healthy buildings at reduced energy cost
TRANSCRIPT
HVAC Control Strategy
Pressure Dependent Volume Control
MW
Pressure Independent Volume Control
Δp
V
M
W
Pressure Independent Volume Control
DpV
t
DpV
t
Dpv
+
Dpv
+
Pressure Air Flow
V
Air Flow Measurement
Flow Characteristics
D6l .min =D
Round Duct
Rectangular ductπ
whl
4.2
min=
Dl ⋅= 2min
Honey-Comb Air flow Straightener
With Honey-Comb Air Flow Straightener We get,
!
• Drastically Reduced Straight Length required for Accurate & Reliable Air Flow Measurement.
!
• Accurate & Reliable Air Flow Measurement, even at non ducted application such as outdoor air intakes.
Without Air Flow
Straightener
With Air Flow
Straightener
Non Linear Calibration
Healthy buildings at reduced energy cost.
Why Optimal Ventilation is Critical?
• Under Ventilated buildings suffer from reduced productivity levels. • Over Ventilated Buildings result in increased humidity levels. • Ventilation rates also have a direct bearing on energy costs !!• Demand Controlled Ventilation, or DCV
– Reduces indoor airborne viruses and bacteria which can led to ‘Sick Building Syndrome’.
– Reduce the cost of operating the HVAC system.
Traditional Approach
Use of pressure dependent volume control
Traditional Approach
In Multiple Space using one CO2 sensor
How Optimal Ventilation Can be Achieved?
• First and foremost is to measure the amount of outdoor air coming into a building.
!
• And then, Reset intake air flow (Demand Controlled Ventilation) in response to variations in zone population and ventilation efficiency both.
Demand Controlled Ventilation – Various Methods
• Reset based on occupancy – Occupancy Schedule
• Predicts the current population based on the time of day – Occupancy sensor
• It detects the number of people in each monitored zone – CO2 Sensor (Most Effective)
• Monitors the concentration of CO2 produced !• Reset based on ventilation efficiency
– Reset Intake air flow in response ventilation efficiency Variation
DCV - CO2 Based
DCV – SINGLE ZONE
DCV - Single Zone CO2 based
DCV - Single Zone CO2 based
DCV - MULTIPLE ZONE● CO2 Based DCV alone ● Ventilation Reset alone ● Ventilation Reset Plus
CO2 based DCV
ASHRAE Standard 62.1-2007-Multiple Space Equation 6-1
ASHRAE Standard 62.1-2007-Multiple Space Equation 6-1
ASHRAE Standard 62.1-2007-Multiple Space Equation 6-1
CO2 Based DCV Alone
CO2 Based DCV Alone
Ventilation Reset
CO2 Based DCV with Ventilation Reset
VAQ Station
An Effective Solution for Pressure Independent Volume Control
VAQ Station-Selection Chart
VAQ Station-Earn valuable LEED Credits
Questions?