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NANO2021-Nanoteknologi og nye materiale

HOME holistic monitoring of indoor environment

Alternative title: HOME helhetlig overvåking av innemiljøet

Awarded: NOK 9.6 mill.

HOME, toward lowest possible energy use and best possible indoor environment The construction sector is currently the main consumer of energy, both in Norway and in most countries. The energy consumption of buildings must decrease in order to create a sustainable future for new generations; the question is HOW do we do it? The main objective of the project was to develop new technological solutions to reduce the energy demand in the buildings of the future, as well as to create a comfortable thermal and visual indoor environment. The sub-goals were to develop hydrogen-based smart window technology (Institute for Energy), a smart "shutter" for thermal insulation of windows (NTNU/architect), a control system that ensures full comfort for users (NTNU/electronic) and architectural solutions for the best interaction between building systems (NTNU/architect). In addition, the inherent humidity balance between air and materials was intended to create thermal comfort quickly and efficiently (Treteknisk). The project resulted in several groundbreaking results. The first is related to the experience of comfort in buildings. Our research at NTNU (Architect and Electronics) shows that the lack of one type of comfort, such as noise from a ventilation system, has an influence on the experience of other types of comfort, i.e. thermal or visual comfort. In addition, the negative experiences are summed up when evaluating overall comfort in the room. We can withstand a moderate degree of uncomfortable condition if it is limited to one comfort type, but if we are additionally simultaneously exposed to another type of discomfort we will not endure. The experiment was unique internationally, since there are very few studies that have been conducted in cold climates and with low daylight levels outside. These are important findings that must be used in the development of multi-user room management systems, where the system must take into account contradictions of individual user needs. Time adjustments in any control system depend on the sensitivity of surface materials and the technical systems used. Experiments conducted by the Treteknisk Institute show that the "sauna effect" can, to some extent, be used as an energy saving strategy, since the average temperature in the room can be kept somewhat lower over time. The premise is that large parts of the space are covered with untreated wood panels and that moisture is added to the room, then it is absorbed or emitted by panels depending on the thermo-hygric state. Photochromic glass experiments at IFE have been mainly related to understanding the photochromic effect of thin films deposited on window glass with oxygen-containing yttrium hydride. Photochromic glass has the ability to adjust the amount of light coming through the glass according to the strength of the solar radiation automatically. In this way, photochromic glass has an advantage over electrochromic glass that must be controlled by electronic devices. Photochromic glass has a lower limit of light transmission between 30 and 40% which means that in closed condition, considerable amount of solar radiation will pass through, therefore the glare from the sun must be controlled in another way, e.g. by internal curtains/blinds. The thickness of the coating is crucial for the light transmission in open condition. The development of this technology resulted in two patents! The detailed design, construction and testing of movable thermal insulation panels attached to the outside of the window (shutters) were carried out at NTNU/architecture and tested in the "Hot-box", an instrument for measuring thermal qualities of building elements at SINTEF, with very promising results. The shutter acts as an additional layer of thermal insulation located on the outside of the window. The shutters potential in terms of energy saving depends on its thickness and the thermal qualities of used materials (especially vacuum insulation), technical detailing and the precision of the workmanship. The system is particularly sensitive to air leakage between the shutter and the wall. The insulation properties of the window are also important; the effect of additional insulation in the form of shutters is greatest for windows with low thermal standard, ie high U-value. Another promising result, not planed from the beginning, has been produced at NTNU/architect, namely laser cut acrylic plates with a smart design that can be used on the window surface. In addition to reflecting sunlight up to the ceiling, as the previously patented plates do, they spread the light to the sides. Strong sunspots, which can otherwise seem disturbing and partly blending in interiors, no longer exist, sunlight is evenly distributed. This makes it possible to use sunlight directly as lighting without risking visual discomfort. The photochromic glass, shutters and laser cut acrylic plates have become prototypes and may be used in building.

In this project, we propose to develop and test advanced technology for energy saving through smart control of the indoor environment. The objective is to enable a localized indoor climate control, by utilizing rapidly responsive materials and technologie s in combination with holistic control system. The intelligent control system will enable much more conscious use of energy in buildings; it will use energy to create the desired indoor comfort only at places where people are and during the time when pe ople occupy the space. The idea of rapidly responsive materials will be realized by the usage of hygric building materials (here wooden panels), this will enable rapid changes of temperature in line with the user presence. This means that the overall tem perature of the building can be kept lower. Another rapidly responsive technology is the switchable glazing that can adjust the solar and light transmittance intact with the solar radiation during the day and, additionally, that can significantly increa se the thermal insulation of the glazing during the night by reflecting long-wave radiation back to the interior. An interesting possibility in this project is the interaction of smart windows with the wooden panels. The heat transmitted by the glazing may be charged or discharged locally in the wooden panels contributing to the stable indoor climate. In the project we will combine strong competence in biotechnology (wood science), nanotechnology (hygric surface physics), ICT (sensor and control system ) and architecture. The pilot-building will become an especially powerful way of demonstration of all the systems as well as a method for integration of the systems in a piece of architecture. It will also enable testing of the user interaction with the control system and acceptance of the solution.

Funding scheme:

NANO2021-Nanoteknologi og nye materiale