1,721,163 research outputs found
Including EAHX (earth-to-air heat exchanger) in early-design phases considering local bioclimatic potential and specific technological requirements
No full textHorizontal ground systems for ventilative cooling/heating, such as earth-to-air heat exchangers (EAHX), are a valid pre-heating and pre-cooling low-energy techniques to reduce the building energy consumptions for space heating and cooling. Nevertheless, the potential of these systems, such as others passive solutions, is local specific and need for devoted design methodologies. In particular, EAHXs need to be included in the design process as soon as possible in order to maximise the potentiality and allow for their integration – operational, technological and environmental issues. The paper will introduce a design methodology to define the local climatic potential of EAHX since the building programming phase by defining specific boundary conditions in well-known bioclimatic chart instruments. The effect of different design choices will be analysed for a set of three representative Italian locations. Furthermore, main functional, operational and environmental requirements will be discussed for this technical system. This analysis is based on the performance-drive approach to environmental and technological design – see for example UNI 8290-2:1983 – and is hence compatible with the technological-design practice and early-design consolidated methodologie
Fictitious cooling/heating: from free-floating thermal discomfort to energy needs, different approaches toward labelling free-running buildings
Full text linkFree-running (FR) buildings and technologies, e.g. ventilative cooling, are generally
not considered and valorised in energy labelling schemes. The paper analyses three approaches
to transfer discomfort conditions into comparable fictitious energy needs in order to evaluate FR
building performances. The first approach adds a virtual mechanical system to the FR building;
the second approach includes in the previous the effect of controlled free-running potentialities,
e.g. ventilative cooling in summer, while in the third one, fictitious energy needs are calculated
by coupling a double simulation flow, i.e. FR vs mechanical-treated building, assuming energy
needs from the latter when the first is exceeding assumed discomfort thresholds. The paper
underlines a very high correlation between energy needs and parallel FR indoor temperatures.
Initial results show how the first approach loses the FR potential, while the second and the third
can valorise FR technologies. The choice of different discomfort thresholds can be used to orient
the impact of FR technologies from very to slightly positive
School-based citizen-science action measuring IAQ comfort levels
Full text linkIndoor Air Quality (IAQ) is an essential comfort domain in public spaces, especially
educational ones. This growing interest is underlined in the post-COVID pandemic period,
requiring the testing and diffusion of different solutions, from mechanically driven solutions to
controlled natural ventilation ones. The latter may also be easily applied to existing buildings,
requiring minimal interventions, including installing intelligent monitoring solutions that allow
end-user alerting and support self-actuation actions. This paper investigates this issue,
proposing a citizen-science methodology based on six steps developed during an H2020 IA
project and involving six schools and 42 classes in a long measuring period. This work
introduces the methodology and initial results. Results show improvements in the IAQ
conditions after the students’ activation, with, in some cases, a slight decrease in the level of
attention after a specific period. However, in 75% of the classes where a student lecture is
given, IAQ improves in the short and the long run
Environmental design strategies in different density-urban contexts / Strategie di progettazione ambientale in contesti urbani a diversa densità
Full text linkThe paper deals with the dichotomy between the horizontal and vertical development of the built environment in urban contexts while taking into consideration different densities and settlement logics by following the specific approach of environmental and technological design. The research focuses on two well-known environmental parameters, wind and sun, identifying specific performance indicators related to natural ventilation (pressure coefficient and wind speed profile) and envelope-related energy needs (percentage of openings, shape and orientation of a spatial unit). For each indicator, a sensitivity analysis was carried out taking into consideration density and building height variations to evaluate the design choices from early-design phases
Climatic potential maps of ventilative cooling techniques in Italian climates including resilience to climate changes
No full textBuilding energy consumptions for space cooling is a globally rising voice. Considering the need to reduce the total energy consumptions and related GHG, alternative solutions based on natural heat sinks are essential. Unfortunately, these technologies, such as passive cooling systems, are vey local specific and their geoclimatic applicability needs to be studied to correctly choose and integrate them since early design phases. The paper studies the distribution of climate-related demand for cooling in the Italian context, by mapping local CDH (Cooling Degree Hours) together with the local potential of ventilative cooling dissipative technologies (e.g. controlled natural ventilation), for present and future climate conditions. A geo-referenced matrix – considering all the 7978 Italian Municipalities – of typical meteorological years will be generated and further analysed on hourly base by developing Python scripts. Results of this analysis are visualized in devoted maps of applicability able to underline the local expected potential of wind-driven ventilative solutions. These maps can act as a reference toolkit for designers considering early-design evaluations. Finally, the expected resilience of local climate-potential of these technologies to climate changes is analysed
Ventilative Cooling in Combination with Other Natural Cooling Solutions: Direct Evaporative Cooling—DEC
No full textThis chapter analyses the potential combination of ventilative cooling solutions with direct evaporative cooling (DEC) systems. The focus is on passive downdraught evaporative cooling (PDEC) towers, whose performance is described based on the analysis of monitored results. The main design aspects of PDEC towers are explained, including basic relationships and support tools for system optimization. A series of case studies is reported, illustrating different integration strategies and providing a series of examples for designers. Finally, a simulation-based approach to analysing the local potential of PDEC to reduce thermal discomfort in naturally ventilated buildings is introduced, providing a method by which DEC systems can be integrated in building projects from the early-design phases
Geo-climatic applicability of earth-to-air heat exchangers in North America
No full textEarth-to-air heat exchangers (EAHX) systems have the potential to provide low energy heating and cooling in line with current appeals for energy efficiency and reduction. The lack of a geo-climatic description of EAHX applicability in North America, useful for pre-design decision making, motivated the creation of the Eahx geo-CLImatic Potential Script, or “ECLIPSe”, capable of describing EAHX applicability by comparing the cooling and heating degree hours prior to, and after being conditioned by a virtual system. The applicability was derived for varying values of system effectiveness and depth as well as soil surface conditions and thermal properties. Improved system effectiveness enhanced system applicability, particularly for those climates with either a dominant heating or cooling need, while increased depths appear to have diminishing returns past 2.5–3 m. EAHX systems are less sensitive to soil thermal properties and surface conditions. The results indicate EAHX systems are best suited for temperate climates where there is a balance in heating and cooling needs relative to climates which are dominated by either need. The approach can be further utilized to provide a preliminary regional assessment of EAHX applicability for different areas and future climates useful for designers looking to implement low energy technology
Free-running control logic via a 24-hour forecasting platform: self-actuation testing in a Turin demo building
Full text linkThis study investigates a new approach to optimise the integration of bioclimatic
natural cooling solutions in smart free-running buildings to exploit the untapped potential of
climate and weather conditions, assuring indoor thermal comfort without the need for an active
mechanism. This work introduces a methodological pipeline based on white-box dynamic
energy models, allowing for the prediction, optimisation, and suggestion of hourly schedules
for shading and ventilation to users (or automatic control systems), with the aim of maximising
the adaptive thermal comfort behaviour of a building through the prevention, mitigation, and
dissipation of heat gain. The developed platform was initially tested in a demo low-tech case in
Turin, Italy, involving user self-actuation of shading and ventilation mechanisms. The initial
results confirm the module’s reliability in enhancing comfort, although limitations were
observed in terms of user adherence to the suggested self-actuation scheme. White-box modelbased
digital twins can be used to optimise free-running building conditions. However, direct
integration within building management systems may be preferable, thus avoiding the need for
additional user involvement
Contrasting climate-based approaches and building simulations for the investigation of Earth-to-air heat exchanger (EAHE) cooling sensitivity to building dimensions and future climate scenarios in North America
No full textEvolving cooling needs have promoted the examination of passive low energy cooling solutions such as Earth-to-air heat exchangers (EAHE). These systems heat or cool passing air based on the seasonal air-soil temperature differences, therefore exhibiting a natural correlation between system performance and climate. Key performance indicators (KPIs) of EAHE cooling potential generated from climatic indicators were compared to building simulation results, for a multitude of system and building configurations, baseline cooling thresholds, and future climate scenarios to identify sensitivity of these indices useful for pre-design evaluations. The analysis was conducted for nine representative locations in North America. Using weather files representative of future climate scenarios, the potential for EAHE cooling was shown to persist in cooler climates in contrast to cooling dominated regions like Miami and Phoenix whose use of the EAHE was not effective. In terms of building and system design, shading and control natural ventilation (CNV) were identified as the ideal additions to promote EAHE cooling. Mean soil temperature was also identified as a possible metric for estimating EAHE cooling as cooler soil temperatures expectedly perform better. The comparison between the two approaches demonstrated climate indicators consistently reflected the behaviour predicted by building simulation despite changes to building dimensions. As a result, climate indicators have been shown to be effective pre-design tools in estimating EAHE cooling potential. These can be used by stakeholders evaluating the benefit of EAHEs in providing sustainable cooling in various climates and future climate conditions
Mapping winter climate zoning variations in Europe under climate change scenarios
Full text linkThe attribution of a specific climate zone to a Municipality or a Local
Administrative Unit (LAU) level in the European Member States is fundamental to support the
definition of EPBD correlated decisions, e.g. activation periods of heating systems or minimal
U-values. Climate change also impacts this specific attribute, requiring progressively
upgrading this indicator. The paper computes local climate zones, adopting the Italian
regulation approach, based on daily heating degree days with a base temperature set to 20°C.
Zoning is applied to the whole European territory with a detail of about 10km, i.e. 0.1° in both
latitude and longitude. This high precision allows to understand climate change variations
better. The calculation is supported by integrating, inside our new dynamic simulation platform
PREDYCE, this Key Performance Indicator (KPI) and by computing it via our server facility.
Different climate databases are managed: ERA5-land re-analysis (1950–2023) database and
four EUROCORDEX couples of global-regional climate models (historical 1970–2005, and
future projections 2010–2100). A series of maps showing the progressive variations of the
local climate zone, from A (less than 600 HDD) to F (more than 3000 HDD), is produced. The
study shows substantial variations in climate zoning, with a growing progressive impact from
Southern European regions to Northern European ones. Outcomes suggest the need to align
EPBD-correlated regulations with constantly upgraded climate databases
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