GREEN HOUSE RISING – A new home in the design stage in Valle Verde, Pasig strikes a wise relationship between habitation, natural light, seasonal wind movements and new eco-friendly technologies for geothermal cooling.
The new technology of mylar coated tubes allows natural light into a building. It could be combined with a solar-powered heliostat to track the sun’s movement to allow constant natural light in.
Green House Rising By Dan Lichauco Philippine Daily Inquirer First Posted 11:35:00 01/29/2008
THANKS TO THEIR FULL EXPOSURE by the media, the ideas, concepts and notions of sustainable and environmental design have reached public the consciousness.
There have been discussions about new ideas from art and industry. Ideas like bio fuels, methane harvesting, electric jeepneys and tricycles, fuel cells, solar power have moved from theory to reality.
But architecture, as a combination of both art and industry, may be one of the last to move toward sustainable and environmental correctness.
Although there are numerous built examples in other countries, a truly “green” structure, using most of the tools and concepts, will be few and far between.
This also because architects must struggle to make the new ideas acceptable, they will have to look for clients willing to explore and experiment with new technologies.
But there are some exceptions. At Archion Architects, we’re in the process of designing a house to use the least amount (not zero!) of electricity from the Meralco grid. The house is located in Valle Verde and is the residence of Lasse and Maricar Holopainen.
Interestingly, Lasse is the president of the Philippine Electricity Marketing Corp., a corporation mandated to “establish, maintain, operate and govern an efficient, competitive, transparent and reliable market for the wholesale purchase of electricity and ancillary services in the Philippines in accordance with relevant laws, rules and regulations.” (Check the WESM website)
Like all our projects, our first job as designers is to understand the clients’ needs and requirements. To make the building “green,” one should not sacrifice comfort, function and beauty. Cost should also be a factor since the judicious use of the technologies is important. With this in mind, and in partnership with a client with the will and desire to create an energy-efficient structure, we have embarked on the journey of designing and building a green showcase.
Design phase
We are currently in the design stage and hope to start construction by the second quarter of 2008. With a building program of about a year, it will actually take another year or two full seasons to evaluate the effectiveness of the built structure. In architecture, two years is a short time for such a project, and we will hopefully learn more from the process.
The house has to work in the traditional sense of a dwelling, but will also include other elements that propel the design direction.
First and foremost, it should look like a regular house—stylish, current and mainstream. I do not think the owners were looking at some “mother ship”-type residence that would stick out like a sore thumb in the subdivision.
As such, functional requirements are based on the family’s lifestyle. They include a junior suite for Lasse’s mom, a guest room, a workroom, a service kitchen, maid’s quarters, pool, etc. It will be a regular house for a regular family, in short.
What makes this house special is the Holopainens’ commitment to certain lifestyle changes. For an environmental house to work, the inhabitants have to make commitments and adjustments to maximize its benefits of the residence. This is the foundation and the beginning of its design.
In this limited space, I will concentrate on the basic design and technological parameters and concepts. These ideas have far-reaching consequences in cost, construction and effectiveness, however. This article will illustrate the broader concepts to try and show where the house is going. As in all architecture, the devil is in the details critical to the success of the project.
Orientation
Proper orientation is the first step to making an environmental house. Paradoxically, the lot has an east/west orientation, in which a view of a valley is on the site’s eastern side. This view is logically one of the major design considerations for room locations and layouts.
Unfortunately, the eastern view corridor gets the full morning sun. The street side is oriented west, a more difficult (and hotter) orientation. But prevailing wind directions, the amihan and the habagat, work to the advantage of the design.
The site analysis diagram shows the relationship of the structure to the elements.
Heat
Protecting the house from heat gain, while maintaining the views, is one of the difficult problems in creating the design. To solve this:
a. The form and the shape of the house are designed to capture the amihan and the habagat. By indenting the rooms in a saw-tooth pattern, we maximize the surface area to be hit by the prevailing winds.
b. To further enhance the wind effect, the balconies and eaves are slanted to act as wind scoops to draw the air into the windows, ventilating the different rooms naturally.
c. Either the vertical sunshades or the wide horizontal overhangs protect all the windows facing east or west. The wide overhangs are actually the balcony-gardens. These balconies protect the floor below. We are counting on vegetation on the perimeter of the lot to add further protection from the sun. The gardens on the balconies will also act as vertical sunshades without obstructing the view.
d. These vertical sunshades are about 24 inches away from the glass and exterior wall of the house. This makes a double wall that will act as a heat stack and a double skin to draw hot air away from the windows. This hot air is dissipated from the cut-outs in the eaves.
Wind scoops/heat stacks
To properly ventilate a space, you have to allow cooler air to enter spaces and hot air to exit them. Heat stacking is an effect where rising hot air draws cooler air into the space it exits. All this works in conjunction with wind scoops.
The stairwell in the Holopainen residence will act as the heat stack that will allow hot air from the living spaces to exit the building while naturally illuminating parts of the basement. The roof of the stair tower will serve as an additional wind draw/ scoop to properly ventilate the larger spaces.
New technologies
Aside from these, there are technologies that can be adapted for the residence. Some of the ideas we are currently exploring are:
Geothermal cooling. This is based on the notion that the temperature of the earth six feet underground is between 18-20°C. The idea is to run pipes under the house that allow outside air to be cooled by the earth. Solar-powered fans draw this air from the exterior. The result should be an ambient indoor temperature of about 24-26°C, which is very comfortable.
It would be interesting to note that you could actually save power on your air-conditioning if you set it at 24°C, not the freezing 18°C that everyone seems to use. This, plus the fact that the AC is cooling colder air, will make it work more efficiently.
Night air, which is also cooler, may be pumped into the bedrooms, allowing the room temperature to further decrease during sleeping time when the AC is mostly in use.
Light tubes. These will be used to illuminate the basement. Light tubes are mylar coated tubes that allow natural light into different parts of a structure. A solar-powered heliostat may also be used to track the sun’s movement, allowing constant natural light into the basement.
Roof insulation/ garden deck systems/ rainwater harvesting. One of the general ideas of environmental design is to prevent excess heat from entering the building through the roof. This residence is looking to employ a garden-deck system to be used on a flat slab roof. This system uses a water-retentive, anti-root, lightweight garden system that will allow plants and shrubs to be grown on roof decks.
The beauty of this system is that it also acts as an insulator to the house as well as a collector and filter for rainwater. The excess roof rainwater will be channeled to a gray-water cistern for storage and use during the summer months.
Solar power and photovoltaic cells. Given the current state of available solar technologies, studies have shown that the cost of electricity from the grid still ends up cheaper than the cost of electricity from solar sources, unfortunately. This is due to the fact that solar panels are still not efficient and will require large surface areas to operate well. Moreover, there are the prohibitive costs of the equipment like batteries, converters, etc.
But the house is designed to adapt to solar power in the future. Although there is an intention to draw at least some power needs from this source, we are still exploring ways to allow the residence to be self-sufficient and allow at least for some solar-power generation.
Solar water heaters, however, have proven to be efficient and reliable in heating water for washing and bathing. These systems will be included in the design of the residence.
Lighting fixtures. The selection, location and connection (switching) of all lighting fixtures will be carefully studied. It is important to use energy-efficient lighting fixtures such as LEDs and T8 fluorescent bulbs. Halogens are to be avoided as much as possible. The location and switching are also important. Naturally sunny areas should have lights independently controlled from a room’s other lighting fixtures. For example, if there are four down lights in a room, one switch should control the ones closer to the window while another switch should control the ones farther away. If a single switch controls all lighting fixtures, then the ones by the window will only add light to a sunny bright area.
Other systems. Other systems that are being considered are computerized control systems that can regulate lighting, cooling and security. These systems are readily available in the market and can have a full range of controls that can be added, making the green house a “smart house” as well.
Gray-water harvesting is also being considered as a viable option for water conservation. The rainwater cistern is designed to hold relatively clean rainwater to be used for bathing the dog, washing the car and watering the plants. This source can be augmented during the summer months with harvested gray water from sinks and baths. A separate filtration system will be included to realize this.
Bio-gas production is also another consideration. Human and kitchen waste may be funneled into a digester that produces methane. The gas can be used as an alternative to LPG and if volumes allow, it can run a micro-turbine generator.
All together, these design and concept considerations, plus the various available technologies, tempered with cost and function, should allow us to build an ecological residence that will serve the needs of its owners.
But our role as designers and architects can only be as effective as the firm commitment of our clients. As we explore new ways of design and construction, we are confident the house will use less electricity from the grid without sacrificing comfort and convenience. Just how much power will be saved will be seen in the next couple of seasons. Let’s keep our fingers crossed.
Dan Lichauco is an architect and a faculty member of the College of Architecture of the University of Santo Tomas.
Copyright 2008 Philippine Daily Inquirer. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
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