2. Energy Management and Planning MSJ0210
Energy consumption
Eduard Latõšov

3. Energy consumption

4. Contents
General
Fixed load
Preassigned load
Temperature depended load

5. General

6. ENERGY CONSUMPTION ANALYSIS
SIMPLE, but ….
….needs systematic analysis and understanding of presumable obstacles

7. Description of energy profile
Energy consumption
Description of energy profile
PLANNING
best economic solution
best technical solution
best environmental solution
Energy profile is the core of planning.

8. DATA EXACTNESS/PRECISION
High
Design, final investment decision
Pre-design
DATA EXACTNESS/PRECISION
Feasibility study
Pre-feasibility study
Expert opinion
Low

9. Energy consumption ADVISE: DOUBLE CHECK CONSUMPTION INITIAL DATA.
TAKE IT SERIOUSLY.
MAKING CHANGES AFTERWARDS IS MONEY AND TIME CONSUMING PROCESS!

10. Types of energy load REAL ENERGY LOAD FIXED
mainly combination of fixed, preassigned and temperature depended loads.
PREASSIGNED
TEMPERATURE DEPENDED

11. Fixed load

12. FIXED LOAD
Capacity,
P, [MW]
Qconst , [MWh]
8760
Duration, [h]

13. FIXED LOAD
[MWh] per year 
[MWh] / 8760 [h] = 1,14 [MW]

14. FIXED LOAD FIXED HEAT LOAD EXAMPLES:
TECHNOLOGICAL PROCESSES OR AUXILIARY SYSTEMS WHICH NEEDS CONSTANT ENERGY SUPPLY
(some dryers, chemical processes, data servers …)
SPA, AQUATIC CENTERS
DOMESTIC HOT WATER

15. Temperature depended load

16. Temperature depended load
In a certain interval ratios P1 / T1 = P2 / T2 =P3 / T3 = Pi / Ti= const, linear dependence
Capacity,
P, [MW] 3 P3 2 P2 1 P1 T1 T2 T3
Temperature, T [oC]

17. (except of domestic heat water preparation)
Temperature depended load
Temperature depended heat load examples:
Heating
DISTRICT HEATING
(except of domestic heat water preparation)
i.e.
Ventilation

18. Temperature depended load
District heating 1
Capacity,
P, [MW] 2
~ -25oC
~ +15

19. Temperature depended load
District heating 1
VÕIMSUS,
P, [MW]
Winter time outside temperature for planning of maximum capacity of heating and ventilation capacities (~-25°C).
Regulations:
Example: EVS 844: Hoonete kütte projekteerimine
Real drop is not sharp. It depends on exact heat substations installed in the buildings!
Very often mistakes are done in design of heat exchanger.
~ -25oC

20. Temperature depended load
District heating
1. Different base temperature (12 – 17oC in average ~15°C). – depends on technical conditions of the building. Takes into account internal heat gain from people, electronics.
Regulations: 2
VÕIMSUS,
P, [MW]
Example: EVS 844: Hoonete kütte projekteerimine
Human factor
Forced suspension of heat consumption during transition periods (in the beginning of autumn and at the end of spring).
~ 15oC

21. Preassigned load

22. PREASSIGNED LOAD preassigned i – time unit (hour, minute, day)
Capacity,
P, [MW]
preassigned
i – time unit (hour, minute, day)
8760
Duration, [h]

23. PREASSIGNED LOAD preassigned Mainly when:
CREDIBLE STATISTICAL DATA IS AVAILABLE. LOW PROBABILITY TO BE CHANGED IN THE FUTURE (simple case)
Prediction:FEATURES OF TECHNOLOGICAL PROCESS/CONSUMER
Prediction: Raw materials supply features

24. Be sure, that load fluctuation is missing.
PREASSIGNED LOAD
STATISTICAL DATA
Periodicity of data
DATA:
Year average
Month average
Day average
Hour average
Minute average
Industrial load
District heating
RISK!
Be sure, that load fluctuation is missing.

25. PREASSIGNED LOAD RISK (1/3) STATISTICAL DATA EXAMPLE
Capacity,
P, [MW]
EXAMPLE
According to DAILY data we have fixed heat load
5 MW
365
Duration, [päev]

26. PREASSIGNED LOAD RISK (2/3) STATISTICAL DATA EXAMPLE
According to one day HOURLY fluctuation
Capacity,
P, [MW]
Daily average
5 MW 24
[h]

27. PREASSIGNED LOAD RISK (3/3) STATISTICAL DATA
5 MW energy unit can cover 100% of demand
10 MW energy unit will cover ~35% of total energy demand
Add more energy production units?
Large energy production unit?
Energy storage?

28. Optimisation and selection of equipment
PREASSIGNED LOAD
STATISTICAL DATA
INDUSTRIAL CONSUMERS
Type of energy (hot water, steam)?
Properties of energy?
HIGH IMPACT!
Optimisation and selection of equipment

29. INITIAL SITUATION.
Boiler. Steam production with parameters in accordance to maximum consumed parameters.
INDUSTRIAL CONSUMER
Example. Energy quality.
25 bar
Oil boiler
10 t/h
100%
TT 1
TT 2
TT 2
Consumers
(saturated steam)
25 bar
10 bar
5 bar
1 t/h
10%
1 t/h
10%
8 t/h
80%
EXPECTED SOLUTION
New steam boiler (75 bar, 500oC) and steam turbine for CHP.

30. To illustrate this example an explanation of steam turbine based power plant is needed
(introduction to technologies).

31. Steam power plant cycle
To visualize Rankine cycle use T-s diagram
1–2:   The condensed water is pressurized by a feed pump and delivered back into
           the boiler
2–3: Liquid pressurized water is evaporated in a boiler by input of heat. Steam is superheated in a superheater 3–4:   The steam expands associated with mechanical power output. In power plants
           the mechanical energy is transformed into electrical energy by a generator. 4–1:   The expanded steam is condensed to water with associated heat output

32. explanatory notes Rankine cycle Boiling point 100oC pressure
760 mmHg = 0,101 MPa
Liquid water is evaporated.
Wet steam.
Boiling without temperature increase
Liquid water
evaporation
You need 2260 kJ/kg to evaporate 1 kg of water at 100oC

33. 1–2:   The condensed water is pressurized by a feed pump and delivered back into
           the boiler
2–3: Liquid pressurized water is evaporated in a boiler by input of heat. Steam is superheated in a superheater 3–4:   The steam expands associated with mechanical power output. In power plants
           the mechanical energy is transformed into electrical energy by a generator. 4–1:   The expanded steam is condensed to water with associated heat output

34. explanatory notes
Rankine cycle 
The areas represented in the diagram can be explained as follows: while the blue area corresponds to the heat lost at condenser, the purple area corresponds to useful energy at the turbine. Therefore the aim is to maximise the orange area and to minimise the blue area.
Condensation (4-5) should take place at temperatures as low as possible. On the contrary, the temperature for evaporation (1-2) should be as high as possible. This corresponds to high pressure. Superheating (2-3) should be as high as technically possible.

35. It's just not as energetically efficient.
Introduction to technologies
Rankine cycle 
Technically, its is possible to compress low-temp steam, reheat it, and run a turbine that way.
It's just not as energetically efficient.

36. Simple Rankine cycle power plant
(main components)

37. Extractions

38. SOLUTION 1.
New steam boiler (75 bar, 500oC) and steam turbine for CHP.
INDUSTRIAL CONSUMER
Example. Energy quality.
GENERATOR
1,4 MW
75 bar
Steam turbine
Boiler
10 t/h
100%
25 bar
10 t/h
100%
TT 1
TT 2
TT 2
Consumers
(saturated steam)
25 bar
10 bar
5 bar
1 t/h
10%
1 t/h
10%
8 t/h
80%

39. SOLUTION 2.
New steam boiler (75 bar, 500oC) and steam turbine for CHP.
INDUSTRIAL CONSUMER
Example. Energy quality.
GENERATOR
1,5 MW
75 bar
Steam turbine
Boiler
10 t/h
100%
25 bar
10 bar
5 bar
TT 1
TT 2
TT 2
Consumers
(saturated steam)
25 bar
10 bar
5 bar
1 t/h
10%
1 t/h
10%
8 t/h
80%

40. 0,1 MW 7% 1,4 MW 1,5 MW INDUSTRIAL CONSUMER SOLUTION 1
Example. Energy quality.
GENERATOR
1,4 MW
0,1 MW 7%
0,1 [MW] x 8000 [h] kW/h = 800 [MWh]
800 [MWh] x 40 [EUR/MWh] = [€/a]
[€/a] x 15 [a] = [€]
GENERATOR
1,5 MW
Additional income if optimized in accordance with energy parameters
SOLUTION 2

41. Thank you