Impact of external wall insulation thickness on internal surface temperature behaviour

During the last years, the concept of low-energy buildings based on high insulation levels becomes the reality. The aim of this paper is to assess some alternatives of insulated and uninsulated external walls with respect of thermal inertia. The thermal damping factor, phase shift, together with the daily courses of indoor surface temperature of the external wall have been analysed. Analysed surface temperatures show the ability of constructions to accumulate heat gains, which can arise during the day

Antbots: A feasible visual emulation of pheromone trails for swarm robots

Abstract. In this paper we present an experimental setup to model the pheromone trail based foraging behaviour of ants using a special phosphorescent glowing paint. We have built two custom addons for the e-puck robot that allow for trail laying and following on the glowing floor, as well as a way for the robots to mimic the ants capability of using polarization patterns as a means of navigation. Using simulations we show that our approach allows for efficient pathfinding between nest and potential food sources. Experimental results show that our trail and sun compass add-on boards are accurate enough to allow a single robot to lay and follow a trail repeatedly

Ultra-lichtgewicht beton - bouwfysische alleskunner of simpelweg een ander type beton?

Goed doordacht gebruik van thermische massa speelt een belangrijke rol bij ontwerp en ontwikkeling van duurzame en energie-efficiente gebouwen. Doordat alle gebouwen in de toekomst energieneutraal gebouwd gaan worden, zal het belang van thermisch comfort alleen nog maar toe gaan nemen. Kleine temperatuurschommelingen en een laag risico op oververhitting in gebouwen worden als positieve eigenschappen beschouwd met betrekking tot thermisch comfort. Thermische massa kan hierbij helpen, maar kan in sommige situaties ook leiden tot lage binnentemperaturen en hoger energieverbruik. Het meest geschikte type constructie voor een gebouw is afhankelijk van veel factoren. In de meeste gevallen moet er een compromis gesloten worden tussen het gedrag tijdens opwarmperiodes en het risico op oververhitting. De uitdaging om hier een oplossing voor te bedenken heeft geleid tot de ontwikkeling van een nieuw materiaal, ultra-lichtgewicht beton (ULB)

Ultra-lightweight concrete: energy and comfort performance evaluation in relation to buildings with low and high thermal mass

Ultra-lightweight concrete (ULWC) was recently introduced as a novel building material that combines moderate thermal insulation properties with load-bearing capacity. Its intended use as monolithic building envelope brings new opportunities in building physics, by merging characteristics of both heavyweight and lightweight construction types. This paper investigates the potential of ULWC building envelopes in terms of energy efficiency and thermal comfort. The dynamic thermal characteristics of a monolithic structure of ULWC were first compared to more conventional constructions using EN-ISO-13786 calculation methods. The main contribution of this article lies in the subsequent development and application of a simulation strategy for predicting the energy and comfort performance of ULWC on the whole-building level. The quality of the simulations in EnergyPlus was first ensured in an analytical validation study, and then applied to assess the performance of ULWC for commercial and residential case studies in the Netherlands. Results show that ULWC constructions are comparable to heavyweight buildings in long-term behaviour, whereas they resemble the performance of lightweight building envelopes for short-term heating periods. ULWC can therefore be a suitable construction type in buildings with intermittent operation, but in other cases it can get outperformed by conventional constructions with low or high thermal mass

Infrared reflector based on liquid crystal polymers and its impact on thermal comfort conditions in buildings

There has been a huge increase in the global demand of energy over the last few years. One of the main contributors to energy consumption in buildings, cars, greenhouses and indoor spaces is the cooling devices needed to maintain the indoor temperature at comfortable levels. To reduce the energy used by cooling devices, we need improved light control in transparent building elements, such as windows. Infrared (IR) reflectors applied to the windows for rejection of infrared light would be very attractive, especially if they do not affect light in the visible region. A method to selectively and precisely control infrared transmission is via the use of cholesteric liquid crystal (Ch-LC) polymer reflectors. Ch-LCs, also known as chiral-nematic LCs, reflect circularly polarized light as a result of their self-organizing molecular helices. The pitch of the helix in these networks determines the wavelength of reflection. In contrast to existing alternatives, they are characterized by a very sharp cut-off between the transmissive and the reflective state enabling exact tailoring of the heat reflection. In this article we have focused on fabrication of infrared reflectors using Ch-LCs and a computational model was used to predict the energy savings of this IR-reflector in an office building in Abu Dhabi which indicated that 6 % energy savings can be realized