InDeWaG is the acronym of title "Industrial Development of Water Flow Glazing Systems" - Innovation action project funded under Horizon 2020, a Public Private Partnership on "BUILDINGS DESIGN FOR NEW HIGHLY ENERGY PERFORMING BUILDINGS". Support for innovation is provided to actions where partners focus together and join forces to remove existing barriers through market uptake measures in order to build capacity and provide support for sustainable energy policy implementation. Their mission is to foster sustainable energy investments and the uptake of technologies relevant to energy efficiency in buildings.

InDeWaG establish new technical knowledge and explore the concept of a new improved technology and product. Demonstration activity will show technical feasibility in a near to operational environment. InDeWag project introduce a new, disruptive building envelope system which has at least 15% building cost reduction potential and could be brought to industrial ripeness. The unique approach of InDeWaG is to enable maximum use of daylight by a transparent glass façade and at the same time meet nZEB performance. The consortium will undertake a quantitative analysis of different "modular" approaches: the active fluid flow glazing will combine water as heat transfer media with compressed air and solar-thermal energy conversion with BIPV (Building Integrated Photovoltaic), to enable the optimal ZEB performance for a multitude of building types in different climates.


The ambition of InDeWaG project is to bring to industrial ripeness a façade and interior wall system based on radiant heating and cooling glass surfaces made from water and/or air flow glazing, abbreviated as WFG and AFG, which harvests solar energy for various use at large scale. Such building elements will be made ready for commercial application in the building sector and will be designed to become easy adoptable for 21st century façade and overall building technology, especially for cost effective ZEB technology with increased daylight use, variable ventilation and individual control comfort. The benefits of fluid flow glazing façade technology were proven over the past 8 years on the level of few demonstrator projects, but there are still many difficulties for the right practical implementation.

The concept for extending the State of Art in water flow glass façade systems is oriented towards a system that will be able to satisfy the cooling requirements and the hot water needs for a whole building. This is achieved through the integration of a series of transparent, translucent or opaque solar thermal absorbers which operate at different nominal temperatures, namely 30ºC for heating and seasonal energy storage, 60ºC for sanitary hot water supply and 90ºC for cooling through absorption chillers. In this way, a complete glass curtain wall façade will be able to deliver all the levels of thermal energy required by a building while retaining its architectural aesthetics. In addition, implementation of radiant surfaces inside the building will be investigated by building simulation with IDA ICE and TRNSYS. The components will be tested in Demonstrators situated in two different climate zones - Bulgaria and Spain.

A proven design method, a tested and certified façade system unit, application possibilities and a focused market analysis are crucial for the fast market uptake of the Fluid Flow Glazing. The industrial development of this exciting façade technology is the main goal of InDeWaG consortium, enabling an important step forward towards achieving nZEB standard /stated by the 2020 EU policy in the Directive 31 from May 19th 2010/.



The main objective of InDeWaG is to develop an industrial technology for fabrication of cost affordable general-purpose Fluid Flow Glazing façade elements, which give maximum daylight utilization and maximum interior comfort at energy consumption level of nZEB. In addition, also interior radiant elements will be developed. This technical development is accompanied by the development of an open access software tool for design of buildings with this new type of façade and interior radiant cooling and heating elements.

The cost reduction of at least 15% is achieved by following the LowExergy9 principle and adjustment of the temperature difference between the exterior environment and the interior to a minimum value which is relevant for significant reduction of HVAC energy demand and lighting energy consumption.

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Investigation of Thermal Behaviour of Innovative Fluid Flow Glazing Modular Unit

Energy consumption in buildings is approximately one third of the total energy consumption. In modern architecture, the area of the glazing is getting bigger and bigger, and this leads to an increasing influence of the windows on energy efficiency of the buildings. A huge amount of electricity is consumed to provide a comfort room temperature through air conditioning. Instead of this advance glazing technologies and materials can be used to reduce buildings energy demands and improve indoor environment.

Based on construction and architectural design trends and due to its unique characteristics the water flow glazing - WFG module is a product of the future. It is a vertical-shaped modular unit which consists of a triple glazing sized 1.3m x 3m (one fluid/water chamber and an argon chamber), a circulator allowing fast flow rates up to 8 l/min per window, and a modular aluminum frame that encloses the glazing and the circulator. Depending on the combination of the glass type and the position of the argon and water chambers the three types of WFG modular units are designed - HeatGlass, CoolGlass and iThermGlass.

The thermal behavior of WFG modules is investigated by using mathematical models covering all physical processes - heat exchange, fluid flow dynamics, optical and structural behavior as well as environmental influences.

To predict the performance and behavior of the WFG, as well as to optimize the modular unit and its components, mathematical and simulation models were developed by Polytechnic University of Madrid in Spain. The software model is successfully integrated under the existing and widespread software product IDA-ICE and describes the change of the thermal conductivity of the glazing due to varying fluid flow rate (g- and U-values) as well as the energy gain in the WFG.

Two main parameters characterized the thermal behavior of WFG. One is water heat gain, which is the solar energy absorbed and transported by the water chamber. The other is internal heat flux - the total heat transfer through the glazing. Figures below presents the average monthly results of the water gain parameter and internal heat flux in Sofia.

The annual Water Heat Gain for iThermGlass shows the biggest fluctuation on the monthly based. CoolGlass is stable during this period. Only for HeatGlass the mean Water Heat Gain is positive, which means that we are harvesting energy through the whole year.

The annual Internal Heat Flux variations are strongly related to the annual changes of the external temperature and solar radiation. For a location like Sofia the best performing WFG unit is HeatGlass.

The results show that the structural configuration and the type of coating play important role for the effective operation of the units. Relying on the simulation software developed under the InDeWaG project we can successfully predict the behavior of the WFG modules and we are able to choose the appropriate configuration of the glazing according to climatic conditions to reduce the energy consumption in buildings.