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Oud-Heverlee, Belgium

Langmans J.,Building Physics Section | Desta T.Z.,Redco N.V. | Alderweireldt L.,Redco N.V. | Roels S.,Building Physics Section
Energy Procedia | Year: 2015

The article presents detailed experimental results on the hygrothermal performance of various ventilation cavities. In total 8 full-scale test walls have been installed in a test house to study the impact of different cladding materials (fibre cement sidings/brick veneer cladding) and the size of ventilation openings on the conditions in the cavity. Two measuring methods, hot bead anemometry and air pressure registration, are used to investigate the ventilation rate within the cavities configurations. In addition, equipment was installed to monitor the effect of the ventilation rate on the temperature and humidity conditions within the walls. The results indicate that the air change rate behind brick veneer (1-10ACH) is typically two orders of magnitude smaller than the ventilation behind wall systems with sidings (>100-ACH). © 2015 The Authors. Source


Das P.,University College London | Van Gelder L.,Building Physics Section | Janssen H.,Building Physics Section | Roels S.,Building Physics Section
Journal of Building Performance Simulation | Year: 2015

There are a myriad of options when it comes to designing an uncertain optimization scheme. This work explores the impacts of several of these options using a case-study retrofitting of Swedish attics developed during the Annex 55 project of the International Energy Agency Energy Buildings and Community programme. We find that not considering maintenance costs, increments in energy costs with time, and discount rates in the economic criterion can impact the derived optimal design option. However, for our case study no difference was found between criteria that examined absolute returns, fractional returns, and annulized returns, despite emphasizing different aspects of the investment. If multiple moments of the economic criterion distribution are combined with weights to create a single objective function then several weights should be explored. Alternatively a single moment could be sought, such as the probability that the economic criterion is negative as a sufficient single objective, avoiding having to choose a weight. A hybrid genetic algorithm may offer a more efficient method of determining the optimal design option but a multi-layered sampling scheme offers more flexibility regarding subsequent analysis. © 2015 International Building Performance Simulation Association (IBPSA) Source


De Coninck R.,Applied Mechanics and Energy Conversion | Baetens R.,Building Physics Section | Saelens D.,Building Physics Section | Woyte A.,3E | Helsen L.,Applied Mechanics and Energy Conversion
Journal of Building Performance Simulation | Year: 2014

Grid saturation has been reported in electricity distribution systems with a high penetration of photovoltaic (PV) systems. This saturation is often caused by overvoltage and results in curtailing or shutting down of the PV inverters, leading to a loss of renewable electricity generation. The presented work assesses the potential of rule-based demand-side management (DSM) applied to domestic hot water (DHW) production with heat pumps in dwellings for reducing the non-renewable energy use of the neighbourhood. The studied case consists of 33 single-family dwellings connected to a single phase distribution grid in a moderate European climate. Each dwelling is designed as a net-zero energy building by adequate design of a heat pump and PV system. A detailed dynamic simulation model is implemented by use of a cross-domain Modelica library for integrated district energy assessment. The user behaviour is obtained from a stochastic model based on Markov chains and survival analysis. Different rule-based DSM control strategies are applied to the individual dwelling's DHW systems. The results show that for balancing the PV production, active thermal energy storage in the DHW storage tanks is very promising. Even with very basic control algorithms and small storage tanks of 0.3 m3, curtailing losses can be reduced by 74%. This represents a net energy saving on a neighbourhood level of 3.4%. © 2013 © 2013 International Building Performance Simulation Association (IBPSA). Source

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