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Energy Efficient Ventilated Façades for Optimal Adaptability and Heat Exchange enabling low energy architectural concepts for the refurbishment of existing buildings

Periodic Reporting for period 3 - E2VENT (Energy Efficient Ventilated Façades for Optimal Adaptability and Heat Exchange enabling low energy architectural concepts for the refurbishment of existing buildings)

Periodo di rendicontazione: 2017-07-01 al 2018-06-30

The system directly targets a special typology that correspond to suburban multi-storey residential buildings built in the 60’s 70’s that are characterized by a high energy consumption, bad air quality due to the lack of air renewal motorized system, and with low architectural interest.
To tackle all those problems with one refurbishment strategy: we propose an innovative yet simple modular and adaptable system E2VENT. This new system improves the energy efficiency of the European residential buildings stock, reducing the energy consumption and increasing the indoor air quality but also improving the aesthetics of a building, increasing the value of the asset and providing healthier conditions for the occupants.

The E2VENT system is an external thermal building refurbishment solution with external cladding and air cavity that embeds different breakthrough technologies that will ensure its high efficiency:
• A Smart Modular Heat Recovery Unit (SMHRU) for the air renewal allows the heat recovery from the extracted air using a double flux exchanger. Indoor Air Quality is ensured while limiting the energy losses.
• A Latent Heat Thermal Energy Storage (LHTES) based on phase change materials provides a heat storage system for heating and cooling peak saving.
• A smart management that controls the system on a real time basis targeting optimal performances
• An efficient anchoring system that limits thermal bridges and allows an easy and durable installation.

Requirements and specifications of the technical solution were defined considering European & National legislation and standards, current approaches for building retrofitting, social acceptance and behavioural aspects, and preliminary market assessment. Based on the design, the first prototypes were manufactured and tested while working on the overall design of the module and especially its integration in the façade in parallel. Once fully developed and tested on the test bench in Anglet, France, the two buildings in Gdansk, Poland and Burgos, Spain will were retrofitted with the E2VENT module. The analysis once installed highlight that the E2VENT module allows a major energy consuption reduction while improving the internal confort. though some barriers remain, as the difficult access for maintenance and difficult maneuverability of the LHTES system.
All along the project the exploitation and dissemination activities will respectively allow to prepare the module for the market and to maximize its impact.
Value chain requirements & specifications.
The collection of value chain requirements and specifications was carried out at the beginning of the project using the following categories: hygrothermal performance, energy performance, fire performance, sound performance

Development of elements composing the system: Methodology and design
The E2VENT module embeds two distinct active systems. The SMHRU is aheat recovery unit that allows the air renewal while limiting the thermal losses; the LHTES based on phase change materials provides a heat storage system that can be used for cooling peak shaving. Those two systems are piloted by a Buildiing Energy Management System. The designs of SMHRU and LHTES are visible in the following illustrations.
Fig1: Illustration of the SMHRU integration in the wall
Fig2: Illustration of the LHTEs integration in the wall and its functioning modes

Both heat exchangers are integrated in a box manufactured by ELVAL. The efficiency of the systems relies on the convective thermal exchange obtained but also on the energy consumption of fans and the robustness of the system. The prices of each components are evaluated and an equilibrium between costs and efficiency is discussed.

Prototypes, measurements and testings on a test bench
Once manufactured the prototypes were shipped, assembled and installed on the test bench in Nobatek's premises. The correct functioning of the two piloted systems was tested, validating the piloting rules. Then acoustic, IR measurements, piloting modes were assessed.
Fig 3: Pictures of the SMHRU (left); LHTES partially assembled (center) and the 3 types of PCM encapsulation (right)
Fig 4: Picture of the SMHRU, LHTES and BEMS on the test bench.

Pilots
The baseline for the two buildings as demo cases was first measured. Then the overall design of the renovations were proposed. Due to the absence of cooling needs, no LHTES was installed in Gdansk.
The installation was successfull on both sites at the end of 2017, and the commissioning and monitoring showed the benefice of the E2VENT module in reducing the energy consumption of the buildings while improving the internal confort.
Fig5: Pictures of the renovation in Burgos
Fig6: Pictures of the renovation in Gdansk

Exploitation and dissemination
The Key Exploitation Results have been defined and assessed regarding their market potential. For public dissemination, 2 websites are online - one focusing on the project and one on the product providing all necessary information. Regarding scientific dissemination, 7 articles in peer reviewed journals have been published, and participation in conferences, fairs, workshops were numerous.
The two main technical developments of the system went from a concept to a first prototype. For both, requirements and specifications were defined according to the WP1 analysis, then 3 iterations of manufacturing - assembling - testing of prototypes were carried out ; it allowed to improve the design especially taking into account easiness of installation, acoustic considerations so that the market and social acceptance are ensured.

The SMHRU is novel as it is a very thin double flux exchanger that can be integrated in a façade renovation module. The measured efficiency is of 70% meaning that it allows to have a very efficient air renewal that ensures the indoor air quality while limiting thermal losses. The fact that it is piloted with CO2 and RH sensors is also novel and increases its efficiency.
Regarding LHTES, first, the industrial partner ELVAL manufactured some tubes made in aluminum in order to ensure the PCM encapsulation, which does not exist on the market. This encapsulation allows a better heat exchange between the air and the PCM and thus a higher efficiency for the overall system.
For the whole system, the overall performance has been assessed first on a test bench in an almost real environmnent and then on the two buildings that were renovated with the E2VENT module: in Burgos, Spain, and in Gdansk, Poland. The analysis shows that the E2VENT module allows a drastic reduction of the energy consumption while improving the intenal confort. The installation process was validated by the blue collar workers validating the installation process. But some barriers remain for it to enter the market. For the SMHRU a sound level that is considered too high by some of the occupants, and for the LHTES a high weight which causes a difficult maneuverability.
Illustration of the LHTEs integration in the wall and its functioning modes & of the components of t
Illustration of the SMHRU integration in the wall
View of the renovation in Burgos
View of the renovation in Burgos
View of the test bench, and close up on the cell with the SMHRU, LHTES and BEMS systems installed.
Pictures of the SMHRU (left); LHTES partially assembled (center) and of 3 types of PCM encapsulation