BCIL's Way of Building Green

BCIL's Way of Building Green

Bio-Gas Digester:

This is basically a process that converts wet, degradable kitchen waste and other such organic wastes into a combustible gas that can light kitchen stoves. The calorific value of this gas is lower than LPG -- and it takes about 10 more minutes to cook rice with this gas compared to LPG.

At BCIL, T-Zed Homes, we have installed a bio-gas digester of 150 kg capacity (which is the minimum that you can secure as equipment goes). The capacity generation at T-Zed of kitchen waste is about 60 kgs. at this stage, from 45 homes that are occupied, of the total of 95. The number of people to a home is an average of 3, and so the residual wet waste is also not high. Most of us Indians eat very little red meats, which also adds to the low-load factor.

We have now invited two other residential enclaves in the neighbourhood to feed this digester all their kitchen waste. The T-ZED residents have set up a Green Council with 3 members who are wanting to drive this initiative of getting waste from outside of T-ZED Homes. At 100 kgs. of wet waste, we should get about 4.5 kg. of biogas a day -- enough to run the community kitchen.

The digester can also take sludge which comes out of the tertiary sewage treatment plant. The sludge is free of odour and can also be used as compost for the plants on campus. Insted, in our case, at T-ZED, we are diverting this sludge also to our digester since we want to use the full capacity of the digester.

There are aerobic digesters and anaerobic ones. We have used the latter system. There are a few safety precautions one has to take when the system is being put into place since the gas is combustible, but they are very standard safety features. A digester of this size takes no more than a space of 12’x10’. This, therefore, is ideal for apartment homes where land is normally at a high premium.

Natural Swimming Pools:

What is natural about the Swimming Pools that BCIL builds?

We use no ceramic tiles. Instead we go for options such as a hard-sand, simulated ceramic-coated granular surface which lasts long and is easy to scrub and clean of algae, moss, etc. [Trans Indus swimming pool is illustrative.]

We also use natural stone surfaces for cladding the walls and floor of pools. [TZed Swimming pool is an example.]

Standard maintenance procedures with vacuum cleaners are as practicable as they are with ceramic tiles in conventional pools.

Why no ceramic tiles?

Ceramic tiles are a combination of sand (which erodes river beds -- in the proximity of such factories) and glass which is energy-intensive in manufacture - ceramic tiles consume as much as 1200ºC of energy in the making.

Natural stones are near zero energy since there is only a little polishing and the transportation energy cost that you have to live with. They offer aesthetic appeal and serve the function of offering different appealing colours to the surface of the water - azure, aquamarine, etc.

Our treatment system at BCIL for purifying pool water, eschews completely all chemicals. Chlorine leaves the user with a “red-eye” syndrome.

BCIL gives us a combination of ionizing (inducing copper ions) on a catalytic, low-energy online process – the same effect that our ancients got with use of copper vessels for drinking water and ozonation, which is today a well-known established technology for treating water to a point when it sparkles.

BCIL is among a rare few in India who have successfully demonstrated the use of these treatment systems for swimming pools to keep them chemically free and natural.

Natural Air Conditioning:

Regular air-conditioning uses CFC and HCFC as refrigerants for cooling air. At BCIL, we have gone back to the post-war technology of ammonia serving as refrigerant. Ammonia is a benign chemical and is risk-free in home settlements.

The system of air-conditioning that BCIL T-Zed Homes employs as technology is called ‘district refrigeration’ where a central chiller plant, driven by ammonia distributes the thermal temperature through a network of pipes to each of the homes.

We have designed a fan coil unit [an IP held by BCIL] like your regular air-conditioner box at home with the unique difference that it draws in fresh air which is cooled by the refrigerant from the central chilling plant. This is a 100% fresh air system and is fully free of CFC or HCFC which are ozone-depleting substances (ODS). BCIL’s non-ODS ozone air conditioning makes a big difference.

Energy cost of running this air-conditioner is about 40% lower than a regular AC. The system also offers the advantage of having no compressor at each of the AC units (FCU’s) at home. This means that there is zero energy consumed inside your home for air-conditioning. Residents, therefore, have to pay a monthly cost for the air-conditioning only on the basis of number of hours of use which is pro-ratized for the community. In case of BCIL, every home pays as little as Rs.4 or 5 per hour of usage against Rs.9 or 10 you pay for a regular air-conditioner of similar size.

Other Natural Airconditioning Systems We Employ

BCIL has taken innovation in internal air quality one further step. At BCIL Collective, we employ another system of air-conditioning for 72 master bedrooms. This is a blend of earth tunnel ventilation and nocturnal cooling systems. The ET ventilation takes advantage of the mean temperature of a region that resides at about 4 meters below the earth’s surface. For example, in Bangalore if the max. temperature is 35ºC and the minimum is 14ºC, the mean temperature bandwidth will be 24- 27ºC. This temperature is captured and transferred to each of the master bedrooms for enhancing the living comfort of residents.

This is combined with nocturnal cooling which draughts in the cool night air in a way that it supplements the efficiency of earth tunnel ventilation.

In this technology, energy is not used at all inside your home. The system works with low-energy pumps for every set of four bedrooms. The system is easy to execute and costs about Rs.200/- per sq. ft. Customer are always willing to pay for higher comfort. In this system, the cost per home in a month does not exceed Rs.400/- for 24x7 comfort of natural air-conditioning.

The regular air-conditioners, you must note, can use only 8% fresh air. This is the reason for what is called the sick building syndrome when you have conventional air-conditioning.

A third system of air-conditioning at BCIL Collective is the “stack effect”. This exchanges the heat trapped at the top of the duct shafts in a way that we can achieve forced ventilation in a room. It is somewhat like having cross ventilation in a room but with higher impact on the room's living comfort in terms of fresh air circulation.