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| Energy Energy efficiency of a building relies equally on the design and on its operation. The best buildings tend to match demand and supply through careful performance monitoring, attention to user’s complaints, and well designed diagnostic systems. A tenant operation manual should be developed based on the recommendations in the Department of Energy, Utilities and Sustainability (DEUS) Tenant energy handbook. Occupant complaints should be investigated with a high level of communication and follow up to develop and ensure a satisfactory solution. Efficient handling of occupant complaints has been shown by UK Probe studies to have a significant impact on the productivity of staff. The Australian Building Greenhouse Rating (ABGR) Scheme is a national benchmark program for measuring the greenhouse performance of commercial buildings based on the energy consumption. The rating goes from a scale of 1 to 5, the more stars that the building receives the better the greenhouse performance. DEUS operates the ABGR scheme in NSW it consists of three possible ratings:
Government policy relating to required ABGR ratings for base buildings and tenancies is detailed in Premier's Memorandum 2004-04, greenhouse Performance of Government Office Buildings and Rental Properties. The Memorandum states that: Where an existing building is owned by the agnecy, the agency must
Agencies that build new government offices are to commit to a 4.5 star rating for the new building. Where an agency is a tenant, the agency must
A full description of the policy is attached to Premier's Memorandum 2004-04 and is available from the Premier's Department website. ABGR Base Building: Ensure that the ABGR rating complies with policy in PM2004-04. An ABGR accredited assessor should certify all ABGR ratings. The following categories are a guideline to energy performance within a building:
ABGR Tenancy: Ensure that the ABGR complies with guidelines established. An ABGR accredited assessor should certify all ABGR. The following categories are a guideline to energy performance within a building:
Whole Building ABGR: Ensure that the ABGR complies with the policy detailed in Premier's Memorandum 2004-04. An ABGR accredited assessor should certify all ABGR. The following categories are a guideline to energy performance within a building:
Base Building ABGR
Click here to see larger Diagram
Building Orientation/Massing The most cost effective method of developing May energy efficient buildings are to develop a coherent effective building massing, orientation and space planning strategy. The following issues should be considered when selecting a building:
Façade Design and Performance
One of the largest energy loads in a building is due to envelope gains and losses. Limiting these loads will improve energy performance and improve occupant comfort. This applies primarily to air conditioned spaces however is also relevant to naturally ventilated spaces. A target level of 70 W/m2 peak summer façade heat gain is recommended for air- conditioned spaces. This value is not relevant for naturally ventilated space however due to the need to limit external loads to achieve comfort in natural ventilated spaces this target may still apply. In addition an occupant comfort rating should not exceed 20% PPD adjacent to the facade. A target level of winter peak heat loss is 50 W/m2. There are several strategies to minimise the adverse effects of the exterior environment. These strategies insulate the occupied space from extreme temperatures and shade the space from solar gains as needed. At the same time, however, these systems will need to be easily maintained. Optimising the size and distribution of glazing for orientation, view and daylight is one of the most significant forms of improving occupant comfort and energy efficiency. Reducing the size and quantity of west facing glazing should be given a priority. North East and North West façades should be considered along the same lines. The size of window should be optimised considering all the following issues to develop an effective shading coefficient and the possible benefits of low angle solar heating in winter months. Shading should be used to protect the façade from solar energy lowers cooling loads. Shading also helps control glare and thermal discomfort that occupants may experience due to high solar gains. The most effective shading devices will vary with latitude and orientation as the sun's position and intensity changes with time of year and time of day. To ensure energy targets are being maintained the tenants operation manual should provide guidance on the following:
Heating, Ventilating, and Air-Conditioning (HVAC)/Commissioning The air conditioning running and operating costs contribute significantly to the energy demands on the building. Ensuring that the correct air conditioning system for the space has been installed can significantly reduce the energy output from the building. Design criteria for office staff, large gains within the space (continuous occupancy and equipment loads), natural ventilation alone may not maintain thermal comfort conditions during summer months, therefore an air conditioning system will be applied. The system used should be one of the following, Variable-Air-Volume (VAV) system, displacement system or chilled ceilings, however, each of the systems may be better suited to various applications. For meeting rooms, council chambers etc where the noise level is important, air conditioning should be used during occupancy; a VAV system would be recommended. The VAV system will react to the varying occupancy within the space when occupied and also shut down when unoccupied. For areas where there is a large volume of space, for example an auditorium, the displacement system would be recommended, the cooling capacity of a displacement system is increased with increase in height within the space. A combination of chilled ceiling and displacement systems should be investigated in administration. Removing part of the heat load through chilled water would reduce the requirement for air. Therefore only the minimum fresh air would be supplied resulting in reduction in running costs and reduction in plant size and improved indoor air quality. The design criteria for an area of interaction (a mix of outside and administration) more flexibility should be allowed. In general, these areas natural ventilation should be used with spot heating and cooling applied where necessary. It is also critical that the HVAC system is maintained. Verify and ensure that fundamental building elements and systems are designed, installed and calibrated to operate as intended. The building supervisor should use the operation manual with particular emphasis on the following:
Consider additional improvements to energy efficiency:
Measurement and Verification Ensure that there is ongoing accountability and optimisation of building energy and water consumption performance over time. Some of the following approaches should be considered:
Air Conditioning Refer to section Heating, Ventilating, and Air-Conditioning (HVAC) Tenancy ABGR
Click here to see larger Diagram Ensure that the ABGR rating complies with guidelines established by Department of Commerce. An ABGR accredited assessor should certify all ABGR ratings. The following categories are a guideline to energy performance within a building:
Lighting One of the major consumers of electricity within a building is the lighting systems. The introduction of natural daylight can reduce the need for artificial lighting and increase the connection occupants have with the outside. Lowering the artificial lighting loads also lowers cooling loads and thus increases the benefits of passive ventilation and cooling. As daylight is highly variable, it should be used primarily for ambient lighting. Ambient light levels should be targeted at 320Lux for offices and 250Lux for classroom spaces. The real benefit of an effective daylighting system is that it redistributes the light in the space so that a better uniformity throughout the space is achieved. A suitably designed light shelf can control glare near the perimeter and daylight spaces located 6-7m from the perimeter. The flexibility of such systems needs to be considered in office layout and partitioning. Other spaces may or may not be effectively daylit depending on the use, the light levels required and the sensitivity to glare. Where this is the case artificial lighting will be required. The use of high efficiency luminaries and appropriate switching systems to turn lights off will ensure that energy savings associated with lighting will be reduced. Minimise the number of lights controlled from a single switch so that only areas that are occupied have lighting turned on. Circulation areas and the general office space may be designed to have a background illumination whilst task lighting is provided in work areas where tasks require particular lighting levels. A target average lighting load of 8.5W/m2 is recommended as a minimum. As a minimum daylit areas should have daylight linked luminaries. The following should be considered for installation of energy efficient lighting:
High efficiency systems with flicker free electronic ballasts are reliable, the savings in energy and maintenance costs provide a good return on investment:
These systems may easily be modified and altered during the life of the building thus the tenant operations manual should consider the following issues:
User Equipment Office equipment can be a major contributor to the energy load on a building. Office equipment can consist of computers, printers, faxes etc. Some of the following approaches should be considered when reviewing the equipment load:
Whole Building ABGR
Ensure that the ABGR complies with guidelines established by Department of Commerce. All ABGR should be certified by an ABGR accredited accessor. The following categories are a guideline to energy performance within a building:
Base Building ABGR Refer above. Tenancy ABGR Refer above. Renewable Energy Encourage and recognise increasing levels of self-supply through renewable technologies to reduce environmental impacts associated with fossil fuel energy use. Investigate funding opportunities (Greenhouse Gas Abatement Program (GGAP), Renewable Commercialisation program, utility providers etc) Some of the following issues should be considered when assessing renewable energy:
Options that may be cost effective are as follows:
Adapting the building to new fuel source or installing photovoltaic require only minor adjustments to architectural, HVAC or electrical systems. Purchase of Green Power Encourage the development and use of grid-source energy technologies on a net zero pollution basis.
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