Curtain Wall with Solar Preheating of Ventilation Air. Full Scale Experimental Assessment

Heating load in Commercial buildings is highly related with ventilation systems, while at the same time local discomfort in the vicinity of glass walls occurs due to overheating. In this paper, a novel double envelope curtain wall is presented, which extracts heat from the façade by means of a ventilated cavity which is then incorporated to the ventilation air intake. A substantial reduction of heating loads is achieved. Whenever solar gains are not sought, a bypass element allows the natural ventilation of this air cavity, acting as a ventilated façade. An integrated control system with embedded electronics and actuators allows for a smart control of the system. The system is designed for integration with existing rooftop ventilation systems. Design considerations are discussed, and the outcomes of a full-scale experiment conducted in Bilbao (Spain) along 2019 presented

Design of a Calorimetric Test Facility to Replicate Real Boundary Conditions in the Gulf Countries

The design and modelling of a calorimetric test infrastructure for building envelopes is performed for the side-by-side assessment of different building envelope systems. The infrastructure is designed for representing transient weather conditions in Middle east. It consists of 3 “cold” experimental chambers and a larger “hot” experimental chamber. All three cold chambers have one equally sized envelope element exposed to the larger chamber. The test facility is designed to allow testing on walls and roofs, where different envelope insulation systems will be installed over a common substrate. Heating and cooling loads of all experimental chambers are calculated, and systematic load differences assessed. Heat flow across test samples and other surfaces in the test are calculated. Insulation levels of envelope surfaces in experimental chambers are specified to provide a good match between heat transfer across test samples and heat input to experimental chambers

Designing a generalised reward for Building Energy Management Reinforcement Learning agents

The reduction of the carbon footprint of buildings is a challenging task, partly due to the conflicting goals of maximising occupant comfort and minimising energy consumption. An intelligent management of Heating, Ventilation and Air Conditioning (HVAC) systems is creating a promising research line in which the creation of suitable algorithms could reduce energy consumption maintaining occupants' comfort. In this regard, Reinforcement Learning (RL) approaches are giving a good balance between data requirements and intelligent operations to control building systems. However, there is a gap concerning how to create a generalised reward signal that can train RL agents without delimiting the problem to a specific or controlled scenario. To tackle it, an analysis and discussion is presented about the necessary requirements for the creation of generalist rewards, with the objective of laying the foundations that allow the creation of generalist intelligent agents for building energy management.The work described in this paper was partially supported by the Basque Government under ELKARTEK project (LANTEGI4.0 KK-2020/00072)

Monitoring and thermal performance evaluation of two building envelope solutions in an apartment building

A bio-based multi-layer building envelope assembly has been developed for its integration in newly built and retrofitted buildings. Forest-based materials and biocomposite profiles are used as an alternative to fossil-based insulants and metallic framing, providing a well-insulated and low-thermal-bridge technical solution. The wall assembly has been installed as the external envelope of one apartment of a housing block in Donostia-San Sebastián (Basque Country, Spain). A comparative study has been performed for the bio-based wall and the reference wall of the building. Their in-situ thermal resistance has been obtained by means of three different methods: (1) the steady-state average method, (2) a semi-dynamic method from heat balance at the internal surface, and (3) a dynamic multiple regression method. Reasonably consistent results have been obtained with the three methods: a discussion is provided on the influence of measuring periods and boundary conditions. Outputs from this experimental campaign are valuable as a counterpoint to desktop studies and tests under controlled laboratory conditions. Learnings and outputs from the present study should contribute to a better understanding of the in-situ performance of building envelope assemblies and their assessment methods.The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement ID 609067

Experiences when employing different alternatives for envelope upgrading

The challenges of achieving the 2020 goals in terms of energy savings and improving efficiency are guiding numerous research initiatives looking for more insulated envelopes, dealing with thermal performance of insulation materials and envelope systems. Nevertheless, the envelope integrates within the building and this improvement on the insulation performance has to be properly adopted, taking into account the interrelation of main elements composing the overall system (facade, frame, slabs, openings, partitions etc.), as well as side effects originated not only for new erected buildings, but specifically in renovation and retrofitting works. This paper describes real experiences when considering various options for upgrading the facade through the increase of the insulation capacity, starting from external overcladding prefabricated panels and ventilated facades, advancing to more sustainable low carbon systems and ending with even more highly insulated solutions employing aerogels. Lessons from these cases, where energy and hygrothermal assessments have being carried out, demonstrate the influence of the design and construction phases and the relevance of disregarded effects such as minor thermal bridges, uncontrolled craftsmanship on site, and moisture transfer for the different technologies considered. Finally, possible alternatives are provided to overcome some of the detected difficulties, such as combination with non-metallic structural components and building membranes, and being prepared for future challenges and new developments when these isolative elements are combined with other technologies, as for example, renewable energy harvesting devices

Double Envelope Unitized Curtain Wall for solar preheating of ventilation air

Despite recent efforts on energy performance improvement, curtain walls remain a significant contributor to the energy consumption of commercial buildings. A novel double envelope unitized curtain wall system is presented, aimed at the substantial improvement of the energy performance of glazed systems. Outdoor air is ventilated through an integrated cavity in its paths to the ventilation air intake of the air handling unit. In its path through the glazed envelope, the air is heated from both incident solar radiation and transmission losses recovered from the indoor environment. A substantial energy performance improvement is achieved by means of the preheating of fresh air. Energy consumption is reduced in the heating season, and even net gains above the heating demand are delivered under favorable conditions. By-pass elements are integrated to allow free cooling and natural ventilation when required in cooling mode. In this way, the double envelope also provides advantages in summer mode, where solar heat gain coefficients are substantially lower than for other systems due to the double envelope and the ventilation of the cavity to the ambient. The overall architectural concept, engineering design and outcomes of an experimental campaign over a 2-story full scale test in Spain are presented

Lessons Learnt from Substation Inspection on Low Temperature District Heating Networks

District heating networks are considered to be a key element for the decarbonization of Europe. The RELaTED project seeks to contribute to the decarbonization of these infrastructures with the demonstration of low temperature district heating networks. One of the demonstration sites consists of more than 50 substations within a subsection of a larger network in the city of Tartu (Estonia), where the temperature was lowered by 10 ◦C. To ensure the benefits of this new generation district heating network and the fulfillment of comfort requirements, data have been monitored and analyzed at the substation level in an automatic way to facilitate the inspection of every user.This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 768567. This publication only reflects the authors’ views, and neither the Agency nor the Commission are responsible for any use that may be made of the information contained herein

Data-driven assessment for the supervision of District Heating Networks

There is an ongoing trend towards temperature reduction in District Heating Networks, allowing for the reduction of distribution heat loss and enabling the integration of low exergy heat production systems. There is a clear scientific consensus on the improved sustainability of such systems. However, there is not sufficient knowledge on how to deliver a successful transition to a low temperature District Heating system, while ensuring the operational levels of the existing system. This paper presents the experience on the progressive temperature reduction of a district heating subnetwork over the 2018–2021 period in Tartu, Estonia. Data from heat meters is extensively used to assess the capacity of substations and network branches to deliver the required heat and quality levels. Faulty substations are identified for targeted assessment and improvement works. Several substations have been identified as missing some of the performance criteria. This has led to further analysis, closer supervision and interventions in the operational conditions of the network. This is an ongoing process, expected to remain in the established procedures of the DH network operator. At the end of the process, a temperature reduction of 7 ºC has shown an improvement of 4.8% in network heat loss.This study has been carried out in the context of RELaTED project. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 768567

A Conceptual Design of an Integrated Façade System to Reduce Embodied Energy in Residential Buildings

(1) The overall energy requirement of a building may be impacted by the building design, the selection of materials, the construction methods, and lifecycle management. To achieve an optimum energy-efficiency level when dealing with a new building or renovation project, it is important to improve the entire construction process as it is not enough to merely focus on the operational phase. If conventional construction practices do not evolve, compromise, or adapt to necessary changes, then it becomes challenging to deliver an ultimate low energy building. (2) This paper demonstrates the trend of off-site prefabrication and its production principles and the notions of open-building design and Design for X, as well as offering an overview of the development of automation in construction, which provides both insights and evaluations based on the context of the research. (3) Three European Union Horizon 2020 research projects were evaluated, and the outcome of the projects served as the backbone for the research and inspired the design of the proposed integrated façade system. Two design scenarios were proposed to demonstrate the potential improvements that could be achieved in a new build as well as in renovation projects. (4) The research lays a foundation for establishing a larger cross-disciplinary collaboration in the future.This research was funded by ZERO-PLUS, from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 678407. The authors would like to thank to following research projects: BERTIM received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 636984. HEPHAESTUS received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 732513

Monitoring and thermal performance evaluation of two building envelope solutions in an apartment building

A bio-based multi-layer building envelope assembly has been developed for its integration in newly built and retrofitted buildings. Forest-based materials and biocomposite profiles are used as an alternative to fossil-based insulants and metallic framing, providing a well-insulated and low-thermal-bridge technical solution. The wall assembly has been installed as the external envelope of one apartment of a housing block in Donostia-San Sebastián (Basque Country, Spain). A comparative study has been performed for the bio-based wall and the reference wall of the building. Their in-situ thermal resistance has been obtained by means of three different methods: (1) the steady-state average method, (2) a semi-dynamic method from heat balance at the internal surface, and (3) a dynamic multiple regression method. Reasonably consistent results have been obtained with the three methods: a discussion is provided on the influence of measuring periods and boundary conditions. Outputs from this experimental campaign are valuable as a counterpoint to desktop studies and tests under controlled laboratory conditions. Learnings and outputs from the present study should contribute to a better understanding of the in-situ performance of building envelope assemblies and their assessment methods