Transcript Energy demand analysis for small and medium scale heat

Energy demand analysis for
small and medium scale heat
users in Rotorua aiming at
converting existing heating
systems to bioenergy
Dr Per S. Nielsen,
Mr. G. Estcourt,
Mr. M. Shepherd
Acknowledgement
 EECA
 Rotorua Energy Charitable
Trust
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Introduction
 Evaluation of heat demand at
school in Rotorua
 The driver for us has been to
evaluate the long term
competitiveness of wood pellet
heating systems.
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Energy Grade
Optimisation
Waste minimisation
Energy savings
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Reuse
Energy grade optimisation
Recycling
Combined heat and power
Energy Recovery
Fuel switching
Energy demand at
schools
 Electricity
 Space heating
 Water haeting
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Space heating profiles
 Annual profile
 weekly
 Daily
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Energy use survey on
Schools in Rotorua
 27 schools
 Primary as well as secondary
schools
 Interview with each school
 Basic energy sue information
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Results
 40-45% of energy use is
relate4d to space haeting
 45% of the schools use coal as
the main fuel source for sapce
heating in old buildings
 In prefabs electricity is used for
heating
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Fuels sources at the
schools
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Heating costs related to
type of fuel use
0.160
Electricity
0.140
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Elect / Coal
0.120
Gas
Heating 0.100
Energy
0.080
Cost
($/kWh) 0.060
Coal
Geothermal
0.040
0.020
0.000
A
B C D E
F G H
I
J
K
L
M N O P Q R
School
S
T
U V W X U
Z AA
Heating costs per
student
$45
$40
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$35
Annual $30
Heating
Energy $25
Cost $20
per
Student $15
$10
$5
$0
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
School
P
Q
R
S
T
U
V
W
X
Y
Z AA
regression
150,000 kWh/year
125,000
100,000
75,000
50,000
25,000
0
0
5
y = 4050.9x + 24873
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10
15
Number of Class Rooms
20
25
Energy PRO evaluation
0.2
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0.1
0
Sun 26/05
Mon 27/05
Tue 28/05
Gas engine
Wed 29/05
Boilers
Thu 30/05
Heat consumption
Fri 31/05
Heat blow off
Sat 01/06
Sun 02/06
Conclusions
 45% of the schools have a coal boiler,


which heats the part of the school
(more than 20 years old).
In new buildings electricity heaters are
the preferred solution.
On fuel costs alone, a wood pellet cost
of 6c/kWh will be competitive with the
school on electricity and electricity/coal
and comparable to natural gas, but not
competitive to the schools using coal.
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Acknowledgement
 EECA
 Rotorua Energy Charitable
Trust
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