Indoor Air Quality System

Posted on January 29th, 2010

IAQ system at Paharpur Business Centre

IAQ system at Paharpur Business Centre, saves Energy:  ‘We grow fresh air’ at PBC, with an IAQ system retrofitted in the building.  Paharpur Business Centre ( is a 50,000 sqft office building offering “instant office” solutions. The IAQ system helps us save 30% on the fresh air load in our HVAC system.


‘We grow fresh air’ at PBC, with an IAQ system retrofitted in the building.

Natural bio method of purification has been adopted using green plants.

This was presented at TED 2009 Conference, held at Long Beach, California, ‘how to grow your own fresh air indoors’ with just three varieties of plants, namely, Areca palm, Mother-in-Law’s Tongue and Money Plant.

Ambient air picked from a height of 120 feet is passed through an air washer having pre-filters of MERV 6 and scrubbed using UV treated soft water.

This pre-filtered air is made to flow into a Green House holding over 300 plants of the three specific species and grown in hydroponic culture.

These plants not only convert CO2 into O2, but also remove toxins like VOC’s from the air and absorb microbial pollutants.

This oxygenated air is then fed into a Heat Recovery Wheel, which increases the efficiency of HVAC system by pre cooling /pre-heating the incoming air.

Further, demand control ventilation system is used by means of CO2 Sensors & fresh air dampers in the Air Handling Units (AHUs) located on each floor of the building.

Electronic filters are used to clean the incoming fresh air.

AHU has a combination of pre-filters (MERV 8 ) and bag filters (MERV 13 ) to clean the re-circulated air.

UV light installed on the cooling coil in AHU has a germicidal effect on micro-organisms.

This treated and conditioned air is supplied to building floors.

Regular duct inspection and cleaning ensures that the ducts are free of microbial growth.

As per ASHRAE 62.1: 2007, the fresh air ventilation rate required to control both, people related source and building related (or area based source), is the sum of ventilation required to control each of the sources for the breathing zone.

As per ASHRAE, for offices, fresh air base rate is 0.06 cfm/ft2 to handle building sources and to this is added the base occupant rate of 5 cfm per person. (For typical occupant densities and typical ventilation system efficiencies).

This total building fresh air ventilation rate usually results in an overall ventilation rate of about 20 cfm per person for office spaces.

The various IAQ initiatives resulting from use of Green Plants in the PBC building, have allowed the Facility Manager to maintain IAQ as per ASHRAE and USGBC LEED(for Platinum rated buildings – i.e. 30% over ASHRAE base) specs. with minimum 15.3 CFM per person fresh air, resulting in energy savings.

Thus, as compared to ASHRAE recommended 20 CFM, PBC saves 4.7 CFM/ person of fresh air load, on the HVAC system.

The fresh air load is 0.60 watts per ft2, a reduction of 0.18 watts/ft2.

This gives an energy saving of 30% in terms of reduced load.

For Reference:
energy savings

PBC facility is rated as one of the healthiest buildings in Delhi, by Govt. of India, in a report published by Central Pollution Control Board in September 2008.

Compared to other buildings in the city, the incidence of eye irritation was found to be reduced by 52%, respiratory symptoms down by 34%, headaches by 24%, lung impairment by 12%, and incidence of asthma by 9% at PBC.

VOCs and RSPM samples have also been collected by Lawrence Berkeley National Laboratory, USA in January, 2010 for validation of PBC’s IAQ system and results are expected by February, 2010.

The IAQ System not only leads to a fresher indoor air, but also increases productivity by almost 20%.

After studying the effects these plants had on air quality at PBC, it was found that there was a 42% probability of increasing saturated blood oxygen levels by 1% simply by being in the building for 8-10 hours compared to an adjoining building which did not have the green plants.

PBC runs a conference, interviews and training facility provider business, besides renting fully serviced offices for short and long term.

The Trainers find their students learning faster as retention of information in these learning events is higher for students, due to the healthy IAQ.

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