energy management: 2013/2014 energy in buildings prof. tânia sousa [email protected]
TRANSCRIPT
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Gestão de Energia
Slide 2 of 53
• Buildings account for 31% of global final energy consumption (20 to 40%)
• Energy Services?
Energy Consumption in Buildings
1MWh=3.6GJ
16.45GJ
66.96GJ
34.70GJ
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Gestão de Energia
Slide 3 of 53
• Buildings account for 31% of global final energy consumption (20 to 40%)
• Energy use in buildings: thermal confort, refrigeration, hygiene, nutrition, illumination, etc
Energy Consumption in Buildings
1MWh=3.6GJ
16.45GJ
66.96GJ
34.70GJ
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Gestão de Energia
Slide 4 of 53
Energy Consumption in Buildings
• Final Energy use in buildings by fuel in 2007 in EJ
– Differences?
Residential Commercial &Public
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Gestão de Energia
Slide 5 of 53
Energy Consumption in Buildings
• Final Energy use in buildings by fuel in 2007 in EJ
– Combustible and renewables is the most important fuel in residential buildings while electricity dominates comercial buildings
Residential Commercial &Public
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Gestão de Energia
Slide 6 of 53
• What about Portugal?– In 2007 the final consumption of services + domestic sector
represented 29% of the final energy consumption
– In 2007 the final consumption per capita was 21.34 GJ which is 61.5% of the EU-27
– Electricity is 49% of the final energy used by buildings (68% in comercial and 36% in residential)
Energy Consumption in Buildings
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Gestão de Energia
Slide 7 of 53
• What about Portugal?– In 2007 the final consumption of services + domestic sector
represented 29% of the final energy consumption
– In 2007 the final consumption per capita was 21.34 GJ which is 61.5% of the EU-27
– Electricity is 49% of the final energy used by buildings (68% in comercial and 36% in residential)
– Do you think that the fraction of primary energy would be higher or lower?
• Electricity is 22% of total final energy
Energy Consumption in Buildings
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Gestão de Energia
Slide 8 of 53
Energy Consumption in Buildings
• Most effective strategy to reduce energy use in buildings (Harvey, 2010):– Reduce heating and cooling loads through a high-
performance envelope • high degree of insulation, windows with low U values in cold
climates and low solar heat gain in hot climates, external shading and low air leakage
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Gestão de Energia
Slide 9 of 53
Energy Consumption in Buildings
• Most effective strategy to reduce energy use in buildings (Harvey, 2010):– Reduce heating and cooling loads through a high-
performance envelope • high degree of insulation, windows with low U values in cold
climates and low solar heat gain in hot climates, external shading and low air leakage
– Meet the reduced load as much as possible using passive solar heating, ventilation and cooling techniques while optimizing the use of daylight
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Gestão de Energia
Slide 10 of 53
Energy Consumption in Buildings
• Most effective strategy to reduce energy use in buildings (Harvey, 2010):– Reduce heating and cooling loads through a high-
performance envelope • high degree of insulation, windows with low U values in cold
climates and low solar heat gain in hot climates, external shading and low air leakage
– Meet the reduced load as much as possible using passive solar heating, ventilation and cooling techniques while optimizing the use of daylight
– Use the most efficient mechanical equipment to meet the remaining loads
– Ensure that individual energy-using devices are as efficient as possible and properly sized
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Gestão de Energia
Slide 11 of 53
• How much energy reduction can we achieve?– Passive house standard:
heating 15kWh/m2 per yearcooling 15 kWh/m2 per yearTPE 120 kWh/m2 per yearn50 ≤ 0.6 / hour
Energy Consumption in Buildings
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Gestão de Energia
Slide 12 of 53
• How much energy reduction can we achieve?
Energy Consumption in Buildings
Triple-glazed windows with internal venetian blinds & mechanical ventilation with 82% heat recovery
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Gestão de Energia
Slide 13 of 53
Heating needs decreased from 220 kWh/m2/year to 30 kWh/m2/year
• How much energy reduction can we achieve?
Energy Consumption in Buildings
Triple-glazed windows with internal venetian blinds & mechanical ventilation with 82% heat recovery
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Gestão de Energia
Slide 14 of 53
• How much energy reduction can we achieve?
Energy Consumption in Buildings
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Gestão de Energia
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• How much does it cost?
Energy Consumption in Buildings
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Add
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alIn
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t(€/
m2 )
ofP
assi
veR
owH
ouse
s 1991 Prototype: experimental house,4 dwellings in Kranichstein usinghandicraft batch production
PH in Groß-Umstadt:Reduced costs bysimplification
Settlement in Wiesbaden:Serially produced windows & structural elements
Settlements in Wuppertal,Stuttgart, Hanover
Row houses in Darmstadt, 80 €/m2
Profitability with contemporary
interest rates & energy prices
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Gestão de Energia
Slide 16 of 53
Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on insulation levels in the walls, ceiling and basement
– Insulation levels control the heat flow by conduction &
convection through the exterior and the interior
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Gestão de Energia
Slide 17 of 53
Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on insulation levels in the walls, ceiling and basement
– Insulation levels control the heat flow by conduction &
convection through the exterior and the interior
Q U T Area
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Gestão de Energia
Slide 18 of 53
Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on insulation levels in the walls, ceiling and basement
– Insulation levels control the heat flow by conduction &
convection through the exterior and the interior
– U value (W/m2/K), the heat transfer coefficient, is equal to the
heat flow per unit area and per degree of inside to outside
temperature difference
– The U value of a layer of insulation depends on its thickness l
and type of material (conductivity – C)
Q U T Area
U C l
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Gestão de Energia
Slide 19 of 53
Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on insulation levels in the walls, ceiling and basement
Foam insulation
The most highly insulated houses have a heat transfer coefficient of U=0.1-0.2 W/m2/K
Blown-in cellulose insulation (fills the gaps)
Vaccum insulation panels
Q U T Area U C l
Cork 0.06-0.07 W/m/K
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Gestão de Energia
Slide 20 of 53
• Evolution for the heat transfer coefficients in new buildings in Portugal
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Gestão de Energia
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Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on the insulation levels of windows
– Windows offer substantially less resistance to the loss of heat
than insulated walls
– Single glazed windows have a typical U-value of 5W/m2/K
which can be reduced to to 2.5 and 1.65W/m2/K with double
and triple glazing because of the additional layers of air
– The U-value of 2.5W/m2/K of double glazed windows can be
reduced to 2.4W/m2/K and 2.3W/m2/K with Argon and krypton
– Double and triple glazing vaccum windows can reduce the U
value to 1.2 and 0.2W/m2/K
Q U T Area U C l
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Gestão de Energia
Slide 22 of 53
• The effectiveness of the thermal envelope depends on the gain/loss energy by radiation – Windows permit solar energy to
enter and loss of infrared radiation
– The solar heat gain coefficient, SHGC, is the fraction of solar radiation inicident on a window that passes through the window
– Low emissivity coatings reflect more (reduce SHGC), i.e., reduce heat gains in summer and winter
– Low emissivity coatings can reduce loss of heat by infrared radiation
Buildings – High Performance Envelope
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Gestão de Energia
Slide 23 of 53
Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on the air leakage– The net heat flow due to an air exchange at rate r is:
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Gestão de Energia
Slide 24 of 53
Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on the air leakage– The internal energy change due to an air exchange at rate r is:
– The stack effect promotes air leakage• Warm air is lighter• Stack effect can account for up to
40% of heating requirements on cold climates
– The wind effect
p,airU V c Tair air
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Gestão de Energia
Slide 25 of 53
Buildings – High Performance Envelope
• The effectiveness of the thermal envelope depends on the air leakage
– Careful application of a continuous air barrier can reduces rates
of air leakage by a factor of 5 to 10 compared to standard
practice (enforcement of careful workmanship during
construction)
– Buildings with very low air
leakage require mechanical
ventilation (95% of the available
heat in the warm exhaust air
can be transfered to the
incoming cold air) to keep indoor air quality
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• Heat Exchangers: – Used in power plants, air conditioners, fridges,
liquefication of natural gas, etc– Transfer energy between fluids at different
temperatures
Energy Balance in Open Systems
22
, ,2 2ji
in i i i out j j ji j
vvdEQ W m h gz m h gz
dt
Counter-flow Heat exchanger
Direct Flow Heat Exchanger
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Gestão de Energia
Slide 27 of 53
Buildings – The role of shape, form, orientation and glazed %
• Building shape & form– Have significant impacts on heating and cooling loads and
daylight because of the relation between surface area and volume
– Which one minimizes heat transfer by conduction and convection?
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Gestão de Energia
Slide 28 of 53
Buildings – The role of shape, form, orientation and glazed %
• Building orientation– For rectangular buildings the optimal
orientation is with the long axis facing south
– Why?
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Gestão de Energia
Slide 29 of 53
Buildings – The role of shape, form, orientation and glazed %
• Glazing fractions– High glazing fractions increase energy requirements for heating
and cooling– There is little additional daylighting benefit once the glazed
fraction increases beyond 30-50% of the total façade area
0
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30% Base 60% Base 60% Upgraded
100% Base 100% Upgraded
En
erg
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Heating Cooling LightingEquipment Pumps & fans Server rooms
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Gestão de Energia
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Buildings – The role of shape, form, orientation and glazed %
• House size– The living area per family member increased by a factor of 3
between 1950 and 2000 in the US
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Gestão de Energia
Slide 31 of 53
Buildings –Passive (almost) solar heating, ventilation & cooling
• Evaporative Cooling:
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Gestão de Energia
Slide 32 of 53
Buildings –Passive (almost) solar heating, ventilation & cooling
• Evaporative Cooling:
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Gestão de Energia
Slide 33 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
Earth Pipe cooling
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Gestão de Energia
Slide 34 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
Large Atria
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Gestão de Energia
Slide 35 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
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Gestão de Energia
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Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
Wind catcher
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Gestão de Energia
Slide 37 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Passive Solar Heating & Lighting
Shading
Light tubes
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Gestão de Energia
Slide 38 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Passive Solar Heating & Lighting
Parede Trombe
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Gestão de Energia
Slide 39 of 53
Buildings: Mechanical Equipment
• In evaluating the energy efficiency of Mechanical Equipment the overall efficiency from primary to useful energy should be taken into account
• This is particularly important in the case of using Mechanical Equipments that use electricity (produced from fossil fuels)
final
primary
E
E
useful
final
E
E
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Gestão de Energia
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Buildings: Mechanical Equipment for heating
• Furnaces– heat air and distribute the heated
air through the house using ducts; – are electric, gas-fired (including
propane or natural gas), or oil-fired.
– Efficiencies range from 60 to 92%(highest for condensing furnaces)
• Boilers– heat water, and provide either hot
water or steam for heating; – heat is produced from the combustion
of such fuels as natural gas, fuel oil, coal or pellets.
– Efficiencies range from 75% to 95%(highest for condensing boilers)
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Gestão de Energia
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Buildings: Mechanical Equipment for heating & cooling
• Electrical-resistance heating– Overall efficiency can be quite
low (primary -> useful) • Heat-Pumps
– Overall efficiency can be quite good– It decreases with T– Air-source and ground-source– For cooling & heating
• District Heating/Colling– For heating & cooling– Users don’t need
mechanical equipment
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Gestão de Energia
Slide 42 of 53
Buildings: Mechanical Equipment for cooling
• Chillers– Produce cold water which is circulated through the
building– Electric Chillers: use electricity, COP = 4.0-7.5 (larger
units have a higher COP)– Absorption chillers: use heat (can be waste heat from
cogeneration) , COP = 0.6-1.2
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Gestão de Energia
Slide 43 of 53
Buildings: HVAC Systems
• Ventilate and heat or cool big buildings• All air systems: air at a sufficient low (high) T and in
sufficient volumes is circulated through the building to remove (add) heat loads– CAV: constant air volumes– VAV: variable air volumes– Air that is circulated in the supply ducts may be taken entirely
from the outside and exhausted to the outside by the return ducts or a portion of the return air may be mixed with fresh air
– Incoming air needs to be cooled and dehumidified in summer and heated and (sometimes) humidified in winter
• Restrict air flow to ventilation needs and use additional systems for additional heating/cooling
• Heat exchangers that transfer heat between outgoing and incoming air flows
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Gestão de Energia
Slide 44 of 53
Buildings: Mechanical Equipment for water heating
• Electrical and natural gas heaters– Efficiency of natural gas heaters is 76-85%– Efficiency of oil heaters is 75-83%– There is heat loss from storage tanks– Point-of-use tankless heaters have losses associated
with the pilot light• There are systems that recover heat
from the warm wastewater with 45-65 % efficiencies
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Gestão de Energia
Slide 45 of 53
European Directives
• European Directives on the Energy Performance of Buildings– Directive 2002/91/EC of the European Parliament and Council
(on the energy performance of buildings):– http://ec.europa.eu/avservices/video/videoplayer.cfm?ref=I
048425&videolang=en&sitelang=en– This was implemented by the Portuguese Legislation RCCTE and
RCESE – Directive 2010/31/EU of the European Parliament and Council
(on the energy performance of buildings)– This is implemented by the Portuguese Legislation DL 118/2013
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Gestão de Energia
Slide 46 of 53
Directive 2010/31/EU: Aims
• Reduction of energy consumption• Use of energy from renewable sources• Reduce greenhouse gas emissions• Reduce energy dependence• Promote security of energy supplies• Promote technological developments• Create opportunities for employment & regional
development
• Links with aims of SGCIE?
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Gestão de Energia
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Directive 2010/31/EU: Principles
• The establishment of a common methodology to compute Energy Performace – including thermal characteristics, heating and air
conditioning instalations, renewable energies, passive heating and cooling, shading, natural light and design
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Gestão de Energia
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Directive 2010/31/EU: Principles
• Set Minimum Energy Performance Requirements– Requirements should take into account climatic and local
conditions and cost-effectiveness
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Gestão de Energia
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Directive 2010/31/EU: Principles
• Energy Performance Requirements should be applied to new buildings & buildings going through major renovations
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Gestão de Energia
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Directive 2010/31/EU: Principles
• Set System Requirements for: energy performance, appropriate dimensioning, control and adjustment for Technical Building Systems in existing and new buiildings
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Gestão de Energia
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Directive 2010/31/EU: Principles
• Increase the number of nearly zero energy buildings
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Gestão de Energia
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• https://www.youtube.com/watch?v=pQFJr5E7_R0
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Gestão de Energia
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• Establish a system of Energy performace certificates.– Energy Performance certificates must be issued for
constructed, sold or rented to new tenants
– Buildings occupied by public authorities should set na example (ECO.AP in 300 public buildings in Portugal)
Directive 2010/31/EU: Principles
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Gestão de Energia
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• Regular maintenance of air conditioning and heating systems
• Independent experts
Directive 2010/31/EU: Principles
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Gestão de Energia
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Implementation of the directives
• Directive 2002/91/EC was implemented with:
• Directive 2010/31/EU was implemented with:– DL 118/2013 (SCE, REH e RECS)
1. DL 78/2006, the National Energy Certification and Indoor Air Quality in Buildings (SCE).
2. DL 79/2006, Regulation of HVAC Systems of Buildings (RSECE).
3. DL 80/2006, Regulation of the Characteristics of Thermal Performance of Buildings (RCCTE).
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DOCTORAL PROGRAM AND EXECUTIVE MASTER IN SUSTAINABLE ENERGY SYSTEMS ENERGY MANAGEMENT – 4TH GROUP WORK
56
Legislative Framework
1/17/2014
Despachos15793-C/2013 Pre-certificates and Certificates templates
15793-D/2013 Conversion factors
15793-E/2013 Computation simplification rules
15793-F/2013 Climatic data
15793-G/2013 Testing and maintenance plan
15793-H/2013 Renewable energies
15793-I/2013 Energy demand calculation
15793-J/2013 Energy classification rules
15793-K/2013 Thermal parameters
15793-L/2013 Economic analysis methodology of energy efficiency measures
Decreto-Lei n.º 118/2013 SCE – Buildings Energy Certificate System REH – Residential Buildings Energy Performance RegulationRECS – Commerce and Services Buildings Energy Performance Regulation
Lei n.º 58/2013Defines rules for SCE technicians
Legislative framework is complemented by:
5 portarias10 despachos
Portarias349-A/2013 Role of SCE managing entity
349-B/2013 Methodology and requirements to classify residential buildings’ energy performance (REH)
349-C/2013 Permitting procedures and usage authorization of urban buildings
349-D/2013Methodology and requirements to classify commerce and service buildings’ energy performance (RECS)
353-A/2013 Indoor air quality
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Gestão de Energia
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• Buildings that SCE applies to:– Edifícios ou fracções novos ou sujeitos a grande
intervenção
– Edifícios área útil > 1000m2 ou > 500m2
– Edifícios ou fracções a partir do momento da sua venda
RCCTE – Domain of applicationSCE – Domain of Application
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Gestão de Energia
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SCE – Fiscalização e Gestão
• Fiscalização e Gestão
• Obrigações Proprietários
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Gestão de Energia
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SCE – Edifícios ZEB
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Gestão de Energia
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REH
• Objectivos:– Requisitos mínimos para edifícios de habitação novos ou
sujeitos a grandes alterações– Metodologia de caracterização do desempenho
energético em condições nominais– Metodologia de desempenho dos sistemas técnicos
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Gestão de Energia
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• I3 (higher heating needs) and V3 (higher colling needs)
RCCTE - Outdoor conditions
Reference Outdoor conditions:
• Portugal is divided in winter and summer climatic zones
Reference Indoor conditions
• 18ºC in heating season• 25ºC in the cooling season• Consumption of 40 liters of water at T+35ºC/occupant . day
REH and RECS
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Gestão de Energia
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RCCTE - Outdoor conditions
Reference Winter Outdoor conditions:
REH and RECS
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Gestão de Energia
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Climate
• Heating Degree-days are:
• Where:• Tb is the desired indoor temperature (18ºC)
• Tj is the temperature outside the hours j
• The Degree-days are calculated for an entire year
• For example, to Lisbon, for Tb = 18 º C, heating degree days are 1071 º C. day. Knowing the heating season is 5.3 months (160 days), the average daily GD (GDI) will be 6.7 º C.
24
se;1i
days Heating
1iiannual 24
where jb TTj
jb TTGDGDGD
Heating Degree Days
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Gestão de Energia
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Heating Degree Days – a comparison
0
1000
2000
3000
4000
5000
6000
Edmonto
n
Win
nipeg
Toronto
Vanco
uver
Berlin
Vienna
Helsi
nki
He
ati
ng
De
gre
e D
ay
s (
K-d
ay
s)
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Gestão de Energia
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RCCTE - Outdoor conditions
Reference Summer Outdoor conditions:
REH and RECS
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Gestão de Energia
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• Heat transfer coefficient:
• Factores solares
RCCTE – Indices e parameters
U Heat transfer coefficients of walls
Umax The corresponding maximum permissible
Fs Solar factor of fenestration (for windows not facing NE-NW with area > 5%)
Fsma
x
The corresponding maximum permissible
REH – Minimum requirements
more demanding for harsher winters
more demanding for harsher summers
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Gestão de Energia
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• Annual useful energy needs for cooling and heating in new buildings:
• Annual total primary energy in new buildings:
RCCTE – Indices e parameters
Nic Nominal Annual Needs of Useful Energy for Heating
Ni The corresponding maximum permissibleNic ≤ Ni
Nvc Nominal Annual Needs of Useful Energy for Cooling
Nv The corresponding maximum permissibleNvc ≤
Nv
REH – Thermal Behaviour
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Gestão de Energia
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Heating
Heating: Maximum Useful Nominal Needs (Ni) [kWh / (m2.year)]
Heating: Useful Nominal Needs (Nic) [kWh / (m2.year)]
Nic < Ni
REH - Heating
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Gestão de Energia
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Heating
Heating: Maximum Useful Nominal Needs (Ni) [kWh / (m2.year)]
Heating: Useful Nominal Needs (Nic) [kWh / (m2.year)]
Nic = (Qtr,i + Qve,i – Qgu,i) / Ap
Qt = 0.024 x GD x (A x U)
Qv = 0,024 (0,34 x R x Ap x Pd) x GD Qt: heat loss by conduction & convection through the surrounding
Qv: heat losses resulting from air exchange
Qgu: solar gain and internal load
Nic < Ni
REH - Heating
Corrected if there is heat recovery
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Gestão de Energia
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Current average residential heating energy use (Harvey, 2010)
• 60-100 kWh/m2/yr for new residential buildings in Switzerland and Germany
• 220 kWh/m2/yr average of existing buildings in Germany
• 250-400 kWh/m2/yr for existing buildings in central and eastern Europe
• Passive house standard: 15 kWh/m2/yr
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Gestão de Energia
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Cooling
Cooling: Maximum Useful Nominal Needs (Nv) [kWh/(m2.year)]
Cooling: Useful Nominal Needs (Nvc) [kWh / (m2.year)]
Nvc = Qg * (1 - ) / Ap (kWh/m2year)
Qg : Total gross load (internal + walls + solar + air renewal)
: Load Factor
Nvc < Nv
REH: Cooling
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Gestão de Energia
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Cooling
TPE: Maximum Nominal Needs (Nt) [kgep/(m2.year)]
TPE: Nominal Needs (Nvc) (Ntc) [kgep/(m2.year)]
REH: Total Primary Energy
Ntc < Nt
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Gestão de Energia
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REH: Conversion to Primary Energy
Comparação com SGCIE - 1MWh needs 0.217 toe?
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Gestão de Energia
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REH – Equipment Energy Efficieny
• Os equipamentos de aquecimento e arrefecimento ambiente e de aquecimento de águas devem cumprir requisitos de eficiência
• A instalação de equipamento solar térmico para AQS (ou de outras renováveis) é obrigatória desde que a exposição solar seja adequada
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Gestão de Energia
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• Valor mínimo de renovação de ar de 0.4 por hora
RCCTE – Indices e parametersREH – Thermal Behaviour
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Gestão de Energia
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Energy label
A A+
B- B
C
D
E
F
G
New buildings
1
2
3
R
R = Ntc / Nt
Energy Performance Certificate
• Energy Labelling:
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Gestão de Energia
Slide 77 of 53
• https://meocloud.pt/link/34d44317-19bb-467b-915e-78588c145383/Novo_CE_720p.mp4/