Greenest of all

Model building design that helps save energy and money by exploiting the sun’s movement

By Disha Singh
Last Updated: Sunday 07 June 2015

Greenest of all

Landscaping in front of the PEDA building buffers sound and pollution

Designing sustainable buildings in a composite climate is a challenge. The techniques that are effective during summers do not work in winters. But a building in Chandigarh has achieved this. More than 10 years ago, the Punjab Energy Development Agency (PEDA) decided to construct an office building that utilises the movement of the sun for lighting, cooling and heating.

The Rs 5.5 crore building, a pilot, was ready in 2004. Six years later, the Bureau of Energy Efficiency (BEE) awarded it a five-star rating, the highest grade of energy efficiency. With a built-up area of 6,146 sq m, the building incorporates the techniques of passive solar architecture that is based on seasonal and diurnal variations in the sun’s movement (see ‘Know the building’). Monuments like the Red Fort in Delhi were designed using these techniques. The PEDA office has an energy performance index (EPI) of 14 kWh/m2/year (the lowest in the country) in the category of non-air-conditioned buildings.

EPI is the ratio of the total energy used to the total built-up area. The EPI of commercial buildings is above 180 kWh/m2/year and the benchmark set by BEE for buildings compliant with the Union power ministry’s Energy Conservation Building Code (2007) is 140 kWh/m2/year. By following passive solar techniques, the PEDA office has become one of the most energy-efficient buildings without adhering to the code, which came later, says Harsimran Singh, an architect in Chandigarh. According to the PEDA building’s architect, Arvind Krishan, unlike conventional buildings, the office’s design is in accordance with the external envelope, which he calls solar envelope.

This envelope refers to the features and materials used in the building’s skin that makes it responsive to varying weather conditions. The internal structure has floating slabs which help in air circulation. The building is oriented in the north-south direction, minimising solar exposure on the western and eastern facades. Although a building’s southern facade can be shaded, the western façade remains exposed to the setting sun and cannot be shaded, he explains.

A simulation-based study by the University of Nottingham in the UK says the PEDA building functions successfully as a passive solar complex.



The PEDA building, designed for 500 people, is currently occupied by 100 individuals



They are made of two layers of bricks with a 5 cm air gap in between. In southern and western façades, insulation (consisting of 60 cm by 60 cm panels of 5 cm thick rock wool wrapped in polyurethane sheets) has been placed between the layers of bricks in addition to the air gap. This is done to reduce the amount of heat transferred from the outside to the inside through the walls. The combination of a brick wall with air gap reduces heat transfer by 50 per cent as compared to a conventional brick wall. If insulation is added along with the air gap, the heat transfer decreases by 85 per cent.


As maximum heat gain is through the roof, a rockwool-and-polyurethane insulation at an air gap of 5 cm from the concrete slab has been placed. Top layer is made of mud phuska and brick tiles for further heat-proofing.


These concrete domed structures on the southwestern façade are one of the well-recognised innovations of this project. The domes have horizontal and vertical intersecting fins with glass fixed in the voids. These voids allow natural light with reduced glare. The shading action of the fins allows indirect sunshine to enter the building in summers and direct sunshine in winters (see figure).


imageA portion of the roof of the atrium (open space in the centre of the building) is covered by a lightweight shell roofing. The roofing consists of 10 cm of high-density EPS (extruded polystyrene) sandwiched between high-grade FRP (fibre-reinforced plastic) sheets reinforced with steel.

In summer the sun is almost overhead at noon while in winter it is at a lower angle. Keeping this in mind, the shell roof is angled in such a manner that the opening beneath the shell is shaded from the summer sun but allows the winter sun to penetrate.


Shell roof (yellow) and the 25 kWp solar photovoltaic plantThere is an integrated 25 kWp solar photovoltaic plant in the building. More than half of the building’s electricity requirement is provided by the panels. The panels are placed on the roof of the atrium, in between two sheets of toughened glass. This helps filter daylight.


These are operational during hot and dry months (April to June) and help decrease the interior temperature through direct evaporative cooling


The wind tower (7) is expected to function as a non-mechanical air-conditioning system, but the mechanical component for the tower (ambiator) is yet to be installed. It will soon be installed, say PEDA officials. The ambiator uses the method of indirect evaporative cooling in which water cools the air without coming into contact with it. This method works well in humid conditions, says Darshi Dhaliwal, responsible for devising the ambiator. Currently, the tower is used to expel hot air from within the building.

Fresh air rushes in from the openings in the envelope, passes over the floor and escapes through the tower top. Due to the building’s expanse and workstation panels (8), this flow is inadequate to maintain thermal comfort. So, coolers have been installed.


Sunlight entering through solar shells, shell roofing, glass-integrated photovoltaic panels and windows made of unplasticised PVC meets the building’s lighting requirement, including that of the basement.


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  • Nice article Disha! "The

    Nice article Disha!

    "The project was ready in 2004. Six years later, the Bureau of Energy Efficiency (BEE) awarded it a five-star rating." very impressive!

    Good to know about architects who are truly interested and working to make a building green.

    Posted by: Anonymous | 8 years ago | Reply
  • A building sized for 500

    A building sized for 500 persons only housing 100 persons will have a tragically poor carbon footprint, regardless of its current energy consumption. The most ecologically efficient building is the one that is never built. One that is 5 times oversized is at the other end of the spectrum.

    Posted by: Anonymous | 8 years ago | Reply
  • The building was designed for

    The building was designed for 500 persons as the PEDA authorities were planning to set up various departments for renewable energy such as wind power, solar energy harnessing etc. But as of now this is still in the pipeline.
    It is estimated that even with an increase in workforce the buildings energy consumption would increase only slightly due to the passive design techniques which have been applied. Also, simultaneously with an increase in workforce reaches the wind tower ambiator shall also be installed which should be able to completely satisfy the cooling requirements within the building.

    Posted by: Disha Singh | 4 years ago | Reply
  • Congratulations to the team

    Congratulations to the team who made PEDA Building whose design has helped to save the energy and money (Greenest of all, DTE 31st Oct 2012). This building design and way of saving energy & money is the most needy to all in general and particularly for developing country like India.

    Now our Country is facing severe Power crises and affected the production and finally the quality of life of the people. Though the initiations for the alternatives like Bio Gas, Hydro thermal, Wind energy, Solar energy and others are at initial stage and could not come out with sustainable ways. At this stage, the design of PEDA and its claim on saving energy & money is the welcome step and more such things should come into the reality.

    Now, the need of the hour is to know about its:

    £ Scale up, Replication and Sustainability (SRS)
    £ Conveniences and comfortability
    £ Cost effectiveness
    £ Affordability & Accessibility
    £ suitability at all terrains and environments
    £ extent of Eco-friendliness ....................

    If the answer to the above points is acceptable to the stakeholders at all levels, then the Government should encourage the Institute to do more research if necessary to replicate the designs matching to the needs of the local environment and people.

    Posted by: Anonymous | 8 years ago | Reply
  • Dear Lakshmi Narayana Thank

    Dear Lakshmi Narayana
    Thank you for your comment. I am in complete agreement with the points that you have raised. The PEDA building was built as a prototype so that the principles and techniques used could be suitably modified and applied in buildings located in similar weather conditions.
    The endeavour through this article is to get the message out there as a number of people have no idea about the passive design features of the buildings.
    Although,it is in the hands of the government to promote the construction of buildings designed on passive principles, but the same may be achieved if the public is also made aware of such strategies.

    Posted by: Disha Singh | 4 years ago | Reply
  • Thanks for the quick

    Thanks for the quick response. It is true that the implementation and transformation of technologies is in the hands of Government. Parallel to this, creation of public awareness among the stakeholders and community helps to create pressure to the Government for an effective implementation.

    Looking forward to expect that the media takes this as a mission for effective transformation...

    Posted by: Anonymous | 8 years ago | Reply
  • Dear Ms. Disha, liked the

    Dear Ms. Disha,

    liked the article. We have a started a platform called addressing the issues of ecology, environment & cityscape in & around Pune. If you permit, wd like to post your article with due mention of the DTE in the ecology section.

    Await your response.


    Posted by: Anonymous | 8 years ago | Reply
  • Dear Abhijit Thank you for

    Dear Abhijit
    Thank you for your appreciation. You can post the article, but please mention the link of this article along with mentioning DTE.

    Posted by: Disha Singh | 4 years ago | Reply
  • Dear Disha Is the ECBC EPI

    Dear Disha
    Is the ECBC EPI benchmark for air-conditioned buildings? If it is so then should we compare it with the EPI of a non-airconditioned building?
    The PEDA building 'appears' to be truly green. Of course the greatest wisdom of this building is that it knows how to respond to the sun-path and shade its interiors from the harsh summer sun. BUT can there be a 'measure' of the green quotient of this building.
    A building that does not adhere to the ECBC code gets a 5-star rating! This should raise many questions in the minds of the building professionals and those who decide the benchmarks for the 'green'.

    Posted by: Anonymous | 7 years ago | Reply
  • Dear Seema The ECBC does not

    Dear Seema

    The ECBC does not provide any benchmarks, it is the BEE which awards star ratings for specific EPI ranges. These ranges differ for air conditioned and non air conditioned buildings. The star rating system provides different EPI ranges for conditioned and non conditioned buildings for them to achieve a particular star rating.

    For example, In order to achieve a BEE 5 star rating an office building in a composite climate requires an EPI of less than 40 Kwh/sqm/year for a non conditioned building and less than 90 Kwh/sqm/year for a conditioned one.

    As you correctly mention the achievement of the PEDA building is that it is sustainable because it responds to the climate and not because it adheres to a particular energy code. Hence for such a building, measuring the green quotient shall always be a challenge as different agencies or rating systems shall have a different set of parameters.

    I am in complete consensus with your observations and the PEDA building highlights the fact that a 'sensibly' designed building can perform far better than a badly designed building even if it is compliant with the benchmark of any energy code or rating system.

    Posted by: Disha Singh | 4 years ago | Reply
  • With the amount of synthetic

    With the amount of synthetic polymers (polyurethanes, polystyrenes, fibre reinforced plastics, etc.) used in this building, is it really green ? Sure, it may be using far less energy on a day-to-day basis, but the amount of energy invested in making these synthetic materials are huge. aren't they ?

    Posted by: Anonymous | 7 years ago | Reply