1. Lecture Objectives: Finish with thermal storage systems Plumbing Hydronic distribution systems –Chiller/Boiler – Storage – Building

2. Installation of Thermal Storage System DownstreamUpstream Increases chiller efficiency Increases chiller capacity Overall system efficiency ??? Decreases storage capacity Simplifies system layout ….. Decreases chiller efficiency Decreases chiller capacity Overall system efficiency ??? Increases storage capacity …… Does not allow chiller shut down!

3. Modeling Write energy and mass balancer equation for each section

4. Plumbing Arrangement for Chillers (and Boilers) Primarily water circulation loop only Primarily & Secondary circulation loops Primarily & Secondary & Tertiary loops …. Reading assignment: Chilled Water Plant Design Guide (Section 4) http://energydesignresources.com/media/2305/EDR_DesignGuidelines_CoolToolsChilledWater.pdf

5. Hydronic systems for district cooling/heating and buildings Constant-Flow System, Single Chiller, Single Coil Constant-Flow System, Single Chiller, Multiple Coils Mixing valve that control by-pass flow Major pumping force is the chiller pump

6. Control of coil temperature Mixing valve that control the flow through the coil Flow Variation as a Function of Valve Position Major pumping force is the chiller pump Same pressure drop like a cooling coil

7. Multiple chiller (or boilers) Parallel Serial

8. Primary-Loop Only Variable Speed Flow Single chiller Multiple chillers

9. Primary and Secondary Loop Variable Flow Design Parallel chillers Serial chillers

10. Large Plant or Building Distribution Systems Primary/Secondary Loops with Variable Flow and Distributed Pumping

11. Primary/Secondary and Tertiary Pumping

12. Primary Pump Arrangements Dedicate a pump for each chiller Provide a common header for the pumps

13. Coil Pumping Strategies Variable speed pumps vs. Single pas Valve vs. Mixing valves vs. Diverting Valves

14. Impact of Piping Coil

15. Plumbing Arrangement in Building’s hydronic systems Fan coil systems Baseboard heaters Radiators

16. Hydronic Terms Head loss Open-loop vs. closed loop

17. Head Loss

18. Fittings

19. Pumps Raise pressure and produce flow Main type Centrifugal Inline Base mounted Example of Turbine pump

20. Pump curves NPSHR = Net Positive Suction Head Required

22. Changing Pump Speed

23. Curve for Multiple Pumps

24. Net Positive Suction Head (cavitation)