slides 4- energy analysis energy analysis. slides 4 – energy analysis structure of a...
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Slides 4- Energy analysis
ENERGY ANALYSIS
Slides 4 – Energy analysis
Structure of a company's energy system
Supply Conversion Distribution Consumption
Heat recovery
Disposal
Slides 4 – Energy analysis
Energy efficiencyTypical areas of improvement
Cooling/refrigerationHeatingCompressed air InsulationHeat recoverySeparation processesLighting ...
Slides 4 – Energy analysis
Efficient energy use
Not only a question of best technology!
Slides 4 – Energy analysis
Energy management
Organization Set up an organizational unit,identify responsibilities and determine
the budgetAnalysis and Inventory and description
Planning of the energy situation search for energy saving options
Control Control of the energy plants, work out energy indicators
Consulting Energy reports, internal consulting and market analysis
Implementation Implementation of energy saving options
maintenance of energy plants
Slides 4 – Energy analysis
Documentation of load curves
Documentation ofcurves for
A year
A week
A day
Analysis of load curves
Winter – summer ratioCombined use of heat and
power
Switched off or reduced operation at weekends
Days with high energy demand
BottlenecksEnergy demand after
production
Slides 4 – Energy analysis
Annual energy consumption
Collection anddocumentation
for all energy carriers
QuantityCostReference quantitiesDefinition of
indicators
Analysis and interpretation
Distribution of quantities
Distribution of costsVariation of indicatorsComparison of indicators
with other companies or publications
Slides 4 – Energy analysis
Analysis of consumers
Heat Thermostatic valves Separate control of plants Adequate temperatures No internal sources of heat
and humidity in cooled areas
Use shades for heat protection
Frequency-controlled fans Use heat cascades ...
Electric power Avoid partial load and use
adequate machines Adapt power (e. g. fans) Optimize lights (cleaning,
modern lighting, analyse demand)
Clean and service (air filter, nozzles, etc.)
Compressor location and pressure
Peak load management
Slides 4 – Energy analysis
Heat losses detected with an infrared camera
Slides 4 – Energy analysis
90 91 92 93 94
Specific energy consumption
Example:Energy consumption of a brewery
Indicator:MJ/hl
Measure:June 1992Installation of a vapour recompression plant
150
100
125
Slides 4 – Energy analysis
Energy, work and power
Work is the transmission of energy.
The unit of work and energy is JOULE.
The speed at which work is performed is power [J/s = W].
Slides 4 – Energy analysis
Heat capacity
To heat up a body with a mass of m by T, the following amount of heat is required:
Q = c m T
The specific heat capacity cof the material depends on the temperature. The specific heat capacity is the amount of energy required to heat up 1 kg of material by 1 °C.
Unit: [c] = 1 J.kg-1.K-1
Gold Iron Oxygen Benzene Water
Specific heat capacity
Slides 4 – Energy analysis
The performance of 1 kWh
Lifts 1 ton of steel by 367 m367 m!
Accelerates a car (1 ton) to approx. 60 km/h60 km/h (without losses 305 km/h305 km/h)!
Heats up 1 000 l of water by 0.86 °C0.86 °C!
Source: Karl Lummerstorfer, Energie Institut Linz
Slides 4 – Energy analysis
Efficiency in a steam system
85 – 98%Heat exchange
75 – 90%Steam transportation
(70-) 82 – 90%Steam boiler
EfficiencyPart of the steam system
Slides 4 – Energy analysis
Steam system
Reduce leaks.
Improve operation of steam traps.
Increase condensate recovery.
Increase flash steam recovery.
Use lower steam pressure if possible.
Use direct steam for heating if possible.
Slides 4 – Energy analysis
Cooling process
Consequences:The lower the temperature difference the better:
Check the necessary cooling temperatureAllow the temperature in the condenser to be as low as possible (e.g. water cooling)Maintain the heat exchanger (especially evaporator)...
The higher the cooling temperature the betterOthers:
Remove water from groundAvoid high temperature of the incoming product...
Efficiency = Qcond. / P ~ Tcond. / (Tcond. – Tevap.)Q: HeatP: PowerT: Temperature
Slides 4 – Energy analysis
Cooling process
M
Qo Qu
P
To Tu
Qu = Qo + P
Efficiency = Qo / P = To / (Tu – To)
Evaporator
Compressor
Condenser
High pressureLow pressure
Collector
Slides 4 – Energy analysis
Cooling and freezing
Raising the cooling temperature by 1 °C saves approx. 4% of electric energy.
Choose the adequate temperature: frozen meat at -20 °C, cooling at 0 °C to 4 °C.
Clean the condenser regularly and provide sufficient cool air supply.
Use the capacity of the storage rooms, collect goods, switch off unused cooling units.
Keep storage rooms closed to avoid entrance of humidity and warm air.
Defrost cooling rooms.
Slides 4 – Energy analysis
Cooling – 2 Insulation
Recommendations for PU-foam insulation: Insulation thickness
Evaporator:Optimize defrosting
CompressorClose to evaporatorCentral location makes servicing and use of heat easier
Condenser:Outside of building, sun-protectedClean regularly
Use R134 a, R22 or ammonia
0 to -8 °C 0 to -15 °C below -15 °C80mm 110mm 150mm
Slides 4 – Energy analysis
8
Ti ToTd
Q1
Q2
Q4
Q3
QT
•Fresh air drying
•Fresh air drying with heat recovery
•Circulating air drying with/without heat recovery
•Heat recovery with condensation of humidity (heat pumps, thermo-compression)
Drying process
Typical options for improvement:
Q1 = Insulation of drier
Q2 = Pre-drying, pre-concentration of the product
Q3 = Control of temperature and humidity
Q4 = Heat recovery, humidity control of flue gas, good housekeeping
Slides 4 – Energy analysis
Compressed air
Shut down compressor, drier and the network
Reduce the pressure level(as far as possible)
Avoid leakages
Lower the temperature of incoming air
Avoid compressed air for cleaning
Carry out maintenance
Use electrically-driven equipment
Foster heat recovery
Source: Karl Lummerstorfer, Energie Institut Linz
Slides 4 – Energy analysis
Lighting
Turn off when not needed
Use timer or motion detector
Use daylight as much as possible
Service and clean
Clean windows, ensure efficientdesign of rooms
Use energy saving bulbs
Slides 4 – Energy analysis
Heat recovery cooling units – 1
Compressor
Evaporator
Air-cooled condenser
Water-cooled condenser
Slides 4 – Energy analysis
Heat recovery cooling units – 2
Slides 4 – Energy analysis
ECOPROFIT-company: BreweryAnnual production: > 1 million hl, ISO 14000
Saving of water, energy and chemicals due to CP options:
Cold filtering/sterilization New filling line Heat/power co-generation Vapour compression ...
Slides 4 – Energy analysis
Specific heat consumption of a brewery
0.00
10.00
20.00
30.00
40.00
50.00
in k
Wh
/hl
spec. heat 38.60 40.67 47.30 42.62 41.42 37.56 34.19 29.91 27.58 24.47
1993 1994 ´95 ´96 ´97 ´98 ´99 2000 2001 2002
Slides 4 – Energy analysis
Multistage evaporation
Source: Ignatowitz 1994
1. evaporator
1. concentrate
steam
feed
steamcondensate
1. vapourcondensate
2. vapourcondensat
e
3. vapourcondensat
e
2. evaporator
2. concentrate
3. evaporator
finalconcentrate
condenser
vacuumpump
1. vapour 2. vapour 3. vapour
Slides 4 – Energy analysis
Evaporation with vapour compression
concentratefeed
solution
pre-heater
preheated feed
evaporator
compressor
vapour
vapour-
condensate
steam
(start-up)
Source: Ignatowitz 1994