The project was designed in the intersection of 6th Avenue and Clark Street in Des Moines. The area characterized by high diversity among the inhabitants demonstrates the need in public space. Thus, the project of the mixed-use building with the restaurant, daycare center and residential units and the community center including children activity spaces, public library and media center for job search is the optimal solution for the local community needs due to the encouragement of social interaction. The project also aims to achieve sustainability goals through the use of various environmental strategies and utilization of effective materials in structure.
Measure 1. Design & Innovation
Facing the challenging climate of the Midwest and trying to meet the context needs led to the process of form finding based on the south orientation and gaining the benefits from natural ventilation opportunities. The system consisting of the two buildings form the neighborhood as a new place on the street. The neighborhood serves as a point of attraction for different groups, which is based on the central location on the street as well as the surrounding with mainly residential typology and a couple of commercial buildings. With the massive volumes of commercial buildings on the left side of the site and the prevailing relatively smaller volumes of residential buildings in the surrounding area, it was logical to place the transitional element, which was solved as a composition of two buildings, performing as a system in a state of dialogue with each other and the connection for the neighborhood: the first volume that continues the edge of the commercial buildings in the block for the community center and the “lightened” second volume of the mixed-use building, which resulted in a form of the court yard. In addition to urban fit, the form of the courtyard is beneficial in terms of providing sufficient daylight in the buildings.
Measure 2. Regional/Community Design
Revitalization of the community, that is characterized by a high diversity, was one of the major goals of the project. Following the concept of encouraging social interaction, the program of public space, that will bring the unification to the community, was chosen. Thus, the programs of the buildings promote the interaction in the community. The school located nearby makes the community center (which includes library) a perfect place for children’s education. Also, bicycle parking lot was designed in front of the restaurant in order to encourage the eco-friendly transportation alternatives.
Measure 3: Land Use & Site Ecology
The on-site vegetation system is developed in the project as a response for local ecology support requirement. The system includes green roofs, courtyard in the mixed-use building with local flora of Iowa and vegetated medians of the 6th Avenue. Thus, the project supports regional ecosystem.
Measure 4: Bioclimatic Design
The strategies for internal heat gain (insulation and double-skin façade), sun shading devices that protect the internal spaces from the intense direct sunlight in summer, natural ventilation cooling (provided by the cross ventilation, stack ventilation in chimney), high thermal mass (lightweight concrete advantageous thermal performance) all together provide 58,5% of comfort hours in a year, that is represented in the psychrometric chart.
Measure 5: Light & Air
The interior of the project performs as a comfortable environment in terms of the daylight and ventilation. Firstly, for providing sufficient sunlight in the rooms south facing glazed areas were designed. Sefaira analysis shows that satisfying level of daylight is provided in the both buildings; underlit and overlit areas were mitigated through the design process by enlarging the window areas and adding shading devices. Secondly, for providing natural ventilation, window openings were placed at north and south facades of the buildings, which resulted in the airflow going on the different floors of the building. In addition, stack ventilation in the community center allows to get rid of the hot air in the space, providing comfortable conditions inside of the building.
Measure 6: Water Cycle
Water collection system was designed as the united for both buildings. The water is collected from the roofs and then is stored in a water tank underground. The collected water can be further utilized as greywater for the bathrooms and watering plants, which contributes to the economy of the resources.
Measure 7: Energy Flows & Energy Future
The Sefaira analysis demonstrated that the building performance can be evaluated as net-zero and energy efficient after going through the process of the step-by-step reduction in energy consumption. Besides the improvement in the buildings performance using the effective materials and shading devices, the issue of energy flows is addressed by incorporating ground source heat pump underground. The pipes of the GSHP connect two buildings into the one system and promote the energy exchange between the community center and the mixed-use buildings. Finally, the use of PV-panels on the roofs of the two buildings allowed to achieve the net-zero challenge.
Measure 8: Materials & Construction
Considering sustainability goals, all the materials used in the project are supposed to be received from the local resources, what decreases the energy consumption. Our proposal for the building envelope is the use of prefabricated concrete elements with insulation of 150 mm thickness, that comes from the Sefaira analysis for well-insulated building for roofs, walls and slabs. Lightweight concrete can be utilized in structure due to the fact of performing in a more beneficial way in terms of sustainability. The embodied energy is lower for the lightweight concrete that for the normal weight concrete. Furthermore, recycled timber is suggested for the interior finishing and the construction of the landscape (stairs) on the outside of the buildings. The finishing for walls is provided by gypsum board and wood. The flat plate slab system was chosen for structure. In windows triple glazing can be used for higher effectiveness because of the best SHGC.
Measure 9: Long Life, Loose Fit
In terms of the materials, lightweight concrete used in the structure has a potential for recycling and can be further utilized in the road construction as well as the other architecture. Also, the adaptability of the project is provided by the successful performance in both summer and winter-when extreme thermal conditions are met. The spaces of the community center are of a flexible use, which promote potential long-term use of the project.
Measure 10: Collective Wisdom & Feedback Loops
One of the important goals set for the project is to educate the inhabitants and the community in general about the sustainability priority of the two buildings and encourage the economy in the energy consumption. In order to communicate the ecological concern, the informative electronic dashboards inside of the buildings were designed.