Hotel Building Control Retrofit Case: Non‑stop‑operation Construction, How Much Energy Is Actually Saved?

The hotel’s building control system has been in service for more than a decade. Hardware remains operational, yet energy consumption keeps rising: chillers run under full load for long hours, air‑conditioning terminals stay active after guests leave, and public lighting relies entirely on manual patrols. While a system upgrade is desirable, shutdown‑related business losses are a major concern.

This hotel adopted a phased building‑control system upgrade with zero business interruption.

The Biggest Challenge Lies Not in Hardware, But in Construction

The hotel holds over 180 guest rooms, with guest quarters, restaurants and conference areas fully operational. Construction must avoid prolonged power outages and disturbance to guests.

Prior to site execution, comprehensive inspections were carried out on chillers, air‑handling units, fresh air units, public lighting and water pump circuits. Control cabinets were fully assembled and pre‑tested in the factory. On‑site construction followed a floor‑by‑floor and system‑by‑system schedule, with switching operations performed at night. Only one zone was retrofitted at a time, while manual control modes and temporary bypass circuits were maintained throughout.

Should anomalies occur during new‑system commissioning, on‑site operators can quickly revert to the original control logic to sustain normal air‑conditioning, lighting and water supply.

What Was Modified Inside the Control Cabinets?

This retrofit was far more than component replacement; it restructured the overall equipment operation logic.

Schneider Acti9 iC65N miniature circuit breakers serve for power distribution protection, while ComPacT NSX moulded‑case circuit breakers are deployed for high‑power loops. Schneider TeSys D‑series LC1D AC contactors control fans and water pumps, and PowerLogic PM5000‑series power meters collect power‑consumption data.

A hybrid DDC‑and‑PLC control architecture forms the core. Siemens S7‑1200 PLCs are implemented in selected zones, and ABB AF‑series contactors are adopted for certain power loops according to site requirements. All equipment statuses, fault alarms and energy‑consumption data are centrally uploaded to the building‑management platform.

After upgrade, the system dynamically adjusts chilled‑water temperature, pump frequency and fresh‑air unit start‑stop logic based on outdoor temperature, hotel occupancy and business hours. Public lighting is no longer kept on overnight; it runs automatically according to schedules, ambient light levels and scene settings.

How Much Energy Has Been Saved?

Post‑retrofit operational data over three consecutive months was compared against data from the same period in the previous year, with corrections applied for occupancy rates and outdoor temperatures.

Measured outcomes: overall hotel power consumption dropped by 18.7%. Air‑conditioning‑related power use decreased by 26.3%, and public‑lighting power consumption fell by 21.5%. Calculated at the local electricity tariff, annual electricity‑cost savings are estimated at around 380 000 CNY.

Beyond energy savings, early‑warning for equipment faults eliminates the need for engineers to conduct layer‑by‑layer manual inspections. Guest complaints have declined, and equipment runs with enhanced stability.

The value of hotel building‑control retrofit is not merely swapping control cabinets and components. It ensures every piece of equipment runs only when needed and operates under optimal conditions.

Non‑stop‑operation construction does not equal risky construction. Thorough pre‑project audits, factory‑prefabricated cabinets, phased zone switching and emergency bypass solutions are the keys to achieving energy‑saving renovation alongside normal hotel operations.

Reference Component Models for Similar Projects

Schneider Electric

• A9F18216: Acti9 iC65N Miniature Circuit Breaker
• A9F18320: Acti9 iC65N 3‑pole Miniature Circuit Breaker
• LC1D18M7: TeSys AC Contactor
• LC1D32M7: TeSys AC Contactor
• LRD16: Thermal Overload Relay
• GV2ME14: Motor Circuit Breaker
• LV429630: ComPacT NSX Moulded‑case Circuit Breaker
• METSEPM5560: PowerLogic Multifunction Power Meter
• ATV320U15N4B: Altivar Variable‑speed Drive

Siemens

• 6ES7214‑1AG40‑0XB0: S7‑1200 CPU 1214C
• 6ES7221‑1BF32‑0XB0: SM 1221 Digital Input Module
• 6ES7223‑1BL32‑0XB0: SM 1223 Digital Input / Output Module

ABB

• AF09‑30‑10‑13: AF‑series AC Contactor
• AF16‑30‑10‑13: AF‑series AC Contactor
• AF26‑30‑00‑13: AF‑series AC Contactor

The above models are for project configuration reference only. Actual selection shall be determined by equipment power, load current, control voltage, short‑circuit breaking capacity and field operating conditions.