Sangath 3 - Test and Refine - Rainwater and Catchment

Analysis of rainwater and collection - Original Design

Lake Bennett Average Rainfall Intensity: 366 mm / hour
Lake Bennett Average Annual Rainfall: 160.83mm
Roof Catchment Area Of Original Design:
Guest Bedrooms: 154m2
Permanent Bedrooms: 185m2
Living Area: 205.25m2
Total Catchment Area: 544.25m2
Annual collectable water = Catchment area x Average annual rainfall
Annual collectable water = 875,320L
Water consumption / year = No. People x Daily consumption x 365
Water Consumption / Year = 8 x 166 x 365 = 484,720L
Shear line Gutter on each roof connected to two 100x75 box gutters to service 20m2 of roofing each
26,000L tank under living area of dimensions 3800 d x 3000 h

The main issue with the original design is that the roof catchment area is excessively large, being able to catch more than twice as much rain water than necessary for a years worth of usage. This means that more water than the tank is capable of storing will be filtered into the tank during the monsoon season leading to overflowing and flooding underneath the kitchen area. This can lead to erosion of the footings as the soil is highly erosive in this area.

Analysis of rainwater and collection - Refine Design

Area A = 5.5 x8.4 x 3.14 = 145.14m2
Area B = (7.3 x 4.5 x 3.14) x 0.6 = 61.92m2
Area C = (6.1 x 3.3 x 3.14) x 0.45 = 28.54m2
Total Roof Catchment Area = 235.6m2
Lake Bennett Average Annual Rainfall: 160.83mm
Annual collectable water = Catchment area x Average annual rainfall
Annual collectable water = 378,915L

The rainwater is collected off the membrane roof in six locations at the base of the bamboo structure.
The collected water is channeled into a 45,500L tank of dimensions 3420mm high and 4400mm deep.
This tank is located underneath the kitchen decking and is semi submerged into the ground to maintain a stable temperature.
A spoon drain surrounds the structure on the west to stop erosion of the footings during the wet season.

Water consumption / year = No. People x Daily consumption x 365
Water Consumption / Year = 8 x 118 x 365 = 344,560L

The refined design has a smaller roof catchment area which means both the ability to catch less water than the original, but also the optimum amount of water to survive for the entire year off the grid is being caught. Furthermore a larger tank has been added so that during the dry season there can be enough water stored to survive. The spoon drain still surrounds the structure on the west side to prevent water runoff from the hill being trapped under the building.

Sangath 3 - Ross's Test and Refine Calculations

Shadow Analysis

Shadow Calculations

Shadows Original

9:00am Winter Solstice
Azimuth = 54dg Altitude= 24 dg
Sun Penetrates the entire floor area
0% Shade

12:00pm Winter Solstice
Azimuth = 15dg Altitude= 53dg
Rooms are in 100% Shade

4:00pm Winter Solstice
Azimuth = 303dg Altitude= 32dg
Sun Penetrates 50% of room floor area
50% Shade from hot sun

In order to stop sun penetration, louvers must be closed, therefore no ventilation!

Shadows Refined

9:00am Winter Solstice
Azimuth = 54dg Altitude= 24 dg
Shading prevents sun heat penetration.
100% Shade

12:00pm Winter Solstice
Azimuth = 15dg Altitude= 53dg
Shading prevents sun heat penetration.
100% Shade

4:00pm Winter Solstice
Azimuth = 303dg Altitude= 32dg
Shading prevents sun heat penetration.
100% Shade from hot sun


0% Sun heat penetration due to Reiri screen. Only natural light!



Ventilation Analysis

Ventilation Original
Winds from North
- Good ventilation through an open design.
- Angled Roof blocks wind high up

Winds from South-East
- Bad design fins dont direct the wind, they
block it

Winds from East
- bad design where the fins block wind
- See white air-pockets

VENTILATION NOT AS GOOD AS FIRST HOPED!

Ventilation Refined
Winds from East
- Excellent ventilation by eliminating fins

Winds from South
- Excellent ventilation by eliminating the fins

Winds from East
- Perfect Ventilation by removing major roof pitch

Air is able to flow the entire way through the building -
Perfect for Kakadu.

Refine

HEATING AND COOLING CALCULATIONS

Original Design:

- Total Area: 342 m2

- Total Volume: 1226 m2

- Total Building Fabric Heat Loss: 8293.06 Watts

- Total Building Fabric Heat Gain: 8367.43 Watts

- Steady State Heat Loss: 529.36 Watts

The main source of heat loss from the original was the timber decking with a total figure = 3821.23 Watts

The main source of heat Gain in the original design was also from the timber decking, = 5155.78 Watts

It would be beneficial in the refine to decrease these figures, as the climate is very hot and with such a great figure for heat gain established from the floor. This can be reduced by decreasing the total area of the design.

By reducing the area and by effect the volume, it would also benefit the Embodied energy and water figures.

Refined Design:

- Total Area: 235.6 m2

- Total Volume: 353.4 m2

- Total Building Fabric Heat Loss: 4427.27 Watts

- Total Building Fabric Heat Gain: 6067.67 Watts

- Steady State Heat Loss: 276.03 Watts

The Main Source of Heat loss in the redesign was from the Timber decking with a total = 2632.40 Watts

The Main Source of Heat Gain in the redesign was found also from the Timber decking = 3551.76 Watts

Total Reductions:

- Total Area: Reduced 32 %

- Total Volume: Reeduced 71.2%

- Total Building Fabric Heat Loss: Reduced 45%

- Total Building Fabric Heat Gain: Reduced 25%

- Total Steady State Heat Loss: Reduced 47%

Conclusion:

Overall by reducing the total area and volume of the original design as well as changing the materials and their heat loss U values, the refined design benefited massively.

Though the Heat Gain was still relatively high through the timber decking, there was still a huge reduction of 31.12 %.

Sangath 3 - Test and Refine - Embodied Energy and Water

Embodied energy is the amount of energy required to produce a material and transport it to the site. Similarly the embodied water of a material is the amount of water used in its production. Both of these factors contribute to how environmentally sustainable a material is and how renewable it is. In the refinement of our Domus design there have been significant changes to materiality, which has meant a notable reduction in the embodied water and energy, as well as life cycle and sustainability benefits.

Embodied Energy of the original design

The problem with the original design mainly lies in the embodied energy of the materials which were proposed. The main structure of the bedrooms was constructed of a hot rolled portal frame which has an excessively high embodied energy rate of 84.285GJ/t. The embodied energy of this material alone is greater than the entire embodied energy of the entire refined structure.
Similarly, the floor area of the original design was almost 1.5 times the refined floor area. This meant that more hardwood flooring was required which significantly increased the environmental effects of construction. With sustainability being a major issue in todays design practice, it is imperative to choose renewable materials in order to reduce environmental effects. In the original design there was much wastage of materials with the use of mechanical timber louvers for walls, this was not only high in embodied energy, but required regular maintenance, meaning a greater life cycle expense.

Embodied Energy of the refined design

The most significant reduction in the redesign is the roof structure which is now made of a paper based tensional membrane supported by bamboo ribs. This has meant that a portal frame structure is no longer necessary. Likewise, the use of curtains constructed from organic fibers has seen an enormous reduction in terms of energy, water and recyclability, with the materials being biodegradable and renewable. The amount of floor area reduction has also seen mass decreases in the amounts of material required.

The refined design gives a total reduction of embodied energy of 6124.2KJ/Unit. This is a saving of 70.2% due to using significantly less Hot Rolled Steel and using recycled and environmentally friendly materials such as Ramie Fabric and Bamboo.

A Reduction in Embodied Water of 9226.8 KL/Unit has been achieved with the refined design through the use of renewable and recycled materials with a low embodied water rating. This has helped to achieve a saving from the original design of 62.6%.

Sangath 3 - Test and Refine - Materiality and Roof construction

Outer Curtains
Ramie is a similar fabric to linen and is made from an inexpensive plant fiber. It is naturally cream in color, has a high luster and an unusual resistance to bacteria and molds. Ramie has excellent abrasion resistance and has been tested to be three to five times stronger than cotton when spun or woven into a fabric. Ramie is a rapidly renewable resource and is both reusable and biodegradable. This will be used for the exterior curtain.

Inner Curtains
Providing protection from mosquitoes, yet being breathable for ventilation and see through for capturing views, Midge Mesh will be used for the internal curtain. It is both light-weight, durable and inexpensive.

Roof
The external shell will be comprised of a composite paper based membrane. A combination of recycled paper, ramie fabric and warmcel cellulose, all of the materials are renewable and biodegradable.

Insulation
Warmcel Cellulose is an insulative, paper based material. It is comprised of recycled newspaper and mineral compounds and is both fireproof and pest proof. The composite paper based membrane is:
- waterproof
- fire retardant
- insulative
- moss proof
- breathable

Structural Ribs
One of the world’s most renuable resources, Bamboo is both flexible and strong. with a low embodied energy and embodied water, the cost of bamboo is also significantly less than other timber products.

Refine

Addressing the Criticism:

Criticism: Clashing of forms

Refinement: Creating one continuous form. This also decreases many figures, including embodied energy and water, heat gain, improves ventilation.

ORIGINAL

REDESIGN

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Criticism: Using Heavy Cantilevered frame

Refinement: Use of Natural Reusable Bamboo ribbing

ORIGINAL:REDESIGN: ___________________________________________

Criticism: Toilet design and privacy

Refinement: Enclosing them more, rotating them towards the inside of the house.

Doors have been added having them enclosed on 3 sides.
Incorporating a screen door for privacy.

ORIGINAL:

REDESIGN:

______________________________________________

Criticism: Use of mechanical Louvers with high embodied energy.

Refinement: Removing Louvered walls completly.

Using a taught curtain to separate rooms, and keeping most of the other rooms open underneath the tent.

ORIGINAL:
REDESIGN:

_______________________________________________

Criticism: Drawing Graphics need to read better

Refinement: Using better lineweights, hatching, colour. We also used many sectional drawings, showing materials, construction details and sun diagrams.

________________________________________________

Criticism: The connection between the living area and the bedroom wings.

Refinement: Creating it into one space, which also benefits water catchment

ORIGINAL:

REDESIGN:

_________________________________________

Criticism: Ribbing will not benefit the ventilation to the building

Refinement: Through fluid mapping we found this to be true, we removed the ribbing and used a tent structure which did not disrupt the ventilation through the house.

ORIGINAL:

REDESIGN:

Sangath 6: Test & Refine A2 sheets