Retro-Commissioning

Retro Commissioning

What is Retro Commissioning?

Retro-commissioning is the process of commissioning an existing building controls to regain efficiency. This would involve fine-tuning the programming of the building controls.

Typical Problems in an Old Building

As a building ages, there are many minor issues accumulate over the years, such as

1. Equipment Replacement
2. Hidden Manual Override
3. Changing users occupancy patterns
4. Aging of existing equipment

These issues imply that the original design commissioned becomes less efficient, yet our company sees new opportunities here.

Energy Saving Opportunities

Many energy saving opportunities that would require no additional capital expenses, for example (Source: EMSD HK):

1. Chilled Water Flow adjustment during low load
2. Chilled Water Temperature Reset during low load
3. VAV temperature setpoint review
4. Chiller sequencing based on part-load performance
5. Cooling Tower sequencing
6. Schedule and timer reprogram in BMS

There are also opportunities that would require additional sensors, for example occupancy sensors, energy meter and smart thermostats.

Continuous Commissioning

Since equipment replacement, maintenance and usage pattern change over time, constant retro-commissioning is necessary for more efficient use of energy.

Continuous commissioning is the process of performing on-going retro commissioning. This is made possible by gathering data continuously from the running system and an associated analytics platform for revealing the energy saving opportunities.

1. Proactive predictive maintenance of potential issues
2. Maintain the energy saving from the initial retro commissioning
3. Data stream gathered would allow more advanced control methodologies

The energy saving from a retro commissioning exercise varies with buildings based on their existing controls, with a typical payback period of 2 years.