Central air conditioning systems can consume a lot of electricity if they are not operated to match cooling demand, heat exchangers are dirty, or the control system has not been optimized. To reduce electricity costs, businesses should consider operating hours, equipment condition, air and water flow rates, and overall system efficiency together. HRT shares the following energy-saving solutions for central air conditioning to help businesses assess and choose an option suitable for their buildings.
Why Do Central Air Conditioning Systems Consume a Lot of Electricity?
The electricity consumed by a central air conditioning system depends on the cooling load, operating hours, environmental conditions, and equipment efficiency. Energy may be wasted when the system runs outside usage hours, the temperature is set inappropriately, or the controls do not respond to the actual load.
In addition, dirty heat exchangers, clogged air filters, and unsuitable water or airflow rates can affect heat transfer and operating efficiency. In Chiller systems, chilled-water pumps, condenser-water pumps, and cooling towers also consume electricity, so the entire system should be assessed rather than just the chiller.
Read More VRV Industrial Air Conditioning
Energy-Saving Solutions for Central Air Conditioning
Optimize Operating Hours
Businesses should adjust system schedules to match the actual usage hours of each area. Operating air conditioning when a room does not need cooling can increase electricity consumption without delivering a corresponding benefit.
For buildings with a central control system, check the on/off schedule and how the equipment coordinates with one another. System start-up and shutdown times must also be considered to ensure the building reaches the required temperature conditions when use begins.
Set the Temperature Appropriately
The set temperature affects the cooling load and how the air conditioning system operates. Businesses should therefore choose a setting that meets comfort needs, usage patterns, and the specific requirements of the building, rather than setting the temperature too low when unnecessary.
For Chiller systems, the chilled-water supply temperature should also be assessed against the cooling load and the capacity of the AHU and FCU to meet demand. Do not change settings without first considering the equipment's operating limits and humidity-control requirements.
Clean and Maintain Equipment Regularly
Dust on air filters and heat exchangers can obstruct airflow or reduce heat-transfer capacity. As a result, the system may operate less efficiently and fail to meet cooling demand effectively.
Businesses should inspect air filters, outdoor units, indoor units, and related components according to actual conditions. Maintenance should follow the manufacturer's instructions and include checks for unusual temperatures, flow rates, and noise. Energy savings achieved after maintenance depend on the equipment's condition beforehand.
Read More Packaged Industrial Air Conditioning
Check Airflow, Water Flow, and Piping
Air and water flow rates must meet design requirements and operating conditions. If the flow rates are unsuitable, heat-transfer capacity and cooling performance may be affected.
For Chiller systems, check the pumps, valves, water-line filters, and pipe insulation. For VRV/VRF systems, pay attention to airflow through the indoor units, the condition of the heat exchangers, and factors affecting heat transfer. All adjustments must remain within the equipment's technical limits.
Optimize Chiller System Operation
For Chiller systems, energy savings depend not only on chiller efficiency but also on chilled-water pumps, condenser-water pumps, and cooling towers. Businesses should assess the electricity consumption of the entire plant against the actual cooling load.
Adjustments to chilled-water temperature, condenser-water temperature, or the number of Chillers in operation should be based on operating data and the characteristics of each unit. Running fewer units does not always save electricity if the operating unit is subjected to an unsuitable load. The goal is to select an operating mode that meets the cooling load while keeping total electricity consumption reasonable.
Optimize Pumps and Fans, and Use Variable-Frequency Drives When Appropriate
Pumps and fans can consume a significant amount of electricity in HVAC systems. When flow demand varies, adjusting motor speed with a variable-frequency drive can help reduce electricity consumption under suitable conditions.
However, the benefits depend on load characteristics, operating hours, control methods, and the system's technical limits. Installing a variable-frequency drive should be assessed based on actual site conditions; it should not be assumed to be effective in every case.
Read More Chiller Industrial Air Conditioning
Inspect the Cooling Tower
In water-cooled Chiller systems, the cooling tower rejects heat to the environment. The condition of the heat-transfer surfaces, fan, pump, and water distribution system can affect cooling performance.
Businesses should inspect and maintain the cooling tower according to technical guidelines and assess the condenser-water temperature under actual operating conditions. Do not assume that lower water temperatures always reduce total electricity consumption, as the Chiller, pumps, and cooling-tower fan may consume different amounts of electricity under different conditions.
Check Sensors and the Control System
Temperature sensors, control valves, and operating signals provide the basis for the air conditioning system to adjust capacity according to demand. If sensors are inaccurate or the control program is unsuitable, the equipment may not operate according to actual conditions.
Businesses should check sensor accuracy, operating schedules, and coordination between equipment. For buildings with a BMS, assess how the system is configured and used rather than relying solely on the fact that a building management system has been installed.
Monitor Electricity Consumption and Efficiency Regularly
Monitoring electricity consumption helps businesses identify usage trends and detect unusual changes. Data to review may include electricity consumption, power, operating hours, cooling load, and weather conditions.
For Chillers, COP or kW/ton can be used to assess efficiency within a defined measurement scope. However, the performance indicator for the Chiller alone does not fully represent whole-system efficiency unless auxiliary equipment is included. Comparisons before and after optimization should also account for cooling load, weather, and equivalent operating hours.
Read More R-Refresher HVAC: Solutions for Improving System Efficiency
How to Save Electricity in VRV/VRF and Chiller Systems
For VRV/VRF Systems
Priority measures include adjusting operating schedules by area, setting suitable temperatures, cleaning air filters and heat exchangers, and checking sensors and control modes. Outdoor and indoor units should be assessed under actual operating conditions.
Technical settings and adjustment procedures must follow the documentation for the specific product line. Do not apply the settings of one model to an entire VRV/VRF system.
For Chiller Systems
In addition to inspecting the chiller, businesses should consider chilled-water pumps, condenser-water pumps, cooling towers, and related AHU/FCU equipment. Coordination between the equipment during operation can significantly affect total electricity consumption.
Optimization options should be based on cooling-load data, water temperature, flow rates, and equipment operating limits. Do not change individual settings without first assessing the impact on the entire system.
Read More Criteria for Choosing a Reputable VRV Contractor
Mistakes to Avoid When Saving Electricity with Central Air Conditioning
A common mistake is to focus only on adjusting the temperature while overlooking equipment condition and operating schedules. The system may still consume a lot of electricity if heat exchangers are dirty, flow rates are unsuitable, or equipment runs longer than necessary.
In addition, businesses should not install variable-frequency drives without assessing load characteristics, or optimize only the Chiller while ignoring pumps and the cooling tower. Changes to temperature, flow rate, and pressure must meet the system's technical requirements.
In particular, do not promise a fixed percentage of energy savings without inspecting the existing system and obtaining reliable measurement data.
When Should You Survey and Optimize an HVAC System?
Businesses should consider a technical survey if electricity consumption increases unexpectedly, temperatures vary between areas, equipment frequently reports faults, or the system does not adequately meet cooling demand.
The assessment process should begin with operating data, equipment condition, and relevant technical parameters. Only then can a specialist determine which items should be prioritized and select an option suited to the building.
Read More How to Maintain a VRV Air Conditioning System Correctly
HRT HVAC Services
HRT provides consulting, surveying, design, equipment selection, installation, commissioning, warranty, and maintenance services for HVAC systems. Depending on the building's existing conditions and requirements, businesses can discuss with HRT options for their central air conditioning systems.
Assessing the existing conditions before selecting a solution helps identify the items that need attention and avoids adjusting equipment without adequate technical grounds.
Conclusion
Saving electricity with central air conditioning requires a combination of optimized operating hours, appropriate settings, equipment maintenance, flow control, and performance monitoring. For VRV/VRF and Chiller systems, solutions should be selected according to each system's configuration, usage load, and technical limits.
Businesses should use operating data and survey findings to determine priority items rather than applying a one-size-fits-all formula to every building. Contact HRT to discuss consulting, surveying, and selecting an HVAC option suited to the system's existing conditions.
Read More Optimize Chiller Performance Based on Operating Conditions
Contact Information
HRT Air Conditioning and Ventilation Company
Address: No. 9TT7, Foresa 7A Street, Tasco Eco Urban Area, Xuân Phương Ward, Hanoi, Vietnam
Hotline: 0916 181 080
Email: CEO@hrt.vn
Frequently Asked Questions
How can you effectively save electricity with central air conditioning?
Check the operating schedule, set temperature, equipment condition, and air and water flow rates, and monitor electricity consumption. The appropriate solution depends on the system type and the cause of the electricity consumption.
Can maintaining central air conditioning reduce electricity consumption?
Maintenance can improve operating efficiency when the system is dirty, obstructed, or has components that are not operating as required. The level of improvement depends on the equipment's condition before maintenance.
Can installing a variable-frequency drive save electricity with central air conditioning?
A variable-frequency drive can help reduce electricity consumption when a motor needs to operate at varying speeds and system conditions are suitable. Its effectiveness should be assessed based on load characteristics and actual operating conditions.
Can the energy-saving percentage be determined in advance?
A reliable percentage cannot be provided for every building without baseline data and survey findings. Savings should be assessed based on operating conditions before and after the solution is implemented.