Improving climate performance
Our project is all about the home owner and so we have focused hard on providing them with the best quality internal environment.
The Skin consists of two sides: the cold side, the North-West in the case of Honselersdijk and the warm side, the South-East. On the North-West side an extra layer of insulation is added to the existing structure, diminishing heat losses during cold seasons. On the South-East side a smart glasshouse is added. These aspects are optimized further by the adaptability of the Skin. In winter the skin is closed, in spring and autumn the skin provides indirect natural ventilation for the house and in summer the skin is completely open to maximise natural ventilation using the stack effect, maintaining a comfortable temperature.
The innovation in ‘Home with a Skin’ can be found in the adaptive characteristics of the Skin performing different in all four seasons, making the house energy neutral and adding quality to the home regarding health and comfort. Besides making the house energy efficient the ‘Home with a Skin’ also increase awareness of the inhabitant and try to improve its behaviour to a more energy efficient standard with help of the Comfilux system. But the most important statement in energy efficiency is that the ‘Home with a Skin’ improves the existing building stock rather than encourage demolishing houses and building new. The Skin make use of the existing building, improving it and adding decades to the live time of the Home. With help of the toolbox the Skin can be applied in different situations in The Netherlands and Europe.
In the Netherlands one of the largest energy consumers is the heating of the house, especially for bad insulated row houses. The action to put an extra layer covering the house with a second Skin is similar to putting on an extra layer when you are getting cold. The southern Skin with the glasshouse, functioning as a buffer, already reducing the energy demand by 34%. Combined with replacing the windows with triple-E glazing, making the house more air tight, insulating the exterior walls and roofs result in a total energy reduction of 79% to yearly 1780 kWh. The heat for the heating and hot tap water is produced by the Solar Compleet system. Two energy panels extract the heat from the glasshouse and transport it towards two heat pumps which heat a 300 litres water tank to 55 °C. The system has a COP of 4,5 by average and has enough power to warm the 6 already existing radiators in the house. The radiators can be heated with a lower temperature since the energy demand is reduced (and only need 1900W instead of 8500W). Replacing the showerhead by a water saving one and adding a shower heat recovery pipe also reduces the need for hot water. The performance of the Solar Compleet system is upgraded by the pre-heated air in the closed glasshouse.
The ventilation system also make use of the pre-heated air in the glasshouse and brings the temperature to the demanded level with the Heat Recovery Unit (96% efficiency). The balanced ventilation is CO2 driven and only ventilates when necessary to reduce energy usage. The ventilation system is applied to improve the health and comfort of the inhabitants and is mandatory after making the house airtight to prevent mould and unhealthy air.
Spring and Autumn
During the mild and wet seasons in the Netherlands the Skin shows other features, such as collecting water and solar heat. After a cold Winter it could be lovely to sit in the glasshouse heated by the sun to a comfortable temperature. At some point the windows and doors to the glasshouse can be opened to enable passive heating of the house. For this the domotica plays a major role in advising the inhabitants. The inhabitants have the possibility to control for example the sun shading with the domotica manually, but it also has an automatic system. The users can decides which
temperatures are desired in the rooms and the Comfilux system will control the installations to reach this demand, by for example opening the windows of the glasshouse, heating the radiators, or deciding where to take the fresh air from. Besides that it can also advice to open or close the windows of the house to the glasshouse at certain temperatures. In addition, the Comfilux is a tool for improving the energy efficiency of the inhabitants behaviour. An energy efficient house is one, but an energy efficient user is another thing. The Comfilux screen can show the energy consumption and production. The user can compare and monitor the consumption and try to improve his behaviour. The Comfilux also gives the possibility to control the system form a distance, for example to switch off all the lights with one click or to control the heating to warm up the house just before you wake up or before you come home from work or vacation. This will reduce the waste of energy and improve the efficiency of the house. The Solatubes add value to the ‘Home with a Skin’ by improving visual comfort and by saving energy. The Solatubes illuminate the living room and bathroom with free solar light. The final characteristic of the Skin which is effective during the wet Spring and Autumn is the water collecting feature. The gutters are connected with a storage tank of 1,700 litres and the water is used to flush the toilets and water the plants, saving 29,500 litres water every year a reduction of almost 20%. The northern roof is covered with sedum which buffer water and improve the ecology. In conclusion the innovation of the Skin in Spring and Autumn is the re-use of rainwater, the use of solar energy and mainly the domotica Comfilux system which improves the energy efficiency of the house and the users behaviour.
In the Summer the function of the Skin is to retain comfortable temperatures in the house by blocking the solar heat and creating natural ventilation, mainly with passive systems. The Northern side protects the house with the extra isolation layer and with the green roof. The Southern Skin has a double function, on one hand it blocks the solar heat with the sun shading system and effectively remove the heat by opening the glasshouse in the top and at the façade. Calculations show that the temperature in the glasshouse will not exceed more than 2,5 °C of the outside temperature. And on the other hand the Southern Skin has a feature to harvest the energy of the sun with the PV panels of 4.9 Wp power, producing yearly over 3.700 kWh. The Skin opens op to the garden and adds the space to the outside while protecting the house against the sun and rain. The second step to retain comfortable temperatures in the house is partly a passive and active system. The HRU unit will take its fresh and cooled air from the PCM Box rather than from the warm glasshouse. The Phase Change Materials (PCM) will provide the prototype house in Versailles with extra thermal mass and functions as a passive system. The PCM will provide the house with cooling during the day and it can be recharged with cool air in the night. The cooled inlet air will bypass the heat recovery unit and the warm air from the house is discharged through the chimney. The PCM box will not be applied in the case study of Honselersdijk for the reason that the house has its own thermal mass in the concrete walls and floors to keep the house on temperature in the Summer. Also for the Summer the Comfilux domotica will give advice in opening or closing the windows to the greenhouse, showing figures of the production of the PV panels and give the forecast of the weather. This gives the possibility to use and charge the most energy demanding appliances during the midday when the PV’s produce the most power to improve the energy balance. For example turning on the washing machine, charging the electric bikes and heating the hot water tank during peak hours. In conclusion the innovation of the Skin in Summer is the possibility to open it fully and create natural ventilation and protect the house from solar heat, while harvesting the energy of the sun with the PV panels.
Inside the glasshouse there is a risk of a poor acoustic comfort regarding reverberation time for it consist only of hard surface materials, such as single glazing. So the interior design of the glasshouse is essential for creating acoustic comfort. This has been accomplished by using a wooded floor, applying a lot of greenery and by the previously mentioned movable fabric shading pan-els. By for example adding edible green walls in the glass-house the absorption is increased.By applying the skin the facade airborne insulation, the capacity of the facade construction to limit the access of
sound pressure of an external source inside a habit, has increased drastically. This is mainly a result of the extra in-sulation on the North-West side, limiting access, and the glasshouse, forming a cavity providing an extra acoustic insulation layer.Finally the acoustic comfort related to the noise levels of the installations is taken into account in the design. The critical aspect in this regard is the HVAC-unit. This unit would be placed on the attic in the original situation in Honselersdijk, however to comply with Solar Decathlon competition rules, this attic had to be removed to fit with-in the Solar Envelope. This resulted in placing the HVAC- unit on the first floor, next to the main bedroom against the exterior wall. Based on the design implementation mentioned above, the acoustic comfort of the part of the pavilion that rep-resents the existing house complies with the Solar De-cathlon rules, partly as a result of applying the Skin.