Increasing cooling demands in the built environment call for innovative technical solutions and systems for application in buildings. Cooling loads represent an important share of the total energy consumption in warm climates, especially in commercial and office buildings. Moreover, mechanical systems will still be needed in most cases to cope with cooling loads, even after considering passive cooling strategies in the design of the building and its façade. Solar cooling technologies present interesting assets, being based on environmentally friendly cooling processes, driven by solar and thus renewable energy. However, their application in the built environment remains greatly limited. This paper assesses several solar cooling technologies in terms of their potential for façade integration; aiming to promote widespread application in buildings throughout the development of integrated architectural façade products. The assessment is based on a state-of-the-art review and discussion of key attributes for façade integration of selected technologies; and a qualitative evaluation of their suitability to respond to main product related barriers for the integration of building services identified in an earlier work by the authors. The cooling principles behind the operation of the assessed technologies have been extensively presented in the literature, so this paper focuses exclusively on key aspects to overcome barriers related to the technical feasibility, physical integration, durability, performance, and aesthetics of future integrated concepts. Results show that the suitability of the assessed technologies varies according to each particular barrier. Hence, no technology currently fits all required aspects. Nonetheless, the use of thermoelectric modules and compact units based on absorption technologies are regarded as the most promising for the development of either integral building components, or modular plug & play systems for façade integration. In any case, this is heavily conditioned to further efforts and explorations in the field to overcome identified challenges and knowledge gaps.@en

Although the interrelations between urban microclimates and energy demand have been acknowledged, few workflows integrate microclimatic boundary conditions to predict energy demand in parametric morphological studies. This paper helps bridge this gap by introducing a novel workflow which brings together energy and microclimatic modelling for a synergetic assessment at the block scale. The interrelation between form, energy and urban microclimatic conditions is explored here in the climatic context of Tel Aviv by coupling Envimet and EnergyPlus. The potential of this coupling is explored in three different block typologies, each tested for four different density scenarios focusing on the cooling demand on a typical hot day. Results show the substantial increase of as high as 50% in cooling demand when the microclimatic weather data is taken into account and indicate the potential to capitalize on new computational tools which allow to quantify the interrelations between urban form, microclimate and energy performance more accurately.

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Cooling demands of commercial buildings present a relevant challenge for a sustainable future. They account for over half of the overall energy needs for the operation of an average office building in warm climates, and this situation is expected to become more pressing due to increasing temperatures in cities worldwide. To tackle this issue, it is widely agreed that the application of passive strategies should be the first step in the design of energy efficient buildings, only using active equipment if it is truly necessary. Nonetheless, there is still further need for information regarding the potential limits derived from their application.
This paper explores the effectiveness of selected passive cooling strategies in commercial buildings from warm climates, defining performance ranges based on the assessment of multiple scenarios and climate contexts. This task was conducted through the statistical analysis of results from documented research experiences, to define overall ranges and boundary conditions; and through software simulation of selected parameters to isolate their impact under a controlled experimental setup. General findings showed that the mere application of passive strategies is not enough to guarantee relevant savings. Their effectiveness was conditioned to both the harshness of a given climate and different building parameters. Specific recommendations were also discussed for the selected passive strategies considered in the evaluation.@en

Small-scale systems and integrated concepts are currently being explored to promote the widespread application of solar cooling technologies in buildings. This article seeks to expand application possibilities by exploring the feasibility of solar cooling integrated façades, as decentralized self-sufficient cooling modules on different warm regions. The climate feasibility of solar electric and solar thermal concepts is evaluated based on solar availability and local cooling demands to be met by current technical possibilities. Numerical calculations are employed for the evaluation, considering statistical climate data; cooling demands per orientation from several simulated scenarios; and state-of-the-art efficiency values of solar cooling technologies, from the specialized literature. The main results show that, in general, warm-dry climates and east/west orientations are better suited for solar cooling façade applications, compared to humid regions and north/south orientations. Results from the base scenario show promising potential for solar thermal technologies, reaching a theoretical solar fraction of 100% in several cases. Application possibilities expand when higher solar array area and lower tilt angle on panels are considered, but these imply aesthetical and constructional constraints for façade design. Finally, recommendations are drafted considering prospects for the exploration of suitable technologies for each location, and façade design considerations for the optimization of the solar input per orientation.@en

Cooling demands in buildings have drastically increased in recent decades and this trend is set to continue into the near future, due to increasing standards of living and global climate change, among the most relevant factors. Besides energy consumption, the use of refrigerants in common vapour compression cooling technologies is a source of concern because of their environmental impact. Hence, there is a need to decrease cooling demands in buildings while looking for alternative clean technologies to take over the remaining loads. Solar cooling systems have gained increased attention in recent years, for their potential to lower indoor temperatures using renewable energy under environmentally friendly cooling processes. Nonetheless, their potential for building integration has not been fully explored, with the exception of scattered prototypes and concepts. This paper aims to address these knowledge gaps by presenting the results of the PhD research project ‘COOLFAÇADE: Architectural integration of solar cooling technologies in the building envelope’. The research project explored the possibilities and constraints for architectural integration of solar cooling strategies in façades, in order to support the design of climate responsive architectural products for office buildings, driven by renewable energy sources. This paper explores different aspects related to façade integration and solar cooling technologies, in order to provide a comprehensive understanding of current possibilities for façade integration, while drafting recommendations based on identified barriers and bottlenecks at different levels.@en

The integration of decentralised building services into façade components presents advantages from functional and constructional standpoints. However, this integrated approach has not been massively implemented, having only stand-alone buildings and façade concepts as examples. This paper seeks to identify the main perceived problems at design, production and assembly stages of the facade development process, to generate new knowledge based on practical experience; and to discuss the perceived barriers to overcome in order to promote widespread building service integration in façade systems. The employed method was an exploratory survey addressed to professionals with practical experience in the development of façade systems for office buildings, situated at any stage of the process. The survey was conducted from mid-September to mid-November 2015 and was distributed both as an online form and in printed format among several professional and research networks related with façade design and construction. After the campaign, 133 questionnaires were received, comprising a final number of 79 valid questionnaires. Results show that the main problems of the overall process are related to coordination issues among different disciplines and stakeholders, while other problems such as costs and lack of knowledge have more impact on particular stages within the design and construction process.

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Solar cooling systems have gained increased attention these last years, for its potential to lower indoor temperatures using renewable energy. However, architectural integration of these systems in buildings has not been fully explored. Current developments such as small scale solar driven heat pumps and solar cooling kits commercially available for application raise questions about how to successfully integrate these systems into buildings, while present interesting opportunities for the development of new performance based façade components or even self-sustaining cooling façade modules for high-performing commercial buildings.

The present paper seeks to discuss current possibilities for façade integration of solar cooling systems, generating a framework for the understanding and further development of solar cooling façade systems. The proposed framework was made by means of a review of solar cooling technologies and solar cooling façade concepts found in the literature. The outcomes of this study are a matrix outlining the possibilities for the integration of several components and subsystems from the entire cooling process (cooling generation, distribution and delivery), and an assessment of the development level of state-of-the-art experiences within the field considering examples from current research projects and working prototypes, for the development of solar cooling integrated façade concepts.@en

Solar energy has been actively promoted as a clean energy source since 1973’s oil crisis, evidenced by the emergence of initiatives such as the Solar Heating & Cooling Programme of the International Energy Agency or the US Department of Energy. Nonetheless, solar technologies have not been widely used in the built environment, limiting their operation to industrial and macroscale applications. Commercially available products such as building integrated PV panels (BIPV) or building integrated solar thermal collectors (BIST); and novel prototypes and concepts for solar cooling integrated facades are seen as interesting alternatives for the development of new performance based façade components for high-performing commercial buildings. However, there are barriers to overcome in order to promote widespread application of architecturally integrated solar components. The present paper seeks to discuss perceived barriers for widespread façade integration of solar technologies, in order to define the current scenario and generate guidelines for future developments. In order to achieve this, the paper presents the results of a survey addressed to professionals with practical experience in the development of façade systems for office buildings, situated at any stage of the design and construction process. Hence, architects, façade consultants, system suppliers and façade builders were considered. The outcome of this study is the definition of the main perceived barriers for façade integration of solar technologies, discussing the results from the survey along with other related experiences found in the literature.This study is part of the ongoing PhD research project titled COOLFACADE: Architectural integration of solar cooling strategies into the curtain-wall, developed within the Façade Research Group (FRG) in the Green Building Innovation programme (GBI) of the Faculty of Architecture and the Built Environment, TU Delft.@en

Solar cooling systems have increasingly been a subject of attention during the past couple of decades, for its potential to lower indoor temperatures using solar (and thus renewable) energy. Several initiatives supported by private developers and public organisations such as the Solar Heating & Cooling Programme of the IEA, have been promoting the use of these technologies by showing their advantages while increasing the efficiency of the systems to allow for massive commercial application. Nonetheless, architectural integration of solar cooling systems into the building envelope has not been the focus, except for experiences related with the integration of certain components such as solar thermal collectors or PV panels into façade elements. Current developments such as small scale solar driven heat pumps and solar cooling kits commercially available for application raise questions about how to successfully integrate these systems into buildings while at the same time they present interesting opportunities for the development of new performance based façade components or even self-sustaining cooling façade modules for high-performing commercial buildings. The present paper seeks to discuss current possibilities for façade integration of solar cooling systems, generating a framework to promote further developments. This framework is made by means of a review of solar cooling technologies and an early assessment of their potential for façade integration, considering the necessary components to be integrated according to each particular technology. The outcome of this study is a matrix outlining the possibilities for the integration of several components and subsystems from the entire cooling process (cooling generation, distribution and delivery), considering examples from current research projects and working prototypes for the development of solar cooling integrated façade concepts. This study is part of the ongoing PhD research project titled COOLFACADE: Architectural integration of solar cooling strategies into the curtain-wall, developed within the Façade Research Group (FRG) in the Green Building Innovation programme (GBI) of the Faculty of Architecture and the Built Environment, TU Delft.@en