Most frequent questions and answers
Slimbouwen is a construction paradigm almost, in which conventional construction is reconsidered and waste of materials, space and time are minimized. By reducing wall and floor thickness, less material is used and valuable space (especially in cities!) is saved, increasing the amount of floor space for a given plot. Furthermore, by applying a service core, we reduce complexity of utilities while increasing flexibility, so that installation and service costs go down. The money saved in this ‘slimbouwen’ method will be partially used to fund sustainable technologies, while especially in the long run building costs can go down while increasing quality of life.
Demountable is part of our sustainability view, as houses should be adaptable. We do not know what people want their houses to look like in fifty years, so if we build something now, we should make it in a way in which it can stand for at least fifty years. In that sense, durable building is part of sustainable building, as it reduces the frequency of material usage. If a structure can be easily taken apart and upgraded or moved, it is likely to last longer, as there is no reason to demolish it, where a structure that is rigid and expensive to upgrade might be fully demolished and replaced.
Prefab greatly reduces the time to build, it increases the quality to industrial standards, and can decrease building cost, especially if combined with slimbouwen in a smart way. This would make it possible to assemble homes in a few days, which becomes especially interesting if it is to be implemented on a large scale. Waste and transport can also be reduced to a minimum, as only the building itself has to be transported, instead of the whole building gear/machinery. It is also safer than conventional construction and reduces the disruption of the area that comes with construction. Therefore, we see lean prefab building as essential for sustainability and modern construction.
A sustainable building fundamentally means that the material usage is reduced to a minimum and all energy used by the building is generated in a sustainable way. Materials that are used should be cradle to cradle when possible. Sustainable energy use should not only mean that you generate all the energy you need during a year, it also means that your generate it (approximately) when you need it. This means that the electricity grid is not strained too much. In our case, the Seasonal Thermal Energy Storage (STES) will make sure that you can shower during the winter, with hot water generated in the summer.
So far, sustainable buildings have often compromised on quality of life, or have been unaffordable for most people. In our design, we will take care of air quality by ventilating better than most super-efficient buildings, so that the building is not only sustainable for the planet, but also for human health and well-being. Furthermore, instead of removing or fully minimizing windows facing north ‘because they are a waste of energy’, we make them a little bit bigger so that you actually have a nice house. As long as cradle-to-cradle materials and renewable energy are used, there is no problem in this, much like ‘waste’ from plants is sustainable. In order to be affordable, less material will be used, and the ‘slimbouwen’ method will reduce building costs. The aspect of this that is especially positive is the fact that if sustainable houses are nicer than unsustainable ones, people will actually want to live in them.
A DC (Direct Current) grid is unlike the normally used AC (Alternative Current) grid. There is quite a debate surrounding this. In our case, solar panels generate a direct current while most applications (those with converters: laptops, phone chargers, etc) use DC. When changing from AC to DC or the other way around, about 10% of energy is lost. This means that about 19% of energy produced by solar panels and used in DC applications is turned into heat. By using a DC grid, (most?) of these losses can be prevented. Although most applications are built to use in an AC grid, european law requires all applications to have an ? converter. This means that we can built around this. We do this because we feel that in the near future, DC grids will be used inside of homes because it is far more efficient.
BIPVT stands for Building Integrated PhotoVoltaic Thermal, which means that the system produces both electricity and hot water. This means that the panels are cooled which increases their efficiency. The hot water is stored underneath the house, and used for showers and heating. During the summer, far too much hot water and electricity will be produced. Instead of putting it into the grid, which strains the grid, a heat pump will be ran with the access electricity, making the water even hotter. This can then be stored in a large (about 50.000 liter) tank and used in the winter. Because during the winter hot water from the summer can be used, the energy demand from the grid/solar panels is far lower, increasing or independence from the grid. This means that if every house would be built like ours, grid problems will be hardly present, while NOM (null-on-the-meter) houses would ask for large amounts of fossil energy during the winter.
Seasonal Thermal Energy Storage (STES) is a system with which energy can be stored throughout the year. In our case, a Building Integrated Photovoltaic Thermal (BIPVT) system will be used to generate two things: solar electricity and hot water. Building integrated means that we do not put the system ón the roof, the system ís the roof, which reduces installation costs and material use. The solar electricity will be used to power the electrical appliances, while the hot water will be stored (STES) underneath the house because the demand for hot water is highest during the winter and the supply is biggest during the summer. This means that you can actually heat your house, shower, et cetera during the winter using heat generated on your roof during the summer. In comparison to electric heating, this is more efficient and reduces the necessary roof area. In our view, STES is superior to electrical heating because we simply can not generate all our heat demand during the winter with affordable renewable energy.
Currently, many newly built houses have solar panels and a heat pump to heat the house. The problem with this is that solar panels generate most energy when the sun is shining and during the summer, while heat pumps use most energy when the sun is not shining and during the winter. This means both that the electricity grid will be strained, and non-renewable energy will be used to heat homes in the winter. It would be possible to generate the electricity for all these heat pumps (if every home were to have one) in the winter with wind energy, but that would mean that there is too much electricity during the summer, and solar panels are useless. Because we envision a future where homes actually have access to renewable energy during the winter, we will install a battery pack into our house to greatly reduce grid dependence. This means that if the sun is shining during the day, the electricity used in the house can actually be stored for a few hours, so that people can still power their homes with renewable energy. If there will be a long, cloudy period in which a lot of electrical energy will be used, especially during the winter the solar panels will not be enough. This problem can as of yet not be solved in an affordable way. This means that we will still be connected to the grid, and can use the energy provided by the grid. Still, this will not strain the grid too much if done in a smart way, because the battery pack can be charged when the grid is providing sufficient energy. We will also try to use hot water were possible (heating, dishwasher, washing machine, even the tumble dryer). This means that the problem is greatly reduced from year-round problems, to an occasional use of the grid. We believe that this problem will be solved in the future. Until then, being almost fully sustainable in an affordable way is a very good thing.
In current practice, there is usually little communication between domotics systems, as many companies operate in their own ‘language’. Companies are usually not willing to share their language or adapt to the language of others. For this reason, we ask all domotics companies to adhere to a neutral, open source platform. This increases the communication between systems, which increases the user experience and reduces energy use. An extreme example of communication problems could be a house in which both the heating ánd the cooling system is turned on. This is not comfortable, as heat distribution will be far from optimal, but it is also a waste of energy. For this reason, we want our domotics systems to work together as effectively as possible, which also creates opportunities for new user experiences.