LEED II Consideration in HVAC System Design
What Is Green Building
Buildings or homes that are more energy-efficient,
produce less waste and are healthier to be inside.
The main aim of the green building concept is to
-Save energy and water
-Reduce waste and reuse.
-Improve health and productivity
-Use of material which is environment friendly.
-Minimize the use of natural resource during the construction of the building.
Watch vedio on #LEED
HVAC design plays a very important role in getting leed certification. As HVAC is high power consuming service in the building and related to the air quality of indoor which can impact human.
In India, multiple agencies are there for green building such as
-BEE (Bureau of energy efficiency)
-IGBC ( Indian green building council)
-Griha ( Green Rating for Integrated Habitat Assessment)
LEED
-The Leadership in Energy and Environmental Design
(LEED)
-It is a Green Building Rating System.
-It is introduced in 2000.
-It Promotes
Water savings, Energy efficiency, Materials selection,
Indoor environmental quality.
Type of Rating
Point Required for LEED Certification
As we can see, Major points come from indoor air quality and equipment energy savings. As we know that the major energy consumption is of the HVAC system in the building. This is the reason optimization is very important in HVAC and LEED to do exactly the same. It encourages to select energy-efficient unit.
1.Projects earn points to satisfy green building
requirements.
2.Within each of the LEED credit categories, projects
must satisfy prerequisites and earn points.
3.The number of points the project earns determines
its level of LEED certification.
LEED-certified buildings are designed to:
• Lower operating costs and increase asset value
• Reduce waste sent to landfills and use space more
efficiently.
• Save energy and water
• Be healthier and safer for occupants by improving
indoor air quality
• Reduce harmful greenhouse gas emissions
LEED SPECIFICATIONS TO BE INCLUDED IN THE HVAC
1.Refrigerant in all the HVAC & R systems should
be chlorofluorocarbon (CFC) free
refrigerant.
2. Certain minimum COP Requiredk
Air-cooled VRF
- above 3.2
Air Cooled Chiller
- above 2.95
Water Cooled Chiller - above 5.9
3. VFD drives to be provided for pumps and Air
handling units.
4. Variable air volume (VAV) boxes in the interior
HVAC air distribution system to be also provided.
5. Heat recovery units to be provided to achieve
energy savings through pre-cooling of fresh air.
6. The HVAC system to be designed with a minimum fresh
air requirement as per ASHRAE 62.1 Standard. Providing 30% more fresh air for
all areas than the minimum indicated as per ASHRAE 62.1.
Standards
for Volatile Substances
Formaldehyde
levels less than 27 ppb. Total volatile organic compounds less than
500 μg/m³
Standards
for Particulate Matter and Inorganic Gases
Carbon monoxide less than 9 ppm.
PM₂.₅ less than 15 μg/m³.
PM₁₀ less than 50 μg/m³.
Ozone less than 51 ppb.
Radon less than 4 pCi/L in the lowest occupied level of the project
7. Provide efficient filter (MERV 14 filters or above)
for all regularly occupied areas.
UVGI and EAC type unit can help in improving indoor
air quality at higher level which helps in gaining more leed point.
8. Minimum of 2-week building flush out has to be
carried out to remove particulates/ VOCs etc. before occupancy as per LEED
requirement.
9. Provide independent exhaust for each space where hazardous gases or chemicals may be present or used. In Battery room exhaust with hydrogen, the sensor should be provided. For Pantry or cafe area air scrubber should be used as it removes oil, moisture, the smell from the air going to the atmosphere.
10. For areas with more than 40 sq ft per person density: Airflow monitors to be installed to provide feedback on the ventilation system performance to ensure that the ventilation systems-maintained design
minimum ventilation requirements. Each fresh air duct
to each AHU to be fitted with an airflow monitor to continuously measure the
fresh air and in case the same goes +/- 10%of the designed fresh air quantity
to generate an alarm in the IBMS system.
11.Demand control ventilation
For areas with less than 40 sq ft per person occupancy: such as conference rooms, meeting rooms, cafeteria, some workstation areas etc. we need to include CO2 sensors and monitoring in the IBMS system. CO2 monitor locations shall be between 3 ft and 6 feet and 1 CO2 sensor for every 1000 sq ft area shall be provided and all the
fresh air dampers shall also be motorized to ensure we
bring in more fresh air
when the CO2 levels inside are 600-800 ppm greater than
the Co2 level outside. For this, we will also need to install a CO2 sensor
outside to measure the outside CO2 levels at all times.
12. Duct
Protection
1.Ducts Sealed
and protected from possible contamination during construction.
Background
noise levels in the following areas to meet the following Noise Criteria
Open Office ‐ Max NC 40,
Closed
rooms ‐ Max. NC 35,
conferences
& break out ‐ Max NC 30
teleconference
rooms ‐ Max NC 20.
14. Welding
Try to minimize the welding on the construction site as it generates smoke which is harmful to human and atmosphere. Groove fitting can be used to minimize welding in HVAC and fire fighting work.
Measuring of IAQ
To maintain proper air quality of any space, we need data for same space
For that we should first install air quality testing equipment,
Sensor to track VOC, temperature fluctuations, humidity changes, oxygen level ,air contamination.
After getting data you can make changes in your system to achieve heigher IAQ. This is why measuring of air qualir is very important.
Conclusion
As we know , construction is responsible for air pollution
And it is very dengerous for human helath
So we should go with green and sustainable building.
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