VIEWS: 22 PAGES: 6 POSTED ON: 9/7/2011
LOW-COST SUSTAINABLE HOUSE PROTOTYPE FOR TIJUANA Ryan Hansanuwat Matthew West Architectural Undergraduate Student Regenerative Studies Graduate Student Cal Poly Pomona Cal Poly Pomona Pomona, CA 91768 Pomona, CA 91768 email@example.com firstname.lastname@example.org Mark Lyles Pablo La Roche Ph.D. Architectural Graduate Student Associate Professor Cal Poly Pomona Department of Architecture, Adjunct Professor Lyle Pomona, CA 91768 Center for Regenerative Studies email@example.com Cal Poly Pomona Pomona, CA 91768 firstname.lastname@example.org ABSTRACT The Tijuana Low Cost Sustainable House Prototype housing project for Tijuana. This paper discusses some of explores the development and integration of sustainable the prototypes that are under development in this project and technologies for low-cost housing in Tijuana. This project that are being tested in full-scale at the low-cost house under emphasizes readily available materials and technologies that construction at the Lyle Center for Regenerative Studies at are appropriate for the cultural and economic conditions of Cal Poly Pomona (Fig. 1). The prototypes discussed in this Tijuana. Students and Faculty of the Department of paper are a recycled plastic bottle thermal mass wall system, Architecture and the Lyle Center for Regenerative Studies at a low-cost window prototype, low-cost green roof, and Cal Poly Pomona’s College of Environmental Design, are papercrete walls. working on a full-scale prototype of a house at the Lyle Center for Regenerative Studies, in which several low-cost sustainable systems are being tested. 1. INTRODUCTION Sustainable architectural principles are being incorporated into more buildings every day, but they are still out of reach of many low income families. Nevertheless, many traditional societies learned to build collaborating with nature, basing their buildings on an intuitive knowledge of the environment and climate, constructing buildings at a very low cost. In the development of this project we Figure 1: Tijuana Low-Cost Prototype House under implemented strategies and systems based on proven construction at the Lyle Center at Cal Poly Pomona. traditional principles of sustainability, combining them with more advanced technologies but that could still be built at 2. TIJUANA very low costs, with local materials, providing adequate thermal comfort while being sustainable. A significant 2.1 The climate of Tijuana reduction in performance would be acceptable if the cost reduction is significant. Tijuana is a temperate climate with moderate winters and summers. The temperatures during the winter range from 5 This research project explores the development and C to 23 C, and in the summer they range from 18 C to 30 C. integration of low-cost technologies in a very low cost The biggest challenge for existing homes in Tijuana is that interior temperatures tend to closely track exterior making it possible to build in these steep and very temperatures because most homes do not have heating or dangerous slopes. cooling systems, or insulation. This creates thermally uncomfortable spaces, which can also be dangerous to the dwellers, especially the smaller children, the sick, or the elderly who cannot stay warm enough in the winter nights. We did not find climate data for Tijuana but used the climate data for San Diego, located just to the north. The psychometric chart in Climate Consultant indicated that passive strategies can provide thermal comfort year round (Fig. 2). Thermal comfort can be achieved with passive solar heating in the winter, and night flushing with thermal Figure 3: Plan phase 2 mass or daytime ventilation during the summer. Figure 4: Section phase 2 4. THERMAL MASS WALL WITH RECYCLED PLASTIC BOTTLES Figure 2: Analysis of data using Climate Consultant 3. 4.1 Purpose of wall prototype 3. THE PROTOTYPE The need for insulation and thermal massing in low-cost Tijuana housing is evident. Many houses currently built are The goal of the house is to create low cost sustainable made of inexpensive, recycled, local materials. Many of housing for the residents of Tijuana. The house will have them have been built using recycled garage doors or even very low construction and operating costs, providing left-over pallets. These systems have sufficed to provide comfortable spaces year round, security for the residents and shelter for the families, but have done little to maintain should be easy to build using local materials and labor, interior temperatures at a comfortable level. What this while integrating indoor and outdoor spaces to offer greater prototype attempts to do is to utilize similar inexpensive, usability of the individual sites. recycled local materials, but provide added value by providing for passive heating and cooling, providing for Because of the complexity of sustainability issues the mechanisms of heat transfer, thermal mass, and insulation. students in this team proposed to focus on three main objectives: local sustainable building materials, use of Previously, in order to achieve thermal mass, builders would passive heating and cooling systems, adaptation to local have to make many sacrifices. Walls could be made with topography and site restrictions. poured concrete, but this is an expensive solution for the area and can be dangerous if constructed improperly. Most The project evolves from an “L” form to a “U” shaped of the 2x4 walls are built using only the studs and the building that maximizes surface to the south, while exterior plywood. There are no interior materials. permitting cross ventilation through the spaces as needed. Simple elements, textures and natural materials are used to The bottle wall solves both of these needs, inexpensive, give a feeling of “home” to the building. Three gabion walls readily available materials, while providin thermal mass that that can be adjusted help to regulate the topography, which can be used with passive heating and cooling systems to is an important consideration in Tijuana’s colinas. Even provide thermal comfort. It is designed to be constructed though these gabion walls might seem high (fig 4) they can using only three materials, recycled PVC tubing, recycled 2- be adjusted to different heights depending on the slope liter soda bottles, and concrete or earth. The PVC tubing holds the bottles, while they extend beyond the wall. The bottles are filled with water and absorb the heat throughout 4.3 Performance of the Wall the day. They can be fixed in place or be removable, so that they can be placed on a south-facing wall to collect heat, Summer and can be brought to other parts of the house to radiate the During the summer months, the biggest concern is with heat during the night. In order to prevent infiltration shading during the daytime to prevent heat gains into the between the PVC tube grid, a filler is placed in the open space, and ventilation during the night. The exterior cover spaces. folds up to shade the wall from the high winter sun, while still allowing for ventilation as needed (Fig. 4a). During the 4.2 Construction of the Wall night, there are some cases where night flushing with high thermal mass can be advantageous. For such a need, the The wall is designed to be built using local labor. The basic upper rows of bottles can be removed, allowing for air to concept of the wall is a grid of recycled PVC tubes tied flow through the building as needed (Fig. 4b), this will together and then to a studded wall. The tubes are cut at a lower the internal temperature to a more comfortable level. thirty degree angle into pieces that will fit within the width With walls placed on opposite ends of the space, cross- of the stud wall. String or twine is tied onto the ends of the ventilation is achieved. As the wind passes around and tubes to keep the bottles from sliding out of the holders. through the wall, it cools the bottles on the outside, and They are then tied to each other using available material cools the space on the inside. such as string or twine. For infiltration purposes lengths of weather strip can be inserted into the tubes if available. Once the grid is complete, the wall is erected into place and tied or nailed to the studs. Concrete or mud is placed into the cracks left between the circular tubes and left to cure. Once the wall is complete, empty recycled plastic bottles are filled with water and placed into each individual slot with caps facing into house for ease of maintenance (Fig. 5). a b Figure 6: Summer conditions a: Daytime shading. b: Nighttime cooling. Winter In the winter months, the spaces can be heated and insulated using the bottle wall. The water in the bottle will increase in temperature, mostly through the effects of exterior solar radiation (Fig. 7a). As the heat is stored into the water it is also transferred by waters’ convection effect into the wall. As the exterior temperature lowers, there is no solar radiation available to continue heating the bottles, and interior temperatures are lowered beyond the comfort level, the bottles are pulled into the wall, and an insulated back is closed on the exterior of wall (Fig. 7b). The heat stored in the water continues to radiate into the interior space. If heat is needed in other areas, the bottles can be removed and placed in other room, as a portable heating system, and leaving a cap on the empty holder. The bottles then heat up that space, while the stored energy from more water bottles in the wall continue to heat the original space. Figure 5: Recycled Plastic Bottle Thermal Mass Wall For the foam shelf liner we have used Velcro to create a tight seal around the window when the shade is closed. If an open position was desired this material could be rolled or folded to a position above the window. We have also developed an exterior shutter system that would provide shade during the day when opened. At night the shutter would be closed to provide a layer of air between the exterior of the window and shade which would act as a second layer of thermal lag for the window. The frame would be hinged above the window allowing the shutter to a b be easily propped open during the day. For the purposes of Figure 7: Winter conditions a: Daytime absorbing and our tests we are using an old rain jacket but it is our intent heating. b: Nighttime heating. that any durable fabric could be substituted or recycled for this purpose. This material would be stapled to the frame which would be provided to the residents. 5. LOW-COST WINDOW PROTOTYPE Starting with the least expensive 24” X 24” window 6. LOW-COST GREEN ROOF SOLUTION available in the market we set out to develop a user-friendly system that would make this window more efficient. We A low cost green roof has been implemented on the larger considered passive solar techniques that were consistent west-facing roof of our prototype in order to provide to with the total design of the house. In it current form this provide protection from the hot afternoon sun. On top of the window loses much heat due to infiltration and conduction wood decking we have placed an impermeable layer of in the winter and gained to much heat by radiation in the plastic as a moisture barrier (Fig. 9). “Cal Earth” bags (rice summer. The challenge was to allow as much solar radiation sack material) are filled with a growth medium which is a during the winter day as possible and retain this warmth mixture of native soil and vermiculite (to reduce weight) through the cold winter night. Our design consisted of a and are placed on the roof in rows perpendicular to the slope simple awning system coupled with an interior shade (Fig. of the roof (Fig. 10). These bags are designed to store earth 8). Both of these features are operable thereby allowing for and are very inexpensive, lightweight, easy to transport, and solar radiation to penetrate when needed. The retention of biodegradable to sunlight. They allow water to pass through this collected energy is critical to maintaining comfort levels them while containing the growth medium. The benefit of within the structure so we wanted to make sure we used a this bag system is that it allows the bags to be easily material in our shading system that had a high R value but transported onto the roof as well as providing a structure that was also relatively inexpensive. With this in mind we around the soil while allowing the roots to establish selected an easy to find foam shelf liner that could be cut themselves. When positioned on the roof the top side of the into the correct dimension. The total cost of the window unit bag was cut open and a variety of sedums and succulents including exterior and interior shades would be about $45. native to Tijuana were planted. These plants were chosen for their drought resistance, low maintenance, and shallow root systems. This green roof system is very inexpensive and its thickness can be adjusted from 3 to 10 inches. This allows for flexibility depending on the load that the roof can carry. Should one bag need to be replaced it is easy for it to be pulled out without having to replace the entire roof. A green roof provides several benefits over conventional roofs: reducing the storm water runoff, reducing CO2 levels, reducing solar loads in the winter and with the soil itself which is un-insulated and thermally coupled to the interior it can provide thermal mass for heat storage in the winter and as a heat sink in the summer. Figure 8: Low-Cost Window Prototype System Parts 7.2 Construction and Performance of Papercrete Due to its 60% waste paper content, papercrete is relatively lightweight and boasts exceptional energy efficiency, R- 3/inch. Thus, a 10-12 inch thick wall can be expected to have an R-30 performance. Preliminary results of compression tests indicate that the material can perform as a load bearing system up to one story. Blocks are stacked and bonded together with a papercrete mortar, creating a solid papercrete wall with minimal thermal bridging through the wall as is experienced with stick frame wall studs. Doors and windows can simply be cut out of a solid wall with a chainsaw. Reinforcing rebar can be drilled vertically down into the wall system after it has been erected. A wall system Figure 9: Section of Cal-Earth green roof prototype. would typically be finished with a protective coating of lime plaster. The breathability of the lime allows moisture to 7. PAPERCRETE pass out of the wall should any accumulate within. A more permanent seal could trap moisture inside and cause 7.1 Purpose of Papercrete structural instability and provide a medium for mold growth. The issue of moisture accumulation and its effects Many homes within informal settlements of Tijuana within Papercrete is still being investigated. At this time experience poor thermal comfort during the winter months research indicates that papercrete is most adaptable and best due to lack of insulation and infiltration of cold air suited for hot and dry climates where there is minimal throughout the entire building envelope. Poor thermal exposure to moisture. comfort can be attributed to lack of sufficient funds and materials to build a comfortable home. An analysis of locally available waste materials was performed for the design of a low cost, durable, energy efficient building material that could be implemented throughout informal settlements of Tijuana. Papercrete is comprised of waste paper and cement. The material can be easily formed into blocks and used for the construction of walls and roofs. Tijuana generates a considerable amount of paper waste though its numerous manufacturing facilities, office use, and newspapers. Very little of this paper waste is recycled into additional post consumer products. Papercrete takes advantage of this abundant waste material. 7.3 Local Manufacturing of Papercrete Papercrete can be easily manufactured on a local scale as well as directly on the construction site. Waste paper does not need to be pre shredded or manipulated in any way. For example whole newspapers can be blended with water into a paper pulp and then mixed with Portland cement. Cement acts as a bonding agent within all the paper fibers. Sand can also be added for additional compressional strength of the material. Typically for a load bearing structure equal portions by weight of paper, cement and sand would be mixed together for the desired material. Papercrete can also serve as an infill material for a non load bearing structure, sand would not be required in this instance as it could 8. ACKNOWLEDGEMENTS: inhibit the thermal resistance of the material reducing its Financial support for this project was provided by the energy efficiency qualities. A normal cement mixer is not National Collegiate Innovators and Inventors Alliance. suitable for the mixing of papercrete, as there is no way to effectively rip the paper apart during the mixing process. The following students also participated in the development Many different mixers have been designed for the mixing of of these systems in Pablo La Roche’s course ARC 333 in papercrete, all with the commonality of blending the paper the Spring of 2006: John K. Whitsett, Leslie Lum, Ruth Oh, into a pulp during the mixing process. For the purposes of Christy Perez, Julia Molina, Marina Moraes, and Diego the prototypical structure being constructed at Cal Poly Urrego. Pomona a mixer was designed and constructed to be towed behind a pickup truck. A giant drum set upon a rear axle The following students have also collaborated in the was designed to have a blade spin inside the drum as the construction of the house: mixer was towed behind the truck. This mixer had the Students in ARC 499, Winter 2006 with Professors Kyle capacity to mix 150 gallons of papercrete at a time. Brown, Irma Ramirez & Pablo La Roche: Kristian Whitsett, Kim Wehinger, Mauricio Carranza, Leslie Lum, Sonya Reed Students in ARC 333 Energy Conservation in the Spring of 06 with Professor Pablo La Roche:Dicle, Salvador, Ceja, ,Mark Chak, Lesley Felton, Ryan Hansanuwat, Stacy Hoppes, April KaufmanMichele,Ciavash Loghmani, Mark Lyles,Sergio Marquez, Julia Molina, Marina Moraes, Ruth Oh, Christy Perez, Alondra Rodriguez, Audrey Sato, Danny Schapker, Diego Urrego,John K Whitsett. Students in ARC 499, Spring 06 with Professor Irma Ramirez: Wes Bassett, Ivan Contreras, Randy Machado, Jimmy Macias, Ben Millet, Charles Thrash, Matty West Masters of Science in Regenerative Studies: Matty West Travel expenses to ASES 2007 were made possible by the Lyle Center for Regenerative Studies at Cal Poly Pomona and the President’s Travel Fund at Cal Poly Pomona. Similar types of “blending” mixers can be designed for stationary use and larger capacity. The potential for a locally based, cooperative, papercrete-manufacturing business is certainly apparent. A block making facility built and run by local residents providing building material for the community made of waste product could support a local economy as well as the construction of energy efficient homes. 7. CONCLUSION It is expected that by utilizing low-cost, locally available and recycled materials, thermal comfort can be achieved in very low cost housing, benefiting residents that can not afford to buy and operate heating and cooling systems. Housing in Tijuana can utilize inexpensive sustainable prototypes to maximize comfort while minimizing cost. The results of this research should be disseminated to residents in the area, so that the tenants can implement the changes themselves without having to hire builders or specialists in order to have a home that provides more thermal comfort and is more sustainable.
Pages to are hidden for
"LOW COST SUSTAINABLE HOUSE PROTOTYPE FOR TIJUANA"Please download to view full document