Ashrae 15 Edvc Calculation

ASHRAE 15 EDVC (Energy Design Ventilation Credits) calculation is essential for determining the ventilation requirements of buildings according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62.2. This guide provides a comprehensive explanation of the calculation, its importance, and how to use our calculator tool.

What is ASHRAE 15 EDVC?

ASHRAE 15 EDVC refers to the Energy Design Ventilation Credits specified in ASHRAE Standard 62.2. These credits allow buildings to meet ventilation requirements with less mechanical ventilation when certain design strategies are implemented. The EDVC calculation helps determine the amount of mechanical ventilation that can be reduced based on the building's design features.

ASHRAE Standard 62.2 is the standard for ventilation and indoor air quality in buildings. It provides minimum requirements for ventilation rates and effective filtration to protect building occupants from airborne contaminants.

Key Components of EDVC

The EDVC calculation considers several key components:

Building Type: Different building types have different ventilation requirements.
Occupancy: The number of occupants in the building affects the ventilation needs.
Design Strategies: Features like natural ventilation, demand-controlled ventilation, and energy recovery systems can provide EDVC.
Ventilation Rate: The required ventilation rate for the building.

How to Calculate EDVC

The EDVC calculation involves determining the amount of mechanical ventilation that can be reduced based on the building's design features. The formula for EDVC is:

EDVC = (Ventilation Rate × Area) - (Natural Ventilation + Demand-Controlled Ventilation + Energy Recovery)

Where:

Ventilation Rate: The required ventilation rate for the building (cfm per square foot).
Area: The total floor area of the building (square feet).
Natural Ventilation: The amount of ventilation provided by natural means (cfm).
Demand-Controlled Ventilation: The amount of ventilation provided by demand-controlled systems (cfm).
Energy Recovery: The amount of ventilation provided by energy recovery systems (cfm).

The result of the EDVC calculation is the amount of mechanical ventilation that can be reduced, expressed in cubic feet per minute (cfm).

Formula and Assumptions

The EDVC calculation is based on the following formula:

EDVC = (Ventilation Rate × Area) - (Natural Ventilation + Demand-Controlled Ventilation + Energy Recovery)

Assumptions

The EDVC calculation makes the following assumptions:

The building is designed according to ASHRAE Standard 62.2.
The ventilation rate is based on the building type and occupancy.
Natural ventilation, demand-controlled ventilation, and energy recovery systems are properly designed and installed.
The calculation does not account for other factors that may affect ventilation requirements.

Worked Example

Let's consider a building with the following details:

Ventilation Rate: 0.05 cfm per square foot
Area: 10,000 square feet
Natural Ventilation: 500 cfm
Demand-Controlled Ventilation: 1,000 cfm
Energy Recovery: 800 cfm

Using the EDVC formula:

EDVC = (0.05 × 10,000) - (500 + 1,000 + 800)

EDVC = 500 - 2,300 = -1,800 cfm

In this example, the EDVC calculation results in a negative value, indicating that the building's design features do not provide enough ventilation credits to reduce mechanical ventilation. The building would still need to meet the full ventilation requirements.

Interpretation

The EDVC calculation provides valuable information about the building's ventilation requirements and the potential for reducing mechanical ventilation. A positive EDVC value indicates that the building's design features provide enough ventilation credits to reduce mechanical ventilation. A negative EDVC value indicates that the building's design features do not provide enough ventilation credits to reduce mechanical ventilation.

Building owners and designers can use the EDVC calculation to:

Determine the amount of mechanical ventilation that can be reduced.
Evaluate the effectiveness of design strategies for reducing mechanical ventilation.
Ensure compliance with ASHRAE Standard 62.2.

It's important to note that the EDVC calculation is based on specific assumptions and may not account for all factors affecting ventilation requirements. Building owners and designers should consult with a qualified professional to ensure compliance with ASHRAE Standard 62.2.

FAQ

What is the difference between ASHRAE 62.2 and ASHRAE 15 EDVC?

ASHRAE Standard 62.2 provides minimum requirements for ventilation and indoor air quality in buildings. ASHRAE 15 EDVC refers to the Energy Design Ventilation Credits specified in ASHRAE Standard 62.2, which allow buildings to meet ventilation requirements with less mechanical ventilation when certain design strategies are implemented.

How do I calculate EDVC for my building?

You can calculate EDVC using the formula provided in this guide. You will need to know the building's ventilation rate, area, and the amount of natural ventilation, demand-controlled ventilation, and energy recovery provided by the building's design features.

What factors affect the EDVC calculation?

The EDVC calculation is affected by the building's ventilation rate, area, and the amount of natural ventilation, demand-controlled ventilation, and energy recovery provided by the building's design features. Other factors, such as building type and occupancy, may also affect the calculation.

Can I use the EDVC calculation to reduce mechanical ventilation in my building?

Yes, you can use the EDVC calculation to determine the amount of mechanical ventilation that can be reduced based on the building's design features. However, you should consult with a qualified professional to ensure compliance with ASHRAE Standard 62.2.

What are the limitations of the EDVC calculation?

The EDVC calculation is based on specific assumptions and may not account for all factors affecting ventilation requirements. Building owners and designers should consult with a qualified professional to ensure compliance with ASHRAE Standard 62.2.