Slides 4- Energy analysis ENERGY ANALYSIS 4 – Energy analysis Slides Structure of a company's energy system Supply Conversion Distribution Consumption Heat recovery Disposal.
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Transcript Slides 4- Energy analysis ENERGY ANALYSIS 4 – Energy analysis Slides Structure of a company's energy system Supply Conversion Distribution Consumption Heat recovery Disposal.
Slides
4- Energy analysis
ENERGY ANALYSIS
4 – Energy analysis
Slides
Structure of a company's energy system
Supply
Conversion
Distribution
Consumption
Heat recovery
Disposal
Slides
4 – Energy analysis
Energy efficiency
Typical areas of improvement
Cooling/refrigeration
Heating
Compressed air
Insulation
Heat recovery
Separation processes
Lighting
...
Slides
4 – Energy analysis
Efficient energy use
Not only a question of best technology!
Slides
4 – Energy analysis
Energy management
Organization
Analysis and
Planning
Set up an organizational unit,
identify responsibilities and determine the
budget
Inventory and description
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 of
curves for
A year
A week
A day
Analysis of load curves
Winter – summer ratio
Combined use of heat and
power
Switched off or reduced
operation at weekends
Days with high energy demand
Bottlenecks
Energy demand after
production
Slides
4 – Energy analysis
Annual energy consumption
Collection and
documentation
for all energy carriers
Quantity
Cost
Reference quantities
Definition of indicators
Analysis and
interpretation
Distribution of quantities
Distribution of costs
Variation of indicators
Comparison of indicators
with other companies or
publications
Slides
4 – Energy analysis
Analysis of consumers
Heat
Electric power
Avoid partial load and use
adequate machines
Separate control of plants
Adapt power (e. g. fans)
Adequate temperatures
Optimize lights (cleaning,
No internal sources of heat
modern lighting, analyse
and humidity in cooled areas
demand)
Use shades for heat protection
Clean and service (air filter,
Frequency-controlled fans
nozzles, etc.)
Use heat cascades
Compressor location and
...
pressure
Peak load management
Thermostatic valves
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4 – Energy analysis
Heat losses detected
with an infrared camera
4 – Energy analysis
Slides
Specific energy consumption
150
Example:
Energy consumption
of a brewery
125
Indicator:
MJ/hl
100
Measure:
90
91
92
93
94
June 1992
Installation of a vapour
recompression plant
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].
4 – Energy analysis
Slides
Heat capacity
To heat up a body with a mass of m by DT, the following amount of
heat is required:
Q = c m DT
The specific heat capacity c
of the material depends
on the temperature.
Specific heat capacity
The specific heat capacity is the
amount of energy required
to heat up 1 kg of material by 1 °C.
Gold
Unit: [c] = 1 J.kg-1.K-1
Iron
Oxygen Benzene Water
Slides
4 – Energy analysis
The performance of 1 kWh
Lifts 1 ton of steel by 367 m!
Accelerates a car (1 ton) to approx.
60 km/h (without losses 305 km/h)!
Heats up 1 000 l of water by 0.86
°C!
Source: Karl Lummerstorfer, Energie Institut Linz
Slides
4 – Energy analysis
Efficiency in a steam system
Part of the steam system
Steam boiler
Efficiency
(70-) 82 – 90%
Steam transportation
75 – 90%
Heat exchange
85 – 98%
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.
4 – Energy analysis
Slides
Cooling process
Efficiency = Qcond. / P ~ Tcond. / (Tcond. – Tevap.)
Consequences:
Q: Heat
P: Power
T: Temperature
The lower the temperature difference the better:
Check the necessary cooling temperature
Allow 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 better
Others:
Remove water from ground
Avoid high temperature of the incoming product
...
4 – Energy analysis
Slides
Cooling process
P
Qu = Qo + P
M
Compressor
Qo
Evaporator
Qu
Condenser
To
Tu
Collector
Low pressure
High pressure
Efficiency = Qo / P = To / (Tu – To)
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
0 to -8 °C 0 to -15 °C below -15 °C
80mm
110mm
150mm
Evaporator:
Optimize
defrosting
Compressor
Close
to evaporator
Central location makes servicing and use of heat easier
Condenser:
Outside
of building, sun-protected
Clean regularly
Use R134 a, R22 or ammonia
4 – Energy analysis
Slides
Drying process
•Fresh air drying
Q1
•Fresh air drying with heat recovery
8
•Circulating air drying with/without
heat recovery
Q4
Q3
Ti
•Heat recovery with condensation of humidity
(heat pumps, thermo-compression)
Td
Q2
QT
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
To
Slides
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
4 – Energy analysis
Slides
Lighting
Turn off when not needed
Use timer or motion detector
Use daylight as much as possible
Service and clean
Clean windows, ensure efficient
design of rooms
Use energy saving bulbs
4 – Energy analysis
Slides
4 – Energy analysis
Heat recovery cooling units – 1
Air-cooled
condenser
Water-cooled
condenser
Evaporator
Compressor
Slides
4 – Energy analysis
Heat recovery cooling units – 2
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4 – Energy analysis
ECOPROFIT-company: Brewery
Annual 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
...
4 – Energy analysis
Slides
Specific heat consumption
of a brewery
50.00
in kWh/hl
40.00
30.00
20.00
10.00
0.00
spec. heat
1993
1994
´95
´96
´97
´98
´99
2000
2001
2002
38.60
40.67
47.30
42.62
41.42
37.56
34.19
29.91
27.58
24.47
4 – Energy analysis
Slides
Multistage evaporation
1. evaporator
2. evaporator
1. vapour
3. evaporator
2. vapour
condenser
3. vapour
vacuum
pump
feed
steam
1. concentrate
steam
condensate
Source: Ignatowitz 1994
final
concentrate
2. concentrate
1. vapour
condensate
2. vapour
condensate
3. vapour
condensate
Slides
4 – Energy analysis
Evaporation with vapour compression
evaporator
vapour
preheated
feed
pre-heater
steam
(start-up)
compressor
vapour-
condensate
feed
solution
Source: Ignatowitz 1994
concentrate