Diapositiva 1 - Università degli Studi di Roma "Tor Vergata"

Transcription

Università degli Studi di Roma "Tor Vergata"
Facoltà di Ingegneria
USE EFFICIENCY
EPBD
First Level Audit
Ing. Giulia D’Angiolini
First Level Audit:EPBD
The Directive on the energy performance of buildings (EPBD) is the Directive
2002/91/EC (EPBD, 2003) of the European Parliament and Council on energy efficiency of
buildings. The Directive came into force on 4 January 2003 and had to be implemented by
the EU Member States at the latest on 4 January 2006. It was inspired by the Kyoto
Protocol which commits the EU to reduce CO2 by 8% by 2010, to 5.2% below 1990 levels.
The directive came into force on 4 January 2006 and requires member states to comply
with Article 7 (Energy Performance Certificates), Article 8 (Inspection of boilers) and
Article 9 (Inspection of air conditioning systems) within three years of the inception date,
the deadline being 4 January 2009.
EPBD
http://www.seai.ie/Your_Building/EPBD/deap_1_.pdf
STUDY ON ENERGY PERFORMANCE OF BUILDINGS (February 2009)
http://www.europarl.europa.eu/activities/committees/studies/download.do?file=24491
The EPBD Buildings Platform is a European Commission initiative in the framework of the
Intelligent Energy - Europe programme, which provides information services for practitioners and
consultants, experts in energy agencies, interest groups and national policy makers in the European
Member States for helping the implementation of the European Energy Performance of Buildings
Directive (EPBD).
http://www.buildup.eu/it/home
Università degli Studi di Roma “Tor Vergata” – USE E FFICIENCY- TRAINING COURSE
First Level Audit:EPBD
The EPBD Recast prescribes:
• All new buildings across Europe must be built to a very low energy standard by 2020.
• Energy efficiency measures must be taken when an existing building undergoes any type of
major renovation.
• Technical building systems will have to meet minimum energy performance requirements
when replaced.
The proposal for a EPBD recast was part of the European Commission’s wide-ranging
energy efficiency package of November 2008, which gives a new boost to energy security in
Europe, supporting the 20-20-20 climate change. Buildings consume 40% of Europe’s
energy, and energy efficiency in buildings represents the most cost effective potential for
emission reductions. Clearly there is a growing justification and political commitment to
tackle energy efficiency in buildings and this requires moving swiftly towards very lowenergy retrofit and passive design new build en mass. Both demand-side as well as supplyside solutions should be considered following the principles of the “Trias Energetica”
applied to the building:
1. Reduction of energy demand;
2. Introduction of renewable energy sources and cogeneration/tri-generation);
3. Use of fossil fuels as efficiently as possible (if still applicable).
EPA methods
Energy Performance Certificate (EPC)
EPCs are now required for all commercial buildings whenever sold, rented or built. The
certificate records how energy efficient a property is as a building and provides A-G ratings,
where A is very efficient and G is least efficient (Communities and Local Government 2008). EPCs are
identical to the labels now provided with domestic appliances such as washing machines. They
are generated using standard methods and assumptions about energy use so that the energy efficiency of
one building can be easily compared with another building of similar type. This provides information for
tenants, owners, prospective buyers, occupiers and purchasers on the energy efficiency and
carbon emissions from their building so they can take into account energy efficiency and fuel costs as
part of their investment. EPCs are accompanied by reports that list cost effective and other measures
(such as low carbon generating systems) for improving the building’s energy rating.
Display Energy Certificate (DEC)
DEC shows the energy performance of a building based on actual energy consumption as
recorded annually for duration of time up to the past 3 years (the Operational Rating). Its rating is
similar to that of EPC that is A to G. DECs are required to increase public awareness of energy use by
informing visitors to public buildings about the energy use of a building. This is based on the building’s
energy use as recorded by electricity meters, gas meters and other meters. The DEC should be clearly
displayed to the public all the time. This is accompanied by an Advisory Report that contains a list of
cost effective measures for improving the energy rating of the building. The DEC is valid for one year
whereas the Advisory Report is valid for seven years.
EPA methods
EPC
DEC
The difference between a Display Energy Certificate (DEC) and Energy Performance Certificate (EPC) is
that the DEC is based on the actual energy used in the building. This is known as an Operational Rating
and means that two structurally identical buildings can have two different ratings due to how the
occupants use the energy supplied to the building. Whereas an EPC is an Asset Rating which looks at the
energy efficiency of structure and it is not directly affected by the energy consumed by the
occupants. It’s calculated in standard use condition
EPA Methodologies
EPCs and DECs have to be produced using the relevant calculation tools specified in the
National Calculation Methodology, which have to be approved by the Secretary of State
(Building Regulation 2000). A number of EPA methodologies have been developed (or are in
the process of being developed). Some of which are:
- SAP (Standard Assessment Procedure for residential buildings)
- DSM (Dynamic Simulation Model)
- SBEM (Simplified Building Energy Model)
- MCOR (Method for Calculating Operational Ratings for buildings)
- RdSAP (Reduced Data Standard Assessment Procedure)
Others include CIBSE TM22 (CIBSE 2006) and EPA-NR (Energy Performance Assessment of existing
Non-Residential buildings). Some of these methodologies are applicable for dwellings and others
for non-dwellings.
EPA-NR (Energy Performance Assessment of existing Non-Residential buildings)
The EPA-NR method is a complete consultancy process suitable for issuing an Energy
Performance Certificate for existing Non-Residential buildings that is based on a set of tools. It
is the most power energy assessment tool that is applicable to all EU member states (B Poel 2007). It
only needs some adjustment to local conditions to make it an effective national software package.
The assessment it provides is in two different categories. The first category is for buildings that need an
Energy Performance Certificate and the second category is for buildings that need a complete energy
analysis and assessment of different energy refurbishment scenarios. For the first category EPANR process can be used at a simplified level of detail.
The second category needs a more elaborate
approach in terms of inspection of the building
and energy saving recommendations. The
software is unique in its architecture; it contains
certain common utilities and libraries, while
other parts of the software allow adaptation to
the local context. The calculation engine which
takes care of the physics and financial
calculations has a typically more unique
character. An output interface producing the
EPC according to national requirements can be
easily connected to the software. Also more
advanced input and output interface can be
included with relative ease to incorporate
specific functionalities like graphical output
and data storage.
EPA Methodologies: Update of the UseEfficiency Project
The EPA-NR method can provide complete energy analysis and assessment, with necessary
adjustments to local conditions. This tool is applicable to all EU member states and in
UseEfficiency project it is suitable for:
•
•
•
•
•
University of Rome Tor Vergata, Coordinator (Italy)
Aristotle University of Thessaloniki (Greece)
Universidad Politècnica de Valencia (Spain)
Malardalen University (Sweden)
Vilnius Gediminas Technical University (Lithuania)
CIBSE TM22 methodology is a complete consultancy process, its applicability to United
Kingdom and Ireland has been verified, it is suitable for:
•
•
Brunel University (UK)
Dublin Institute of Technology (Ireland)
EnEV EPA methodology is the software tool adopted by HafenCity University Hamburg
(Germany).
The software can provide complete energy analysis and assessment, but it’s not clear
if it’s available in english version, in this case delays in data comparison activities may
occur.
First Level Audit: Method
Prior to more detailed analyses at the universities (second level audit) a first level audit has
been carried out focusing on establishing an overview of state-of-the-art at the universities
and selection of two buildings per university for a more an in-depth analysis within the
second level audit.
Within 1st level audit analysis the overall goal is to give a “strong standardized methodology
that may be used for all university buildings whenever required”. The methodology has to be
simple, clearly defined and transferable to similar situations like energy management in large
building stocks.
In particular, 2 out of a maximum of 6 buildings of the partner department faculty campus
are to be reasonably identified for further analysis in a 2nd level audit.
In the first level audit university partners produced a Display Energy Certificate (DEC).
EPBD does not explicitly distinguish between different levels of audits. But energy
performance certificates (EPC) have to be made available for existing buildings not only in
the case of a major renovation but, according to EPBD Article 7 Energy performance
certificates, also when being sold or newly let. Paragraph 3 of this article applies also to
University buildings as being occupied by institutions providing public services to a large
number of persons.
Apart from EPBD, in energy consulting it is a common approach to the energy performance
assessment of large building stocks to start with an operational rating of measured final
energy consumption for many buildings, compare these data with national benchmarks
and sort out critical buildings with comparatively high specific and/or absolute consumption
values for further analysis.
Benchmarks: for operational rating schemes for building energy consumption are usually
derived from statistics of many comparable buildings. Energy consumption benchmarks
ecomp are differentiated according to typical building utilizations, weather corrected and
related to some reference area and a standard accounting period of one calendar year.
The second level audit differs from the first level analysis by involving students directly
in a realistic implementation activity on energy saving plans. The activities will start from
a data selection based on chosen EPA tools requirements and standard guidelines from the
EPBD.
Specific Approach to the Analysis
Procedures for 1st level audit should be characterized by:
• Easily manageable data acquisition in large building stocks where usually detailed data on
the individual buildings are scarce.
• Operating personnel can do it. No external experts should have to be involved.
• No on site inspection of individual buildings is necessary.
Therefore we chose an approach that takes advantage of data collected anyway for reasons
apart from this project namely for compliance with EPBD and its national transposition
respectively.
Scope of asset rating (AR) vs. operational rating (OR)
OPERATIONAL RATING
Building data
General building data are required to describe type, main utilization and size of the building,
such as:
• Location (ZIP code, climate zone),
• Year of construction
• The main types of building utilization, f.i. office, laboratory, lecture hall, storage …
• Reference area, f.i. net floor area and conditioned net floor area, fraction of different
building utilizations
• Number of storey, rough sketch of building shape and floor plan
The following building characteristics help to assess the pure numbers of energy consumption
• Building envelope (i.e. type of façade, fraction of total window area, U-values …)
• Technical installations (i.e. type of ventilation, air conditioning, fraction of conditioned net
floor area, …)
• Current state of repair and year of latest major renovation of building envelope and main
technical installations respectively
OPERATIONAL RATING
Energy data
While for electricity the metered values represent the energy consumption immediately,
thermal energy is metered as the amount of fuel consumed and needs to be converted to
energy units via gross or net calorific values of the fuels. The following energy data are
needed for an operational rating and should be available via the national DECs:
• Accounting period, time correction
• Measured consumption of electricity for the last 3 years
• Utilizations of electricity included in the measured values (i.e. lighting, ventilation, air
conditioning, cooking, IT, elevators …)
• Measured consumption of fuels for the last 3 years
• Utilizations of thermal energy included in the measured values (i.e. heating, hot water,
absorption chillers …)
• Energy generation in the building (cogeneration, solar thermal, PV, …), measured
production of the last 3 years
OPERATIONAL RATING
Weather correction
Typically, the heating fraction EVmH of the measured thermal energy consumption EVm is
considered to be directly proportional to the ambient temperature during the accounting
period. Usually the accounting period is one calendar year. Thus, it is corrected from actual
weather conditions to long term mean values in order to rule out accidental biases in data
assessment and comparison with benchmarks. Most common is a degree day scheme for
weather correction, degree days D being defined appropriately like
mean room temperature in [°C]
mean ambient temperature on day n in [°C]
number of days [d] per accounting period with
heating limit temperature in [°C]
The correction itself is figured out via a rule of proportion calculation
corrected heating energy consumption
metered heating energy consumption in the accounting period
degree days in the accounting period
long term mean degree days
Critical buildings
OPERATIONAL RATING
Buildings are considered to be critical when f.i. some of the following criteria are fulfilled:
• Mean value of the weather corrected, area related energy consumption ec of the last three
years is considerably greater than national benchmarks: e c >> e comp .
• Very bad rating of the building energy consumption compared to national indicators or legal
standards according to the national rating scheme.
• High absolute values of energy consumption, electricity as well as thermal energy.
• High consumption is not related to special secondary uses within the building (data centre,
kitchen).
• Measures for considerable improvement of energy efficiency obvious or already proposed.
• No building specific metering is installed, but the building is assumed to not be energy
efficient and to have a savings potential.
Special issues
OPERATIONAL RATING
German EPC and DEC procedures for existing public buildings consider the following special
cases explicitly. We proposed to apply these solutions in other countries also in case that there
has been no other national approach defined.
•No building specific metering:
In case there is no metered energy consumption of the buildings but only of a property
consisting of several buildings structures the operational rating may comprise the whole
property. The benchmark to compare with is the weighted mean of the different buildings in
particular when comprising different building utilizations.
•Weather correction:
Only the heating fraction of the thermal energy consumption has to be corrected on a
degree day basis. The thermal energy consumption for hot water generation has to be
subtracted beforehand as a fixed percentage, say 5% in average office buildings, or derived
from hot water consumption.
•CHP integrated in the building:
Only heat and electrical energy consumed in the building should be considered.
Special issues
OPERATIONAL RATING
• Heat pumps:
The electrical energy to run heat pumps (as well as for direct electrical heating) is supposed to
be compared with statistical benchmarks from conventional heating systems for the sake of
simplicity.
•District heating:
Where should losses in generation and distribution be considered? Final energy consumption
in the sense of the amount of energy delivered to the building limits does not include these
losses. An efficiency of about 85% seems to be a plausible assumption.
•District cooling:
In case the building is being supplied with cold water for cooling and air conditioning from
centralized chillers this amount of energy is added to the final energy for heating
•Building let to different tenants:
Metering of electrical energy consumption may be difficult to get from all tenants. In that
case approximately 70% of the data records
For some of these issues we will therefore apply pragmatic solutions with simplifications legitimate for a
1st level analysis and leave detailed analysis to 2nd level analysis.
First Level Audit: Results
Consumo finale di energia volumico
Volume-specific data were available only from 4 universities. But still the difference in
building utilization supposedly is the main reason for a wide spread “cloud” of the values
Indice di consumo: energia totale.
Only indexes are displayed, defined as the ratio of the weather corrected, area related energy
consumption ec of the last year over the national benchmark ecomp. An index value of 100% equals to the
corresponding national benchmark. Now depending on how well differentiated the national benchmark
scheme is with respect to building utilization the better the data allow to compare different building
utilizations and to raw conclusions regarding the real energy performance of the building. Of course in
the national comparison it is obvious that benchmarks in Ireland seem to be easier to meet than those in
Greece or Italy for example.
Indice di consumo, energia primaria
First Level Audit: Conclusion
Problems with the data that occurred are well known from other benchmarking projects.
Some problems result from a lack of correct data
• Building areas and building specific metering to figure out specific energy consumption
values are not always available for individual buildings. Assumptions have to be made
then.
• National benchmarks comparable with the category of the actual building are not always
available, particularly in cases with multiple utilizations within one building.
• Weather data for correction may not always be available, particularly in countries where
an OR is not mandatory.
If these problems have been ruled out
• Some specific values are high, some are implausibly high. Why?
• Was it procedural problems like incorrect readings from energy meters, inaccurate area
values, incompatible weather data? Have fuel amounts been converted to energy units via
gross or net calorific values?
• Or was it real problems with the building envelope, inefficient mechanical or electrical
installations or flawed building regulation systems that caused high energy consumption?
These questions are the starting point for further analysis within 2nd level audit analysis.
First Level Audit: Caso Università di Tor Vergata (UNITOV)
EDIFICI OGGETTO DI CALCOLO
•
EDIFICIO DI INGEGNERIA INDUSTRIALE DELLA FACOLTA’ DI INGEGNERIA
•
EDIFICIO LABORATORI DI INGEGNERIA INDUSTRIALE DELLA FACOLTA’ DI
INGEGNERIA
•
EDIFICIO “DIDATTICA” DELLA FACOLTA’ DI INGEGNERIA
•
EDIFICIO “A” DELLA FACOLTA’ DI ECONOMIA
•
EDIFICIO “B” DELLA FACOLTA’ DI LETTERE E FILOSOFIA
1) REPERIMENTO DATI
PRESSO L’UFFICIO TECNICO:
- Piante Autocad in formato elettronico e cartaceo di tutti gli edifici
- Stratigrafie e tipologie dei pacchetti murari caratteristici ricorrenti in tutti gli edifici
PRESSO OPERAI DELLA SOCIETA’ TECKAL:
- Piante Autocad e caratteristiche tecniche (portate, pressioni, potenze etc.) impianti termici
primari siti nella centrale termica asservente tutti gli edifici (di fronte ed. Didattica)
2) SOPRALLUOGO
•
RILIEVO TRAMITE INDAGINE IN SITO DELLE CARATTERISTICHE (DIMENSIONI, NATURA,
STRATIGRAGIA) DELLE STRUTTURE E DELLE PARTI CHE HANNO INFLUENZA DIRETTA
SULLE DISPERSIONI TERMICHE:
- Elementi di involucro opachi verticali e orizzontali confinanti con locali non riscaldati o con l'esterno:
pareti, solai;
- Serramenti opachi e trasparenti: porte ignifughe di sicurezza e infissi comprensivi di eventuali persiane
o sistemi di schermatura solare, sottofinestra e, in presenza di tapparelle, soprafinestra (cassonetti).
•
RILIEVO TRAMITE INDAGINE IN SITO DEGLI ASPETTI IMPIANTISTICI:
- Impianti esistenti di produzione (centrale termica, caldaia);
- Impianti esistenti di distribuzione (colonne montanti e/o di distribuzione);
- Impianti esistenti di emissione del calore (corpi scaldanti);
- Sistemi di regolazione dell'impianto sia di tipo centralizzato (centraline climatiche) sia esistenti a
livello dei singoli corpi scaldanti.
3) CONSUMI STORICI
•
MEDIA DEI CONSUMI RIFERITA AGLI ANNI PRECEDENTI:
- Comprensione nelle condizioni attuali di utilizzo delle effettive esigenze di fabbisogno dell'edificio,
non necessariamente corrispondenti a quelle individuate su base convenzionale in fase di
certificazione;
- Relativa al solo utilizzo termico;
- Stimata a partire da potenza impianti termici di produzione primaria presenti nella centrale termica
asservente il complesso degli edifici, in base a tipologia edificio, numero di occupanti e involucro,
causa mancato reperimento di bollette.
4) STIMA DATI CLIMATICI SITO
• DA NORMATIVA:
- Gradi giorno del Comune di Roma pari a 1415 GG (D.P.R. 412 del 26/08/93)
- Zona climatica in cui ricadono gli edifici: "D", pertanto il periodo di riscaldamento previsto per legge è
di giorni 166 e precisamente dal 1/11 al 15/4.
- Temperatura minima di progetto dell'aria esterna secondo norma UNI 5364 pari a 0.00 °C.
- Temperature medie mensili determinate in base alla norma UNI 10349:
4) STIMA DATI CLIMATICI SITO
• Umidità relative medie mensili esterne (Norma UNI 10349):
•
Irradiazioni medie mensili (espresse in MJ/giorno) relative al periodo di riscaldamento determinate
in base alla norma UNI 10349:
• DA STAZIONE METEO (tetto dip. Ingegneria Industriale): Velocità media vento pari a 2.60 m/s
5) REPORTAGE FOTOGRAFICO E IMMAGINI DA SATELLITE DEGLI EDIFICI
•
Per il rilievo più approfondito di particolari architettonici, dimensioni, materiali, colori e per un
inquadramento territoriale degli edifici oggetto di studio.
6) INSERIMENTO DATI NEL PROGRAMMA TERMUS
•
SOFTWARE CERTIFICATO DELLA ACCA S.p.A.
•
CONSENTE UNA VALUTAZIONE DELL’EFFICIENZA ENERGETICA DEGLI EDIFICI A
PARTIRE DALLA VALUTAZIONE DELLE SOLE DISPERSIONI TERMICHE
DELL’INVOLUCRO, DEI CONSUMI TERMICI PER IL RISCALDAMENTO INVERNALE E
DELLA PRODUZIONE DI ACS (non presente negli edifici), TRASCURANDO I CONSUMI
ELETTRICI PER L’ILLUMINAZIONE, PER GLI ACCESSORI DEGLI UFFICI E PER LA
REFRIGERAZIONE ESTIVA.
• DA STAZIONE METEO (tetto dip. Ingegneria Industriale): Velocità media vento pari a 2.60 m/s
INSERIMENTO DEI DATI NEL PROGRAMMA TERMUS
DATI
GENERALI
RISULTATI
ELEMENTI
STRUTTURALI
DATI PORTE
E
FINESTRE
ASSEGNAZIONE
ZONE
DATI
GENERATORE
DATI GENERALI
DATI
GENERALI
RISULTATI
ELEMENTI
STRUTTURALI
DATI PORTE
E
FINESTRE
ASSEGNAZIONE
ZONE
DATI
GENERATORE
ASSEGNAZIONE ZONE
DATI
GENERALI
RISULTATI
ELEMENTI
STRUTTURALI
DATI PORTE
E
FINESTRE
ASSEGNAZIONE
ZONE
DATI
GENERATORE
DATI GENERATORE
DATI
GENERALI
RISULTATI
ELEMENTI
STRUTTURALI
DATI PORTE
E
FINESTRE
ASSEGNAZIONE
ZONE
DATI
GENERATORE
RISULTATI
DATI
GENERALI
RISULTATI
ELEMENTI
STRUTTURALI
DATI PORTE
E
FINESTRE
ASSEGNAZIONE
ZONE
DATI
GENERATORE
RISULTATI OTTENUTI PER GLI EDIFICI OGGETTO DI CALCOLO
EDIFICIO DI INGEGNERIA INDUSTRIALE
EDIFICIO LABORATORI INGEGNERIA INDUSTRIALE
EDIFICIO “A” FACOLTA’ DI ECONOMIA
EDIFICIO “B” FACOLTA’ DI LETTERE E FILOSOFIA
EDIFICIO “DIDATTICA” DELLA FACOLTA’ DI INGEGNERIA
L’Audit di I livello limita i suoi obiettivi solo ad uno screening di tipo preliminare degli edifici
universitari consentendo di ottenere una certificazione energetica di prima approssimazione che non
può prescindere da valutazioni successive più approfondite (Audit di II livello).
La bontà dei risultati è da ritenersi alterata da diversi fattori:
• insufficienza di dati input reperiti (es. dati specifici sulle stratigrafie dei materiali di muri e solai
• per ogni edificio e dati sui consumi storici per un riscontro finale);
• insufficienza di strumenti di misura durante i sopralluoghi;
• approssimazioni notevoli (es. trascurare nella ricostruzione geometrica degli edifici le pareti interne,
considerando un gradiente termico tra i diversi locali nullo e ritenendo solo l’involucro esterno
responsabile di dispersioni);
• scarsa conformità del tool Termus, e dei tool italiani in generale, alla normativa nazionale in materia
di certificazione energetica, che non considera i contributi dei consumi elettrici e dei consumi per il
raffrescamento estivo, nella realtà non trascurabili.

Diapositiva 1 - Università degli Studi di Roma "Tor Vergata"

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