Designing the Malqaf for summer cooling in low-rise housing an experimental study

peer reviewedThe malqaf or windcatcher is Egyptian vernacular archetypal device that traps the wind into the building. For centuries, the malqaf has been used as a viable solution to ensure natural ventilation. However, for the last 50 years, Egyptian practice has failed in combining traditional architectural devices into new techniques that could lead to sustainable and energy aware buildings. In Egypt, more than half of the urban peak load of energy consumption in the mean time is used to satisfy air conditioning demands alone. Therefore, the objective of the research is to develop a viable passive alternative to active cooling by exploring the potentials and design parameters of windcatchers as solution for passive cooling and natural ventilation during the summer season for low-rise housing. Experimental wind tunnel and smoke visualisation testing were conducted to compare the air flow in a scale model room with and without windcatcher on top of the roof with different orientations. The final result shows that the performance of the windcatcher depends greatly on the position, orientation and size of the inlet and outlet opening in relation to the wall ratio. The study developed a comparative matrix for examined parameters to support architects with the basic principles for windcatchers design

Comportamiento termico de edificios de departamentos en Santiago de Chile: segmentación de nichos en el mercado inmobiliario privado a partir de las exigencias de la reglamentación térmica nacional

Santiago, capital de la República de Chile, se sitúa en el valle central del país en los 33º 27’ de latitud sur y 70º 42’ de longitud oeste, presentando un clima templado cálido con una estación seca prolongada de 7 a 8 meses de duración. La temperatura media anual es de 12,2°C y la oscilación térmica es considerable: hay casi 13°C de diferencia en la temperatura media entre el mes más cálido (enero) y el más frío (julio) y la diferencia entre las medias de las temperaturas máximas y mínimas para todos los meses del año fluctúan entre 10 y 16°C. De acuerdo a datos del Instituto Nacional de Estadísticas de Chile (INE), el 37,4% de los permisos de edificación de viviendas nuevas del 2006, declara que el ladrillo es su material predominante de muros, mientras que otro 36,0% está asociado con el hormigón armado. Dada la generalmente nula presencia de aislación térmica en estos sistemas constructivos y su alta inercia térmica de absorción, se podría esperar para Santiago un comportamiento térmico - en términos de confort - más bien desfavorable en invierno y favorable en verano. Sin embargo, estudios recientes presentan un escenario opuesto, dado que un gran porcentaje de usuarios encuestados acusa un alto nivel de sobrecalentamiento en sus viviendas. Esta aparente contradicción podría entenderse desde las limitaciones propias de esta base datos del INE del año 2006, puesto que por ejemplo, no refleja el impacto de la implementación de la 2° etapa de la Reglamentación Térmica nacional. Esta regulación, en vigencia desde enero de 2007, establece valores máximos de transmitancia térmica admisible para los diversos elementos de la envolvente de una vivienda. A partir del valor exigido en muros en Santiago (1,9 W/m2K), los nuevos edificios de departamentos han tenido que necesariamente incorporar al menos 10 mm de aislante térmico en su envolvente vertical, modificando su comportamiento térmico tanto en invierno como en verano.Este artículo propone la simulación del desempeño energético y condiciones de confort térmico para invierno y verano, de edificios de departamentos en Santiago para estratos socioeconómicos medios y medios altos, con el objetivo de establecer los impactos de las soluciones constructivas adoptadas en estos. Estas simulaciones numéricas se realizarán sobre tipologías de productos de vivienda ofertadas en el mercado privado durante el periodo 2006-2007, incorporando su materialidad y los datos de mercado, precios y atributos inmobiliarios, según datos de oferta del Portalinmobiliario.com. Estas tipologías de vivienda se traducirán en nichos, los cuales serán determinados a partir de la generación de grupos homogéneos de viviendas mediante a la técnica de generación de conglomerados, sobre las variables de cada producto inmobiliario. Estos grupos de viviendas se encontrarán en los mismos sub mercados inmobiliarios, evaluándose diferentes combinaciones de atributos asociados a las materialidades. Las simulaciones numéricas del comportamiento térmico en invierno y en verano, se realizan mediante el software de evaluación de desempeño energético TAS, mediante un sistema dinámico que calcula las condiciones de las viviendas en régimen horario, evaluando las condiciones de confort térmico. Se espera probar que las soluciones técnico-arquitectónicas actuales, y su interpretación de la Reglamentación Térmica vigente, generan desfavorables condiciones de confort independiente del nicho de mercado donde estén compitiendo. Estas conclusiones permitirán establecer desafíos y oportunidades para el mercado inmobiliario privado, tanto en términos de tecnología de la construcción, como en el diseño arquitectónico, permitiendo el desarrollo de nuevas propuestas para integrar las exigencias de la Reglamentación Térmica nacional a la realidad del mercado de vivienda privada.Santiago de Chile (33°27’S and 70°42’W), capital city of the country, is placed in the central valley. It has a Mediterranean climate with a long dry season (between 7 and 8 months). Its annual average temperature is 12,2°C, whereas the thermal oscillation is considerable: there is almost 13°C between January and July average temperatures (hottest and coldest months, respectively) and the difference between maximum and minimum temperatures ranges between 10°C and 16°C during all the year. According to the National Statistics Institute, 37.4% and 36.0% of new housing during 2006 were built using mainly brick masonry and concrete in their walls, respectively. In both cases, thermal insulation was not generally considered. On the contrary for the heating period, a favorable thermal performance in summer should be expected (low thermal insulation in combination to high thermal mass). However, some recent studies show the completely opposite scenario, since an important percentage of users declare overheating in their own dwellings. This apparent contradiction could be understood from a database limitation, due to these official data do not reflect the impact of the current thermal regulation, which is in force since January 2007. Notwithstanding the required standards are weak in comparison to the international state-of-art (e.g. 1,9 W/m2K as maximum U-value for walls in Santiago), nowadays apartment buildings in Santiago are including at least 20 mm of thermal insulation in their walls to give compliance to the code. This paper proposes a series of dynamic thermal simulations to apartment buildings in Santiago, with the aim of establish the impact of different constructive solutions by means of thermal behavior, both in winter and summer. These digital models are statistically based on the typologies offered in the private real estate market during both periods 2001-2002 and 2006-2007, according to a database from Portalinmobiliario.com. These were determined using a multivariate analysis of their attributes – producing homogeneous market niches - through the hierarchical clustering technique. These homogeneous niches were identified in the real estate private submarkets, assessing different attributes. Thermal simulations were made using the TAS software, a dynamic-state digital tool. According to the results, the implementation of the thermal regulation – intended mainly to reduce heating consumption – have produced unfavorable comfort conditions in all the studied market niches, in comparison with the business as usual scenario. These conclusions allow establishing challenges and opportunities for the private real estate market, in order to integrate new thermal regulations with the private market reality.Peer Reviewe

Impact of the current Thermal Regulation in the private real estate market in Santiago de Chile

Presentació en Power-PointPeer ReviewedPostprint (published version

SUSTAINABLE RETROFITTING OF DWELLINGS IN BRUSSELS CAPITAL REGION: FIVE SCENARIOS OF EVOLUTION USING A MULTI-SCALE AND -CRITERIA PRE-ASSESSMENT TOOL

peer reviewedIn the next decades, most of the energy consumption of the building sector in Europe will be due to the buildings that exist today. The present paper presents the first results obtained by a web-based tool developed to enable a clear visualisation of existing dwelling stock in Brussels Capital Region and to help major stakeholders and public institutions of the region to define their strategies to retrofit the dwellings built before 1945. The tool is structured with six different scales and the characterisation of building stock is based on a set of criteria focused on three main topics: energy, environment and heritage value. Existing dwellings are grouped in seven different types and each type can be retrofitted in a specific manner (envelope, systems and number of dwellings per building). This paper presents and compares five scenarios of evolution of the dwelling stock. This tool can only be used to analyse Brussels Capital Region for the moment, but the methodology can be applied to other regions in the world. Enlarging the scope of this tool will help to meet the environmental, social and economic challenges of the contemporary world and to foster the transition of building sector towards a sustainable development

Comportamiento termico de edificios de departamentos en Santiago de Chile: segmentación de nichos en el mercado inmobiliario privado a partir de las exigencias de la reglamentación térmica nacional

Santiago, capital de la República de Chile, se sitúa en el valle central del país en los 33º 27’ de latitud sur y 70º 42’ de longitud oeste, presentando un clima templado cálido con una estación seca prolongada de 7 a 8 meses de duración. La temperatura media anual es de 12,2°C y la oscilación térmica es considerable: hay casi 13°C de diferencia en la temperatura media entre el mes más cálido (enero) y el más frío (julio) y la diferencia entre las medias de las temperaturas máximas y mínimas para todos los meses del año fluctúan entre 10 y 16°C. De acuerdo a datos del Instituto Nacional de Estadísticas de Chile (INE), el 37,4% de los permisos de edificación de viviendas nuevas del 2006, declara que el ladrillo es su material predominante de muros, mientras que otro 36,0% está asociado con el hormigón armado. Dada la generalmente nula presencia de aislación térmica en estos sistemas constructivos y su alta inercia térmica de absorción, se podría esperar para Santiago un comportamiento térmico - en términos de confort - más bien desfavorable en invierno y favorable en verano. Sin embargo, estudios recientes presentan un escenario opuesto, dado que un gran porcentaje de usuarios encuestados acusa un alto nivel de sobrecalentamiento en sus viviendas. Esta aparente contradicción podría entenderse desde las limitaciones propias de esta base datos del INE del año 2006, puesto que por ejemplo, no refleja el impacto de la implementación de la 2° etapa de la Reglamentación Térmica nacional. Esta regulación, en vigencia desde enero de 2007, establece valores máximos de transmitancia térmica admisible para los diversos elementos de la envolvente de una vivienda. A partir del valor exigido en muros en Santiago (1,9 W/m2K), los nuevos edificios de departamentos han tenido que necesariamente incorporar al menos 10 mm de aislante térmico en su envolvente vertical, modificando su comportamiento térmico tanto en invierno como en verano.Este artículo propone la simulación del desempeño energético y condiciones de confort térmico para invierno y verano, de edificios de departamentos en Santiago para estratos socioeconómicos medios y medios altos, con el objetivo de establecer los impactos de las soluciones constructivas adoptadas en estos. Estas simulaciones numéricas se realizarán sobre tipologías de productos de vivienda ofertadas en el mercado privado durante el periodo 2006-2007, incorporando su materialidad y los datos de mercado, precios y atributos inmobiliarios, según datos de oferta del Portalinmobiliario.com. Estas tipologías de vivienda se traducirán en nichos, los cuales serán determinados a partir de la generación de grupos homogéneos de viviendas mediante a la técnica de generación de conglomerados, sobre las variables de cada producto inmobiliario. Estos grupos de viviendas se encontrarán en los mismos sub mercados inmobiliarios, evaluándose diferentes combinaciones de atributos asociados a las materialidades. Las simulaciones numéricas del comportamiento térmico en invierno y en verano, se realizan mediante el software de evaluación de desempeño energético TAS, mediante un sistema dinámico que calcula las condiciones de las viviendas en régimen horario, evaluando las condiciones de confort térmico. Se espera probar que las soluciones técnico-arquitectónicas actuales, y su interpretación de la Reglamentación Térmica vigente, generan desfavorables condiciones de confort independiente del nicho de mercado donde estén compitiendo. Estas conclusiones permitirán establecer desafíos y oportunidades para el mercado inmobiliario privado, tanto en términos de tecnología de la construcción, como en el diseño arquitectónico, permitiendo el desarrollo de nuevas propuestas para integrar las exigencias de la Reglamentación Térmica nacional a la realidad del mercado de vivienda privada.Santiago de Chile (33°27’S and 70°42’W), capital city of the country, is placed in the central valley. It has a Mediterranean climate with a long dry season (between 7 and 8 months). Its annual average temperature is 12,2°C, whereas the thermal oscillation is considerable: there is almost 13°C between January and July average temperatures (hottest and coldest months, respectively) and the difference between maximum and minimum temperatures ranges between 10°C and 16°C during all the year. According to the National Statistics Institute, 37.4% and 36.0% of new housing during 2006 were built using mainly brick masonry and concrete in their walls, respectively. In both cases, thermal insulation was not generally considered. On the contrary for the heating period, a favorable thermal performance in summer should be expected (low thermal insulation in combination to high thermal mass). However, some recent studies show the completely opposite scenario, since an important percentage of users declare overheating in their own dwellings. This apparent contradiction could be understood from a database limitation, due to these official data do not reflect the impact of the current thermal regulation, which is in force since January 2007. Notwithstanding the required standards are weak in comparison to the international state-of-art (e.g. 1,9 W/m2K as maximum U-value for walls in Santiago), nowadays apartment buildings in Santiago are including at least 20 mm of thermal insulation in their walls to give compliance to the code. This paper proposes a series of dynamic thermal simulations to apartment buildings in Santiago, with the aim of establish the impact of different constructive solutions by means of thermal behavior, both in winter and summer. These digital models are statistically based on the typologies offered in the private real estate market during both periods 2001-2002 and 2006-2007, according to a database from Portalinmobiliario.com. These were determined using a multivariate analysis of their attributes – producing homogeneous market niches - through the hierarchical clustering technique. These homogeneous niches were identified in the real estate private submarkets, assessing different attributes. Thermal simulations were made using the TAS software, a dynamic-state digital tool. According to the results, the implementation of the thermal regulation – intended mainly to reduce heating consumption – have produced unfavorable comfort conditions in all the studied market niches, in comparison with the business as usual scenario. These conclusions allow establishing challenges and opportunities for the private real estate market, in order to integrate new thermal regulations with the private market reality.Peer Reviewe

Comportamiento termico de edificios de departamentos en Santiago de Chile: segmentación de michos en el mercado inmobiliario privado a partir de las exigencias de la reglamentación térmica nacional

Postprint (published version

Impact and potential of community scale low-energy retrofit: case study in Cairo

peer reviewedThere are extraordinary opportunities to reduce the consumption of fossil energy as a result of retrofitting the existing buildings in Egypt. For instance, Cairo falls in the arid climate zone with an annual total radiation above 2409 bankable kWh/m2 per annum with approximately 3300 hours of full sunshine. However, the poorly insulated fabric of most buildings shows relatively high demand for cooling and heating energy. To overcome this problem and to examine these opportunities, this study evaluates the retrofit of a middle-income urban residential case in Cairo. The aim of the study is to investigate the potential and impact of retrofits on two different scales. The first is on the building scale, intending to reach a low-energy performance. The second is on a community scale, intending to increase the dependence on renewable sources. The case study employed TRNSYS to evaluate the performance and energy/carbon emissions savings. The research took in consideration passive and active design strategies such as envelope retrofit, internal loads reduction, and natural ventilation; in addition to domestic water heating, photovoltaic panels and solar thermal air conditioning. The results were evaluated to assess the suitability of each strategy based on energy performance. The final result of this study shows the feasibility of improving the envelope performance and installing solar hot water collectors and solar thermal air conditioning. The low-energy retrofit for old residential buildings leads to significant savings in energy consumption when applied on community scale rather than building scale. However, it is urgent to set energy conservation and code-enforced retrofit measures to start a national retrofit process

Qualitative and quantitative criteria for comfortable urban public spaces

peer reviewe

Defining Zero Energy Buildings from a Cradle to Cradle Approach

peer reviewedSeveral bodies including the DOE, ASHRAE and the IEA SHC Task 40 are working on developing definitions for Net Zero Energy Buildings (NZEBs). Most existing definitions are based on setting a performance metric (quantity and quality) such as site energy, source energy, energy costs, or emissions, and a boundary for the energy source. However, the problem of most existing definitions is that they neglect the energy use during the whole building lifecycle, neglect the climatic context, neglect the urban or city scale, derive from a ‘zero’ or neutralizing notion, link the energy use to area separately from occupants and do not specify the intended definition audience they address e.g. policymakers or building developers or construction professionals. On the other hand, the cradle to cradle approach encourages the creation of ecologically positive footprint buildings where buildings are very efficient by design and by using suitable technologies to become energy positive. The cradle to cradle approach allows us to examine broader criteria including the embodied energy, environmental impact, energy storage and the management of plus energy. Therefore, in this paper, we discuss those problems and suggest a necessary shift to approach NZEB definition, from a cradle to cradle approach rather from a balance approach. This paper provides an overview of existing definitions and compares their impact toward cradle to cradle NZEBs. Finally, the paper sets three principles for defining NZEBs and suggests a definition, metric and calculation method from a cradle to cradle approach