three elements in common. They have an in-depth understanding of their energy use captured through monitoring and sensor systems located throughout their buildings, a dedicated project team who are au fait with the relevant technologies and recognise the importance of investing in energy efficiency as a core business function.
Implementing a regular preventative maintenance program coupled with monitoring capabilities such as a BMS (Building Management System) or metering integrated into an existing EMS (Energy Management System) is also an essential strategy in reducing HVAC energy consumption.
More information on commercial building sector energy efficiency opportunities and technologies can be found on www.eex.gov.au