·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC ECONOMY MODE to reduce energy consumption in 195 countries and 8 continents from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC ECONOMY MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC ECONOMY MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC ECONOMY MODE to reduce energy consumption in global built environment, real estate, commercial real estate, housing, property and data centres on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC ECONOMY MODE to reduce energy consumption on earth from June 2024?

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·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC NIGHT PURGE MODE to reduce energy consumption in 195 countries and 8 continents from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC NIGHT PURGE MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC NIGHT PURGE MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC NIGHT PURGE MODE to reduce energy consumption in global built environment, real estate, commercial real estate, housing, property and data centres on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC NIGHT PURGE MODE to reduce energy consumption on earth from June 2024?

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·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC WARM UP MODE to reduce energy consumption in 195 countries and 8 continents from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC WARM UP MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC WARM UP MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC WARM UP MODE to reduce energy consumption in global built environment, real estate, commercial real estate, housing, property and data centres on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC WARM UP MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC COOL DOWN MODE to reduce energy consumption in 195 countries and 8 continents from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC COOL DOWN MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test BMS/BMCS/BAS/DDC COOL DOWN MODE to reduce energy consumption on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC COOL DOWN MODE to reduce energy consumption in global built environment, real estate, commercial real estate, housing, property and data centres on earth from June 2024?

·       How to design, install, control, maintain, service, manage, tune, optimize, monitor, commission, and test HVAC COOL DOWN MODE to reduce energy consumption on earth from June 2024?

HVAC ECONOMY MODE

The economy cycle is one of the energy saving strategies in the operation of heating, ventilation and air conditioning systems. In this strategy, the goal is to reduce equipment energy consumption by using free cooling. Economy cycle is a strategy that uses outdoor air (O/A) directly for space cooling, with the aim to reduce the energy consumption by reducing operation of AC equipment. This strategy provides the added benefit of improved indoor air quality (IAQ) by significantly increasing outdoor air ventilation rates during periods of mild weather.

HVAC NIGHT PURGE MODE

The aim of the night purge strategy is to reduce the use of mechanical cooling in buildings by automatically flushing the building with cool outdoor air (O/A) using natural ventilation at night time or for mechanical ventilation preferably just prior to start-up. By ensuring that the air in the building is displaced by cooler outside air just before the HVAC system starts up, energy consumption is minimised.

HVAC DEMAND CONTROL VENTILATION (DCV) MODE

The objective of demand control ventilation (DCV) is to control ventilation systems to minimise the outdoor air (O/A) ventilation rates used to maintain an acceptable degree of indoor air quality (IAQ) at times when the O/A condition is not suitable for economy-cycle operation. The rate of ventilation is automatically adjusted in response to occupancy or usage levels to achieve IAQ set points. Automatic detection and measurement of air contaminants (typically CO and CO2) is used as an indicator for usage rates. The goal is to bring in only the required amount of O/A based on best engineering design practice and in accordance with the National Construction Code (NCC) and associated standards.

HVAC OPTIMUM START/STOP MODES (WARM UP AND COOL DOWN)

This strategy involves the optimisation of the HVAC system’s start and stop times. An optimum start/stop program provides a reduction in operating hours of HVAC plant by delaying start-up time and stopping the system sooner than the currently scheduled fixed stopping time, while still maintaining acceptable comfort conditions. Optimum start calculates the latest time to start HVAC plant and air conditioning (AC) equipment, based on current indoor and O/A temperature conditions and historical thermal response times for the building to achieve set point, so that comfort space temperature requirements are met when occupants arrive at the scheduled occupancy time. Optimum start controls must be linked to any warm-up or cool-down control strategies. Optimum stop calculates the earliest time to stop HVAC plant while still providing the required comfort conditions and ventilation requirements for a building’s occupants before the scheduled end of occupancy. The algorithm is self-adaptive as it monitors and memorises heating and cooling thermal response times of the building at various combinations of outdoor and indoor air temperatures and uses them when calculating the starting and stopping times of HVAC system. Morning warm-up and cool-down – On days of extreme temperature, the greatest daily demand for heating or cooling may occur in the morning as the building is prepared for occupancy because a significant and rapid change in temperature is needed. The goal for an optimum start procedure is to provide as much cooling as possible to cool down the building (or heating as possible to warm up the building) for the least amount of energy possible, while avoiding demand spikes and set point overshoot.

AHU Economy Mode Control (Example)

AHU-1-1 economy dampers (Economy OA Damper, Return Air Damper and Exhaust Air Damper) control is enabled when all the following conditions are met:

•         Outside air enthalpy is less than the return air enthalpy for 10 minutes (adjustable)

•         Outside dry bulb temperature is between 10°C (Adjustable) and 19°C (Adjustable).

•         Heating Mode is not in operation.

•         Outside air humidity is less than 70% (Adjustable)

•         Outside Air Enthalpy is below 52kJ/Kg (Adjustable) for 10 minutes(adjustable).

Economy damper control is disabled when any of the following conditions is met:

•         Outside air enthalpy is greater than the return air enthalpy.

•         Outside dry bulb temperature is not between 10°C (Adjustable) and 19°C (Adjustable).

•         Heating Mode is in operation.

•         Outside air humidity is more than 70% (Adjustable)

•         Outside air enthalpy is above 52kJ/kg (Adjustable)

AHU Night Purge Control Mode (Example)

A passive Night Purge mode is configured to run each AHU. The night purge program is designed to enable AHU economy dampers in the early hours of the morning to cool the building in the hot weather. The night purge program closes the heating and chilled water valves, disabling the requirement for the chilled water or heating water systems to operate.

The night purge time schedule for each AHU is initially set from 4am to 7am Monday to Friday.

Night purge mode starts whenever all of the following conditions are meet:

·       Night purge time schedule is ‘On’ (4am-7am Monday-Friday).

·       The room temperature is greater than the outside air temperature by 4°C(adjustable)

·       The room temperature is more than 2°C(adjustable) above effective cooling set point of 23.5 °C (adjustable)

·       The outside air enthalpy is below 52kJ/kg (adjustable) for 10 minutes(adjustable)

·       The outside air relative humidity is below 70%(adjustable) for 10 minutes(adjustable)

Night purge mode stops when any of the following conditions is met:

·       Night purge time schedule is ‘Off’.

·       The outside air temperature is within 1°C(adjustable) of the room temperature

·       The room temperature is 1°C(adjustable) below effective cooling set point of 23.5 °C (adjustable)

·       The outside air enthalpy is above 52kJ/kg (adjustable).

·       The outside air relative humidity is above 70%(adjustable)

AHU Return Air CO2 Control (DCV Example)

Demand Control Ventilation (DCV)  is an optimisation strategy whereby the level of ventilation is determined by the actual ventilation needs of the space measured in real-time. The dominant air contaminant is identified and measured in real-time with ventilation rates increased or reduced depending on the measured level of the contaminant. System set points and control parameters are configured to ensure that the concentration of contaminants is always maintained within acceptable limits. Reducing O/A flows during HVAC system operation reduces heating and cooling loads and can also reduce fan energy consumption. The objective of demand control ventilation (DCV) is to control ventilation systems to minimise the outdoor air (O/A) ventilation rates used to maintain an acceptable degree of indoor air quality (IAQ) at times when the O/A condition is not suitable for economy-cycle operation. The rate of ventilation is automatically adjusted in response to occupancy or usage levels to achieve IAQ set points. Automatic detection and measurement of air contaminants (typically CO2) is used as an indicator for usage rates. The goal is to bring in only the required amount of O/A based on best engineering design practice and in accordance with the National Construction Code (NCC) and associated standards.

A return air CO2 sensor is installed in the return duct of each AHU to achieve demand control ventilation functionality. AHU Outside Air Damper is modulated through the BMS to maintain the return CO2 level below 800ppm (adjustable).

AHU A DCV Control :

The AHU outside air damper modulates proportionally between minimum 0% (Adjustable) to maximum 100% (Adjustable) when the highest CO2 value changes from 700ppm (Adjustable) to 800ppm (Adjustable). The AHU damper control minimum and maximum positions will be set during the commissioning phase to meet the outside air design requirements (OA Flow changes from 0 l/s to 1400 l/s when CO2 levels change from 700ppm to 800ppm).

AHU B DCV Control :

The AHU outside air damper modulates proportionally between minimum 0% (Adjustable) to maximum 100% (Adjustable) when the highest CO2 value changes from 700ppm (Adjustable) to 800ppm (Adjustable). The AHU damper control minimum and maximum positions will be set during the commissioning phase to meet the outside air design requirements (OA Flow changes from 0 l/s to 850 l/s when CO2 levels change from 700ppm to 800ppm).

OPTIMUM START WARM UP MODE (Example)

The AHU optimum start program is designed to start the plant before occupancy start time to warm the building in cold weather. AHU supplies tempered warm air to perimeter areas during cool seasons.  

If optimum start warm-up mode is disabled before scheduled occupancy time, AHU control mode changes to occupied mode.

A software selection switch is provided for:

Min|Max|Average selection: Select min zone temperature for warm-up and Select max zone temperature cool-down (default).

Optimum start warm-up mode is activated if the following conditions are met:

·       The average floor space temperature is less than 21°C (Adjustable) or the minimum floor space temperature is less than 21°C (Adjustable)

·       The next Scheduled occupancy time is within 60 minutes (adjustable)

Warm Up mode is deactivated when any of the following conditions is met:

·       All floor space temperatures are above 21°C (Adjustable).

·       The occupancy time is reached.

During warm-up mode, following control is achieved:

·       VAV damper is driven to VMax position during the warm-up mode. VAV damper closes when the VAV room temperature is achieved.

·       VAV electric heaters operate in automatic mode.

·       AHU is not provided HHW coils, AHU Supply Air Temperature is set at 30°C (Adjustable) to disable AHU Cooling Valve operation.

·       AHU Cooling Valve remains closed.

·       AHU operates in recirculation mode (Economy OA Damper = 0%, Min OA Damper = 0%, Return Air Damper = 100% and Spill Air Damper = 0%)

OPTIMUM START COOL DOWN MODE (Example)

AHU optimum start program is designed to start the plant before occupancy start time to cool the building in hot weather. If optimum start cool-down mode is disabled before scheduled occupancy time, AHU control mode changes to occupied mode.

Optimum start cool-down mode is activated if the following conditions are met:

·       The average floor space temperature is greater than 24°C (Adjustable) or the maximum floor space temperature is greater than 24°C (Adjustable)

·       The next Scheduled occupancy time is within 60 minutes (adjustable)

Cool-down mode is deactivated when any of the following conditions is met:

·       All floor space temperatures are below 24°C (Adjustable).

·       The occupancy time is reached.

During cool-down mode, following control is achieved:

·       VAV damper is driven to Vmax open position.

·       VAV electric heating and VAV fans remain off.

·       AHU operates to provide Supply Air Temperature at minimum setpoint TBC°C (Adjustable). Refer technical data for each AHU for minimum and maximum design SAT setpoints.

·       AHU economy dampers operate in automatic control mode (same control as the time schedule mode).

·       AHU fan runs at minimum speed until the lead chiller is proven running for 10 minutes (adjustable).