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Energy Diagnosis
The European Directive 2010/27 on "energy end-use efficiency," transposed by Legislative Decrees 102/2014 and 141/2016, introduced the energy diagnosis as a tool to understand the energy consumption of a building or group of buildings, an industrial or commercial plant, and public or private services. It identifies and quantifies energy-saving opportunities based on a cost-benefit analysis.
In Italy, there is an obligation to conduct an energy diagnosis every four years by EGE-certified entities (Energy Management Experts) according to UNI CEI EN 16247. This obligation applies to large companies and those with significant energy consumption accessing the facilitation for energy-intensive users.
In the civil sector, the energy diagnosis allows a better understanding of a building's actual state, evaluating the most efficient improvement interventions, quantifying energy usage, identifying waste causes, and suggesting improvement intervention priorities to users.
Stages of Energy Diagnosis
The stages of an energy diagnosis can be defined by:
- Collection and analysis of energy expenses
- Collection and analysis of technical documents
- Planning site inspections, with checks on the building envelope and systems
- Analysis of energy services
- Construction of the energy inventory
- Calculation of energy performance indicators
- Identification of improvement interventions
- Cost-benefit analysis
- Evaluation of intervention priorities
These stages can be grouped into:
- Data collection during inspections
- Data processing
The energy diagnosis is crucial for planning an energy requalification program. Understanding building pathologies or plant criticalities involves studying their behaviors and finding specific solutions tailored to each situation.
Improvement Interventions from Energy Diagnosis
Improvement interventions suggested by an energy diagnosis include:
- Adoption of high-efficiency plant systems
- Thermal insulation of buildings
- Installation of high-efficiency lighting fixtures
- Use of regulation, monitoring, and consumption management systems
- Installation of renewable energy source systems
Instrumental Analysis in Energy Diagnosis
Instrumental analyses that can complement an energy diagnosis with non-destructive or micro-invasive techniques include:
Thermo-Hygrometer:
Analyzes temperature and relative humidity over 3-7 days to study user behaviors and analyze some envelope pathologies.
Thermal Camera
Thermographic analysis helps analyze some pathologies in the building envelope and identify faults or critical issues in systems. Infrared images determine surface temperature by measuring emitted infrared radiation, with sensitivity that can reach a few tenths of a degree. It can diagnose various issues such as thermal leaks, thermal bridges, wall texture, and building construction type, defects in thermal coat installation, defects in the airtightness of the building envelope, rising damp, rainwater infiltration, and water leaks from pipes and coils
Thermal Flowmeter
Thermal flowmeter analysis is a non-destructive test that determines the thermal transmittance value of a stratigraphy. This analysis is useful for determining the thermal parameters of a building component (typically a wall) when the stratigraphy and material characteristics are unknown. The test, conducted during winter for 3-7 days with a temperature difference of over 15°C between indoors and outdoors, uses a flowmeter and two temperature sensors inside and outside the stratigraphy to determine the heat flow.
Video-Endoscope
Video-endoscopic analysis, performed through a small hole made with a tapered drill, verifies the consistency, type, and nature of each layer of the analyzed building component. The endoscopic test can investigate hidden areas accessible through a small hole, such as localized breaks in pipes and technological systems, blockages in rainwater or drainage networks, internal gaps and voids in masonry, horizontal floors, pitched roofs, gaps, and load-bearing structures of false ceilings
The analysis of the air permeability of the building envelope of residential, tertiary, and industrial buildings determines the hourly air changes in an internal volume. The instrumentation includes a manometer and an electronically controlled calibrated fan temporarily mounted on the building's entrance door, sealing it perfectly with a panel that adapts to the door's measurements. The blower door test, in accordance with ISO 9972:2015 and European Standard EN 13829, measures the internal and external pressure of the building and the air flow generated by the fan at different ∆P values.
At a pressure difference of 50 pascals between the inside and outside of the building, air tightness defects in the building envelope, such as air leaks from fixtures, structural nodes, cracks, and ducts, are sought. Air tightness defects are identified using thermographic cameras, anemometers, cold smoke generators, and tracing gas fumes. After the blower door test, following the repair of air tightness defects, the test is repeated to verify the benefits of the "repair" intervention.
Making the building airtight allows:
- Saving energy by reducing ventilation losses
- Reducing noise
- Reducing the amount of allergens and pollutants
- Increasing comfort
Energy and Environmental Monitoring Systems
Energy monitoring systems consist of three elements:
- Physical infrastructure (sensors and monitoring instruments)
- Network infrastructure (wired or wireless)
- Software platform for collecting and managing detected data
Measurements can be made with standard or MID-type (Measuring Instruments Directive) meters.
MID-compliant meters, meeting the requirements of European Directive 32/2014, certify measurements and allow access to incentives for energy efficiency.
Various solutions exist for collecting and analyzing measurements, usually with meters connected to a central unit that collects and sends measurements to a cloud database for subsequent analysis on energy efficiency platforms.