Mario Grosso

Wind Pressure Distribution Around Buildings - a Parametrical Model

This report describes the theoretical development of work done within task group “wind pressure distribution” of the COMIS Workshop. The paper is divided into three Sections with an introductory part on the physical fundamentals. The first Section entails the objectives and the meaning of modelling wind pressure distribution as an integrated part of multizone airflow modelling. A literature review is presented, on calculation techniques and wind tunnel tests, and a description of the evaluation of an existing numerical model. The second Section is related to the development of the Cp calculation model. Objectives, characteristics and methodology of the parametrical approach chosen for the analysis are depicted, together with a description of the reference data, the regression technique, the algorithm, and the structure of the calculation model. The third Section is a detailed report of the results of the regression analysis. The curve-fitting process is explained with reference to the main factors affecting the wind pressure distribution on a building envelope: terrain roughness, surrounding buildings, aspect ratios, and wind direction. Figures of the curves are shown. In the Appendix, equations and relevant coefficients of the curve-fitting are presented.

Urban Form and Renewable Energy Potential

Urban form, i.e., the layout, density, shape and orientation of buildings within the street grid of a city, affects greatly the potential of using renewable energy sources such as sun and wind for electricity production and climatisation of buildings. This paper outlines the framework of the European research Project PRECis (assessing the Potential for Renewable Energy in Cities) and, in particular, the role of the Polytechnic University of Turin in that Project.

Horizontal air-to-earth heat exchangers in Northern Italy: testing, design, and monitoring

Abstract Earth heat exchange (EHX) through buried horizontal air ducts (EHXair-hor) can be an effective passive/hybrid system to reduce heating and cooling loads in temperate climate zones. This paper shows the results of field testing, by the authors, of a buried pipe system for a single family dwelling and the design development of a large EHXair-hor system for a High School building. The monitoring plan for the latter is also described. Considerations on critical aspects, such as the terrain warming effect of EHXair-hor systems are also outlined.

Cooling potential of natural ventilation in representative climates of central and southern Europe

ABSTRACT This study analyses the climate-dependent passive ventilative cooling (PVC) potential in central and southern Europe. This analysis was carried out in two phases: (1) evaluation of PVC potential as a climate-dependent variable, in different locations representative of European climate zones for both wind-drive airflow (comfort ventilation) and temperature gradient (environmental and structural cooling); (2) verification of the above PVC potential through dynamic energy simulations on a reference-building model located in selected cities. In the first phase, a parametrical analysis on the typical meteorological year of 55 European cities was carried out considering a new synthetic parameter – ‘residual CDH’ (CDHres) – representing the potential reduction of cooling degree hours due to PVC. In the second phase, the PVC potential was assessed through dynamic energy simulations on an office-building unit located in a sample of locations (10), varying building envelop physical parameters and VAC system configurations. Results show that PVC is an effective strategy for reducing cooling energy consumption in buildings in central and southern European climates. Furthermore, dynamic simulations demonstrate that internal heat capacity has an important role in PVC potential and validate the climatic analysis, especially when temperature gradient is taken into account.

Accessibilità e qualità ambientale del paesaggio urbano. La matrice microclimatica di sito come strumento di progetto

The peri-urban and subtopic urban areas landscapes suffer not only formal irresolution, lack of characterization and indifference to the sense of place, but also lack of environmental quality, which further worsens the possibility of fruition. The environmental quality is directly interrelated with the usability and accessibility of the spaces, ensuring adequate attractiveness for users in performing different activities. In this sense the environmental characteristics, different from the aesthetic ones, bind with them to form a unique, capable of becoming instrument and rule of integration between the landscape and the object of design, giving back to spaces without identity and rule a renewed accessibility. The contribution, defined this essential relationship, explains how to develop a project tool, the site microclimate matrix, able to analyze the vocational nature of spaces to be designed and redefined in a perspective of sustainable development.

Geo-Climatic Applicability of Direct Evaporative Cooling in Italy

This chapter focuses on the climatic applicability of passive direct (downdraught) evaporative cooling (PDEC) techniques in the provincial capital cities of Italy. First, a PDEC potentiality map was produced using a previously developed method based on three variables: wet bulb depression, summer comfort air temperature threshold (25 °C) and cooling degree hours (CDHs). Second, an applicability map was produced by comparing the PDEC potentiality map to the local cooling energy demand. Third, a new method is presented including a calculation of the residual local cooling energy demand, i.e. residual CDH, related to air treatment by direct evaporative cooling. These residual CDH values were calculated considering different step-wise increasing outlet temperatures (WBT; WBT + 1 °C; …; WBT + 5 °C) as a function of the covered amount of wet bulb depression. Finally, three cities chosen as being representative of their respective Italian climatic macro-zones were selected in order to assess in greater detail the yearly variation of CDH aimed at supporting specific design strategies for ventilative passive cooling solutions.

An Environmental Technological Approach to Architectural Programming for School Facilities

This chapter describes synthetically a method integrating functional, technological and environmental aspects of architectural programming for school facilities. This method is based on the analysis of activities and relevant user needs followed by an in-depth assessment of all related functional and environmental aspects usually not considered in current design practices: from the climate response to comfort requirements to the analysis of energy and material flows; from the space–time characteristics of activities to their private/public connotation and interdependency; from the inside/outside interrelationships to the multisensory perception of users. This building programming phase represents a necessary background for the next preliminary architectural composition based on the environmentally sound combination of “virtual” space units through a set of rules aimed at fulfilling the client brief and general sustainability requirements as well as avoiding or, at least, balancing potential conflicts by a tradeoff approach.

Breakthrough of natural and hybrid ventilative cooling technologies: strategies, applications and case studies

The building sector is responsible for almost 40% of total primary energy consumption in industrialised countries considering the energy demand for space heating and cooling, hot water production, lighting, cooking and other appliances (Cuce & Riffat 2016; Orme, 2001). In the USA, the residential sector alone is responsible for 23% of the total annual energy end use in all sectors, and 50% of that is consumed for space winter and summer conditioning (Logue, Sherman, Walker, & Singer, 2013). Electricity use for space cooling is rising in the national balance of several countries due to the global warming effect related to anthropogenic green-gas emissions, to international style building, to the diffusion of a new comfort culture also related to an increase in life standard and due to the increase in internal gains (e.g. computers and electrical equipment). In turn, the rise in electricity use whose primary source is green-gas-generating oil or gas in the majority of industrialised countries further increases the global warming trend. Furthermore, the air-conditioning market in developing countries is rising fast overpassing 70% of growth between 2010 and 2015 (source: Daikin Industries, 2015). The forecast for air conditioner units in stock in Chinese provinces is rising more than 10% each year (Koizumi, 2007), while the parallel increase in efficiency of sold mechanical systems is not enough to reduce the increase in energy consumption and demand. Within this framework, passive and hybrid solutions for cooling buildings are essential for reducing electricity use in the building sector. Technologies able to increase the efficiency of equipment and to reduce energy losses throughout the building envelope are consolidated and favoured in legislation, standards and codes of practice, while much less effort has being made for reducing cooling load electricity. An increase in efficiency of mechanical devices for cooling available in the market is an ongoing process. Nevertheless, this process, that mainly involves industrialised countries and starts to be applied in emerging economy countries (e.g. GEE/IEA, 2015), can only partially reduce the impact of air-conditioning market on national energy consumptions. Only a holistic approach including a wide range of passive cooling methods, tools and technologies can significantly reduce the environmental impact of cooling systems. Passive and hybrid solutions for reducing ‘sol-air’ increments, mitigating internal gains and dissipate heat are able, in fact, to provide comfort conditions without consuming fossil fuel energy, or at least reducing this consumption. This special issue on Breakthrough of natural and hybrid ventilative cooling technologies: strategies, applications and case studies, together with the connected issue Breakthrough of natural and hybrid ventilative cooling technologies: models and simulations, focuses on methods, tools and technologies for reaching the above-mentioned goal through the use of ventilative cooling, i.e. cooling by controlled natural ventilation. The papers presented in this special issue, Breakthrough of natural and hybrid ventilative cooling technologies: strategies, applications and case studies, can contribute to the solution of the above-mentioned challenges by providing a framework for approaching ventilative cooling design in an innovative way, based on experiences, testing results, case studies, models and geographical analyses. The contributions deal with the following main contents’ categories:

Breakthrough of natural and hybrid ventilative cooling technologies: models and simulations

The building sector is responsible for almost 40% of total primary energy consumption in industrialised countries considering the energy demand for space heating and cooling, hot water production, lighting, cooking and other appliances (Cuce & Riffat, 2016; Orme, 2001). In the USA, the residential sector alone is responsible for 23% of the total annual energy end use in all sectors, and 50% of that is consumed for space winter and summer conditioning (Logue, Sherman, Walker, & Singer, 2013). Electricity use for space cooling is rising in the national balance of several countries due to the global warming effect related to anthropogenic green-gas emissions, to international style building, to the diffusion of a new comfort culture also related to an increase in life standard and due to the increase in internal gains (e.g. computers and electrical equipment). In turn, the rise in electricity use whose primary source is green-gas-generating oil or gas in the majority of industrialised countries further increases the global warming trend. Furthermore, the air-conditioning market in developing countries is rising fast overpassing 70% of growth between 2010 and 2015 (source: Daikin Industries, 2015). The forecast for air conditioner units in stock in Chinese provinces is rising more than 10% each year (Koizumi, 2007), while the parallel increase in efficiency of sold mechanical systems is not enough to reduce the increase in energy consumption and demand. Within this framework, passive and hybrid solutions for cooling buildings are essential for reducing electricity use in the building sector. Technologies able to increase the efficiency of equipment and to reduce energy losses throughout the building envelope are consolidated and favoured in legislation, standards, and codes of practice, while much less effort has being made for reducing cooling load electricity. An increase in efficiency of mechanical devices for cooling available in the market is an ongoing process. Nevertheless, this process, that mainly involves industrialised countries and starts to be applied in emerging economy countries (e.g. GEE/IEA, 2015), can only partially reduce the impact of air conditioning market on national energy consumptions. Only a holistic approach including a wide range of passive cooling methods, tools and technologies can significantly reduce the environmental impact of cooling systems. Passive and hybrid solutions for reducing ‘sol-air’ increments, mitigating internal gains and dissipate heat are able, in fact, to provide comfort conditions without consuming fossil fuel energy, or at least reducing this consumption. This special issue on Breakthrough of natural and hybrid ventilative cooling technologies: models and simulations, together with the connected issue Breakthrough of natural and hybrid ventilative cooling technologies: strategies, applications and case studies (vol. 16, issue 1), focuses on methods, tools and technologies for reaching the above-mentioned goal through the use of ventilative cooling, i.e. cooling by controlled natural ventilation (CNV). This strategy is one of the most cost-effective alternatives to air-conditioning systems. Although several application examples of such strategy can be found all over the world, same critical issues are still to be solved to completely demonstrate the effectiveness of ventilative cooling in different local contexts. One of the challenge in the current professional context is due to the lack of methodology and tools to deal with the complexity of air-movement physics. Furthermore, CNV is not considered mandatory in international standards for complying with energy saving requirements, although these being increasingly stricter in building regulations which are aiming at near-zero-energy-buildings. The contributions of the special issue on Breakthrough of natural and hybrid ventilative cooling technologies: models and simulations deal with the following main contents’ categories:

Meta-Design Approach to Environmental Building Programming for Passive Cooling of Buildings

Sustainable design practices are being disseminated all around the world, thanks to a growing interest by users, builders, and politicians in facing the impact of climate changes and the need for a more sustainable future. Nevertheless, although design practices include currently green issues and technologies, these are applied mainly in the last design phases in order to comply with local and/or national regulations and requirements (e.g. minimum values for the energy demand to be covered by renewable sources and for the envelope transmittance). Instead, to integrate sustainable technologies in an energy- and cost-effective way, it is necessary to deal with them since the earliest design phases, i.e. building programming and site analysis. Furthermore, passive and hybrid technical building systems (TBS) are dependent on the specific project context, and this is even more apparent for cooling. In fact, while the performance of passive heating TBS is mainly related to solar access and reduction of energy losses, the one of space cooling TBS depends on other variables such as internal heat gains, heat capacity, and wind environment. The paper describes a methodology to assess the energy-saving potential of passive ventilative systems in the earliest design phases. Site and climate aspects, together with definitions of needs and requirements for building programming, will be described. Results from an application of a method based on Givoni-Milne bioclimatic chart to evaluate the climate-dependent potential of passive system are reported. Criteria for spatial and technological integration of passive cooling systems are also presented.