Bolongaro

Transcription

Bolongaro
Load Balance
Is It Worth Striving For?
Rachel Bolongaro P.Eng.
May 2 2013
The Problem
Outline
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Definitions of Load Balance
The Advantages of Balanced Loads
The Risks of a Balanced System
The Economics of Balancing
Defining Balanced Loads
Heat Transfer in a VCL GHX
Recharge
Conduction
Advection
Balanced Load Definitions
• Balanced Building Loads – Peak and
Annual.
• Balanced Ground Temperatures
• Balanced Borehole Length
“For GHX sizing and costing this is
the most meaningful”
The Advantage of Balanced Loads
The Advantage of Balanced Loads
• Reduced GHX Size
– Footprint and Space Requirements
– Capital Costs
• More Capacity from a Constrained Site
• Lower Overall Cost of Energy
Adding Cooling Loads
Building 1
1,200
1,075 MWhr 1,041 kW
49
1,000
kW/MWhr
800
146
260
600
487kW
453MWhr
400
Required # of BHs
200
Remaining Building 1
Capacity
Building 1
Building 2
Remaining Building 2
Capacity
Adding Cooling Loads
Building 1 and 2
1,200
1,075 MWhr
49
1,041 kW
1,000
150
kW/MWhr
800
256
600
487kW
453MWhr
400
Required # of BHs
200
Remaining Building 1
Capacity
91 kW
90MWhr
-
Building 1
Building 2
-
Remaining Building 2
Capacity
Adding Cooling Loads
3586 MWh
935 kW
356 BHs
1036 MWh
377 kW
Building Loads
No. of Boreholes
Adding Cooling Loads
3586 MWh
278 BHs
2073 MWh
935 kW
754 kW
Building Loads
No. of Boreholes
- Increase peak and annual cooling by 100%
The Risks of Load Balancing
The Risks of Load Balancing
• Risk Factors
– Heat Pump Performance
– Load Accuracy
– Load Predictability
• Risk Mitigation Measures
– Sensitivity Analysis
– Supplemental Energy Sources
– System Monitoring
The Risks of Load Balancing
1439 MWh
934 MWh
569 kW
304 kW
Heating Peak
Heating Annual
Cooling Peak
Cooling Annual
- System is initially balanced
The Risks of Load Balancing
- System is initially balanced
934 MWh
786 MWh
569 kW
152 kW
Heating Peak
Heating Annual
Cooling Peak
Cooling Annual
- Cooling load reduced to 50%
(no. of boreholes the same)
The Risks of Load Balancing
- System is initially balanced
786 MWh
759 MWh
398 kW
152 kW
Heating Peak
Heating Annual
Cooling Peak
Cooling Annual
- Cooling load reduced to 50%
(no. of boreholes the same)
The Economics of Load Balancing
A Case Study – Recreation
Centre
6738 GJ
300 kW
226 kW 196 GJ
Building Loads
GHX and Solar Combo
GHX Sizing
Total Borehole Length
50000
156 x 91m
45000
40000
35000
30000
25000
20000
15000
70% reduction
44 x 91m
10000
5000
0
GHX for 70% Peak Heating Only
GHX for 70% Peak Heating Balanced with Solar Recharge
Capital Costs
1,800,000
1,600,000
1,400,000
47% increase
1,200,000
Solar
$1.13mill
1,000,000
800,000
600,000
GHX
$1.07mill
400,000
GHX
$440K
200,000
GHX for 70% Peak Heating Only
GHX for 70% Peak Heating Balanced with Solar
Recharge
Summary
• Load Balancing can bring benefits in terms of
construction costs and energy capacity.
• Relying on balanced loads has its risks.
• The use of other energy sources to balance
loads requires careful economic consideration.
Take Aways
• Obtain the most accurate load analysis you
can.
• Use a trained professional to analyse the
energy capacity of your field under all likely
circumstances.
• Monitor the performance of your GHX and
adjust your strategies accordingly.
Thank You.
Any Questions?
Rachel Bolongaro – bolongaror@ae.ca