Transcript Total kW Load - Massey University

Dairy Insight Project II:
On Farm Energy Savings
K Hartman & Ralph E H Sims
Centre for Energy Research,
Massey University, Palmerston North
[email protected]
[email protected]
Why Peak Reduction?
3.85 million head
$10,000/MWh
100w/hd
$10/kWh
385 MW peak
$1/hd
The Big Question
How can I save energy?


2 sides of the “savings” coin:
Conserve energy
Reduce costs
Finding the Answer
Where is energy used on the farm
How much am I using
Where can I conserve energy
How can I reduce energy costs
Case studies


Almost there…
What if…
Further assistance
Where is Energy Used on the Farm
Barrie, 2005
Proportion of energy inputs on the average farm surveyed
Survey Results – kWh/day vs # head
700
y = 0.2668x + 43.991
R2 = 0.8736
600
kWh/day
500
400
Overall
<350
300
350-700
Large
200
Linear
(Overall)
100
0
0
500
1000
1500
number of head
2000
2500
Survey Results – kWh/hd/day vs # head
0.70
0.60
Overall
kWh/hd/day
0.50
<350
350-700
Large
0.40
Power
(Overall)
0.30
0.20
0.10
0
500
1000
1500
number of head
2000
2500
Comparison (kWh/hd/day)
Massey
450
Rotary
Forest
550
Herring
Fitz
220
Herring
Waipawa
800
Herring
Forest550
Herring
vacuum
chilling
water heat
Misc
Total
0.22
0.16
0.18
0.15
0.71
0.16
0.13
0.25
0.13
0.66
0.08
0.12
0.13
0.29
0.62
0.11
0.19
0.07
0.24
0.61
0.16
0.13
0.13
0.13
0.54
vacuum
chill
w.h
Misc
31%
23%
25%
21%
24%
19%
37%
20%
13%
19%
21%
47%
18%
31%
11%
39%
29%
23%
23%
24%
Head
Type
How much am I using
Meridian Energy Calculators

Full Model
 Mailed out to customers, CD based
 Intensive

Mini-Calculator
 On-line version (www.meridianenergy.co.nz)
 Simple Model (3-5 minutes)
WWW.Meridianenergy.co.nz/yourfarm
Where can I conserve energy
Major loads
Milking Machine (vacuum pump)
Milk Chilling
Water Heating
Irrigation (not on all farms)
Miscellaneous



Water and effluent pumping
Lighting
Other minor loads (is the kettle major or minor?)
Vacuum Pump (non variable speed)
Constant load

Fully loaded – entire milking & cleaning
Size proportionate to # of clusters

More clusters - larger the load
Vacuum brakes provide reserve capacity

Not doing useful work - 0% efficiency
Milk Chilling
Two parts


Initial cooling of the milk
Maintaining milk temperature <4 °C (10%)
Pre-cooling


Plate heat exchanger (35 – 20 °C)
Dependant on cooling water temperature
 Bore vs surface water
Water Heating
Electric (resistive) heating
Batch or Continuous heat
Initial and Maintenance heat (15%)
Centralized thermal power plant
Fuel – electricity – heat

Can be less than 18% efficient at point of use
 3.5x the primary fuel use than if made onsite
 4x more heat wasted at power plant than
developed at point of use
Water Heating (B.V)
365
355
345
Temperature (K)
335
325
315
HW1
T in
305
T out
T tank
Element
295
285
0:00
2:00
4:00
6:00
8:00
10:00
12:00
14:00
16:00
Time of Day
18:00
20:00
22:00
0:00
2:00
4:00
Water Heating (A.V.)
365
355
345
Temperture (K)
335
325
315
HW1
T in
T out
305
T tank
Element
295
285
0:00
2:00
4:00
6:00
8:00
10:00
12:00
14:00
16:00
Time of day
18:00
20:00
22:00
0:00
2:00
4:00
Irrigation / Pumping / Other
Individual farm dependant
Age/type/condition of pump
 Pumping head (static vs dynamic)
 Saving water saves energy

Other loads

Lighting (Natural vs artificial)
 Incandescent Light bulb ~2% efficient fuel to light
How can I reduce energy costs
Reduce usage




Waste heat recovery – preheat water to cylinder
Additional milk pre-cooling (1 °C ~ 6% cooling load)
Variable speed vacuum pump / pully size
Reduce vacuum demand ? (10/20/70)
Load Shifting / Peak Reduction


$/month per kW peak use charge (?)
Energy Storage (Hot Water, Ice Banks)
Rate schedules


Day / Night / Controlled Rates
Fixed daily charges (higher daily = lower per unit)
Case Study – Almost there…
Smaller farm – 220 head




20 bail herringbone
Day / Night rate (night = 1/3 day rate)
Timers on water heaters (batch w/pre-heat)
Ice bank
 Used for morning and afternoon milking
 Pre-cools milk to 4 °C into the vat

Low vacuum demand (~4 kW)
 Short milk and vacuum runs

Enclosed milk vat, uninsulated
Cumulative Energy Use (kWh)
Cumm Energy Use (kWh)
12
10
8
6
4
2
0
0:00
2:00
4:00
Vat Htr
6:00
8:00
Wash Htr
10:00
12:00
Ice Bank
14:00
Chiller
16:00
18:00
Vac Pump
20:00
Total
22:00
0:00
Case Study – What if…
Mid-sized farm – 550 head
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2x 20 bail herringbone pits
Anytime / Controlled rate
15 kW vacuum demand
2 hot washes per day
Uncovered, insulated milk vat
15 psi artesian bore
27 kW for effluent stir / pumping
Total energy use (before)
50
25%
45
75%
40
35
Vacuum
Chiller
HW
Misc
Vacuum
Chiller
HW
Total
Total
30
25
20
15
10
5
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Hot Water (before)
16
14
12
10
Vacuum
Chiller
HW
Misc
Vacuum
Chiller
HW
Vat Wash
8
System Wash
6
4
2
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Hot Water (after)
16
14
12
10
Vacuum
Chiller
HW
Misc
Vacuum
Chiller
HW
8
6
4
2
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Milk Chiller (before)
16
14
12
10
Vacuum
Chiller
HW
Misc
Vacuum
Chiller
HW
8
6
4
2
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Milk Chilling (after)
16
14
12
10
Vacuum
Chiller
HW
Misc
Vacuum
Chiller
HW
8
6
4
2
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Vacuum Pump (before)
16
14
12
10
Vacuum
Chiller
HW
Misc
Vacuum
Chiller
HW
8
6
4
2
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Vacuum Pump (after)
16
14
12
10
Vacuum
Chiller
HW
Misc
Vacuum
Chiller
HW
8
6
4
2
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Total System (after)
35
55%
30%
Overall
Overall 50%
33% cost
energy
savings
45%
70%
savings
30
Vacuum
Chiller
HW
Misc
Total
25
20
15
10
5
23:00
21:00
19:00
17:00
15:00
13:00
11:00
9:00
7:00
5:00
3:00
1:00
23:00
0
Further Assistance
Dairy Insight Phase II



Identify energy saving techniques and
technologies
Demonstrate on-farm examples
Getting the word out
 Process-specific information sheets

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
Water Heating
Milk Cooling
Milking Machine
Tractor Fuel Use (revisiting Tractor Facts from 80’s)
Lighting / Other
VERSION: 1
DATE: March
2006
CASE STUDY
ENERGY SAVINGS IN DAIRY SHEDS
THE HOT WATER TANK
(40% OF TOTAL DAIRY SHED ELECTRICITY USE)
566 cows, 2 hot washes of 367 litres water per day, uninsulated hot
o
o
water tank, heating to 85.4 C, air temperature: 10 C, total electricity
consumption: 91,078 kWh/yr, electricity price: 12.01 c/kWh.
SOURCE: 2004 SURVEY OF
64 FARMS
Annual Cost of Electricity for Hot Water Tank: $ 4,375
BEST PRACTICE
DETAILS
Insulation Material: Thermowrap, service life: 10 years
Cost: $ 169 for a 400 litre tank
Additional costs: None
INSULATE THE
HOT WATER
TANK
Supplied by: DTS
Phone: 0800-500-387
Address: National
Website: www.dts.co.nz
Annual Cost of Electricity for Heating Water:

Without insulation: $ 4,375

Hager 24 hour timer, service life: 10 years
Cost of timer: $ 170 (excluding installation)
Annual Cost of Electricity for Heating Water:


Installation: DIY (easy)
With insulation: $ 2,511
Annual savings from using insulation: $ 1,695
(Payback time on insulation: less than 2 months)
USE ONE HOT
WASH PER DAY
WITH A TIMER
TO HEAT FROM
1.00 a.m. TO 8.00
a.m.
INFORMATION
Without timer (24 hours): $ 2,511
COST SAVING: 39% of hot
water electricity cost
Supplied by: Julian’s Electrical
Phone: 0800-102-464
Address: National
Website: www.julians.co.nz
With one wash and heater on for 7 hours: $ 1,212
Additional Information
Installation: DIY (if familiar with
electrical circuit) or use an
electrician.
Use a hot wash after the morning milking and a cold wash after the
evening milking. There is no change in the amount of detergent used
in the wash, whether it is a hot wash or a cold wash.
The same timer with a contactor costs about $ 250 with additional
costs if an electrician does the installation.
Annual savings from using timer: $ 1,129
(Payback on timer: 2 months)
COST SAVING: 26% of hot
water electricity cost
Review
Big ticket items – in the shed



Water Heating
Milk Cooling
Milking Machine (vacuum pump)
Fast payback

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

Batch hot water vs constant feed
Day / Night rates
Timers – Lighting / Hot Water
Minimize water use
Future Technologies
On-site co-generation (biofueled?)
Wind/Hydro/PV/solar thermal
Waste-to-energy (AD) systems
Enhanced thermal storage
The Matrix