Presentation on theme: "Transformer De-Energizing & Dairy Plate Heat Exchanger Standard Protocol Proposal Presentation to the RTF February 20, 2013."— Presentation transcript:
Transformer De-Energizing & Dairy Plate Heat Exchanger Standard Protocol Proposal Presentation to the RTF February 20, 2013
Protocol History Adopted “deemed calculator” versions in 2002 Savings Guidelines adopted 6/1/11 which removed deemed calculator category Cascade Energy awarded contract in 2012 to convert deemed calculators to Guidelines compliant Standard Protocols Presented draft protocols at Oct. & Nov. 2012 RTF meetings
Protocol History Received feedback at meetings on likely path – Small Saver recommended at Nov. RTF meeting for both protocols Tabled decisions until updated Savings Guidelines were adopted to allow for Small Saver Standard Protocols Mike Baker reviewed for compliance with updated 12/11/12 Savings Guidelines Presenting revised proposal today
Protocol Summary Eligibility Liquid-filled or dry-type transformers Single phase between 3 kVA – 167 kVA Three phase between 15 kVA – 1,000 kVA Low voltage (<= 600V) Baseline Existing energized transformer with periods of no-load Upgrade De-energize the transformer for periods of no-load Best Practice Savings Estimate 1.Determine no-load loss by measuring the power of the transformer when it is energized, but does not have an electrical load. 2.Collect transformer nameplate data (type, voltage, phase, capacity rating). 3.Determine the number of hours per year the transformer is de-energized based on utility record of date(s) of de- energization and date(s) of re-energization. 4.Savings are calculated as the product of hours of de-energization and no load power draw. 5.Savings are to be determined in this manner each year the transformer is de-energized. Simplest Reliable Savings Estimate 1.Determine no-load loss by: a)Default rated capacity by utilizing default NEMA TP-1 transformer efficiency ratings b)Alternately, use manufacturer published no-load loss or power measurement 2.Remaining steps follow the Best Practice.
RTF feedback from last meeting Using NEMA tables vs. field data collection – Field data collection is costly, and savings are not justified given the expense – Regionally representative default table would be better however not worth the cost to obtain given small savings – Only two utilities run xfmr de-energizing programs – Keep NEMA table as-is and realize protocol is a small saver for the region
Protocol changes since November Cleaned up verbiage to clarify definitions, delivery verification and data collection characteristics Biggest change is restructuring of simplest reliable method to use NEMA default table – Previously had manufacturer rating as primary collection method, default table as secondary – Guidelines require alternate methods to be of sufficient or better reliability
RTF Proposed Motion: “I _________ move that the RTF approve the Transformer De-Energizing Standard Protocol and assign it to a “Small Saver” category with “Active” status and a sunset date of February 20, 2017.”
Process Flow Diagram T T T = temperature measurement
Measure Definition Eligibility Plate and frame heat exchanger Retrofit only Water is the cooling fluid, and has constant flow known cooling water flow rate, and inlet and outlet temperatures, or alternately, known milk outlet temperature Baseline Mechanical refrigeration system to cool milk May or may not have existing milk pre-cooler Upgrade Add milk-to-water plate and frame heat exchanger or replace existing.
Simplest Reliable Method Same equations as Best Practice, different data collection
Simplest Reliable method Total heat rejection Portion removed by water
RTF feedback from last meeting Added heat from transfer pump assumed to be trivial; effect not included in calculation Specify that measurements are taken close to HX to avoid varying system configurations COP sensitivity analysis performed – COP assumptions reasonably accurate across wide range of expected suction/discharge temps Develop COP lookup tables for other common refrigerants
Protocol changes since November Cleaned up verbiage to clarify definitions, delivery verification and data collection characteristics Removed New Construction from eligible projects due to missing standard practice baseline Added language directing practitioner to measure water temperatures as close as possible to the heat exchanger Made all refrigerants eligible for the protocol, with all refrigerants other than R-22 and R-507 assumed to have the same COP as R-404a
Protocol changes since November Added supporting documentation to capture “non-protocol specific” analysis Biggest change is restructuring of simplest reliable method in protocol – Previously had temp probe measurement as primary collection method – Guidelines require alternate methods to be of sufficient or better reliability
RTF Proposed Motion: “I _________ move that the RTF approve the Dairy Heat Exchanger Standard Protocol and assign it to a “Small Saver” category with “Active” status and a sunset date of February 20, 2017.”
Representative Savings Protocol savings are small. Representative calculations of a small and large project are: Smallest Transformer Example Largest Transformer Example
NEMA TP-1 No Load Loss Ratings Default Rating. Default rating is based on NEMA TP-1 2002 transformer efficiency standards. Should be a conservative rating for older transformers. Newer transformer may be more efficient than this standard, with lower no-load losses. However, newer transformers should have the manufacturer rating available. No Load Loss ratings of 185 Eaton dry transformers of varying sizes were compared to NEMA TP-1 calculated NLL. This resulted in 6 models with NLL less than the NEMA TP-1 calculation, and 179 models that were higher than the NEMA TP-1 calculation. 67% of Eaton NLL models had a NLL rating over 20% higher than the NEMA calculation. Eaton data is evidence NEMA TP-1 calculation method is conservative. However, Eaton transformer data is not representative of the transformers currently in service.
COP Sensitivity Analysis COP dependent on refrigerant, suction & discharge pressures Calculator COP assumptions: Suction temp = 20 °F below storage temp Typical discharge pressure = 200 psig Pressure cut-in/cut-out setpoints unchanged if change refrigerant i.e. 200 psig discharge pressure remains typical for all 3 refrigerants Refrigerant is known (R-22, R-404, R-507) Table compares energy savings with fluctuating COP (best practice) vs. simplest reliable method. Conclusion COP assumptions are reasonably accurate across a wide range of suction/discharge pressures