A Rainwater Harvesting System can be installed in a house to reduce mains water usage and maintain water supplies in periods of drought

Rainwater Harvesting

If rainwater is required only for the garden and car washing, the simplest solution is to connect water butts to existing rainwater pipes. If there is surplus rainwater, it can be used in the home for non-drinking purposes, like flushing toilets and to fill a washing machine.

Rainwater Harvesting - Water Meters

Most UK households pay their water and sewerage charges as part of their Community Charge. In order to save money on water supply, it is advisable to contact the water company and arrange to have a water meter fitted. A water meter allows water usage to be monitored and for periodic checks to be made for leaks in the system.

Rainwater Harvesting - Purification

It is possible to replace all the home's water requirements with rainwater harvesting, as long as a purification system is installed in the system. If the house already has a mains supply of drinking water then a purification system is unlikely to be cost effective.

Take Other Measures Before Installing Rainwater Harvesting

Before investing money in rainwater harvesting initiatives, it is advisable to take simpler water conservation measures first.

Rainwater Harvesting System Design

Rainwater harvesting is a specialised field so when considering an installation it is advisable to takes the advice of a competent installer. The rainwater harvesting system must be designed so that the supply of rain water meets the demand. Rainfall is intermittant so it will be necessary to store enough rainwater to avoid running out in dry spells.

Rainwater Harvesting - Back-up Water Supply

It is usual to install a back-up mains supply that will operate automatically when the underground storage tank runs low. The control system is programmed to fill the storage tank from the mains when there is insufficient rainwater available.

Rainwater Harvesting - Collection Surface

Most pitched roofs provide a suitable rainwater catchment area and the existing rainwater pipes and gutters will act as the harvesting system. It is preferable to collect the rainwater that falls onto a house roof.

Rainwater harvested from the ground is more problematical as it is likely to be contaminated and will require additional cleaning. However, contamination may not be a problem if the rainwater is only used for garden watering

Sun tube lights are a simple way of transferring natural daylight deep into a building.  Natural daylight enters the building through a clear plastic dome and is reflected down a mirrored pipe to illuminate the internal space

Effective Lighting from Sun Tube Lights

Sun tube lights are highly effective at transferring daylight into parts of buildings that have little or no natural lighting. They can be used to replace artificial lighting and will therefore substantially reduce the annual energy consumption of a home. In many cases, sun tube lights will be used to provide all the light for an internal space but they can also be used to compliment an artificial lighting scheme.

Light Quality from Sun Tube Lights

Natural daylight is known to give much better quality light than that provided by electric light fittings and is more beneficial to recipients. Even on an overcast day, the quality of light transferred into a house will be considerable when compared with artificial light.

Sun Tube Lights

Where possible, the clear plastic dome should be situated on a south facing roof to gain the maximum amount of daylight. Sun tube lights are highly effective at delivering light into internal and badly lit spaces making it particularly useful for bathrooms, stairs, corridors and any dark areas.

Clear Plastic Domes on Sun Tube Lights

Clear plastic domes are available in unbreakable polycarbonate or impact resistant modified acrylic. They are available in several different sizes depending on the amount of light required and can be located on flat or pitched roofs. 

Fitting a Sun Tube Lights

In normal circumstances, sun tube lights require no structural alterations as the tube system fits comfortably between rafters and ceiling joists. The joints of the tube are sealed using aluminium tape and only a minimum of fixings are required; often just a single fixing at the bottom of the tube. A system can usually be installed within two to three hours. See Sun Tube Light Video for a demonstration

Sun Tube Light Assembly

For maximum effectiveness, the sun tube assembly should be as straight as possible. As it is not always possible to mount the clear plastic dome in line with the ceiling diffuser, bends are available to offset the solar tube near the top and bottom. The tube can be swiveled easily, to target natural light exactly where it is required. The offsets bends are adjustable up to 30 degrees from vertical.

In 1987, the Bruntland Report, on economic development and the environment, defined sustainable development as - ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’

Code for Sustainable Homes

In December 2006, the UK government launched the Code for Sustainable Homes. The Code is a development guide for home designers and builders, and the national standard for the building of sustainable homes.

Code for Sustainable Homes - Lower Energy Use

It is anticipated that the Code for Sustainable Homes will reduce the environmental impact of the construction sector as whole and will form the basis for future Building Regulations. The Government wants to see homes built in a way that minimises the use of energy and reduces harmful carbon dioxide emissions but, more importantly, it adds -

‘We also need to build and use our homes in a way that minimises their other environmental impacts, such as the water use, the waste they generate, and the materials they are built from’

Sustainable Homes Assessment and Rating System

It comprises an assessment and rating system aimed at improving the environmental impact of new homes by introducing minimum standards in nine areas, including the use of energy, carbon dioxide and water.

‘Green Building: First Zero Energy Classroom Debuts in Boston’

Planet Earth is in big need of a greener environment for thousands of reasons. Green technology is the much awaited and of course the need of the hour. Well the wait is over; the Zero-energy has arrived to revolutionize the world,because it is better, greener, faster and cheaper than any one could have ever predicted. A San Fransisco based project called FROG is bringing to life, the biggest ideas of green building.The ‘FROG Zero’ is all about making green, easy and affordable.

‘Project FROG to revolutionize the world with Zero-Energy’

Frog, the world’s first zero-energy building system will be introduced at the Greenbuild, a place where every year thousands of the world’s biggest brains in green building, gather to understand the most sustainable green building products and technologies. School of the future by FROG, incorporates the ideal learning environment into the greenest and the most sustainable commercial buildings. It is a flexible design approach that provides no carbon emission, hundred percent thermal comforts and above all it has the capacity to return five times its energy use through active solar power generation.

‘Solar Power leading the way for a Green World’

Greening the world is a major concern for every country. Towards that end, Zero-energy is a simple and a cost effective solution.

In 2007, eight designers were asked to submit two designs for an international competition for Zero Energy Housing, on six sites in the middle of Sentul Park in Kuala Lumpur, Malaysia. From sixteen designs six designs were chosen to be constructed.

The project is envisaged as one of the the first showcases of Sustainable Zero Energy Housing in the world. The competition brief called for houses that work in harmony with the environment, are made from renewable materials, create their own energy, and recycle water.

Beside requirements that the houses are zero energy, the competition called for innovative and extraordinary designs that contribute to the legacy of contemporary architecture.

The South China Morning Post said: “This project will become as important of a permanent exhibition for sustainable contemporary architecture as the Weissenhofsiedlung Exhibition of 1927 was for the modern movement in architecture last century.” (Nov 16, 2007)

Chicago-based Zoka Zola Architecture + Urban Design is one of the winning design teams whose proposal “Rafflesia House” was selected for construction.

This is how Zoka Zola describe their project:

Our wining design (unintentionally) looks like the Rafflesia, the largest flower in the world and a native to the rainforests of Malaysia. (Rafflesia used to be Malaysian national symbol, but it is now replaced by Petronas Towers.) The Rafflesia develops from the bud into a flower over a period of nine months. The blossom is pollinated by flies attracted by its scent, which resembles that of the carcass. The flower lasts for only a few days. Rafflesia challenges traditional definitions of what a plant is because it lacks chlorophyll and is therefore incapable of photosynthesis. Rafflesia is a parasite. It did not begin its life as a parasite, but evolved this lifestyle. Biologists do not know what the Rafflesia’s function is in its ecosystem.

This mystery incites one of the most elementary questions: What is the function of the humans in the world’s ecosystem?

Rafflesia House is a study of the human habitat that is an integrated part of its tropical, urban, and site-specific ecosystem.

We searched and re-examined the ideas of the right balance between the connection of the building to the outside and the shelter the building provides from the outside elements: plants, creatures, rain, sun, wind, or heat. We designed this house with an interest to understand real human needs relieved from burdens of pre-assumptions, but with an intent to house the whole human complexity.

The building sits on 12 columns to allow other species to develop around it.

Bird Island is a stunning urban renewal project that is currently being developed in Kuala Lumpur, Malaysia. Designed by Graft Lab architects for the YTL Green Home Competition, the project comprises a zero energy home made of sustainably-sourced silicone glass fabric. Its lightness and flexibility will allow it to sway organically with the breeze just like a treetop, and slots in the fabric will give visitors a unique peek into the sky as the wind ebbs and flows.

The YTL Green Homes Competition challenged eight architects and designers from around the world to submit designs for six eco-friendly homes on Bird Island. Graft Lab’s proposal is an airy voluminous structure that utilizes a variety of energy-efficient building practices. The building consists of a lightweight bamboo frame wrapped in a tensile, environmentally-friendly fabric. The material reflects sunlight, keeping the interior cool and reducing the need for AC. Bird Island will also be outfitted with a grey water recycling system that channels water from sinks and showers back into the plumbing.

Graft states: “We have applied an integrated strategy of developing a zero-energy house that seamlessly dovetails the economic and environmental advantages of environmentally friendly living with the needs of a demanding and cosmopolitan clientele. The environmental and economic features of this way of living do not conflict with our client’s lifestyle; rather it furthers their ability to comfortably enjoy their time at home.”

As of yet, no construction date has been set.

+ Graft

+ Bird Island

 

The zero fossil energy consumption principle is gaining considerable interest as renewable energy harvesting is a means to cut greenhouse gas emissions. Traditional building use consumes 40% of the total fossil energy in the US and European Union.^[1][2] In developing countries many people have to live in zero-energy buildings out of necessity. Many people live in huts, yurts, tents and caves exposed to temperature extremes and without access to electricity. These conditions and the limited size of living quarters would be considered uncomfortable in the developed countries.

The modern evolution of zero-energy buildings

The development of modern zero-energy buildings became possible not only through the progress made in new construction technologies and techniques, but it has also been significantly improved by academic research on traditional and experimental buildings, which collected precise energy performance data. Today's advanced computer models can show the efficacy of engineering design decisions.

Energy use can be measured in different ways (relating to cost, energy, or carbon emissions) and, irrespective of the definition used, different views are taken on the relative importance of energy harvest and energy conservation to achieve a net energy balance. Although zero energy buildings remain uncommon in developed countries, they are gaining in importance and popularity. The zero-energy approach has potential to reduce carbon emissions, and reduce dependence on fossil fuels. Most ZEB definitions do not include the emissions generated in the construction of the building and the embodied energy of the structure. So much energy is used in the construction of a new building that this can dwarf the operational energy savings over its useful life.

A building approaching net zero-energy use may be called a near-zero energy building or ultra-low energy house. Buildings that produce a surplus of energy during a portion of the year may be known as energy-plus buildings.

If the building is located in an area that requires heating or cooling throughout parts of the year, it is easier to achieve net zero-energy consumption when the available living space is kept small.

Definitions

Despite sharing the name zero energy building, there are several definitions of what ZEB means in practice, with a particular difference in usage between North America and Europe.^[3]

Net zero source energy use

This ZEB generates the same amount of energy as is used, including the energy used to transport the energy to the building. This type accounts for losses during electricity transmission. These ZEBs must generate more electricity than net zero site energy buildings.

Net zero energy emissions

Outside the United States and Canada, a ZEB is generally defined as one with zero net energy emissions, also known as a zero carbon building or zero emissions building. Under this definition the carbon emissions generated from on-site or off-site fossil fuel use are balanced by the amount of on-site renewable energy production. Other definitions include not only the carbon emissions generated by the building in use, but also those generated in the construction of the building and the embodied energy of the structure. Others debate whether the carbon emissions of commuting to and from the building should also be included in the calculation.

Net zero cost

In this type of building, the cost of purchasing energy is balanced by income from sales of electricity to the grid of electricity generated on-site. Such a status depends on how a utility credits net electricity generation and the utility rate structure the building uses.

Net off-site zero energy use

A building may be considered a ZEB if 100% of the energy it purchases comes from renewable energy sources, even if the energy is generated off the site.

Off-the-grid

Off-the-grid buildings are stand-alone ZEBs that are not connected to an off-site energy utility facility. They require distributed renewable energy generation and energy storage capability (for when the sun is not shining, wind is not blowing, etc). An energy autarkic house is a building concept where the balance of the own energy consumption and production can be made on an hourly or even smaller basis. Energy autarkic houses can be taken off-the-grid.