design 3 : fantasy scenario during phase change), to wall insulation PCMs provided by Fabral Architectural Systems. Boat retrofits As in all scenarios, the de Ceuvel houseboats are retrofitted with improved insulation and windows, to achieve a standard as close to passive house as possible. They are placed on the site to maximize south-facing window area. To achieve multi-purpose insulation, they can be retrofitted with greenhouses with fresnel daylighting systems on one or more sides of each boat. These greenhouses have a U value of 0,21, which is slightly higher than the 0,1 – 0,15 range recommended for passive houses. But this is, of course, a second outside layer of insulation acting as a thermal coat on the building, which has its own inner envelope and windows. The greenhouses would also collect heat and solar energy. For some of the communal areas, new building materials are used for experimental purposes: mycelium bricks, hemp fiber, or kenaf bricks. For example, the de Ceuvel workshop space could be built out of some experimental wall materials, which could even be grown on-site (in the case of the mushroom mycelium bricks). Roofing Houseboat roofs can be used for multiple functions: • • • solar heaters solar PV integrated wind • water collection • • • gardens & food production greenhouses ecosystems An ideal green roof design for the houseboats will integrate all of these functions in a multifaceted combination. ELECTRICITY Generation Electricity generation in all of the scenarios is largely focused on solar photovoltaic systems. This will very likely be the primary technology of choice for its current cost effectiveness. It is interesting to explore different emerging solar PV options, such as organic solar PV, non-semiconductor technologies, silicon nanostructure PV, PV cells that use the infrared spectrum to produce electricity at night, DIY printed solar PV, solar PV integrated into shingles and walls, and emerging flexible PV options. Wind power is generally not considered feasible on this site, however, emerging technologies such as IRWES (an integrated roof technology that does not have a visible turbine), are anticipated to be much more efficient than conventional turbines, and could be tested on one of the communal sites. The IRWES team, based in Eindhoven, is currently looking for urban pilot sites. Another option for electricity generation is microbial fuel cells (energy producing bacteria). A team at Oregon State University recently developed a microbial fuel cell that can extract two kW per cubic meter of organic waste, which is tens of times higher than previously reported technologies. The OSU team, led by PI Hong Liu, is currently looking for a pilot site, ideally a food processing facility that produces a steady supply of certain types of wastewater. Such a pilot could potentially be placed on the Schoonschip site when coupled with the greenhouse and food processing area. It could be interesting to try this technology on a domestic site: we are exploring connections with this and other similar research groups. Finally, hydrogen fuel cells are an option for electricity generation if sufficient hydrogen can be produced on site. Excess electricity in peak periods can be used by a hydrogen generator to electrolyze water. It can then be converted back to electricity using a fuel cell power system. (Hydrogenics has recently developed such a system commercially for Herten, a city in Germany. Their HySTAT 30 hydrogen generator completes the electrolysis step, and their HyPM 50-KW fuel cell power system converts the hydrogen back to electricity.) Hydrogen can also be generated from excess heat from the various heat capture technologies on site to power electrolysis. Hydrogen can also be produced photobiologically from water through green algae. When algae are blocked from performing photosynthesis (by being exposed to anaerobic conditions, which can be simulated by copper exposure), they switch to hydrogen production. The site could feature test algae bioreactors that are tooled to different purposes: some focusing on hydrogen production and others focusing on wastewater treatment coupled with fertilizer production. Hydrogen can be produced directly from microbial electrolysis cells using seawater, river water, wastewater, and organic byproducts. The research group of Bruce E. Logan at Penn State University in the United States recently published findings that their cells were between 58 and 64 percent efficient in producing between 0,8 and 1,6 cubic meters of hydrogen for every cubic meter of liquid through their cells each day. Only 1 percent of the system’s energy was needed for the pumping of water through the system. Finally, excess biogas produced on the site can also be converted to hydrogen using more conventional processes.If all of these production technologies can be used on site, hydrogen can become a useful common “energy currency” for the CTP, though it remains to be seen to what extent this is economically feasible. Pagina 136
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