Articles

The IEA Solar Heating and Cooling Programme (IEA SHC) has been working for a number of years to expand its membership beyond the OECD countries, as we believe that the challenges posed by the transition to a sustainable energy supply based on renewable energy can only be met in cooperation with all global players.

In addition to SACREEE (responsible for Southern Africa) and RCREEE (responsible for North Africa and the MENA region), with which strong cooperation has existed for several years, the cooperation with the ECOWAS Centre for Renewable Energy and Energy Efficiency (ECREEE) is now also being intensified. As a first step, on-site training for 27 West African experts was conducted within the IEA SHC Solar Academy framework on October 10-12, 2023, in Cape Verde.

Two projects are under development and scheduled for approval at the June 2024 IEA SHC Executive Committee. Interested in joining? If from an IEA SHC member country, you are welcome to join the planning stages, simply contact the Task Organizer.

The analysis of 20 Solar Energy Buildings demonstration cases is wrapping up in IEA SHC Task 66 on Solar Energy Buildings. In this article, you will preview some of the high-solar fraction buildings in this collection.

The Solar Rating Certification Corporation (ICC-SRCC) and DIN CERTCO partnered to expand the SOLERGY label to North America. Since 2016, DIN CERTCO has been the designated certification body responsible for granting the SOLERGY collector label in Europe. The principal requirement to get the optional label is to have a valid Solar KEYMARK certificate. As of this October, 23 manufacturers and distributors of flat plate, evacuated tube, and PVT collectors have obtained and registered the SOLERGY label through DIN  CERTCO.
 

10 key questions, 12 authors, and 2 years of drafting time led to a comprehensive paper on planning and design strategies for solar neighborhoods published in the journal Building and Environment. Maria Wall, the Task Manager of IEA SHC Task 63 on Solar Neighborhood Planning, spearheaded this initiative. "We worked hard to choose questions that have
relevance not only for researchers but also for policymakers, practitioners, and urban planners," notes Wall. The idea for publishing a "Ten  Questions" series was initiated in 2016 by the editors of Building and Environment.

The inauguration of the 30 MW parabolic trough plant at the Heineken factory in Seville, Spain, on 30 September 2023 was exactly on time. The investor and plant operator Engie España had to put the plant into operation before the end of September to receive the extensive subsidy of EUR 13.4 million from the European Regional Development Fund. With its 30 MW, it is the largest solar industrial heat plant in Europe. It is followed by two flat plate collector fields – 10.5 MW in Nibbixwoud, Netherlands, for the Mol Freesia farm and 10 MW for Boortmalt´s malting plant in Issoudun, Southern France. A week after the inauguration, a group of experts from the IEA Solar Heating and Cooling Programme visited the enormous installation.

In 2016, air conditioning accounted for nearly 20% of the total electricity demand in buildings worldwide and is growing faster than any other energy consumption in buildings. The main share of the projected growth in energy use for air conditioning comes from emerging economies. Recognizing this developing market, in July 2020, IEA SHC Task 65 on Solar Cooling for the Sunbelt Regions began its work on innovations for affordable, safe and reliable solar cooling systems for the Sunbelt region. The “innovation” is the adaptation of existing concepts/technologies to the Sunbelt regions using solar energy.

The new IEA SHC LED Guideline for the Promotion of Lighting Retrofitting provides suggestions for accelerating the replacement of old lighting systems, harvesting the "low hanging fruits" and managing daylight. With lighting being responsible for about 15% of electricity consumption and about 5% of global CO2 emissions, it needs to be brought up to date with climate protection, energy sovereignty, and economic efficiency while ensuring user comfort at the same time.

Fault detection is essential to ensure the proper operation of solar-thermal plants. Hence, monitoring personnel frequently analyze the data to detect unusual behavior. While visualization approaches may considerably support the monitoring personnel during their work, no existing application can yet deal with the multivariate and time-dependent sensor data, or does not fully support the users' workflow. Thus, this work introduces the visual framework SunScreen. It allows users to explore the sensor data, automatically detected anomalies, and system events (e.g., already detected faults and services). The feedback from the users shows that they appreciate the tool and especially its annotation functionality. However, the SUS results indicate that it does not meet all requirements yet.

The advantage of public action is that it allows projects to be implemented over the long term. This is precisely what the town of Montmélian (Ville de Montmélian), aka Montmélian la Solaire, can boast when it comes to solar energy.
 

In 2021, the cumulative operation capacity of solar thermal systems in China reached 481.94 million square meters, accounting for 72.8% of the world’s installed area. The installed capacity of solar thermal power generation is 588 MW, accounting for 8.3% of the global cumulative installed capacity of solar thermal power generation. In recent years, the total installed solar thermal capacity has plateaued due to competition from heat pumps and photovoltaic systems and a slowing growth rate in the number of traditional small-scale and household solar water heating systems installed. In addition, the overall solar thermal industry growth rate is on a downward trend due to the impact of COVID-19.

EU-SOLARIS ERIC, the European Solar Research Infrastructure for Concentrated Solar Power, held its constitutive meeting and first General Assembly on January 12th, 2023, marking the beginning of its operation.
 

Lucio Mesquita of Natural Resources Canada is a familiar face to many of us and a longtime Task participant starting with Task 25 on Solar-Assisted Air Conditioning of Buildings in 1999.
 

You won’t want to miss the new reports highlighted below. You can read them online or download them for free. Our complete library of publications – online tools, databases, and more – dating back to the start of the SHC Programme can be found on the IEA SHC website under the tab “Publications” or under a specific Task.
 

Our solar cooling work will continue! In June, the Executive Committee approved the development phase for a new Task on Solar Cooling for Emerging Economies. This new work will build on five earlier SHC Tasks, particularly our current Task, Solar Cooling for the Sunbelt Regions. This new Task is focused on three areas, solar cooling for industrial applications, thermal energy storage, and industrial waste heat recovery. Its aim is to demonstrate the potential for sustainable and efficient heating/cooling solutions as a systems approach in Southeast Asia, the Pacific region, Africa and South America.
 

Within the industry’s transition to a circular economy, sustainable wastewater treatment and recovery should be reached without excessive strain on limited energy supplies and by decreasing fossil energy consumption. The efficient supply of energy, the best possible integration of renewable energy sources, and the recovery of resources in a circular economy must go hand in hand. Experts from 14 countries analyzed the potential for solar heat and photons for wastewater treatment in industry and municipal wastewater treatment. This article highlights the most promising outcomes.

Our flagship report, Solar Heat Worldwide 2023 is the most comprehensive evaluation of solar heating and cooling markets with data from 71 countries. The 2023 edition is available for free on the IEA SHC website. Highlighted below are just a few of the findings from this year’s report.

The SHC Programme finalized its work on Solar Energy in Industrial Water and Wastewater Management (SHC Task 62) at the end of 2022. To learn first-hand about the Task’s impact, we asked the Task Manager, Christoph Brunner of AEE, to share his thoughts on this 4-year project.
 

A factor of 0.7 kWth per square meter of aperture collector area for the conversion of area to power for statistics on concentrating collectors is an essential step for international 
market statistics for new solar heat capacities. So far, the factor 0.7 kWth/m² is only used for non-tracking collectors, following a recommendation published by IEA SHC in
2004. However, sales of concentrating collectors are growing worldwide and also need a conversion factor to account for this dynamically developing market segment in global
market statistics.

Among the 6,000 cities and towns in Europe with district heating, 266 already feed solar heat into their grid. For municipalities that plan to expand and develop new district heating systems to reduce their dependency on fossil fuels, IEA SHC Task 68: Efficient Solar District Heating (SDH) Systems has developed a solar district heating info package. The 45-page presentation answers the key questions that city officers will have when considering solar heat as part of their energy infrastructure planning. Together with Euroheat & Power and the Covenant of Mayors, SHC Task 68 experts organized three webinars, which shed light on SDH from different angles.

The demand for “green” energy sources is on the rise! And as countries strive to decarbonize, hydrogen is emerging as an essential commodity. However, the challenge this presents lies in the fact that 99% of hydrogen production still relies on nonrenewable sources. Similarly, other fuels like methane, methanol, and ethanol face this production predictment. Plus, even if these green fuels were exclusively used for industrial purposes, freight and air transportation, the surplus electricity generated from renewable sources such as wind and photovoltaics (PV) combined with electrolyzers could adequately fulfill the demand. Therefore, it is crucial to explore alternative methods - solar energy - to generate these “green gases.” And the IEA SHC Programme is stepping up. 

This work presents operational data of a large-scale solar thermal collector array. The array belongs to a solar thermal plant located at Fernheizwerk Graz, Austria, which feeds into the local district heating network and is one of the largest Solar District Heating installations in Central Europe. The collector array deploys flat plate collectors with a total gross collector area of 516 m2 (361 kW nominal thermal power). Measurement data was collected in situ within the scientific research project MeQuSo using high-precision measurement equipment and implementing extensive data quality assurance measures. Data compromises one full operational year (2017) in a 1-minute sampling rate with a share of missing data of 8.2%. Several files are provided, including data files and Python scripts for data processing and plot generation. The main dataset contains the measured values of various sensors, including volume flow, inlet and outlet temperature of the collector array, outlet temperatures of single collector rows, global tilted and global horizontal irradiance, direct normal irradiance, and weather data (ambient air temperature, wind speed, ambient relative humidity) at the plant location. Beyond the measurement data, the dataset includes additional calculated data channels, such as thermal power output, mass flow, fluid properties, solar incidence angle and shadowing masks. The dataset also provides uncertainty information in terms of standard deviation of a normal distribution, based either on sensor specifications or on error propagation of the sensor uncertainties. Uncertainty information is provided for all continuous variables, with some exceptions such as the solar geometry, where uncertainty is negligible. The data files include a JSON file containing metadata (e.g., plant parameters, data channel descriptions, physical units, etc.) in both human and machine-readable format. The dataset is suitable for detailed performance and quality analysis and for modelling of flat plate collector arrays. Specifically, it can be helpful to improve and validate dynamic collector array models, radiation decomposition and transposition algorithms, short-term thermal power forecasting algorithms with machine learning techniques, performance indicators, in situ performance checks, dynamic optimization procedures such as parameter estimation or MPC control, uncertainty analyses of measurement setups, as well as testing and validation of open-source software code. The dataset is released under a CC BY-SA 4.0 license. To the best knowledge of the authors, there is no comparable dataset of a large-scale solar thermal collector array publicly available.

Fault-Detection (FD) is essential to ensure the performance of solar thermal systems. However, manually analyzing the system can be time-consuming, error-prone, and requires extensive domain knowledge. On the other hand, existing FD algorithms are often too complicated to set up, limited to specific system layouts, or have only limited fault coverage. Hence, a new FD algorithm called Fault-Detective is presented in this paper, which is purely data-driven and can be applied to a wide range of system layouts with minimal configuration effort. It automatically identifies correlated sensors and models their behavior using Random-Forest-Regression. Faults are then detected by comparing predicted and measured values. The algorithm is tested using data from three large-scale solar thermal systems to evaluate its applicability and performance. The results are compared to manual fault detection performed by a domain expert. The evaluation shows that Fault-Detective can successfully identify correlated sensors and model their behavior well, resulting in coefficient-of-determination scores between R²=0.91 and R²=1.00. In addition, all faults detected by the domain experts were correctly spotted by Fault-Detective. The algorithm even identified some faults that the experts missed. However, the use of Fault-Detective is limited by the low precision score of 30% when monitoring temperature sensors. The reason for this is a high number of false alarms raised due to anomalies (e.g., consecutive days with bad weather) instead of faults. Nevertheless, the algorithm shows promising results for monitoring the thermal power of the systems, with an average precision score of 91%.

The Solar Decathlon is a competition for universities from all over the world which focuses on designing, building and operating experimental, solar-powered houses. Participating in the project offers universities a unique and interdisciplinary platform for teaching, learning and research which combines practical experience with research. In 2022, the European edition was held in Germany for the first time. The event took place with a new urban profile to increase both the relevance of the competition and the learning experience. Its main topic was the further development of the European city, and specifically focused on the existing stock of residential apartment buildings. A total of 18 teams from 11 countries with over 500 students took part, with 16 teams ultimately building their houses on a shared solar campus. Demonstrating a balanced or a positive energy balance in practice was one of the essential goals of the competition. This was achieved by 13 of 15 projects in the energy contest. The prerequisites for this were a high level of energy efficiency and the consistent use of solar energy. Both strategies were embedded in convincing architectural concepts. These ranged from the minimised visibility of standard systems on rooftops, through to custom-built systems with full architectural integration in façades. Hybrid solar systems also became a focus, with the goal of making optimum use of the surfaces on the building envelope. This paper focuses on the energy engineering and technical and architectural integration of the solar systems. It also includes the results achieved in the competition linked to the learning experience.

Two new Tasks were approved at the December SHC Executive Committee Meeting. Both Tasks, one on lighting and the other on life cycle and cost assessment, highlight the breadth of work undertaken by the IEA SHC Programme.
 

At the first jointly organized EuroSun between ISES and IEA SHC, having over 480 solar experts from more than 50 countries gather in Kassel, Germany, was a welcome post-pandemic sight. And the silver lining was having Kassel University, the conference host, provide the perfect backdrop for drawing together new and experienced solar experts.
 

ORVI’s housing project provides a simple, affordable, sustainable solar water heating option for 58 locally built homes. Ms. Helvi IIeka, Centre Head, Renewable Energy and Energy Efficiency of the Namibia Energy Institute, Namibia University of Science and Technology (NUST), and Mr. Leonhard Eins, Managing Director of Solsquare Energy (Pty) Ltd, received the award on behalf of the ORVI Social Housing project during EuroSun 2022, the International Conference on Solar Heating and Cooling for Buildings and Industry of IEA SHC and ISES held this year in Kassel, Germany.

Families and members at Airforce Base Makhado in Limpopo are reaping the benefits of yet another energy efficiency project – this time, solar geysers designed to reduce the damage of limescale buildup and the amount of electricity used to heat water in domestic housing. Piloted as one of the projects implemented through a five-year partnership between the South African National Energy Development Institute (SANEDI) and the military (SANDF), this installation is part of ongoing research to ensure sustainable energy as well as quantify energy, cost, and emissions savings through energy efficient and renewable energy interventions.

Heat Changers and the IEA SHC Programme understand the significance of Solar Heat in the push to reach a carbon-neutral world. With our new partnership, we look forward to demonstrating why Solar Heat is pivotal for our changing energy sectors.
 

As 2022 comes to an end and 2023 begins, our team of SHC Task Managers wants to share trends they see coming in their fields of expertise. We hope that by taking the time to stop and think about where solar thermal is headed, we can stay one step ahead of the technological advances and market changes.

It can be a big challenge to contract and design a SHIP (Solar Heat for Industrial Processes) project. SHC Task 64 on Solar Process Heat is working to support planners and investors as they consider such a project. During the recent SHC Solar Academy webinar, three SHC Task 64 experts shared tips and tricks on designing a SHIP project and the success factors to consider. The webinar recording, including the Q&A session, is available at https://www.iea-shc.org/solar-academy/webinar/solar-process-heat.

The energy demand for air-conditioning is growing faster than any other energy consumption in buildings.The main share of the projected growth for space cooling comes from emerging economies and will more than triple by 2050 to 6,000 TWh/a globally. What could be the contribution of PV and solar thermal cooling to meet this increasing demand in the next decade? This was the key question that Dr. Uli Jakob, Task Manager of SHC Task 65 on Solar Cooling for the Sunbelt Region, elaborated on in his keynote presentation, The Future of Solar Cooling, at EuroSun 2022.

Good monitoring is essential to ensure the performance of solar thermal systems. Only then can solar al systems live up to their full potential and provide as much renewable energy as possible.

The International Energy Agency (IEA) has provided the solar hot water sector with a clear mission to deploy at least 400 million residential solar systems by 2030.Dr. Richard Hall, a Vice Chair of the Solar Heating and Cooling Programme (SHC), discusses the implications of this new global mission on the structure of the solar thermal sector.

The combination of abundant solar energy resources and heavy reliance on fossil fuels has led many African nations to look to the sun for solutions. And not surprisingly, they are finding solar solutions for all different applications and community needs. Here are highlights from four of our Southern Africa member countries.
 

IEA SHC is again partnering with the IEA Energy Storage (ES) Programme to tackle storage issues. Building on earlier projects, IEA SHC and IEA ES are collaborating to push compact thermal energy storage technology developments and accelerate the market introduction of these technologies. To achieve these goals requires a diverse international team of experts from materials research, components development and system integration, and industry and research organizations.

Preparations for the second Fall School of SHC Task 63 on Solar Neighborhood Planning are underway. The main objective of the course is to introduce and discuss various strategies and methods to assess and evaluate solar neighborhood strategies and concepts from different perspectives and standpoints.

Solar heat for industrial processes (SHIP) is a pivotal technology to decarbonize the industrial heat demand worldwide. And participants in SHC Task 64 on Solar Process Heat are working on the system level to identify, verify, and promote the role of solar heating plants in combination with other heat supply technologies.

he SHC Solar Award is given to an individual, company, or private/public institution that shows outstanding leadership or achievements in the field of solar heating and cooling and supports the work of the IEA SHC. This year’s SHC Solar Award will recognize a Solar Heating or Cooling project to reduce energy use and costs in social housing. The winner will be announced during EuroSun 2022 in Kassel, Germany.
 

Info on two upcoming projects.

IEA SHC and ISES (International Solar Energy Society) teamed up to present an Out-ofContest Award during the Solar Decathlon Europe this June in Wuppertal, Germany. The driver behind this collaboration was to shine a light on the team that successfully integrated solar
thermal concepts in their building.
 

Worldwide, 250 million dwellings used solar thermal technologies for water heating in 2020. However, to reach carbon neutrality by 2050, as proposed by the IEA in their Net Zero by 2050: A Roadmap for the Global Energy Sector, we estimate that 170 million new conventional solar thermal technologies (e.g., thermosyphons and pumped circulation systems) and 120 million emerging solar systems (e.g., PV-driven systems) are needed.

Our flagship report, Solar Heat Worldwide 2022 is the most comprehensive evaluation of solar heating and cooling markets with data from 70 countries. The 2022 report has a new design to better highlight all the data but covers the same categories – 2021 market development and trends, 2020 global markets, country statistics, distribution by system types and applications, and contributions to the energy supply and CO2 reductions. The full report and key findings are available for free on the IEA SHC website.

The number of large-scale solar thermal installations has increased rapidly in Europe in recent years, with 70% of these systems operating with flat-plate solar collectors. Since these systems cannot be easily switched on and off but directly depend on the solar radiation, they have to be combined with other technologies or integrated in large energy systems. In order to most efficiently integrate and operate solar systems, it is of great importance to consider their expected energy yield to better schedule heat production, storage and distribution. To do so the availability of accurate forecasting methods for the future solar energy yield are essential. Currently available forecasting methods do not meet three important practical requirements: simple implementation, automatic adaption to seasonal changes and wide applicability. For these reasons, a simple and adaptive forecasting method is presented in this paper, which allows to accurately forecast the solar heat production of flat-plate collector systems considering weather forecasts. The method is based on a modified collector efficiency model where the parameters are continuously redetermined to specifically consider the influence of the time of the day. In order to show the wide applicability the method is extensively tested with measurement data of various flat-plate collector systems covering different applications (below 200°Celsius), sizes and orientations. The results show that the method can forecast the solar yield very accurately with a Mean Absolute Range Normalized Error (MARNE) of about 5% using real weather forecasts as inputs and outperforms common forecasting methods by being nearly twice as accurate.

In May, the International Energy Agency published the 224-page report, Net Zero by 2050: A Roadmap for the Global Energy Sector, challenging policymakers with 400 milestones that governments need to realize to achieve the 1.5 °C target. At the report’s online press conference, IEA Executive Director Dr. Fatih Birol made some surprisingly forceful statements about the global net-zero emission targets for 2050 – statements widely quoted in the media since. “This is not a race between nations but a race against time. And no one wins unless everyone finishes,” he said. He also underlined that there is no longer a need for further investment in oil, gas, and coal.

The SHC Programme finalized its work on Integrated Solutions for Daylighting and Electric Lighting (SHC Task 61/EBC Annex 77) in November. To learn first-hand about the Task’s impact on lighting, we asked Jan de Boer, the Task Operating Agent, to share some of his thoughts on this 3.5-year project.

In November, the IEA SHC Programme finalized its work on Renovating Historic Buildings Towards Zero Energy (SHC Task 59/EBC Annex 76). To learn first-hand about the Task’s impact on historic buildings, we asked Alexandra Troi, the Task Operating Agent, to share some of her thoughts on this multi-year project.

The IEA SHC Solar Academy and SOLTRAIN (Southern African Solar Thermal Training and Demonstration Initiative) hosted with the support of SACREEE and SANEDI a specialized course for professionals on Solar Cooling for Sunbelt Regions in November at Stellenbosch Institute for Advanced Study in South Africa. A total of 46 participants from 7 countries took part, with around 8 of them participating virtually.

Solar process heat system yields are simulated during feasibility studies and have a decisive influence on the profitability of the project investment. The large number of simulation tools available means that results can differ significantly and possibly create a lack of trust by investors. This is why a group of IEA SHC Task 64/SolarPACES Task IV: Solar Process Heat researchers, headed by Jose Cardemil, Associate Professor at Pontifical Catholic University of Chile, decided to evaluate several tools by analyzing their
limitations and comparing their results.

Solar neighborhoods are a piece in the puzzle in achieving net-zero energy districts and low-carbon cities. This is why the IEA SHC Task 63: Solar Neighborhood Planning participants are working on solar planning and economic strategies, simulation methods and tools, and case studies. One unique aspect of this project’s work is holding “Fall School” for Ph.D. and Advanced Masters students.

The IEA SHC Programme has worked on different lighting aspects over the years. The first SHC Tasks looked solely into the benefits of efficient daylight usage then shifted to a broader focus beginning with SHC Task 50: Advanced Lighting Solutions for Retrofitting Buildings, which addressed lighting retrofits. The most recent lighting project, IEA SHC Task 61: Integrated Solutions for Daylighting and Electric Lighting, a collaborative project with IEA EBC, looked specifically at the interfaces of electric lighting and daylighting. Up until now, both were often treated as different trades in practice and research – although people work and live in one encompassing lighting environment. This said, the success of highly energy-efficient lighting designs hinges on more than
technological ingenuity. Other key make-or-break factors are smart control strategies and the interaction of lighting users with the built environment. These “other” factors were analyzed over the last three and half years by 55 experts from 37 research institutes, universities, and businesses in 17 countries. This article summarizes the key accomplishments and conclusions of SHC Task 61/
EBC Annex 77: Integrated Solutions for Daylighting and Electric Lighting.

Trade unions, which facilitate collaboration between employees to achieve strategic common employment-related goals, have a complex relationship with the solar sector that can be difficult to untangle. In this article, Dr. Richard Hall, a Vice Chair of the IEA Solar Heating and Cooling Programme (IEA SHC), delves into this relationship to assess whether the IEA SHC Programme should be engaging more with trade unions, and if so, on what issues.
 

Switzerland ratified the Paris Agreement on 6 October 2017, setting a commitment to reduce emissions 50% by 2030 from 1990 levels, with partial emissions reductions from abroad. As an indicative target for 2050, the Swiss government decided in August 2019 that Switzerland should aim for net zero greenhouse gas emissions by 2050. The net zero target is also the subject of a popular 2019 initiative, the “Glacier Initiative.” In response, the government has made a direct counter-proposal, and both the initiative and the counter-proposal are currently under discussion in Parliament.

The IEA SHC Solar Academy and SOLTRAIN (Southern African Solar Thermal Training and Demonstration Initiative) hosted with the support of SACREEE and SANEDI a specialized course for professionals on Solar Cooling for Sunbelt Regions in November at Stellenbosch Institute for Advanced Study in South Africa. A total of 46 participants from 7 countries took part, with around 8 of them participating virtually.
 

The Regional Centre for Renewable Energy and Energy Efficiency of SICA (SICREEE) member countries are Belize, Costa Rica, Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua, and Panama. SICREEE opened its doors in 2021 with the support of the Austrian Development Agency (ADA), the United Nations Industrial Development Organization (UNIDO), and in coordination with the General Secretariat of the Central American Integration System (SG-SICA).

Integrating large-scale solar thermal plants into district heating and cooling grids is playing a crucial role in many countries’ energy transformation to decarbonize their heating sector. Thermal networks offer a dual solution – increasing energy efficiency in urban areas and integrating renewable energies into the heat supply. The participants in IEA SHC Task 55: Integrating Large Solar Heating and Cooling Systems into District Heating and Cooling Networks worked from 2016–2020 on this topic with a holistic focus on solar systems that supply heating and cooling networks with high thermal shares.
 

The SHC Programme wrapped up its third project on large solar systems (Task 55) in December 2020. To learn how the Task impacted this market sector, we’ve asked Sabine Putz, the Austrian Task Operating Agent, to share some of her thoughts on this 4-year project.
 

Dr. Daniel Mugnier, the IEA Solar Heating and Cooling Technology Collaboration Programme’s former Chair shares his thoughts on the future of solar thermal.
 

Through the SOLTRAIN project, coordinated by AEE INTEC and funded by the Austrian Development Agency, the Center for Renewable and Sustainable Energy Studies (CRSES) at Stellenbosch University in South Africa has been collecting data on PV2heat installations in South Africa since 2018.
 

A solar PV/Thermal (PVT) collector produces both heat and electricity thanks to a combination of a PV panel and a solar thermal collector or absorber. IEA SHC Task 60: PVT Systems investigated the possible concepts for the last three years with a group of experts from research laboratories and solar industries. The end results, good examples of different types of installations around the world, simulation models, key performance indicators, and a comparison of concepts. This article summarizes the work and findings of the Task and confirms that PVT technologies can play a vibrant role in the transition towards more solar energy for both heating and electricity production.

The SHC Programme completed its most recent work on PVT Systems (Task 60) in December 2020. To learn how this Task impacted this market sector, we’ve asked Jean-Christophe Hadorn, the Swiss Task Operating Agent, to share some of his thoughts on this 3-year project. 

EUROSUN 2020 paper about the new Task 65.

http://proceedings.ises.org/?conference=eurosun2020

One of the roles of the South African National Energy Development Institute (SANEDI) is to facilitate and coordinate renewable energy and energy efficiency research, development, and demonstration through local and international cooperation, technology transfer, and information exchange leading to the deployment and  commercialization of sustainable, efficient, reliable, costcompetitive and environmentally sound renewable  energy technologies.
 

Within the framework of IEA-SHC Task 59, a multidisciplinary team of experts from around the world has come together to investigate current approaches for energy retrofit of the built heritage with energy efficiency conservation-compatible measures, in accordance with cultural and heritage values, and to check and adapt the new standard EN-16883:2017 for historic buildings. This paper introduces activities within IEA-SHC Task 59 (Subtask C) focused on retrofit solutions with high impact on sustainability, energy efficiency, and the integration of renewables, which is the main goal of the solar group, focused on the integrated solar systems for historic buildings. Relying on an extensive, detailed, and accurate collection of case studies of application of solar photovoltaic and thermal systems in historic buildings, the assessment criteria of the standard have been reviewed and tailored for better solar implementation evaluation in a heritage context. All this is studied based on technical compatibility, the heritage significance of the building and its settings, the economic viability, the energy performances and indoor environmental quality and use, as well as the impact on the outdoor environment of solar renewables.

Historic, listed, or unlisted, buildings account for 30% of the European building stock. Since they are complex systems of cultural, architectural, and identity value, they need particular attention to ensure that they are preserved, used, and managed over time in a sustainable way. This implies a demand for retrofit solutions able to improve indoor thermal conditions while reducing the use of energy sources and preserving the heritage significance. Often, however, the choice and implementation of retrofit solutions in historic buildings is limited by socio-technical barriers (regulations, lack of knowledge on the hygrothermal behaviour of built heritage, economic viability, etc.). This paper presents the approach devised in the IEA-SHC Task 59 project (Renovating Historic Buildings Towards Zero Energy) to support decision makers in selecting retrofit solutions, in accordance with the provision of the EN 16883:2017 standard. In particular, the method followed by the project partners to gather and assess compatible solutions for historic buildings retrofitting is presented. It focuses on best practices for walls, windows, HVAC systems, and solar technologies. This work demonstrates that well-balanced retrofit solutions can exist and can be evaluated case-by-case through detailed assessment criteria. As a main result, the paper encourages decision makers to opt for tailored energy retrofit to solve the conflict between conservation and energy performance requirements.

Buildings of heritage significance due to their historical, architectural, or cultural value, here called historic buildings, constitute a large proportion of the building stock in many countries around the world. Improving the performance of such buildings is necessary to lower the carbon emissions of the stock, which generates around 40% of the overall emissions worldwide. In historic buildings, it is estimated that heat loss through external walls contributes significantly to the overall energy consumption, and is associated with poor thermal comfort and indoor air quality. This paper provides an evidence-based approach on the steps required during assessment, design, and construction, and after retrofitting through a literature review. Moreover, it provides a review of possible measures for wall retrofit within the deep renovation of historic buildings, including their advantages and disadvantages and the required considerations based on context.

Historic building restoration and renovation requires sensitivity to the cultural heritage, historic value, and sustainability (i.e., building physics, energy efficiency, and comfort) goals of the project. Energy-efficient ventilation such as demand-controlled ventilation and heat recovery ventilation can contribute to the aforementioned goals, if ventilation concepts and airflow distribution are planned and realized in a minimally invasive way. Compared to new buildings, the building physics of historic buildings are more complicated in terms of hygrothermal performance. In particular, if internal insulation is applied, dehumidification is needed for robust and risk-free future use, while maintaining the building’s cultural value. As each ventilation system has to be chosen and adapted individually to the specific building, the selection of the appropriate system type is not an easy task. For this reason, there is a need for a scientifically valid, systematic approach to pair appropriate ventilation system and airflow distribution solutions with historical buildings. 

As 2020 comes to an end and 2021 begins, our team of SHC Task managers want to share some trends they see in their fields of expertise. We hope that by taking the time to stop and think about where solar thermal is headed, we can stay one step ahead of the technological advances and market changes.
 

France’s Solar Academy Graduate School is on course to become an international scientific reference on the integration of solar energy. Central to its work is integrating solar energy in the built environment by combining training and research at the highest level.
 

In the context of IEA SHC Task 64: Solar Process Heat, researchers developed a method to estimate the heat load profiles of companies in industry and commerce to facilitate preliminary designs, feasibility assessments and potential studies on renewable heating systems.

Thermal energy storage is key for integrating renewable heat sources into an energy system --from domestic applications to district heating and from industrial applications to the power sector. The flexibility storage provides is necessary for the coupling of energy sectors. When higher temperatures, volume restrictions or very long storage periods come into play, new compact thermal storage technologies are needed, but so is more work on their development for the different energy sectors. It is this need that was the motivation for SHC Task 58/ECES Annex 33: Material and Component Development for Thermal Energy Storage – to further improve the storage materials and components based on a better knowledge of the underlying physics and chemistry.

The collaborative project, SHC Task 61 / EBC Annex 77 on Integrated Solutions for Daylight and Electric Lighting: From Component to User Centered System Efficiency, is wrapping up its work in June 2021 and results from these three and half year project are coming in. This article presents the first results of the Task’s work on user requirements and design support for practitioners against the backdrop of integrating daylight and electric lighting. 

The IEA SHC Programme concluded its joint project with the IEA Energy Conservation through Energy Storage (ECES) Programme on Material and Component Development for Thermal Energy Storage (SHC Task 58/ECES Annex 33). To learn first-hand how this Task supported thermal energy storage market development, we asked Wim van Helden, the SHC Task Operating Agent, to share some of his thoughts on this 3-year project.
 

This publication is in Turkish, with a link to the English translation at the top.

Lila Angelaka, Senior Technical Officer of Technical Research Team from the Scottish Historical Environment, points out that the restoration of the historical environment and historical buildings, especially with local and traditional materials, reduces the carbon emitted during both procurement and production of the material: “We advocate to reuse of existing buildings and their refurbishment. Many traditional buildings have an inherent, in-built resilience to climate impacts”.

ekoiq.com/2020/12/09/our-heritage-is-the-unique-factor-that-can-reduce-carbon-emissions/

Dr. Richard Hall, a Vice Chair of the Solar Heating and Cooling TCP, discusses the role that IEA TCPs play in curating sectoral social capital and how this elusive form of capital is used by governments to efficiently deploy resources in times of crisis.
 

Being a northwestern European country with a temperate maritime climate, the Netherlands spends a considerable share of its energy to heat buildings. Of the 6,000 PJ consumed overall on a yearly basis, 500 PJ is used as heat for the built environment, most of which is produced using natural gas. As part of the commitments made in the Paris Climate Agreement, the Dutch government plans to phase out the use of natural gas in the built environment by 2050.

About 30 consultants, researchers, manufacturers, grid operators and CCREEE staff joined a two-day training course organized by the Caribbean Centre for Renewable Energy and Energy Efficiency (CCREEE) as part of the SHC Solar Academy. CCREEE, the newest member of the SHC Programme, welcomed the opportunity to learn about Austria and Greece’s solar thermal work and the new SHC project, Task 65 on Solar Cooling for the Sunbelt Regions.
 

The integration between solar energy systems and building components is highly critical in sensitive heritage contexts. On the one hand there is the need for finding a balance between the preservation of the aesthetic appearance and the historical values, but on the other hand, finding the space where to effectively integrate the systems might be quite challenging. 

È possibile conservare edifici del passato in modo rispettoso della loro essenza e al contempo migliorarne l'efficienza energetica? Una domanda che concerne non solo i beni culturali riconosciuti, ma anche gli stabili di pregio costruiti negli scorsi decenni, secondo standard diversi da quelli attuali.

Climate change will affect future hygrothermal performance of buildings. This could lead to higher risks regarding energy optimization, thermal comfort and historic building conservation depending on the local climate, building construction and retrofit solutions adopted. This paper explores the risks brought by climate change on a typical residential historic building of South Tyrol. The results obtained show that, although the climate warming will reduce the future heating energy demand, an improvement of buildings' energy performance will still be necessary to increase sustainability and ensure their continued use. Natural ventilation would suffice to prevent overheating in the studied location, but a further analysis is needed for warmer alpine regions. Regarding the moisture-related risks for the historic construction, mould growth should be considered when retrofitting a wooden wall and frost damage should be carefully studied in the case of sandstone walls.

Click here to access the full version. 

The Slovak Republic (SR) became an independent nation in 1993. In 2000, it became a member of the Organization for Economic Cooperation and Development (OECD), a Member State of the European Union (EU) in May 2004, a member of the International Energy Agency (IEA) in 2007, and then in 2016 joined the IEA SHC Programme.
 

The objective of our Task on Building Integrated Solar Envelope Systems for HVAC and Lighting was to answer how solar envelope systems can become common practice in building construction. The SHC team that tackled this challenge was a group of experts from eight countries representing seven companies, six universities, and four research institutes. How they went about it was to tackle the issue from different angles – simulation of multifunctional envelope systems, review of laboratory tests and norms, and market assessments. The following is what they concluded needs to be done and by whom to push this technology further into the building market.

A short article with information about general maintenance of tenement flats and communal areas within Scotland. This includes links to further information and common repairs.

SACREEE, the South African Centre for Renewable Energy and Energy Efficiency, joins four other UNIDO Global Network of Regional Sustainable Energy Centres (GN-SECs) members in the IEA SHC Programme.  That is exciting is that each GN-SEC member brings a different regional focus to our work. SACREEE brings the perspective and experiences of sixteen Southern African countries.
 

The new project, Task 65: Solar Cooling for the Sunbelt Regions, builds upon our past four solar
cooling Tasks. This Task will be different in that it focuses on innovations for affordable, safe, and
reliable solar cooling systems in sunbelt regions. The primary driver for continuing this work is that air-conditioning accounts for nearly 20% of the total electricity demand in buildings worldwide and is growing faster than any other energy use in buildings. If measures are not taken to counteract this increase, the demand for space cooling will almost triple by 2050, with estimates reaching 6,200 TWh or 30% of the total electricity use in buildings.

I write this opinion piece on Sunday the 26th of April 2020, a day when the death toll from the novel coronavirus has reached 200,000. Whilst the situation is starting to stabilize in many parts of the world, the severe impact of the COVID-19 pandemic on both public health and the economy is something that we will all be dealing with for many years to come.
 

Solar thermal for district heating is on the rise worldwide. In Denmark, where the market grew by about 170% in 2019, and other countries like China and Germany, this rise is primarily due to advances in cost competitiveness. Also, driving this growth is the rising demand for industrial and agricultural applications. While residential water heating systems, the largest market sector, were under pressure in China and Central Europe from competing technologies, residential sales increased significantly in South Africa, Greece, Cyprus, and Brazil.

South Africa is demonstrating its commitment to a more sustainable future growth path by supporting renewable energy and energy efficiency measures, together with skills development and job creation through fostering a green economy. South Africa is among the highest emitters of carbon dioxide in the world, currently ranked in the top 20 in terms of top emitters per capita, since more than 75% of our primary energy requirement is derived from fossil fuels. The country responded to the urgent need to reduce fossil fuel dependency, diversify the energy mix and supply, and reduce the country’s carbon footprint with a supportive policy and legislative framework that exploits the excellent local renewable energy resources, especially wind and solar.

New Task on Solar Process Heat Starts in January / Planning Underway for a Working Group on Life Cycle and Cost Assessment for Heating and Cooling Technologies / 

The SECASOL project is implementing innovative solar thermal solutions in wastewater sludge and municipal solid waste drying processes in southern Portugal and Spain.
 

Improving the energy performance of historic buildings has the potential to reduce carbon emissions while protecting built heritage through its continued use. However, implementing energy retrofits in these buildings faces social, economic, and technical barriers. The purpose of this conceptual paper is to present the approach of IEA-SHC Task 59 to address some of these barriers.

This study presents a methodology developed in the framework of Task 54 of the Solar Heating and Cooling (SHC) Program of the International Energy Agency (IEA) to calculate the heat cost per kWh final energy of solar thermal systems. Based on the concept of levelized cost of energy, three indicators are introduced depicting the heat cost of the solar part of the heating system only (LCoHsol,fin), the conventional part (LCoHconv,fin) or the overall solar assisted heating system (LCoHov,fin). The LCoHov,fin enables a comparison with other heating systems using different technologies. Applied to eleven residential systems in five European countries, the results show that the heat cost differs widely, depending on countries and system types. The solar heating system raises the heat cost of the overall solar assisted heating system compared to a reference system without solar assistance (subsidies are not considered) in most studied cases, but some solar domestic hot water systems and solar heating systems for multi-family houses are close to parity under current economic conditions and the assumptions considered in the paper. This work also highlights the importance of calculating the heat cost with a standardized methodology to enable a comparison between different systems.

Photovoltaic-thermal (PVT) collectors are hybrid solutions for the conversion of solar energy into electrical andthermal energy. The development of validated and standardized PVT collector models is important for thecomparison of products, informed decision making based on energetic and economic performance, and topromote the market diffusion of PVT technology. This contribution presents a novel PVT performance model,compares different parameter identification approaches, and validates the model and its implementation in acommon simulation software (TRNSYS) for system simulations.

This research describes the methodology applied to carry out the monitoring campaign on the Milan Duomo, one of the biggest Cathedrals in Italy. The campaign was carried out by means of non-invasive measuring instruments, in order to keep the building intact and ensure the smooth running of the activities. In a second stage, sensors for the long-term monitoring were installed according to the most significant and accessible points inside the Cathedral.

The data collected during one year of monitoring was used to characterize the hygrothermal behaviour of the Cathedral, in order to assess the risks for the main materials which sacred objects, artworks, organs, sculptures and furnishing are made of.

The 12th EuroSun International Conference on Solar Energy for Buildings and Industry was a big success. On September 10th to 13th, more than 130 oral and 180 poster presentations were given to an audience of researchers, professionals, and experts from all over the world in Rapperswil, Switzerland.

Abstract - The aim of this study is to assess the performance of prototype PV façade elements of various PV technologies, colors and textures. Within this context, a prototype PV façade demonstrator was constructed and monitored at SolarBEAT, Eindhoven. This prototype demonstrator consists of 9 façade PV panels of c-Si and CIGS technologies with flat and textured solar glasses and black, grey and red colors. The field-testing results indicate a limited performance drop of less than 20% for all colors and textures.

Abstract - As the interface between interior and exterior spaces, the façade plays a key role for the thermal and visual conditions in buildings. Advanced daylighting systems should fulfill various and in parts contradictory requirements: they must provide sufficient and adequately distributed natural lighting, avoid visual discomfort (glare) while allowing visual contact to the exterior, provide solar gains for heating in winter and protect from high radiation against overheating in summer. Integrating these functionalities often results in products which are more complex than conventional sunshading systems and thus are often not properly characterized and cannot be applied in standard design workflows. We present approaches for the characterization of advanced daylighting systems and introduce DALEC, a simplified tool for combined lighting and thermal simulations that can account for such systems. (...)

Abstract - A new approach of highly-efficient thermal refurbishments of multi-family buildings is presented that has a high potential to reduce costs and simplify the renovation processes significantly. This approach is based on prefabricated curtain wall elements that integrate components for the energy supply system such as heat pumps, PV panels and all the necessary pipework for supply and waste water lines. By using pre-fabricated curtain wall elements, scaffolding and the relocation of inhabitants can be avoided. Three different system concepts have been evaluated and compared to a reference retrofit in terms of primary energy and life cycle costs. It has been shown that the new concepts can reduce the primary energy consumption significantly while reducing the costs over the lifetime of the system. Finally, a functional mockup of such as pre-fabricated façade was constructed and successfully tested in the laboratory.

Abstract - As the interface between interior and exterior spaces, the façade plays a key role for the thermal and visual conditions in buildings. Advanced daylighting systems should fulfill various and in parts contradictory requirements: they must provide sufficient and adequately distributed natural lighting, avoid visual discomfort (glare) while allowing visual contact to the exterior, provide solar gains for heating in winter and protect from high radiation against overheating in summer. (...) We present approaches for the characterization of advanced daylighting systems and introduce DALEC, a simplified tool for combined lighting and thermal simulations that can account for such systems. A comparison between DALEC and TRNSYS proves that the simplified approach is adequate for integrated simulations in early design phases.

Abstract - Within the framework of the Austrian FFG project “SaLüH!” concepts with high energy efficient and cost-effective decentral small scale heat pumps for heating and DHW preparation for the renovation of small dwellings in multi-story buildings are developed and investigated. Very compact heat pumps are developed in order to enable the integration of these units into the window parapet or into the façade. The wall integration has a high potential in pre-fabrication and leads to an optimal solution for renovation of small apartments. The target is to create a complete renovation package with a decentralized (apartment size) exhaust-air heat pump (HP) for ventilation and heating installed in the kitchen and an air-to-water HP for DHW preparation installed in the bathroom. The solutions aim to be cost effective, involving components and technologies with high efficiency and minimum noise emissions. (...)

Abstract - The intension of Living in Light is to create additional space behind a more transparent and flexible building envelope in a transformation of existing buildings. The purpose is to make a more demand driven concept for renewal and transformation of existing buildings to the benefit of the users, the owners and the environment. The transparent building envelope adds new qualities to the building. A part from more space it creates a “Summer Garden”, with daylight and better indoor environment, active facades (PV and thermal sun power) and better energy performance. The Living in Light Box tests the concept. www.livinginlight.info | Paper | Presentation

Abstract - To reach future Net-Zero Energy Buildings as requested by the “Energy Performance of Buildings Directive” the integration of systems for harvesting of renewable energy is decisive. Building integrated solar thermal (BIST) collectors can play an important role in this paradigm shift. In the R&D projects ArKol and TABSOLAR multidisciplinary teams develop different BIST systems for transparent and opaque facades. These solutions help trigger highly qualitative architectural integration of solar thermal collectors and are planned for future realization. This paper describes the basic layout of these systems and the current state of development.
 

The construction sector has now entered the ‘Digital era’, and professionals are slowly getting familiar with many of these innovative technologies. This paper shows how such innovations improve the investigation phase when it comes to energy retrofits on heritage buildings. More specifically, multi-view photogrammetry and wireless sensor networks can facilitate the implementation and enhance the relevance of building hygrothermal and energy simulations: photogrammetry quickens up the reproduction of the building geometry whereas wireless sensor networks facilitate and enlarge the collection of data relative to the existing behaviour of an occupied building. This paper explores the benefits of using those two technologies compared to more traditional solutions, regarding data quality and general workflow. In this purpose, two case studies from research projects ongoing in Belgium are briefly described.

Click here for the full version, p. 156.

The HISTool is a software-based tool for the analysis of the current building status, and a decision support tool for the innovative and sustainable renovation specifically of Gründerzeit buildings. These were built between 1840 and 1918 with partially standardized designs and components in CentralEuropean cities. The tool is designed to be applied particularly in the preparation and decision-making stage of renovation projects in the Gründerzeit building sector, prior to the actual planning phase. For the decision-making process, it is essential to provide solid data on different renovation options in an early phase based on life-cycle costs, without a lot of calculation effort. The calculation is based on a model of the building, which consists of 40 elements according to the specifics of Gründerzeit buildings and the selection of predefined renovation measures. The integrated energy performance and life-cycle cost calculation leads to the derivation of life-cycle costs of different renovation variants. A comparison of life-cycle costs of different renovation options leads to information-based renovation decisions. The aim is to stimulate the Gründerzeit sector in the real estate market to implement more energy-efficient and innovative renovations, which are compatible with the specific requirements of historic buildings, and to contribute to the fulfilment of the climate-protection goals. HISTool particularly reflects the environmental and economic goals of sustainable management of historic buildings according to EN 16883, and supports the planning and decision making procedure in the first phase as well as in the detailed planning phase when it comes to the selection of specific measures and assessment against the initial project targets.

Click here for the full version, p. 227.

The paper presents desktop analyses of potential energy savings in historic buildings, carried out using standard boundary conditions for calculation of energy savings, as prescribed in the European building energy performance certification schemes. Internal insulation of the building’s façades can potentially reduce the theoretical energy demand for space heating by 9 to 43 % compared to the energy demand of the original building if installed moisture-safe. Combined with other commonly used energy saving measures, 43–78 % reduction of the energy demand was estimated.

Click here for the full version, p. 24.

Before deciding how to improve the energy efficiency of historic buildings by applying thermal insulation, an estimation of consequences, e.g. changes in heat and moisture flux, must be made. In the EU-project RIBuild, attempts have been made to cluster historic building materials; enabling a user to choose an appropriate material and include uncertainties. Unfortunately, the decisiveness of properties depended on whether e.g. conditions at external or internal surface of the brick wall were considered.

Click here for the full version, p. 43.

This paper describes a methodology for assessing damage threshold criteria. The methodology includes a survey and determination of threshold values for deterioration, which can then be used to evaluate the risk in specific structures of external walls. The work includes summarizing existing knowledge and adapting and developing models for failure modes based on field and laboratory testing. Failure modes include frost damage of the exterior façade layer, rot and mould growth within the building envelope and adjoining structures, as well as discolouring of façade surfaces due to biological growth.

Click here for the full version, p. 34.

The paper aims to investigate criticalities and potentialities of the Italian Cultural Heritage Ministry’s Guidelines (October 2015) and the European Guidelines for Improving Energy Performance of Historic Buildings (EN 16883 – June 2017), comparing and applying them to selected case studies. The documents represent an instrument to help public authorities and designers to follow an iterative retrofit process; in both cases it is possible to notice some difficulties in their technical application. Thus, we have identified their critical and positive features through the case studies assessment. The scope is to underline possible issues and to suggest new solutions in both cases, improving the existing guidelines with other targets to obtain a calibrated evaluation method, which could guide the retrofit project.

Click here for the full version, p. 285.

The paper aims to present innovative studies concerning removable devices for enhancing thermal performance or mitigating criticalities in listed buildings. The first concerns a “high tech” curtain studied for preventing air drafts from the windows, causing different forms of decay in the Sala delle Asse in Castello Sforzesco (Milano), world known for the Leonardo Da Vinci fresco. The second body of research deals with a new type of “arazzo” (removable and usable seasonally) to improve the insulation of the walls. The study case regards the collection of historic “arazzi” in Sala della Balla, in Castello Sforzesco as well.
The focus is to investigate how the main properties of the removable devices  affect the thermal exchange with the air and the surfaces where they are applied. A third study case is a masterpiece of listed modern architecture, Casa del Fascio in Como, where the new uses require cooling with the addition of a shadowing system.

Click here for the full version, p. 129.

The present paper analyzes the renovation project of a heritage medieval building located in the city center of Bolzano–the “Waaghaus”. The building has been used as case study in the EU-project 3encult, where it has been extensively studied both from heritage and energy efficiency points of view. Our analysis, partly based on the experience gained in the EU-project, aims at validating and improving the renovation project that was developed by a design team commissioned by the owner. In particular three aspects of the renovation are mainly investigated: 1) Reduction of the energy demand 2) Indoor climate and air quality 3) Hygrothermal risk in critical points. Results show that the proposed renovation cuts the energy demand to 60 percent. Moreover they demonstrate that, when renovating a historic building, it is crucial to carefully investigate the ventilation strategy and the critical construction details. Not considering these two aspects can lead to poor air quality and to a significant risk of surface mould and condensation formation.

Click here for the full version, p. 137.

Historic buildings account for more than one quarter of Europe’s existing building stock and are going to be crucial in the achievement of future energy targets. In order to ensure their endurance, conservation compatible solutions are needed. Nevertheless, some alteration in the climate is already certain and therefore the impact of climate change on retrofitted historic buildings should be considered in terms of occupants’ comfort, heritage conservation, and energy performance. Inappropriate interventions might weaken the potential of original passive climate adaptive system, such as thermal mass and night cooling, leading to higher risks of overheating. Similarly, retrofit solutions will change the moisture dynamics of historic envelopes, which might lead to moisture damages when combined with more extreme precipitation events. This paper reviews recent literature that provides evidence of climate change’s impact on retrofitted buildings, reveals potential future risks, and thereby throws light on new factors influencing the retrofit decision-making process.

Click here for the full version, p. 62.

Energy efficiency policies might have a negative impact on the heritage values of buildings, an issue widely recognized in Sweden during and after the extensive energy efficiency programme ‘Energy savings plan for existing buildings’ (EBB 1977–84). The purpose of this paper is to assess the long-term impact of the EBB on an urban district in Gävle, Sweden. The district comprises 69 single- and multi-family detached houses built between the 1920’s and 1950’s. Using archival sources and field studies we describe how the buildings have been modified and trace the role of the EBB on the district as a whole. The results show that despite that the EBB has had a major impact on the district, it is difficult to disentangle its role in relation to other factors. The study raises concerns over the common approach in policy making to draw distinct lines in the sand between heritage and non-heritage buildings.

Click here for the full verison, p. 193.

Abstract - This contribution will present a concept for (translucent) wall elements with switchable U- and g-values. The basic concept of the element consists of an insulation panel (preferably realized by a translucent and light-guiding foam grid or in the future by transparent vacuum glazing) which is arranged inside a glazed closed cavity so that thermally driven convection around the element can either be enabled or suppressed. Supression of convection is realized by a rollable second insulation inside the cavity which can reflect incident solar radiation: If the secondary insulation is fully retracted resulting in high U and g-value and daylight being guided inside the building. By successively rolling down the insulation, convection can be suppressed and the g-value can be varied from almost unchanged to almost zero. In the case of the secondary insulation being rolled fully down, the U-value of the element is also minimal. This state is favourable in a cold winter night or during hot daytime hours in summer. The high translucence, low-U-value case is favourable in conditions where solar gains and good insulation are favourable and the translucent high-U-value case is favourable for example in a summer night to cool the building (...).

Abstract - In this article it is presented an innovative façade system with a solar thermal system. The developed solar system can be classified as modular unglazed collector, designed for low temperature energy capture. It is compatible with a solar combined system that integrates a solar heat pump. The external appearance of the building remains untouched thanks to this innovative system. Experimental works at façade collector level are presented. The integration of the unglazed collector in a heat pump based combined solar system, its performance levels and economic figures are presented.

Abstract - Shading devices are effective in controlling glare and solar heat gains in buildings. However, this occurs at the expense of daylight and outside view. This paper evaluates the thermal and daylight performance of Lumiduct, a sun-controlling dynamic façade system that permits only diffuse radiation inside the building, while producing electricity. This imparts Lumiduct a unique characteristic of acting as a shading device while providing useful daylight and view to the outside. The first part of the paper briefly illustrates the working principle of Lumiduct and its functional characteristics and then, introduces the basic principles of the modelling and simulation strategy used to predict its performance. (...) The results show a significantly higher daylight utilization along with a reduction in glare and energy use for heating and cooling the building.

Abstract  - Im Rahmen des von 2014 bis 2017 laufenden Projektes „Vorgefertigte Fassadenelemente mit maximal integrierten HVAC-Komponenten und -systemen zur Bestandssanierung“ wurden neue Lösungsansätze für intelligente Bestandssanierung aufgezeigt bzw. entwickelt, wobei es unter anderem um die Synergieeffekte für die Modernisierung der Gebäudehülle und der Gebäudetechnik bei konsequenter Nutzung erneuerbarer Energieträger ging. Erklärtes Ziel dabei war die Erreichung eines hohen Vorfertigungsgrades in Verbindung mit Holz- Vorhangfassaden und damit kurze Sanierungszeiten mit geringsten Belastungen der Bewohner, reduzierte Abhängigkeiten von der Witterung im Sanierungsprozess sowie eine gesichert hohe Ausführungsqualität. Entsprechende Energieversorgungskonzepte stellen die auf die Fassade auftreffende Solarenergie effizient dem Gebäude zur Verfügung.

The objective of IEA SHC Task 54 is to reduce the purchase price of solar thermal systems by up to 40 % across the entire value chain. To achieve this, the project partners have been evaluating technical and non-technical cost-saving potential, with low-cost materials, such as polymers, and production technologies bound to play an important role. At an early October workshop in Linz, Austria, about 50 project partners and guests discussed cost reductions made possible by new distribution channels, digital solutions and systems thinking approaches.

Abstract - The switching time and spectral transmission in fully clear and fully opaque states of polymer dispersed liquid crystals (PDLC), suspended particle device (SPD) and electrochromic (EC) switchable windows were evaluated to assess their suitability to control solar heat transmission though glazed façade and comfort to building occupants. The transmission measurement on a SPD film showed a very effective absorption modulation in the visible range but fast decrease in the near infrared region. The switching speed was demonstrated to be related strongly to wavelengths. A SPD film with a larger absorption and faster switching speed in the infrared region was shown to be preferable to control solar heat transfer through glazings and thermal comfort. The PDLC window did not modulate transmission but rather modulated scattering. In the opaque state, the PDLC window was highly scattering resulting in spectral transmission varying at short distances from the window while being constant in the far field ... [read full Abstract and Paper]

Abstract - Present trends on solar thermal systems for building integration define the need of integrated solar technologies for façades. Although other possibilities exist for solar thermal systems in new buildings, solutions for a suitable integration of solar thermal systems into building retrofitting actuations are needed. This paper presents a solar thermal collector system which hybridizes already existing ventilated façade cladding systems into a low temperature solar thermal collector. Numerical and experimental data is presented. Access full paper on Research Gate

Abstract - Present trends on solar thermal systems for building integration define the need of integrated solar technologies for façades. The integration of solar systems in façades allows for the direct connection of solar systems to heated spaces, and automated air solar collectors based on the trombe-mitchell provide a suitable technology for its adoption in multi-rise buildings with decentralized-individual HVAC systems in Central-European and Mediterranean heating dominated climates. This paper reviews the main principles of such building envelope components, and the construction and design considerations of two air-based solar thermal collectors. Full scale preliminary prototypes of these systems were tested at the KUBIK by Tecnalia test facility in an Oceanic Climate (Koppen Geiger Cfb zone). The observed thermal performance is analyzed, and the process of a full scale installation in a real building envelope retrofitting process of a building in Spain is reviewed. Access full paper on Research Gate

Solar thermal collectors and their components are commonly exposed to a wide range of climatic influences. Next to UV radiation, factors like humidity, wind, extremely high or low temperatures, salt, sand and other particles in the atmosphere affect the surfaces and performance of these products. Although these influences are decisive factors for the lifetime and long-term efficiency of solar thermal collectors, there are no validated or binding test procedures for reliability assessment over time or models that allow a location-specific service life prediction.

Abstract - In the on-going Nordic Built Living in Light project, coordinated by Kuben Management, a new concept of urban renewal will be tested at Gl. Jernbanevej in Valby in Copenhagen. Here a 4 storey old housing block from around year 1900 will have new roof top apartments together with an approx. 2 m extension of the housing block towards the courtyard. The extension mainly consists of an innovative window structure from the Danish window company Velfac, and it increases the daylight quality of the apartments considerably without compromising comfort and energy use. At the same time building integrated PV solutions secures an overall CO2 neutral design for the renovation project.

Abstract - The objective of the EC-funded project iNSPiRe is to reduce the problem of high-energy consumption of existing buildings by producing systemic renovation packages that can be applied to residential and tertiary buildings. The renovation packages aim to reduce the 2 primary energy consumption of a building to lower than 50 kWh/(m a) for ventilation, heating/cooling, domestic hot water and lighting. These renovation packages need to be suitable for various climates in Europe while ensuring optimum comfort for the building users. One major goal of iNSPiRe is the development of multi-functional renovation kits that make use of innovative envelope technologies, energy generation systems (including RES integration) and energy distribution systems [...]

The IEA SHC Programme wrapped up its work on Solar Rating & Certification (Task 43) in 2015, and in 2016 started a new Task on Solar Standards and Certification (Task 57). To get a better understanding of the impact of Task 43, we asked Jan Erik Nielsen, the Operating Agent, a few questions.

Historic building heating and, in particular, church heating represents a challenging task because many objectives have to be reached simultaneously; in facts, adequate thermal comfort levels have to be guaranteed for the occupants while ensuring an optimal internal climate suitable for the preservation of valuable and often fragile building components and artworks. Moreover, current requirements for sustainability impose to make efforts, where possible, to minimize the amount of energy needed and the consequent environmental impact. For such reasons, the present work addresses in detail the church heating topic, by analysing different feasible strategies and developing subsequently an original technology, able to combine energy efficiency and cultural heritage preservation aspects.

For the utilization of polymeric materials in high-demanding applications like solar thermal systems it is of utmost importance to define the performance requirements and to investigate the applicability of components for defined systems under service relevant conditions. This paper deals with the lifetime estimation of black-pigmented polypropylene (PP) absorber grades for overheating protected solar thermal collector systems for hot water preparation in five representative climate zones. Based on experimental aging data in hot air and heat carrier fluid at elevated temperatures (95 °C, 115 °C and 135 °C) and climatic input data, as well as deduced loading conditions and absorber temperature distributions, the lifetime was calculated using a theoretical and an empirical extrapolation approach and assuming cumulating damages in service relevant temperature intervals. Depending on the PP grade, the extrapolation method and the location, endurance limits ranging from 8 to 50 years were obtained. The PP grade with ß-spherulithic structures and less carbon black exhibited a superior performance (factor 2) compared to a well-established grade which is currently widely used for swimming pool absorbers.

Driving down the costs of solar thermal systems is not just about cheaper collector production. In fact, post-production processes, such as sales, installation and maintenance account for up to 50% of the price that end consumers pay. This new IEA SHC Task, Price Reduction of Solar Thermal Systems, will investigate these other factors and find ways to reduce systems costs. The Task’s kick-off meeting was hosted by Fraunhofer ISE in Freiburg, Germany the end of October. Researchers and industry representatives from all over the world participated.

Starting from the end of 2020, all new buildings will have to be Nearly Zero Energy Buildings (Nearly ZEBs—ED 2010/31/EU recast). This new ‘energy paradigm’ might be a revolution for architecture and for Photovoltaics (PV) too, but there are both cultural and technical obstacles to overcome. There is a need to re-think the way buildings are designed (integrating renewables for being ZE). There is a need to re-think the way PV is designed in buildings. PV will be gaining an increasing relevance in the ZEBs design, thanks to its features and potentialities (suitability for any kind of energy demand of the building, easiness of building integration, cost). In a ZEB scenario, PV is very suitable for generating energy, ‘on site’ and ‘at site’; this enlarges the perspective of use of PV from the architectural scale to a wider scale, including the space close to the building or even to the urban and landscape scale. In such a new context, the existing research on the relationships between PV and architecture, focusing mainly on the way the PV components are used in relation to the envelope (Building-integrated PV/Building-added (Attached) PV), is no longer sufficient. The authors envision possible formal results, opportunities and challenges, for the use of PV in ZEBs, as well as new research issues for the future relationships between PV and ZEBs from the architecture and landscape design point of view. Copyright © 2012 John Wiley & Sons, Ltd.

Researchers have worked intensively for one-and-a-half years across national borders to find ways of reducing the costs of solar thermal systems and making them more attractive to end users. The members of Task 54 of the IEA Solar Heating and Cooling Programme, Price Reduction of Solar Thermal Systems, have discussed the effects of standardised product designs or changes in product offerings on cost structures. They have also analysed the entire value chain from component manufacture to system assembly and installation to help identify cost-cutting potential. This is the first time that methods of Process Cost Analysis are being adapted for the solar thermal business.

Il rispetto per gli edifici storici può portare a escludere a priori la possibilità di introdurvi nuove tecnologie per il risparmio energetico. Con l'intervento al Castello di Doragno, lo studio deltaZERO mirava a ripristinare «l’anima» dell'edificio dotandolo al contempo di tutte le tecnologie necessarie per garantire le odierne esigenze di comfort.