Figure 7.25. Picture 1 Pathway

Pathway totally believe in sustainable habitat and try to do its bit towards securing the environment forthe future. As an educational institute, it is their responsibility to sensitize these young minds towards nature and its importance. After all they only will carve the future environment. And what better way to make them understand then to walk the talk.

There have been some vey innovative approaches undertaken in the building facilities that area comtributing hugely in terms of reducing the carbon footprint. And what makes this even more interesting is intelligent out of the box approaches like introducing some old-age indian architecture technique that not only makes the buildings environmental friendly but also make them more cost effective.

India has a long history of ancient civ ilizations and kingdoms. In those days there were no technologies available, still the architecture was such that the buildings faired very good in terms of internal conditions both in strong summers and cold winters. There were simple architechtural techniques that were used to reach these kinds of conditions.

Today with the advent of technology and the advancements therein, when we speak of green building, normally we try to use more technologies. But if we fall back on the ancient indian architecture, there are far easier and more effective ways of creating green architecture!!

At patheway, they rely on these simple architectural techniques to build green campus, guven below are some of the silent features.

Source: https://www.pathways.in/aravali/aravali_green_pathways

As normal phenomenon the cool air is heavy and stays down and the hot air is light and always travel up. They have consciously kept the ceiling height above 4.2m thus allowing the space for hot air. The fan coil units are placed a little lower and send the cool air draft downwards thus not hitting the pocket of hot air trapped on the top.

All the exterior walls are constructed as cavity walls. There is a 9” thick brick wall on the outside, then an air gap ranging from 4” to 10” and then a 4.5” or 9” wall on the inside. Thermally during the afternoon until about 3 O’ clock the exterior walls absorb the heat. Then when the sun is on its way down, this heat starts entering inside the building. This air gaps in the cavity wall does not let this heat enter inside the rooms thus the energy required to air condition the rooms is greatly reduced.

While the classrooms are well conditioned, the corridors do not have any equipment provided. As they pump in the treated fresh air in the rooms, maintaining the pressure, the excess air spills out into the corridors and thus the corridors become comfortable. Further, nonconditioned corridors also provide a buffer zone for students coming from warm outdoors and vice versa.

As explained above, the hot air always rises. The buildings are so designed that all the rooms open into a big courtyard having a huge atrium. This atrium has clear openings on top. This naturally creates the ‘Chimney effect’ and all the lost air from all the rooms and corridors travel up the atrium and is vented out into the atmosphere automatically. This ensures comfortable conditions indoors and without any use of additional energy.

They keep a window to wall ratio about 35%. Following techniques are used in terms of keeping such huge glazing area and still not letting the outside heat enter the rooms.

• Because of the air cavity total thickness of the outside walls area about 18” to 20”.

Windows are then placed on the inner edge of the wall. This automatically gives a shade of 18” to 20” and thus the sun does not strike directly on the windows.

• The 35% Window to wall Ratio and 25% light transmission in one hand takes care of the glare thus no blinds/curtains are required and at the same time it ensures maintaining of enough lux levels inside the room and there is very less dependence on artificial sunlight.

They use energy efficient lighting system using CFL and T5 lamps. All the luminaries are selected which are minor optics and focus all the light to the required area and not wasting any light. The ballast used inside the electronic from reputed manufacturers. We benefit on two counts here. CFLs and T5s are the most energy efficient. And the minor optics further reduce the requirement of number of luminaires.

In peak summer the ambient temperature ranges around 42-45 degrees in this part of world. Inside the building the central air conditioning system maintains a temperature of 24 degrees which is comfortable for human beings. Worldwide air conditioning consumes about 65% of the total energy used in buildings. At pathways they have very carefully taking certain out of the box measures that have resulted in reduction of HVAC load to great extent.

• Central air conditioning plant consists of chillers (compressors) as the main machinery. They use “screw” chillers which give efficient power consumption even on part loads.

• While designing the air conditioning (HVAC) of a project, a careful working is performed determining theamount of fresh atmospheric ait to bepumped into the co0nditioned spaces.

And since the temperature being maintained indoors is 24 degrees, it is the job of the central air conditio0ning plant to pick up the atmosphere air of 44 degrees, cool it down to about 23-24 degrees and then pump into the indoors. This consumes a lot of air conditioning load and energy. • Geothermally, 4m below the ground the temperature remains constant round the year. And this temperature is the average annual temperature of the place, which for Delhi NCR is about 25-26 degrees. Therefore, they are routing the atmosphere air through earth air tunnels 75m long buried 4m below the ground. After travelling 75m, this air picked up a 44-45 degree cools down about 28-30 degrees. Now, they will cool this 28-30-degree air to 24 degrees and pump indoors. • There are in all 6 earth air tunnels of 1200mm dia provided and each tunnel is reducing the

HVAC load. This results in less power consumption thus reducing the carbon footprint considerably. • In a school environment there are various timings at various facilities operate. And at the same time, it is very difficult to ensure that the air conditioning and lights of the respective

area are properly switched off during these off hours. Here they regulate the electricity through a PLC (programme logic computer) which shuts off the supply at the non useage hours thus no wastage at all. • While they have saved the electrical energy by the above measure, there is still a lot of energy loses that happen with the chilled water flowing through the multi kilometre of the chilled water lines irrespective of where after the equipment of the particular areas are being used or not. This is a passive loss which no one takes into consideration but has a main impact on the main AC plant load. To arrest this according to the usage, time and pattern, they have divided all their buildings into various zones and intelligently designed the chilled water piping providing motorised butterfly valve at the chilled water return of each zone. Thus, on one hand reducing the pumping load and on the other arresting the unnecessary energy losses that otherwise are incurred with the excess flow of water in the non-operative areas. • All the fan coil units and air handling units are fitted with pressure independent balancing cum control valves that regulate the flow of water required thus optimising the flow which results in reduced water flow and hence saving in pumping energy. • All the floor mounted AHUs are fitted with variable frequency drives which regulates the air flow according to the requirement. This optimisation reduces the total tonnage required for the AHU and hence reduces the load on the chillers.

• All the pumps are fitted with efficiency class 1 motors which gave a better energy efficiency which further increases on part loads. • Cooling towers are selected with lower approach. This reduces the condenser water temperature which in turn reduces the power consumption of chillers. Further the towers are so designed where the highly efficient fans are selected which consume less power. • normally in any HVAC facility the condensate water is channelized to the drain and goes waste. And, this is near distilled quality water and that too at a very low temperature. They have channelized the collected the condensate water of all the FCUs and AHUs into a single tanle which then pumps this cold water to the cooling tower as the makeup water. This on one hand utilises the water which otherwise goes waste. And on the other hand, providing chilled water to the cooling tower increases the efficiency of chillers condensate water by about 6% resulting in huge power savings.

The requirement of fresh air is necessary in indoor sports arena. Yet the comfortable temperature must be maintained for the sports persons. They have used natural methods in attaining these. The indoor sports arena is constructed in the lower ground floor about 3m below