ECOHOUSE DESIGN Heriot Watt University - Dubai
TABLE OF CONTENTS
INTRODUCTION DESIGN STATEMENT SITE ANALYISIS BUILDING ORIENTATION & BUILDING FORM SHADING SPACE PLANNING NEEDS CIRCULATION LIGHTING MATERIALS ROOFING PHOTOVOLTAIC SYSTEM DESIGN PASSIVE SOLAR COOLING & HEATING AND COOLING STRATEGIES WATER MANAGEMENT SYSTEM WATER SUPPLY & LANDSCAPING FOR ENERGY SAVINGS CONCLUSION REFERENCES
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INTRODUCTION •The following brief showcases the design of an Ecohouse in the heart of the city. It begins with a comprehensive site analysis and then continues with the building form, materials used in the construction, and the energy strategies used in laying down the services within the structure. All the structural elements have been chosen to provide stability to the structure as well as ease of construction and at the same time maintaining its aesthetic appeal. The house has primarily been designed keeping passive techniques in mind. •The floor plans have been designed in order to maximize the usable area and all the spaces have been allocated adequate area depending on their function. Lot of thought and care has been put into the positioning of the Ecohouse, in terms of view, topography and accessibility. Taking sustainability into consideration the proposed site will be developed to enhance the natural eco-system.
DESIGN STATEMENT •The main mission of designing this Ecohouse is to rise from all the limitations and constraints of architecture in order to produce a structure which is modern, environment friendly, sustainable as well as economical. This brief aims to provide with an insight into the technology incorporated as a part of this passive solar design, which refers to the use of sun’s energy for the maintenance of temperature in the living spaces. A passive system has been chosen since it is simple, requires little maintenance and produces low energy costs.
Initial Design Idea
•The central idea behind this project is to create something classy yet sober, keeping in mind all the necessities of a perfect and comfortable home. The villa is spaciously crafted with quality materials and ideal energy strategies. •The basic concept that this design portrays is ‘togetherness’. The Ecohouse structure is planned in such a way that the user feels safe and free from all the hustle and bustle of the city. The buildings are connected internally to show a sense of integrity as is in the case of a happy family.
Final Design Idea
SITE ANALYSIS Location: The Ecohouse is in Emirates Hills, Dubai. This luxurious villa is surrounded by handsome neighboring villas (west and east of the plot), lush landscaping including a fine view of the golf course and splendid lake (north-east of the plot). This site is perfect for a villa of this kind since the entire development includes properties of distinctive style. The site is oriented in the north direction. The site is in the shape of a trapezium and is roughly 3240 m 2 in area. The vegetation in this area is rich. The soil in this region is non-cohesive and consists of loose grained sand. The Ecohouse is accessible by a road from the south. The Dubai International Airport is a 30 minutes drive from the site. Some well renowned schools, shopping centers are also situated in the vicinity, which is another advantage for the residents of the community. Climatic Conditions: The site gets direct sunlight from the north whereas the southern side of the villa experiences indirect sunlight. The Ecohouse is positioned in such a way that it collects maximum amount of good wind coming in from the north-west direction and scatters most of the bad wind coming in from the south-east direction. Most of the functional spaces in the villa will get a long view of the beauty that surrounds the site. The climate in the area is hot and arid in the summers with sometimes humidity increasing in the evenings and the winters are pleasant with a few spells of rain. Since the area has abundant flora, the community is benefitted by cool breeze. The site is prone to natural hazards like sandstorms.
Site Area
Site History: There has been no previous construction on the site proposed for the Ecohouse and consequently it is free of any contaminants. It is a level site.
BUILDING ORIENTATION The Ecohouse is positioned in such a way that the large horizontal windows face the north side. This feature allows to scoop in cool air and spread light in places with hot climate. The south direction of the house has smaller windows.
BUILDING FORM •The Ecohouse consists of two buildings, connected internally but having variation in heights. The Ecohouse has a passive design in order to preserve sustainability. Majority of the spaces in the villa which are occupied most of the time, like master bedroom, living and dining areas face the golf course and are exposed to the good winds as well as receive direct sunlight which would in turn increase natural ventilation and lessen the need for artificial lighting, respectively. •This Ecohouse is situated in a hot climate where heating is never required and therefore the opportunities to improve the comfort are limited due to high air temperature and relative humidity. The only available choice is to encourage air movement as much as possible and this is achieved by the open balconies and exterior sitting areas. The curved shape of the house has been designed to navigate the bad winds away from the site and this feature also helps to shade the landscaping and shield it from the affect of storms.
Building 3D Model
Elevation
First Floor Plan Ground Floor Plan
Pergola
SHADING Shade is essential for reducing the effects of the heat on the home. It is the easiest and cost-effective way to keep the house cool and protected. •Roof Overhangs: The roof of the Ecohouse has been constructed such that it extends from the two ends and acts as a roof overhang to shade the north and south faces. The north and south facing aspects have been given the maximum priority since these two sides are the most affected when the sun is high overhead. •Pergola: A covered pergola will also be fixed outside the house for shading against heat and rain. It will also work as an excellent north facing outdoor entertainment area. It will be covered by climbing plants which will offer the bonus of allowing the sun through in the winters.
SPACE PLANNING NEEDS The rooms and outdoor spaces have been situated in such a way in order to maximize the comfort. Keeping this in mind the living areas face north, and service areas like the garages and bathrooms face the south. Depending upon the activity and function of each of the spaces in the house, the area has been decided efficiently. The floor plans, which describe the way the rooms are arranged and the spaces within the house are used, is critical to the overall satisfaction of the residents. Zoning: The floor plans have been made keeping in mind the proper zoning of areas: • The public zone; which consists of the foyer, guest room, living and dining rooms, have been placed on the ground floor of the Ecohouse. This has been done since these spaces accommodate the non-family members also, so need to have an open access. The size of these rooms is quite spacious since many people occupy these areas. The Ecohouse has open style living and dining room since an open floor plan offers better natural ventilation and they can accommodate more people in the event of social gatherings. • The work zone; which includes the kitchen, store and laundry rooms, garage and the study, have been all situated on the ground floor itself. This zone composes of areas where work activities that support the lifestyle of the household take place. • The private zone; which includes the bedrooms, bathrooms, gym and the family sitting areas, have all been placed on the first floor separately for privacy reasons. The areas that fall under this zone are exclusively used by the household members A proper zoning pattern has been followed in making the floor plans since all the areas falling under a zone are placed together. This ensures a confusion free circulation pattern and the household members will not have to cross through the middle of one zone to get to another.
CIRCULATION The circulation paths in the villa have been made as short and direct as was possible, since a circulation pattern which utilizes minimal floor space through the home should be the goal of an efficient residential plan. Long hallways and indirect circulation pathways waste the usable floor space and add significantly to the cost of construction. The central foyers and direct hallways have assisted in the creation of a proper circulation pattern in the home.
Staircase Design: A spiral staircase has also been included in the design of the Ecohouse since they are the most space efficient type of stairs as they effectively take up little more floor space than their diameter. These kinds of stairs are built with treads fanning out around a central column. They also give an excellent modern look from the point of view of aesthetics. The stairs will be made up of wood and steel. Sketch of the Spiral Staircase
LIGHTING DAYLIGHTING: Daylight optimizes natural sunlight entry into a building to minimize the need for artificial lighting. Energy-efficient lighting will be enhanced in the Ecohouse, to achieve the optimal level of light for the lowest energy investment and since the heat gain from natural light will be useful. The indirect light will be collected in the form of daylight from the south side of the Ecohouse. Direct light will be shaded from entering the house during the peak heating season, in order to keep the interior cool and to protect the interior fabrics from exposure to the harmful UV rays, which can damage the colors. Operable windows will be placed mainly on the north and south sides, where the bedrooms are located, since the light can be controlled from these sources. The east and west facing areas would not be used much for the daylighting purposes since excessive glare and heat gain can occur from these orientations.
ARTIFICIAL LIGHTING: Energy efficient lighting is not just installing the best light with least power or the longest lasting light bulb. Proper sizing of the light to the needs of the location and the tasks that will be performed, called task lighting, is an energy saving strategy. Fluorescent and LED lights will be used as part of the artificial lighting system particularly during times when day lighting won’t be enough. LEDs and Fluorescent lights use less power compared to conventional forms of artificial lighting and promote energy performance. Photo sensors will be installed in all the rooms in the Ecohouse. The sensors will automatically switch on the lights in the rooms if the amount of natural light in the room reduces by a certain amount. Manual switches for control of lighting will also be present in all the rooms. Most of the rooms and spaces in the house have been positioned along the perimeter, or in a way that they get the maximum exposure to the day light.
MATERIALS Exterior Façade: Aesthetics are an important feature of the structure since it reflects the thought behind the creator’s imagination and it is the first thing that a person notices, other than the design. The materials used in the Ecohouse are sustainable, ecofriendly and blend with the climatic conditions and the surroundings quite well. Concrete: Concrete has been used for the exterior envelope of the Ecohouse since it is durable and has exceptional strength. Fly ash is added to the concrete to reduce the usage of cement, since cement is responsible for producing carbon dioxide. The main idea of using fly ash concrete is to cut down the greenhouse gas emissions since fly ash is a recycled material. It will also be used for making the foundation, beams, floors and walls in the villa. Some other benefits which make fly ash concrete appropriate for use are: • • •
It can be cast into any shape and size, offering great flexibility in design. Concrete is known for its acoustic properties Fly ash adds strength to the concrete and reduces leakage into the structure.
Double Glazed Glass: Glass is the most significant material which will make up the façade of the house since it lets in natural sunlight as well as radiant heat, which when harnessed properly, can help to heat the house. The glass which will be installed will be double glazed, low emissivity (low-e), argon filled type. Low-e coatings and argon both improve the thermal performance of the glass by reducing the heat flow. A semi-reflective coating, with reflectivity below 20 percent, on the outside of the windows will reduce radiant heat transfer into the house and cut out the sun’s glare. The percentage of reflectivity has been chosen such that it doesn’t annoy the neighbors. This glass is soundproof and will not disturb the interior composed atmosphere. Aluminium: The window frames will be made up of anodized aluminium. Aluminium is preferred since it can be reused, is free of toxins, energy saving, cost effective and safe to handle. Although it is costly to the environment in extraction and processing, it is relatively simple to recycle. The anodization will seal the surface of aluminium, increase its hardness and make it corrosion resistant.
ROOFING Green Roof: The Ecohouse will have extensive green roofing since it encourages biodiversity, provides outstanding sound and thermal insulation, absorbs water run-off. Green roofs are an integral part of sustainable design since it is cost effective and attractive. The green roof will consist of a foam matting on a plastic drainage layer on a waterproof underlay covered with soil and topped with low growing plants. Plants with resistance to wind, drought and requiring little maintenance will be grown. Extensive green roof has been opted since it is lightweight and designed to be self sustaining. Advantages of the green roof in the Ecohouse design:
Green Roof Detail
• It will protect the waterproofing membrane from climatic extremes, UV light and mechanical damage, doubling the life expectancy of the roof. • It will help to cool the building in the summer and so will benefit the passive cooling design. • It will offer attractive green spaces for recreation. • It will absorb the rainwater and help to filter the pollutants.
PHOTOVOLTAIC SYSTEM DESIGN A photovoltaic system uses photovoltaic cells to directly convert sunlight into electricity. Although they incur high initial cost, but this system is reliable and well developed. The use of photovoltaic system is an environment-friendly alternative. This system will help to reduce the need for electricity as it acts as the direct electrical power source. These solar PV panels which will be installed on some parts of the sloping roof of the Ecohouse will not require direct sunlight for their functioning and will even produce electricity on an overcast day. PV panels consist of two or more thin layers of semi-conducting materials that, when exposed to the light, generate electrical charges, which are conducted by metal contacts as direct current into a building’s electricity supply. In the Ecohouse design, monocrystalline panels will be mounted, since they are the most efficient of the kind. These are cut from single silicon crystals and harness 15 percent of the sun’s energy. These panels will be positioned on the south facing roof. Some other benefits of PV system are: •They require very little maintenance, i.e. produce no waste or pollution once installed. •This source of energy is reliable and constant, since the sun rises everyday and the PVs work in all climatic conditions •Fixed cost for electricity as opposed to the increasing cost of mains power.
Photovoltaic Panel
PASSIVE SOLAR COOLING The passive design of the house will lessen the temperature fluctuations, improve the indoor air quality and prove to be more resource efficient. Insulation, thermal mass and shading will reduce the heat gain. Ventilation and Operable windows: For the purpose of natural ventilation, operable windows have been integrated in the façade of the Ecohouse. These windows can be opened to let fresh air into the villa.
HEATING AND COOLING STRATEGIES 1. Since the weather remains hot and humid for most time of the year, a heating system is not required in the Ecohouse. 2. The Ecohouse will be installed with a Central Air Conditioning System. An air conditioning unit controls the internal environment of a building by cleaning, cooling, humidifying or dehumidifying air supplied to occupied spaces. This kind of system has a central air handling unit (AHU) which conditions fresh air from the surroundings to the entire building to maintain the required levels of comfort. The advantages of this system are: •It does not make noise and is very energy efficient •The air distribution can be controlled through duct and diffuser system. •It is suitable for cooling large spaces as it offers high performance. The installation of this system requires a false ceiling and a two-duct system. This facilitates the extraction of used air and the collection of fresh air and spreading in the entire area.
Schematic Diagram of a Central Air Conditioning Unit
WATER MANAGEMENT SYSTEM 1. A simple water butt will be installed for the purpose of managing water. It is a storage unit attached to a drainpipe (image). It is cheap and will provide enough water to irrigate the gardens and washing the cars. It is quite easy to install a water butt. 2. A grey water recycling system will also be installed, which will collect the wastewater from the showers, baths, washing machine and dishwasher in a tank, filter it and reuse to flush toilets, irrigate landscape.
Water Butt
Grey water from the above-mentioned sources will be collected in a tank. The inlet of the tank will consist of a screen which will remove large suspended particles present in the water. The filtrate is then passed into an aeration tank using a submersible pump with a cutter mechanism. This will help remove particles that are larger than 2mm. Chlorine is then added to the water to treat it for reuse. Finally, the effluent is passed into a sand filter to remove any residual particles present in it and is then sent to the distribution tank for circulation to sprinklers and toilet flushes (image). This system uses very less energy, reduces water bills and the amount of water used at a time. It is also quite cheap and easy to install.
Grey Water Unit
WATER SUPPLY The water heaters are placed in every full washrooms for the purpose of heating water. A central water heating system has not been set to conserve water that is lost while waiting for the hot water to travel through the pipes. Approximately 8,000 gallons of water is lost due to central water heating systems in an average household.
LANDSCAPING FOR ENERGY SAVINGS Landscaping can reduce lot of energy costs, which is why the Ecohouse has been surrounded by attractive landscaping. This feature of the design adds an aesthetic finish to the entire site. The shade created by the trees and the effect of grass and shrubs will trim down the air temperatures around the Ecohouse, offer evaporative cooling and comfort. Mainly the west and the north-west sides will be planted with most of the greenery, since that will block the summer setting sun. The setting will also provide for a place to relax for the users, when the temperatures are low. Irrigation: This is an important requirement for replenishing the plants growing around the site. In all the green areas, underground sprinklers are installed through means of basic electronic and hydraulic technology for this purpose.
CONCLUSION One of the main objectives of any building design is to ensure the provision of continuous comfort for its users despite adverse and variable external conditions, and this prerequisite has been taken care of in this Ecohouse Design Brief. All aspects of the house, have been given an eco-friendly touch, and even the operation, construction and maintenance are done in a manner that it does not affect the environment. This design of the Ecohouse has distinct aesthetics that sets it apart from other home designs. The house has been designed in such a way so as to foster harmonious family life and at the same time minister to the privacy of the individuals living in it.
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