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Bolongaro
Load Balance Is It Worth Striving For? Rachel Bolongaro P.Eng. May 2 2013 The Problem Outline • • • • 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
