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Energy Management : 2014/2015
Energy Efficiency in Industry and Energy audits
Prof. Paulo Ferrão
Energy Management
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SGCIE
Sistema de Gestão dos Consumos Intensivos de Energia,
Management System of Intensive Energy Consumption
The PT National Strategy for Energy, by the Decree-Law n. º 71/2008 of 15 April, regulates SGCIE.
SGCIE é uma das medidas constantes do PNAEE – Plano Nacional de Ação em Eficiência Energética.
SGCIE is a measure included in the PNAEE - National Action Plan for Energy Efficiency.
Sistema de Gestão dos Consumos Intensivos de Energia,
Management System of Intensive Energy Consumption
The PT National Strategy for Energy, by the Decree-Law n. º 71/2008 of 15 April, regulates SGCIE.
SGCIE é uma das medidas constantes do PNAEE – Plano Nacional de Ação em Eficiência Energética.
SGCIE is a measure included in the PNAEE - National Action Plan for Energy Efficiency.
Energy Management
Slide 3 of 53
SGCIE
The Plan for the Rational Use of Energy (PREn) is developed based on the energy audits and should identify identify measures with a payback period of the investment (PRI) less than 3 years, or less than 5 years in the case of facilities with power consumption less than 1000 toe / year.
The PREn must also establish targets for energy and carbon intensities and Specific Energy Consumption, where applicable, based on measures provided in the preceding paragraph, taking into account the following indicators:
The Plan for the Rational Use of Energy (PREn) is developed based on the energy audits and should identify identify measures with a payback period of the investment (PRI) less than 3 years, or less than 5 years in the case of facilities with power consumption less than 1000 toe / year.
The PREn must also establish targets for energy and carbon intensities and Specific Energy Consumption, where applicable, based on measures provided in the preceding paragraph, taking into account the following indicators:
Energy Management
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SGCIE
1. Energy intensity, measured by the ratio between the total energy consumption (considering only 50% of the energy derived from endogenous waste and other renewable fuels) and Gross Value Added (GVA) of business activities directly linked to these sites;
2. Carbonic intensity, measured by the ratio between the amount of emissions of greenhouse gases resulting from the use of various forms of energy in the production process and its total energy consumption;
3. Specific Energy Consumption, measured by the ratio between the total energy consumption (considering only 50% of the energy derived from endogenous waste and other renewable fuels) and the volume of production.
1. Energy intensity, measured by the ratio between the total energy consumption (considering only 50% of the energy derived from endogenous waste and other renewable fuels) and Gross Value Added (GVA) of business activities directly linked to these sites;
2. Carbonic intensity, measured by the ratio between the amount of emissions of greenhouse gases resulting from the use of various forms of energy in the production process and its total energy consumption;
3. Specific Energy Consumption, measured by the ratio between the total energy consumption (considering only 50% of the energy derived from endogenous waste and other renewable fuels) and the volume of production.
Energy Management
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SGCIE
The goals referred to in the preceding paragraph are subject to the following values :
a)At a minimum, an improvement of 6% of the indicators referred to in 1 and 3 above, in six years, in the case of facilities with energy-intensive less than 1000 toe / year, or 4% improvement in eight years for other facilities;
b)At a minimum, the maintenance of the historical values of carbon intensity.
The goals referred to in the preceding paragraph are subject to the following values :
a)At a minimum, an improvement of 6% of the indicators referred to in 1 and 3 above, in six years, in the case of facilities with energy-intensive less than 1000 toe / year, or 4% improvement in eight years for other facilities;
b)At a minimum, the maintenance of the historical values of carbon intensity.
Energy Management
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SGCIE
Energy Management
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SGCIE
Energy Management
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ENERGY AUDIT
Energy Management
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• Detailed analysis of the energy use in a certain equipment,
activity, installation , building, campus:
– Where energy is used
– When energy is used
– How energy is used
• Through an audit it is possible to:
– identify/model the required energy services
– Design a solution to improve the energy use and supply
• Equipment replacement, process change, user
behaviour change
Energy audit – key goals
Energy Management
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Energy Audit Phases
• Preparing and Planning
• Facility inspection
• Field Work
• Data analysis
• Energy audit reporting
• Energy Action Plan
Energy Management
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PREPARATION AND PLANNING
Energy Management
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Tasks
• Collect data regarding energy use and production
– Energy bills (at least 1 year)
– Production (at least 1 year)
• Collect data regarding building envelope and equipment's
– Location and weather data
– Building description (blueprints, bill of materials, etc.)
– Characteristics of the main equipment's
– Functional organization, analysis of
• Preliminary data analysis
– Find any awkward result…
Energy Management
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Preliminary visit
• Visit together with the facility manager to see
how the facility operates
• Collect other data (if available)
• Observe the building envelope
• Identify “low-hanging fruit” savings
Energy Management
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Forma de energia E.Eléctrica PropanoUnidade fisica MWh TonGcal/unid. fisica 0.86 11.39GJ/unid. fisica 3.60 46.30Tep/unid. fisica 0.29 1.14
Mês E.Eléctrica Propano E.Eléctrica PropanoMWh Ton MWh Ton
Jan 266.5 176.3 374.0 150.3Fev 285.3 152.6 435.7 171.6Mar 270.8 169.1 397.3 194.3Abr 385.4 165.2 410.0 123.6Mai 322.8 158.7 416.7 180.2Jun 368.6 157.9 468.8 185.7Jul 367.0 151.1 464.1 194.1
Ago 336.1 115.2 292.0 156.9Set 315.4 189.0 494.1 187.9Out 410.5 188.7 398.8 199.1Nov 398.7 196.6 493.4 209.2Dez 431.2 162.8 422.8 158.3
Total 4,158.4 1,983.1 5,067.8 2,111.3
Média 346.5 165.3 422.3 175.9
1998 1999Mês 1998 1999
(fx) (fx)Jan 33,324 56,894Fev 37,658 51,774Mar 40,846 58,383Abr 35,727 43,010Mai 41,889 45,421Jun 45,167 48,938Jul 45,463 52,463
Ago 36,083 35,180Set 63,351 51,809Out 60,443 48,316Nov 67,612 51,692Dez 53,611 30,666
Total 561,174 574,546Média 46,765 47,879
Energy Management
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0
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0 10000 20000 30000 40000 50000 60000 70000Produção Mensal
Factura Especifica ($/(fx))
Energy Management
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y = 0.0025x + 303.13
R2 = 0.1322
0
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0 10000 20000 30000 40000 50000 60000 70000
Produção Mensal
En
erg
ia E
léct
rica
(M
Wh
)
Energy Management
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0
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0 10000 20000 30000 40000 50000 60000 70000
ProduçãoMensal
Co
nsu
mo
Esp
ecíf
ico
Elé
ctri
co(k
Wh
/To
n)
Energy Management
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y = 0.0023x + 214.46
R2 = 0.2301
0
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0 10,000 20,000 30,000 40,000 50,000 60,000 70,000
Produção Mensal
En
erg
ia P
rim
ária
(Te
p/m
ês)
Energy Management
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0
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0 10,000 20,000 30,000 40,000 50,000 60,000 70,000
Produção Mensal
Consumo especifico de Energia Primaria (kgep/(fx))
Energy Management
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FACILITY CHARACTERIZATION
Energy Management
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Objective
• Detailed analysis of the collected data– Evaluate energy consumption baseline (normalize
climate data)– Prepare energy balance– Identify energy services
• Characterize equipment's performance• Heating and cooling
– Hot water and steam boilers
– Chillers and cooling towers– Ait treatment units– Ventilation units– Pumps and pipes– Air conditioning units– Air conditioning controllers
• Hot Water– Tankers
• Lighting– Lights– Ballasts– Controllers
• Elevators and other mechanical transportation systems
• Specific equipment's of the building– Monitors in hospitals, TVs in
restaurants• Refrigeration equipment's in kitchens ,
laundries, pools• Energy generation systems (solar, co-
generation)• The efficiency of every heat generation
system should be verified
Energy Management
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Field Work Plan
• With the collected data and the characterization of the facility, prepare the field work:– The list of equipments that will be measured– The list of equipments that needs to be used for
measurement– The measuring procedure (one point measure, long data
collection)– Interviews to be done to complete information
Energy Management
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FIELD WORK
Energy Management
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Main activities
• Measure energy consumption of main sectors/equipments
– Productive systems, hot water, heating and ventilation
– Identify lack of maintenance
• Verify electric installations
• Verify HVAC and lighting controllers
• Continuous monitoring or main consumption points of
energy to obtain load diagrams
– One day
– One week
Energy Management
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Complementary activities
• Complementary measurements to collect information – Room temperatures– Room luminance
• Characterize schedule of main equipments (interviews, observations)
• Characterize the envelope in detail and how users interact with it (interviews, observations)
• Characterize utilization patterns
Energy Management
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EQUIPMENTEQUIPMENT
Energy Management
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Physical entities• Electricity• Mass flow• Temperature• Humidity• Flue gases composition• Luminance• Total dissolved solids
Equipment• Electrical analyzer• Anemometer (turbine, Pitot)• Thermometer• Humidity meter• O2, CO2, CO analyzer• Luximeter• TDS meter
Energy Management
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Energy Management
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0
50
100
150
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350
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450
0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00
Pot
ênci
a (k
W)
Potência Média Potência Instantânea
Sábado6ª feira5ª feira4ª feira
Energy Management
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0
5
10
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12:00 15:00 18:00 21:00 0:00 3:00 6:00 9:00 12:00
Pot
ênci
a (k
W)
P. Média P. Instantânea
Medições no compressor 793Medições no compressor 793
Energy Management
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Energy balances in energy audits
The energy balance in EAs differs from current thermodinamic energy balances because some unknowns are obtained by measurements.
Unknowns obtained from measurements have an error of measurement
Energy balances in energy audits
The energy balance in EAs differs from current thermodinamic energy balances because some unknowns are obtained by measurements.
Unknowns obtained from measurements have an error of measurement
Energy Management
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Energy audit objectives:
1 - Energy accountability (data)
2 - Energy consumption (measurements)
Direct measurement
Energy balance (equation + measures)
3 - Energy savings
Energy audit objectives:
1 - Energy accountability (data)
2 - Energy consumption (measurements)
Direct measurement
Energy balance (equation + measures)
3 - Energy savings
Energy Management
Slide 33 of 53
Energy balances in energy audits
The energy balance in EAs differs from current thermodinamic energy balances because some unknowns are obtained by measurements.
Unknowns obtained from measurements have an error of measurement
Oftenly we do also need to assume the values of certain parameters and then to check the balances.
Energy balances in energy audits
The energy balance in EAs differs from current thermodinamic energy balances because some unknowns are obtained by measurements.
Unknowns obtained from measurements have an error of measurement
Oftenly we do also need to assume the values of certain parameters and then to check the balances.
Energy Management
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HOT WATER
Energy Management
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Hot Water
• Water used for– Showers– Washing (dishes, clothes, house cleaning)
• Important Variables• Litters of water• Final temperature (Hot)• Initial temperature (Cold)
• Energy
Energy Management
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Water usage
• Reducing water usage reduces energy water consumption
Energy Management
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Water Temperature
• The Final Temperature has two conflicting constraints
– Skin scalding (5s at 60ºC)
– Bacterial Contamination (e.g. Legionella)
• The European Guidelines for Control and Prevention of Travel Associated
Legionnaires’ Disease recommend that hot water should be stored at 60
°C (140 °F) and distributed such that a temperature of at least 50
°C (122 °F) and preferably 55 °C (131 °F) is achieved within one minute at
points of use
• The Initial Temperature
– Depends on the ambient temperature
Energy Management
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Pipes losses
Typical values in Portugal
Energy Management
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Frontier definitionCharacterization of mass and energy flows
Equations identificationDefinition of measurement plan
Equipment selectionMeasurements
Validation
Energy balance sequence:Energy balance sequence:
Energy Management
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Electricalresistance
Wall Losses
3
21
Qelec
Example: Industrial heat generatorExample: Industrial heat generator
Energy Management
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Equations and unknowns:
Mass and energy balance:
Equations and unknowns:
Mass and energy balance:
LossHTCmQTCmTCm
mmm
ppp .332211
321
Unknowns - measurements:
Good confidence: Q, T1, T2, T3
Less confidence: m1, m2
No confidence: m3, Heat loss
Unknowns - measurements:
Good confidence: Q, T1, T2, T3
Less confidence: m1, m2
No confidence: m3, Heat loss
Energy Management
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Case 1: Equilibrium
2 Equations = 2 Unknowns
Measurements accepted:
Q, T1, T2, T3, m1, m2
Unknowns obtained by 2 eq. System:
m3, Heat loss
Case 1: Equilibrium
2 Equations = 2 Unknowns
Measurements accepted:
Q, T1, T2, T3, m1, m2
Unknowns obtained by 2 eq. System:
m3, Heat loss
Energy Management
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AUDIT REPORT & ACTION PLAN
Energy Management
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Objective
• Describe the energy demand of the installation and the costs
• Describe the equipment status• Identify energy efficiency measures, the
investment and its potential payback– Substitution or retrofit of equipment– Use of more efficient controllers– Installation of energy management systems– Introduction of renewable resources generation
• Identify upcoming changes in regulations that may impact on the current energy use
Energy Management
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Action Plan
• From the different measures proposed in the energy audit, identify an implementation plan– Investment plan– Schedule
• Low cost measures should be the first to be implemented
• The return of investment period should be the indicator used to prioritize the measures in the plan
• This should be done closely with the energy manager and the board
Energy Management
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KEY ENERGY SYSTEMS
Energy Management
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SPACE HEATING (AND COOLING)
Energy Management
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Thermal Balance (1)
Applying the 1st law of thermodynamics– Balance between all the gains and
losses• Solar (S) • Internal(I)• Conduction, convection and
radiation through envelope (T)• Air mass balance/ventilation (V)
Energy Management
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• Electric appliances– Computers
• Heat generation in power sources, processor– Lighting
• Radiation and convection– Occupants
• Radiation, convection, latent heat (water vapour)
We do not consider here the heat generation from radiators, fireplaces, AC
Energy Management
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Energy generated by occupants
Energy Management
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Air exchanges and leakages
• Air Exchange between the interior and the exterior originates changes in the internal energy (and thus temperature)
Energy Management
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Dynamic simulation
• It allows to evaluate all heat exchanges and calculates heating and cooling needs
Open Studio
Design Builder
Energy Management
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THE INFLUENCE OF CLIMATE
Energy Management
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Degree Days
• Simple and direct method (though incomplete) to
characterize the climate of a certain region
– It measures the product between the number of days
and the number of degrees that the interior temperature
is lower (heating) or higher (cooling) than a certain
comfort temperature
• Heating degree days (HDD)
• Cooling degree days (CDD)
Energy Management
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HDD and CDD in Europe
Energy Management
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THERMAL COMFORT
Energy Management
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Comfort temperature
“mind state that expresses satisfaction about the thermal environment”
•Human comfort depends on the ability to control the body temperature between 36 and 37ºC•It depends on the balance between heat exchange
– It is not only about air temperature• It depends on the humidity
(evaporation/transpiration)– It depends on the activity, clothes, etc…
Energy Management
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Comfort conditions
• Temperature: 20 to 27ºC• Relative humidity: 30 to 60%
Energy Management
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INSULATION
Energy Management
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Thermal and air leakage insulation
Energy Management
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Thermal bridges
• It describes the disruption of the thermal insulation due to the existence of a material with high conductivity
• They can represent up to 20% losses
Energy Management
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Green roofs and facades
• Adds width (L) with a fairly good insulation – k: 0.18 a 0.41 W/mK– Concrete roof k=1.4 W/mK
• Has impact on radiation and convection through latent heat
