Retail Malls Optimization for REIT Client

The Challenge

One of the largest Hong Kong REIT was looking to achieve their ambitious energy reduction targets in their mid to long term corporate sustainability plan. The shopping malls’ HVAC system was facing multiple technical challenges, for example sensor errors that failed to indicate accurate readings from equipment, set temperature was not being achieved, valves were left fully opened consistently without proper adjustment, the fan speed of one cooling tower was too low in spite of high condenser leaving temperature. Moreover, Carnot spotted chiller short cycling issues in the morning of a complete month, which led to significant waste of energy. The most expensive fault Carnot successfully identified for our client was that one chiller was turned on outside of the operation schedule. 

Our Solutions

Carnot Innovations helped the client develop a strategic optimization plan to consolidate their existing control logics (e.g. supply and return temperatures, various setpoints, etc.). Several optimization opportunities were reviewed with them to outline what their system could look like. As Carnot gained more knowledge about their plant operation, operational limits, and challenges through historical data, a scope of optimization was proposed. Initially, Carnot collaborated closely with the engineering team to put together proposals and technical documents (life of interfacing points that required to be added to the BMS to receive recommendations from optim control). Carnot designed and identified scenarios using different setpoints/equipment combinations to gauge the plant performance and limit test. After obtaining scenario test results, COP at different  timestamps can be extracted and used to compare with previous BMS operations. Carnot found out that running less chillers at high cooling load is more energy efficient than running more small capacity chillers. These faults were demonstrated on our demo sites for our client to review and let them justify which coping actions to take. 


Carnot follows a benchmark reporting system that provides daily, monthly, and yearly review for our client. General reporting features include summary of energy performance of the buildings, status summary of energy saving advice and FDD cases, summary of the healthiness of equipment and system, and Key Performance Indicator (KPI) of system, etc. Besides, monthly electrical bills’ readings are being taken into account when calculating energy consumption. A 10% of energy savings is projected in the coming year end for each independent shopping mall.

Carnot Innovations has helped the client develop a strategic optimization pan to consolidate existing control logics along with achieving their fundamental goal.

Category: Retail malls

Client's Corporate Highlights:
Net Zero Strategy, to achieve Net Zero by 2035. Focus on operational efficiencies, aiming to maximize energy saving potential at asset level.
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