energy management: 2014/2015 energy in buildings prof. tânia sousa [email protected]
TRANSCRIPT
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
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
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
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
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
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
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
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 – Meet the reduced load as much as possible using
passive solar heating, ventilation and cooling techniques while optimizing the use of daylight
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 – 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
Gestão de Energia
Slide 11 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 – 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
• Efficiency label• Annual power consumption (kWh/year)
Gestão de Energia
Slide 12 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
Gestão de Energia
Slide 13 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
Gestão de Energia
Slide 14 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
Gestão de Energia
Slide 15 of 53
• How much energy reduction can we achieve?
Energy Consumption in Buildings
Gestão de Energia
Slide 16 of 53
• How much does it cost?
Energy Consumption in Buildings
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Add
ition
alIn
vest
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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
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
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
Q U T Area
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
– 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
Gestão de Energia
Slide 20 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
Gestão de Energia
Slide 21 of 53
• Evolution for the heat transfer coefficients in new buildings in Portugal
The most highly insulated houses have a heat transfer coefficient of U=0.1-0.2 W/m2/K
Gestão de Energia
Slide 22 of 53
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
Gestão de Energia
Slide 23 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 reduce the absorption of long-wave radiation, i.e., they can reduce loss of heat by infrared radiation in winter
Buildings – High Performance Envelope
Gestão de Energia
Slide 24 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:
Gestão de Energia
Slide 25 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
Gestão de Energia
Slide 26 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
• Heat Exchangers: – 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
Gestão de Energia
Slide 28 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?
Gestão de Energia
Slide 29 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?
Gestão de Energia
Slide 30 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
20
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30% Base 60% Base 60% Upgraded
100% Base 100% Upgraded
En
erg
y In
ten
sity
(kW
h/m
2/y
r)
Heating Cooling LightingEquipment Pumps & fans Server rooms
Gestão de Energia
Slide 31 of 53
Buildings – The role of house size
• House size– The living area per family member increased by a factor of 3
between 1950 and 2000 in the US
Gestão de Energia
Slide 32 of 53
Buildings –Passive (almost) solar heating, ventilation & cooling
• Evaporative Cooling:
Gestão de Energia
Slide 33 of 53
Buildings –Passive (almost) solar heating, ventilation & cooling
• Evaporative Cooling:
Gestão de Energia
Slide 34 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
Earth Pipe cooling
Gestão de Energia
Slide 35 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
Large Atria
Gestão de Energia
Slide 36 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
Gestão de Energia
Slide 37 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Thermal & wind induced ventilation & cooling:
Wind catcher
Gestão de Energia
Slide 38 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Passive Solar Heating & Lighting
Shading
Light tubes
Gestão de Energia
Slide 39 of 53
Buildings – Passive (almost) solar heating, ventilation & cooling
• Passive Solar Heating & Lighting
TrombeWall
Gestão de Energia
Slide 40 of 53
Gestão de Energia
Slide 41 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
Gestão de Energia
Slide 42 of 53
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)
Gestão de Energia
Slide 43 of 53
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
Gestão de Energia
Slide 44 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
Gestão de Energia
Slide 45 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
Gestão de Energia
Slide 46 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
Gestão de Energia
Slide 47 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
Gestão de Energia
Slide 48 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
Gestão de Energia
Slide 49 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?
Gestão de Energia
Slide 50 of 53
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
Gestão de Energia
Slide 51 of 53
Directive 2010/31/EU: Principles
• Set Minimum Energy Performance Requirements– Requirements should take into account climatic and local
conditions and cost-effectiveness
Gestão de Energia
Slide 52 of 53
Directive 2010/31/EU: Principles
• Energy Performance Requirements should be applied to new buildings & buildings going through major renovations
Gestão de Energia
Slide 53 of 53
Directive 2010/31/EU: Principles
• Set System Requirements for: energy performance, appropriate dimensioning, control and adjustment for Technical Building Systems in existing and new buildings
Gestão de Energia
Slide 54 of 53
Directive 2010/31/EU: Principles
• Increase the number of nearly zero energy buildings
Gestão de Energia
Slide 55 of 53
• https://www.youtube.com/watch?v=pQFJr5E7_R0
Gestão de Energia
Slide 56 of 53
• 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
Gestão de Energia
Slide 57 of 53
• Regular maintenance of air conditioning and heating systems
• Independent experts
Directive 2010/31/EU: Principles
Gestão de Energia
Slide 58 of 53
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).
DOCTORAL PROGRAM AND EXECUTIVE MASTER IN SUSTAINABLE ENERGY SYSTEMS ENERGY MANAGEMENT – 4TH GROUP WORK
59
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
Gestão de Energia
Slide 60 of 53
• 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
Gestão de Energia
Slide 61 of 53
SCE – Fiscalização e Gestão
• Fiscalização e Gestão
• Obrigações Proprietários
Gestão de Energia
Slide 62 of 53
SCE – Edifícios ZEB
Gestão de Energia
Slide 63 of 53
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
Gestão de Energia
Slide 64 of 53
• 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
Gestão de Energia
Slide 65 of 53
RCCTE - Outdoor conditions
Reference Winter Outdoor conditions:
REH and RECS
Gestão de Energia
Slide 66 of 53
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
Gestão de Energia
Slide 67 of 53
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)
Gestão de Energia
Slide 68 of 53
RCCTE - Outdoor conditions
Reference Summer Outdoor conditions:
REH and RECS
Gestão de Energia
Slide 69 of 53
• 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
Gestão de Energia
Slide 70 of 53
• 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
Gestão de Energia
Slide 71 of 53
Heating
Heating: Maximum Useful Nominal Needs (Ni) [kWh / (m2.year)]
Heating: Useful Nominal Needs (Nic) [kWh / (m2.year)]
Nic < Ni
REH - Heating
Gestão de Energia
Slide 72 of 53
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
Gestão de Energia
Slide 73 of 53
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
Gestão de Energia
Slide 74 of 53
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
Gestão de Energia
Slide 75 of 53
Cooling
TPE: Maximum Nominal Needs (Nt) [kgep/(m2.year)]
TPE: Nominal Needs (Nvc) (Ntc) [kgep/(m2.year)]
REH: Total Primary Energy
Ntc < Nt
Gestão de Energia
Slide 76 of 53
REH: Conversion to Primary Energy
Comparação com SGCIE - 1MWh needs 0.217 toe?
Gestão de Energia
Slide 77 of 53
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
Gestão de Energia
Slide 78 of 53
• Valor mínimo de renovação de ar de 0.4 por hora
RCCTE – Indices e parametersREH – Thermal Behaviour
Gestão de Energia
Slide 79 of 53
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:
Gestão de Energia
Slide 80 of 53
• https://meocloud.pt/link/34d44317-19bb-467b-915e-78588c145383/Novo_CE_720p.mp4/