Evaluating the performance of passive chilled beams with respect to energy efficiency and thermal comfort

Existing modeling approaches for passive chilled beams determined from tests on individual chilled beams in a laboratory are not adequate for assessing overall energy usage and occupant comfort within building simulation programs. In addition, design guidelines for passive chilled beam systems are needed for identifying appropriate applications and optimal configurations. This thesis includes (i) extensive experimental studies for characterizing the performance of passive chilled beams, in both laboratory settings and in field studies, (ii) development of passive chilled beam performance prediction models, (iii) integration of these models into building simulation models/tools and (iv) use of building simulation for overall assessment of different passive chilled beam system configurations in different climates in order to provide guidelines for appropriate applications. Experiments were conducted with a single passive chilled beam in a laboratory setting and with multiple passive chilled beams installed in a real occupied office space. Based on the experimental results, models that can predict total cooling capacity and chilled surface temperature of passive chilled beams were developed. These models use essential operating conditions of the system and thermal conditions in the environment as inputs and are able to predict the energy and thermal comfort performances of the passive chilled beam system when integrated into a system simulation. The validity of using a model developed from laboratory tests on a single passive chilled beam in a system simulation for spaces with multiple chilled beams was evaluated. Comparison of laboratory and field measurements indicates that the conventional method of predicting total cooling capacity of a passive chilled beam from laboratory measurements underestimates its performance when installed in a system. These differences could have an important impact on system sizing and commissioning. Side-by-side field measurements were conducted to compare energy and comfort performance of a passive chilled beam system against constant and variable air volume systems for nearly identical office spaces. While maintaining very similar thermal comfort levels in the two offices, the passive chilled beam system led to a 57% reduction in electric energy compared to the constant air volume system. However, the variable air volume (VAV) system consumed 21% less energy compared to the passive chilled beam system during the field measurements. This is mostly because of the current configuration of the passive chilled beam system which represents the worst case scenario in terms of system configuration. The parallel air system used in the field measurement is a typical air system including the outdoor air and return air damper system. As a starting point followed by various configurations assessment with computer simulations, the return air damper was closed during the entire field measurements of the passive chilled beam system. In order to consider more realistic energy savings compared to VAV systems, alternative passive chilled beam configurations were evaluated using a system simulation model that was validated with the available measurements. The integrated simulation tool was developed and validated for the case study office space and was then used to perform comprehensive comparisons of alternative passive chilled beam and conventional systems in order to evaluate savings potential in various climatic zones. While maintaining the same thermal environments in spaces, the best passive chilled beam configuration provided electrical energy savings up to 24% for hot and humid climates and up to 35% savings for hot and dry climates compared to a variable air volume system. The radiation cooling effects of passive chilled beams were also analyzed through experiments and simulations. Both experiments and computer simulations revealed that the effect of the radiation cooling of passive chilled beams is not significant in terms of energy savings and thermal comfort improvement. Based on simulation results covering various passive chilled beam system configurations and climatic zones, the percentage of radiation cooling energy relative to total passive chilled beam cooling energy varied between 7 to 15

Indoor Humidity Analysis of an Integrated Radiant Cooling and Desiccant Ventilation System

Radiant cooling is credited with improving energy efficiency and enhancing the comfort level as an alternative method of space cooling in mild and dry climates, according to recent research. Since radiant cooling panels lack the capability to remove latent heat, they normally are used in conjunction with an independent ventilation system, which is capable of decoupling the space sensible and latent loads. Condensation concerns limit the application of radiant cooling. This paper studies the dehumidification processes of solid desiccant systems and investigates the factors that affect the humidity levels of a radiantly cooled space. Hourly indoor humidity is simulated at eight different operating conditions in a radiantly cooled test-bed office. The simulation results show that infiltration and ventilation flow rates are the main factors affecting indoor humidity level and energy consumption in a radiantly cooled space with relatively constant occupancy. It is found that condensation is hard to control in a leaky office operated with the required ventilation rate. Slightly pressurizing the space is recommended for radiant cooling. The energy consumption simulation shows that a passive desiccant wheel can recover about 50% of the ventilation load

Building Performance Simulation and Characterisation of Adaptive Facades:

The book “Performance Simulation and Characterisation of Adaptive Facades” responds to the need of providing a general framework, standardised and recognised methods and tools to evaluate the performance of adaptive facades in a quantitative way, by means of numerical and experimental methods, in different domains of interest. This book represents the main outcome of the activities of the Working Group 2 of the COST Action TU1403 Adaptive Façades Network, “Components performance and characterisation methods”, by integrating in one publication the main deliverables of WG2 described in the Memorandum of Understanding: D 2.1. Report on current adaptive facades modelling techniques; D 2.4. Report on the validation of developed simulation tools and models; D 2.5. Report on the developed experimental procedures. These are extended by additional sections regarding structural aspects and key performance indicators for adaptive façade systems. This book is a comprehensive review of different areas of research on adaptive façade systems and provides both general and specific knowledge about numerical and experimental research methods in this field. The fast pace at which building technologies and materials develop, is slowly but constantly followed by the development of numerical and experimental methods and tools to quantify their performance. Therefore this book focuses primarily on general methods and requirements, in an attempt to provide a coherent picture of current and near future possibilities to simulate and characterise the performance of adaptive facades in different domains, which could remain relevant in the coming years. In addition, specific know-how on selected cases is also presented, as a way to clarify and apply the more general approaches and methods described. The present book is published to support practitioners, researchers and students who are interested in designing, researching, and integrating adaptive façade systems in buildings. It targets both the academic and the not-academic sectors, and intends to contribute positively to an increased market penetration of adaptive façade systems, components and materials, aimed at rationalising energy and material resources while achieving a high standard of indoor environmental quality, health and safety in the built environment

Case Studies:

Adaptive building envelopes can provide improvements in building energy efficiency and economics, through their capability to change their behaviour in real time according to indooroutdoor parameters. This may be by means of materials, components or systems. As such, adaptive façades can make a significant and viable contribution to meeting the EU´s 2020 targets. Several different adaptive façade concepts have already been developed, and an increase in emerging, innovative solutions is expected in the near future. In this context the EU initiative COST Action TU 1403 aims to harmonize, share and disseminate technological knowledge on adaptive facades at a European level. According to the definition given by this COST Action, an adaptive façade is a building envelope consisting of multifunctional and highly adaptive systems that is able to change its functions, features, or behaviour over time in response to transient performance requirements and boundary conditions, with the aim of improving the overall building performance. In order to explore the available and emerging technologies focusing on adaptive façades, Working Group 1 of the COST Action undertook research to form a database of adaptive façade case studies and projects structured in accordance with a simple classification – materials, components and systems. In addition to this, details of the purpose of the systems/components/materials with adaptive features and the working principle of each technology were also collected together with data regarding design practice, technology readiness, and economical aspects, among others. The information was collected with the help of a specific online survey (structured in the following main sections: detailed description - metrics- characterization- economic aspects – references). The database includes 165 cases of adaptive façade systems, components, and materials that allowed a variety of analyses to be carried out. According to the classification adopted within WG1 (materials, components, systems), each of the classification terms are introduced together with examples from the case study database in the following sections. This volume ends with a section dedicated to future developments, where different issues are addressed such as embedded functionality and efficiency amd biomimetic inspirations. The importance of adaptive façades through their flexibility, and intelligent design within the context of smart cities is also discussed. The work within Working Group 1 - Adaptive technologies and products was developed within four distinct sub-groups (SG) in order to provide outputs according to the objectives of this WG and the COST Action: SG1 – Database, SG2 – Educational Pack, SG3 – Publications and Reports and SG4 – Short Term Scientific Missions (STSM). This work was possible due to the strong commitment and work of all WG1 members: Laura Aelenei, Aleksandra Krstić-Furundžić, Daniel Aelenei, Marcin Brzezicki, Tillmann Klein, Jose Miguel Rico-Martínez, Theoni Karlessi, Christophe Menezo, Susanne Gosztonyi, Nikolaus Nestle, Jerry Eriksson, Mark Alston, Rosa Romano, Maria da Glória Gomes, Enrico Sergio Mazzucchelli, Sandra Persiani, Claudio Aresta, Nitisha Vedula, Miren Juaristi

Building Performance Simulation and Characterisation of Adaptive Facades

The book “Performance Simulation and Characterisation of Adaptive Facades” responds to the need of providing a general framework, standardised and recognised methods and tools to evaluate the performance of adaptive facades in a quantitative way, by means of numerical and experimental methods, in different domains of interest. This book represents the main outcome of the activities of the Working Group 2 of the COST Action TU1403 Adaptive Façades Network, “Components performance and characterisation methods”, by integrating in one publication the main deliverables of WG2 described in the Memorandum of Understanding: D 2.1. Report on current adaptive facades modelling techniques; D 2.4. Report on the validation of developed simulation tools and models; D 2.5. Report on the developed experimental procedures. These are extended by additional sections regarding structural aspects and key performance indicators for adaptive façade systems. This book is a comprehensive review of different areas of research on adaptive façade systems and provides both general and specific knowledge about numerical and experimental research methods in this field. The fast pace at which building technologies and materials develop, is slowly but constantly followed by the development of numerical and experimental methods and tools to quantify their performance. Therefore this book focuses primarily on general methods and requirements, in an attempt to provide a coherent picture of current and near future possibilities to simulate and characterise the performance of adaptive facades in different domains, which could remain relevant in the coming years. In addition, specific know-how on selected cases is also presented, as a way to clarify and apply the more general approaches and methods described. The present book is published to support practitioners, researchers and students who are interested in designing, researching, and integrating adaptive façade systems in buildings. It targets both the academic and the not-academic sectors, and intends to contribute positively to an increased market penetration of adaptive façade systems, components and materials, aimed at rationalising energy and material resources while achieving a high standard of indoor environmental quality, health and safety in the built environment

Photovoltaic-Thermal (PV-T) systems for combined cooling, heating and power in buildings: a review

Heating and cooling (H/C) represent the largest share of energy consumption worldwide. Buildings are the main consumers of H/C, while the share of renewable energy for H/C provision still represents a low percentage, 22.0% in 2019. Hybrid photovoltaic-thermal (PV-T) systems are gaining increasing attention both in research and in applications, as they generate both electricity and useful heat simultaneously. The relevance and potential of PV-T collectors and their integration into wider systems are evident, but there is still a lack of review articles that address the potential of these systems in building applications in a comprehensive way. This work aims to review the state-of-the-art of PV-T collectors for building applications, as well as the corresponding PV-T systems for solar combined cooling, heating and power (S-CCHP) provision. The novelties of this work involve the comparison of these systems with conventional solar H/C technologies, the review of the market of H/C technologies, a summary of the challenges for the wider integration of S-CCHP systems and proposal lines of work to improve the cost-competitiveness of these systems. The first section summarises the focus and findings of previous reviews, followed by an overview of the current development status of the main types of PV-T collectors. Then, PV-T-based S-CCHP systems are reviewed, and the potential of PV-T systems’ penetration in the built environment is evaluated and discussedPostprint (published version

hybridGEOTABS project : MPC for controlling the power of the ground by integration

GEOTABS is an acronym for a GEOthermal heat pump combined with a Thermally Activated Building System (TABS). GEOTABS combines the use of geothermal energy, which is an almost limitless and ubiquitous energy source, with radiant heating and cooling systems, which can provide very comfortable conditioning of the indoor space. GEOTABShybrid refers to the integration of GEOTABS with secondary heating and cooling systems and other renewable and residual energy sources (R2ES), offering a huge potential to meet heating and cooling needs in office buildings, elderly care homes, schools and multi-family buildings throughout Europe in a sustainable way. Through the use of Model Predictive Control (MPC), a new control-integrated building design procedure and a readily applicable commercial system solution in GEOTABShybrid, the overall efficiency of heating and cooling will be significantly improved in comparison to current best practice GEOTABS systems and its competitiveness will be strengthened. The present paper is the first of a series that first introduces the hybridGEOTABS project and then specifically focuses on the control-related aspects of the hybridGEOTABS solution, the MPC, providing some interesting insights of its potential development