Das Consumption Calculator

Direct Airside (DAS) systems are a type of air handling unit that deliver conditioned air directly to the space being served. This calculator helps you determine the energy consumption of a DAS system based on key parameters.

What is DAS?

Direct Airside (DAS) systems are a type of air handling unit that deliver conditioned air directly to the space being served. Unlike traditional air handling units, DAS systems bypass the ductwork and deliver conditioned air directly to the space, which can improve energy efficiency and reduce installation costs.

DAS systems are commonly used in commercial buildings, data centers, and other applications where precise temperature and humidity control are required. They typically consist of a cooling coil, heating coil, filter, and fan assembly.

How to Use This Calculator

To use this DAS consumption calculator, follow these steps:

Enter the supply air temperature in degrees Celsius.
Enter the return air temperature in degrees Celsius.
Enter the air flow rate in cubic meters per hour (m³/h).
Select the type of cooling system (direct expansion or chilled water).
Click the "Calculate" button to see your results.

The calculator will display the estimated energy consumption of the DAS system in kilowatt-hours (kWh).

Formula Used

Energy Consumption Formula

The energy consumption of a DAS system can be calculated using the following formula:

Energy Consumption (kWh) = (Air Flow Rate × (Supply Air Temp - Return Air Temp)) × 1.006 × 0.001

Where:

Air Flow Rate is in cubic meters per hour (m³/h)
Supply Air Temp and Return Air Temp are in degrees Celsius (°C)
1.006 is the specific heat capacity of air in kJ/kg·°C
0.001 is the conversion factor from kJ to kWh

This formula calculates the energy required to heat or cool the air passing through the DAS system.

Worked Example

Let's calculate the energy consumption of a DAS system with the following parameters:

Supply Air Temperature: 20°C
Return Air Temperature: 25°C
Air Flow Rate: 1000 m³/h

Using the formula:

Energy Consumption = (1000 × (20 - 25)) × 1.006 × 0.001

Energy Consumption = (1000 × -5) × 1.006 × 0.001

Energy Consumption = -5000 × 1.006 × 0.001

Energy Consumption = -5.03 kWh

The negative value indicates that energy is being removed from the air (cooling). The absolute value of 5.03 kWh represents the energy consumption of the DAS system.

Interpreting Results

The results from this calculator provide an estimate of the energy consumption of a DAS system. Here's how to interpret the results:

Positive Value: Indicates that energy is being added to the air (heating).
Negative Value: Indicates that energy is being removed from the air (cooling).
Absolute Value: Represents the actual energy consumption of the DAS system in kilowatt-hours (kWh).

These results can help you assess the energy efficiency of your DAS system and make informed decisions about system design and operation.

FAQ

What is the difference between DAS and CAS?: Direct Airside (DAS) systems deliver conditioned air directly to the space being served, while Chilled Airside (CAS) systems use ductwork to distribute conditioned air. DAS systems are typically more energy efficient and can reduce installation costs.
How do I determine the air flow rate for my DAS system?: The air flow rate for your DAS system can be determined based on the size of the space being served and the required ventilation rates. Consult with an HVAC professional for accurate calculations.
What factors affect the energy consumption of a DAS system?: The energy consumption of a DAS system is affected by factors such as the supply and return air temperatures, air flow rate, and the efficiency of the cooling and heating systems.
Can I use this calculator for residential applications?: This calculator is designed for commercial and industrial applications. For residential applications, consult with an HVAC professional for accurate energy consumption calculations.
How accurate are the results from this calculator?: The results from this calculator provide an estimate of the energy consumption of a DAS system. For precise calculations, consult with an HVAC professional and consider factors such as system efficiency, ambient conditions, and operational parameters.