1. Advanced Rooftop-Unit Control – Retrofit Savings Analysis Overview 1 February 13, 2015 RTF Commercial Rooftop-Unit Working Group Mira Vowles, BPA

2. Agenda 2 1.Review a)ARC –Retrofit b)Previous work c)Best Practice Method d)Simplified Method(s) 2.Program Implications 3.Simplified Method Analysis

3. What is an ARC Retrofit? Advanced Rooftop-Unit Control (ARC) Retrofit –previously known as Premium Ventilation 3

4. ARC Retrofits 1.Supply Fan Speed Control –Fan-cycling –Multi-speed –VSD 2.Demand Controlled Ventilation 3.Digital, integrated economizer control 4.Web-enabled monitoring and control 4

5. Catalyst ARC Retrofit Supply-Fan Speed Control Strategy  75 or 90% in heating and cooling modes  40% in ventilation mode 5

6. ARC –Lite Retrofits 1.Supply Fan Control –Fan-cycling –Multi-speed –VSD 2.Demand Controlled Ventilation 3.Digital, integrated economizer control 4.Web-enabled 6

7. Summary of Previous Work 7

8. Best Practice Savings Estimate *  Long-term, daily-cycling between standard (baseline simulation) and efficient (ARC –Retrofit) operation;  Interval measurement of RTU true-power to derive daily kWh for each retrofit RTU;  Normalized savings derived from standard and efficient mode models of daily temperature and kWh, projected to annual savings using TMY data. * established in 8/15/13 RTUG Meeting 8

9. Potential Simplified Methods* 1.Use whole building, interval meter data –Requires interval metering –Reliability depends on signal to noise 2.Shorter metering period without cycling –Requires new field data for analysis 3.Use VSD fan-power –Establish a relationship between RTU savings based on fan power using PNNL data * proposed in 8/15/13 RTUG Meeting 9

10. Potential Simplified Methods* 1.Use whole building, interval meter data –Requires interval metering –Reliability depends on signal to noise 2.Shorter metering period without cycling –Requires new field data for analysis 3.Use VSD fan-power –Establish a relationship between RTU savings based on fan power using PNNL data * proposed in 8/15/13 RTUG Meeting 10

11. Simplified Method Analysis Michael Baker, SBW Consulting, Inc. Bill Koran, NorthWrite, Inc. 11