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EMSD
FAQ

FAQ

FAQ


Information

(1) What is Retro-commissioning (RCx)?

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Retro-commissioning is a systematic and cost-effective process to periodically check the energy and other performances of an existing building. The process identifies operational improvements that can optimize energy efficiency performance of the buildings and thus lower energy bills.


(2) Why is Retro-commissioning important?

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Over time, buildings undergo operational and occupancy changes which hinder optimal performance of the building systems. Since systems in building are highly interactive, minor problems/deviation will cause significant impact on overall efficiency. Therefore, buildings waste energy if its systems are without proper tuning.


(3) How is Retro-commissioning different from Energy Audit?

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Retro-commissioning focuses on optimizing existing equipment, while an energy audit focuses on identifying potential capital improvements. Therefore, retro-commissioning differs from an energy audit in two critical areas:

1) The scope of retro-commissioning is generally limited to non-capital intensive adjustments, corrections, and repairs of existing control/monitoring systems; and

2) During an energy audit, potential improvements are simply documented. While retro-commissioning improvements are actually implemented with results being measured and verified.

To obtain the most comprehensive assessment of a building’s energy performance and its energy saving opportunities (ESOs), while also ensuring that all no-cost or low-cost ESOs are considered, both retro-commissioning and an energy audit are recommended.


(4) Is Retro-commissioning suitable for every building?

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Almost every building can be benefited from a tune-up. No matter how efficient it is, there’s always room for improvement. However, there may be mitigating circumstances that would make retro-commissioning inappropriate for specific buildings. For example, smaller buildings often do not have central HVAC systems, and incomprehensive control and distribution systems, which will limit the room for tuning and gain from retro-commissioning.


(5) What are the benefits from Retro-commissioning?

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The benefits of Retro-commissioning are the saving of energy consumption in building, enhance the reliability of building services system, increase capabilities of maintenance staff and improve the indoor environmental quality of the building


(6) What is the estimated energy saving from Retro-commissioning?

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From some past projects reference, there is about 5% of annual electricity consumption from retro-commissioning.


(7) What is the frequency to carry out the retro-commissioning?

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In reality, building performance often deteriorates over time, as fine-tuning after repairs or retrofittings are neglected, system set points are misadjusted, or control sequences no longer match the latest building usage and occupancy patterns. Therefore, to maximize the benefits, retro-commissioning is a process that should be repeated every 3 to 5 years to maintain optimal performance. Furthermore, if the key performance indicators (KPI), which are defined in the on-going commissioning plans (e.g. no. of complaints, energy bills), are found exceeded; the building shall carry the retro-commissioning again.


(8) Is there any incentive scheme from Government on Retro-commissioning?

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Under the Scheme of Scheme of Control Agreement (SCA) with CLP and HEC, CLP and HEC established incentive schemes to support carrying out retro-commissioning. The details of the funding scheme can be referred to the following websites:

Environment Bureau - Agreement;

CLP - Eco Building Fund; and

HEC - Smart Power Building Fund


(9) What is the cost to carry out Retro-commissioning?

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There is no definite cost to carry out RCx. The cost is relating to the scale and complexity of the building systems together with available design and operation information. Building owner can determine the scope and scale of RCx based on their available budget.


(10) What is the normal payback period of RCx?

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The normal payback period of those Energy Saving Opportunities (ESOs) from RCx is usually varied from 3 years.


(11) Who is eligible to carry out the Retro-commissioning?

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If the building in-house O&M staff have sufficient knowledge or instrument to carry out the RCx, the building owner can consider to assign their in-house O&M staff for the RCx. Alternatively, the building owner can engage an independent RCx service provider to carry out the RCx.


(12) What qualification that the personnel or the RCx service provider should have to carry out RCx?

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There is no speicific qualification for the personnel to carry out RCx. However, the personnel or the RCx service provider should have knowledge of design, operation and maintenance of building systems in particular central air-conditioning installation in buildings. Also, they should have sufficient knowledge or experience in measurement & verification in energy efficiency on building performance.


(13) What is the road map of EMSD to promote the RCx?

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At present, EMSD issued the Technical Guidelines on RCx and carried out 6 nos. of pilot projects on RCx. A designated website on RCx was also launched. In near future, more government buildings will be selected to carry out RCx. More presentation and sharing session will be arranged for the promotion of RCx. EMSD will also collaborate with HKGBC and other professional institutions to promote RCx to building owners, property management companies, etc. and organize trainings to practitioners in the RCx trade.