Comparative Building Energy Simulation Study of Static and Thermochromically Adaptive Energy-Efficient Glazing in Various Climate Regions

The building sector contributes approximately one third of the total energy consumption worldwide. A large part of this energy is used for the heating and cooling of buildings, which can be drastically reduced by use of energy-efficient glazing. In this study, we performed building energy simulations on a prototypical residential building, and compared commercially available static (low-e, solar IR blocking) to newly developed adaptive thermochromic glazing systems for various climate regions. The modeling results show that static energy-efficient glazing is mainly optimized for either hot climates, where low solar heat gain can reduce cooling demands drastically, or cold climates, where low-e properties have a huge influence on heating demands. For intermediate climates, we demonstrate that adaptive thermochromic glazing in combination with a low-e coating is perfectly suited. The newly developed thermochromic glazing can lead to annual energy consumption improvement of up to 22% in comparison to clear glass, which exceeds all other glazing systems. Furthermore, we demonstrate that in the Netherlands the use of this new glazing system can lead to annual cost savings of EU 638 per dwelling (172 m2, 25% window façade), and to annual nationwide CO2 savings of 4.5 Mt. Ergo, we show that further development of thermochromic smart windows into market-ready products can have a huge economic, ecological and societal impact on all intermediate climate region in the northern hemisphere

Long term performance measurements and PV testing in a BIPV field test with different amounts of ventilation

PV integrated in the building envelope (BIPV) is seen as one of the key tracks to accelerate PV application in the built environment. However, integration might lead to decreased output and lifespan of PV modules due to less ventilation. To investigate this effect, a BIPV rooftop field test has been realized with 24 first generation Metallization Wrap Through (MWT) modules in 4 segments. The segments have different amounts of ventilation, ranging between forced and non-ventilated, and have been monitored for 3 years. In the non-ventilated segment, higher operating temperatures, higher daily temperature amplitudes and decrease in output have been measured, which increased over the monitoring period. At the end of the monitoring period, IV curves indicate a performance decrease between 7% and 60%, while EL images shows that the modules in the non-ventilated segment have more by-pass diode and cell failures. This study indicates the risk of failures in the investigated first generation MWT modules corresponding with typical damp heat and relative humidity cycle failures and indicates the value of long term field test measurements

Real life lab BIPV field testing in the Netherlands

Integration of PV in the Building Envelope (BIPV) is one of the four key developments necessary for large market PV penetration, together with PV efficiency improvement, price decrease and electricity storage [1]. In the course of BIPV development, Real-Life Lab demonstration projects are realized worldwide to contribute to this goal. In the BIPV Real Life Lab in Heerlen, three different BIPV field tests are realized and monitored, rooftop as well as façade. In the field tests different aspects related to BIPV are covered such as backstring ventilation, condensation and colouring

Comparison and development of sustainable office façade renovation solutions in the Netherlands

Environmental, commercial and societal developments in the Netherlands stimulate the environmental improvement of the existing office building stock. In the Netherlands, about 15% of all office area was vacant in 2012, and the majority of offices have a relative poor energy performance. To measure the improvement, different assessment tools are applied. These tools either focus on one aspect, such as operation energy, and result in a specific outcome such as MJ/m2, or these tools combine different aspects, such as energy and materials, through a weighted system and result in a generic outcome, such as ‘excellent’. In this research, the relation between assessment outcome and actual environmental impact is investigated of both types of tools, by reflecting the outcome of the tool to the carrying capacity of a system. The relation is investigated through a comparison of the energy and material aspect of three office façade renovation solutions using four different assessment tools. Using a tool in which energy and material impact is related to the carrying capacity, current energy focused optimization might lead to a sub optimization of actual environmental impact. To illustrate this, a calculated façade solution is presented with minimal environmental impact based on carrying capacity

The impact of alkali elements on the degradation of CIGS solar cells

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