Last week in Part I, we introduced a Vernacular to Contemporary Adaptation – PDEC – Passive Downdraft Evaporative Cooling. A Vernacular ventilation strategy – Wind Catchers, which is being adapted to Contemporary buildings. We also looked at diagrams explaining the 3 main principles in this Adaptation.
This week we look at Prosand Consof this technology for Contemporary use.
1) Energy Saving
a) Decrease cooling demand
Temperature Drops of upto 13oC can be achieved1. When the outdoors sizzle at close to 44oC, the indoors are at around 30oC.
Night Ventilation using PDEC towers decreases cooling demand and operating time of the primary cooling system the following day3.
b) Less Fluctuations
Indoor Temperature fluctuations of around 3-4oC can be seen over 24 hours, when the outside Temperature fluctuations are between 14-17oC1.
2) Cost/ Applicability
a) Short Payback Period
Electrical Consumption savings helped achieve payback of additional capital cost in less than 1 year for the Torrent Research Centre, Ahmedabad.1
b) Can be used in new / existing buildings with simple construction elements at relatively low cost.
a) Applicable in areas without wind
As Air movement is created by momentum transfer from water to air and density difference; the technology can be applicable in areas without wind 4, 5.
4) Cleaner Air
a) Evaporative Cooling
The air is cleaned during the evaporative cooling process 6.
The cooling capacity maybe insufficient in certain cases, and could need conventional cooling as well 4.
2) Cost/ Applicability
a) High Water Consumption6.
b) Short life of Water Pads
3) Climate Dependency
a) Works best in Hot & Dry Conditions
The technology maybe most effective in hot and dry conditions. However, buildings can be designed to adapt to other conditions and seasons. For example, in the Torrent Research Centre, the system operates normally in the dry season. In the monsoons, the water spray is not used, whereas in Winters, the openings to the rooms and shafts can be controlled (opened or closed) by the occupants 1, 4, 6.
How do You feel about this Vernacular ‘Adaptation’ for Contemporary Buildings?
Have you come across other such Adaptations?
What are your thoughts on the Practicality of this Technology? Let us know!
Paanchal JB, Mehta N. “A Review on Design of Passive Down Draft Evaporative Cooling in Commercial building.” 2017;3(2). https://bit.ly/2B33ZoS.
Bowman, N. T., Eppel, H., Lomas, K. J., Robinson, D., and Cook, M. J. “Passive Downdraught Evaporative Cooling I. Concept and Precedents.” Indoor + built environment 9.5 (2000):284-290.
Etzion, Y., Pearlmutter, D., Erell, E., and Meir, I. A. “Adaptive architecture: Integrating low-energy technologies for climate control in the desert.” Automation in construction 6.5 (1997):417-425.Ford, B. “Passive downdraught evaporative cooling: principles and practice.” Environmental Design. Architectural Research Quarterly 5, Cambridge University Press (2001) : 271-280.
Givoni, B. “Performance of the Shower Cooling Tower in Different Climates.” Renewable Energy, 10, 2/3 (1997):173-178.
Wind Catchers, traditionally known as Badgirs or Malqafs are Natural Ventilation devices. They have successfully been used in countries like Iran, Egypt, Pakistan, Afghanistan for many years.
This Vernacular Method is being ‘Adapted’ and utilized in various Contemporary Buildings. One such adaptation is the Strategy known as PDEC or ‘Passive Downdraft Evaporative Cooling’.
We use diagrams of the Torrent Research Centre, Ahmedabad; to discuss this technique.
3main Principlesare at play-
Evaporative Cooling – Water Sprays Cool the Warm Air Entering the tower
Cool Air Sinks – This Moisture Induced Air is Heavier and thus Sinks
Warm Air Rises – Warm Air in the rooms is Lighter and Rises
This sets up a Loop of Air.
The Project achieves a temperature drop of upto 13oC. When the outdoors sizzle at close to 44oC, the indoors are at around 30oC1. The Building incurred Additional Civil Costs of 13% for its Strategies. However, Energy savings helped payback the investment in less than 1 year2!
How do You feel about this Vernacular ‘Adaptation’ for Contemporary Buildings? Have you come across other such Projects?
What are your thoughts on the Practicality of this Technology? Let us know!
Look out next week, for the Pros | Cons of this Strategy in – Vernacular to Contemporary | PDEC | An ‘Adaptation’ – Part II
CapitaGreen is a 82,000 sq.m., 43-floor skyscraper in the Central Business District of Singapore1. The Video looks at its design for Sustainable Ventilation.
45 m1 tall Wind-Catchers atop the skyscraper are oriented towards the prevailing wind direction2. Designed to scoop winds at this elevation, they channel air down a core known as the ‘Cool Void’3. Air from the cool void spreads horizontally through the levels, reducing Air-Conditioning loads.
While researching various Passive Strategies and Technologies for the Building Envelope, we came across ‘Cool Roofs‘. We realized that this is a simple, low cost technology with large potential benefits. These include – Energy savings, Reduction of Urban Heat Island Effect and Greenhouse Gas Emissions, enhanced Durability of roofs, and Resilience to extreme heat 1.
Thus, this week’s Article and Video are dedicated to this important idea. The Video 2 , 3 , 4 outlines the Need for Cool Roofs and how they Protect Buildings. In the Article, we cover Initiatives by various parties working in the direction. We also look at some successful Case-Studies that could become models for future developments.
Due to multiple possible benefits, the technology has caught the attention of International actors, Indian central, state and local governments, as well as the Private sector. Their attempt is to use Cool Roofs for large scale Impact at the Building and Urban scales.
The Bureau of Energy Efficiency [(BEE), Government of India, Ministry of Power], has prepared a ‘Cool Roof Design Manual‘ 2 to spread technical information about Cool Roofs for the Composite Climate Zone of India.
A Fact Sheet5 and Issue brief6 have been released by Natural Resources Defense Council (NRDC) and Partners to showcase local projects, and to spread the message, so that action can be scaled up.
Green Building Rating systems like LEED, GRIHA, IGBC need compliance with the Energy Conservation Building Code (ECBC) norms. ECBC specifies minimum cool roof values (reflectance and emittance), for roofs with different slopes 6.
IIIT Hyderabad Cool Roof Calculator – The simulation tool by IIIT Hyderabad, uses a base and design case for testing various roof conditions in certain cities of India. A percentage change in cooling energy can be compared 2, 7.
The above efforts are helping common people as well as experts to understand and utilize Cool Roofs, by providing technical information, tools and answers to common questions. The following examples showcase successes in the field.
Ahmedabad’s Cool Roof Initiative, as part of its ‘Heat Action Plan‘ aims to convert 3000 roofs in 6 zones to Cool Roofs. This is being undertaken by city staff and student volunteers. They are using white lime paint, which costs as little as ₹0.50 per square foot 5.
Hyderabad is also witnessing a Cool Roof Initiative as part of its Building Energy Efficiency Program. The Pilot included 25 city roofs in low income areas. A High-Density Polyethylene (HDPE) cool roof membrane (costing ₹13 per square foot in Hyderabad) was supplied by Dupont as part of their CSR initiative 1.
The Indore and Surat ‘Cool Roof Project‘ is using local success stories to make a case for cool roof policies in the future. The project consists of over 100 households. They are using simple materials such as lime concrete, broken earthen pots, China mosaic tiles 6.
A Joint study was conducted by International Institute of Information Technology, Hyderabad (IIIT) and Lawrence Berkeley National Laboratory (LBNL) on 2 office buildings in Hyderabad. The studies saw a drop of approximately 20°C in Roof surface temperatures after application of cool roof coating 2.
We leave you with the following questions –
Have you used ‘Cool Roofs’ in your Project? Do you know of any projects using ‘Cool Roofs’?
What Benefits have you felt after application of the ‘Cool Roof’ technology?
What Problems did you face?
What kind of Assistance if any, did you receive from the Government or any other organisations?
Let us know! We would love to provide a platform, to showcase your project and spread more useful information.
Jaiswal A, Bhagavatula L, Awasthi A, Sarkar S. Keeping It Cool: Models for City Cool Roof Programs. National Resources Defense Council. https://on.nrdc.org/2jLgLPJ. Published 2018. Accessed November 27, 2018.
International Institute of Information Technology Hyderabad, Administrative Staff College of India, Indian Institute of Public Health Gandhinagar, Mahila Housing SEWA Trust. Keeping It Cool: How Cool Roofs Programs Protect People, Save Energy and Fight Climate Change.; 2018. https://on.nrdc.org/2FIxYas. Accessed November 27, 2018.
International Institute of Information Technology Hyderabad, Administrative Staff College of India, Indian Institute of Public Health Gandhinagar, Mahila Housing SEWA Trust. Issue Brief – Cool Roofs: Protecting Local Communities and Saving Energy.; 2018. http://www.phfi.org. Accessed November 27, 2018.
“The harmony of natural law reveals an intelligence of such superiority that, compared with it, all the systematic thinking and acting of human beings is an utterly insignificant reflection.”
Contemplating this powerful quote by Einstein could send chills down your spine. Our insignificance in the face of Nature’s power, begs us to show more humility. Nature doesn’t fear our walls, and everyday Climate related calamities should teach us better. It is ultimately in all of our favor, to Build with Nature, instead of withstanding it!
Following this chain of thought, today we look at Integration of Built with Water. Such a synergy with Water has positive effects on Micro-Climate and Energy Loads.
However, insects can be attracted to areas of vegetation and water. While all insects are not harmful they may not always be welcome in an urban setting.
Let’s look at some ways to address this issue-
1) Deeper water could prevent mosquitoes, since larvae prefer shallow water bodies of less than 2 feet
2) Natural pest Predators like Dragonflies are garden heroes
3) Select Plant Species that repel pests – Lavender, Citronella Grass, Marigolds
Building functions can be zoned according to ventilation strategy for effective management and energy conservation. This is seen in Akshay Urja Bhavan, New Delhi where spaces are divided into zones according to setpoints– Apex, Controlled and Passive. Only around 12% of the area is air-conditioned. Mist cooling systems are used for the Controlled and Passive zones1.
A 16 km (once the campus is completed) tunnel network of Air Earth tunnels, will be running 4 m below the ground in NIIT University, Neemrana Campus. Surface temperature and seasonal variations do not penetrate below this depth, keeping air temperature constant throughout the year. Fans will pull cool air through these tunnels. This would then be taken through precipitators to eliminate dust and would be supplied to the building through ducts. The result! – Pleasant 25oC temperatures indoors, without the use of air-conditioning, when temperatures outside are nearing 50oC1.
This week, we look at LEED AP BD+C:Setting Exam Timeline – 4 Considerations. Setting a realistic timeline is crucial for preparation. It should take into account various factors that would differ between individuals.
LEED Specific Project Experience, Prior Industry experience, Professional and Academic Background
Like mentioned earlier, many of our team did not have prior LEED Specific Project Experience. This makes it harder to pass the exam, although it is still doable. You need to factor this into your timeline. However, our candidates were either Architects, Engineers, or had some prior Sustainability background. This is extremely useful and partially makes up for the lack of LEED Specific Project experience.
You may want to increase or decrease the prep time based on your comfort level and background. From the experience of our team candidates, the average timeline for preparation ranged from 1 – 1.5 months. Once the timeline was set, a date was fixed, and the exam fees was paid. This becomes a push factor to work towards the goal, with a deadline looming ahead.
Having a Gap between the LEED Green Associate and LEED AP Examinations
We would suggest you give both exams (LEED Green Associate and LEED AP) with at least a year’s gap in between.
For one, it is a slightly stressful experience – so taking a break might help.
Secondly, these preparations if tackled well, don’t just help you pass the exam. You get a larger understanding of the Sustainability Industry. To grow as a professional, we suggest you first pass the LEED Green Associate examination. Then try and use the expanded understanding from the exam by engaging in related industry activities for at least a year. You could then apply that experience into your preparation for the next level.
Our team consisted of various kinds of people. Quick and slow learners. Some can retain concepts for longer, while others may need to revise more often. The ability to handle pressure also differs. Stress increases as the exam date nears. It is better to truly assess your personal speed, studying style, level of patience and stress management ability to avoid unnecessary pressure to build up. Ultimately it is preferable to treat the experience as not just an exam, but an opportunity to grow professionally. So self-assess, decide and go for it!