VRF system optimization. Ryan R. Hoger, LEED AP Thank you to our Sponsors

Transcription

1 VRF system optimization Ryan R. Hoger, LEED AP Thank you to our Sponsors 1

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3 Seventhwave G175 VRF system optimization C2496 Ryan Hoger 12/1/15 (then available on-demand) 3

4 Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This course is registered with AIA CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Course Description Variable refrigerant flow systems have gained popularity in the United States over the past 8 to 10 years for a variety of reasons including energy efficiency and flexibility. Learn more about the various types of VRF systems, how they work and how they compare to other technologies. 4

5 Learning Objectives At the end of the this course, participants will be able to: Discuss various types of VRF systems. Identify VRF energy improvement opportunities. Analyze and identify the proper applications for VRF systems. Describe real-world examples of VRF systems in action. Approved for: 1.5 General CE hours VRF system optimization by Seventhwave GBCI cannot guarantee that course sessions will be delivered to you as submitted to GBCI. However, any course found to be in violation of the standards of the program, or otherwise contrary to the mission of GBCI, shall be removed. Your course evaluations will help us uphold these standards.. Approval date: 10/23/2015 Course ID:

6 Agenda VRF History & Heat Pumps Basics VRF Fundamentals Heat Pump vs. Heat Reclaim System Operation Common Applications Economic Comparisons AHRI Rating System VRF vs. Geothermal ASHRAE 15 Refrigerant Safety Case Study: ASHRAE (Atlanta, GA) Case Study: Seventhwave (Madison, WI) ASHRAE hdqtrs renovation includes Heat Recovery VRF 6

7 Heat Pumps Cooling Cycle Reverse Cycle Heating Hot Gas Outdoor Evaporator Coil Supplementary Heater Compressor Indoor Condenser Coil Thermostatic Expansion Valve Heating Cycle Cold Days in Northern Climates Temperature Bin Hours ( 20 F to +65 F )For Midwestern Cities City Total Bin Hours Hours Above 30 % of Total Hours Hours Above 20 % of Total Hours South Bend, IN 6,349 4,829 76% 5,879 93% Moline, IL 6,034 4,520 75% 5,390 89% Chicago, IL 6,014 4,553 76% 5,405 90% Duluth, MN 7,650 4,510 59% 5,770 75% Eau Claire, WI 6,601 4,033 61% 5,154 78% Fargo, ND 6,864 3,956 58% 5,070 74% International 7,638 4,438 58% 5,567 73% Falls, MN Minneapolis, MN 6,522 3,990 61% 5,045 77% Rochester, MN 6,783 4,314 64% 5,321 78% 7

8 Full or Part Load? What is VRF? (VRV) Variable Refrigerant Flow or (VRV) Variable Refrigerant Volume Single or tandem outdoor units Multiple indoor units on same refrigerant network Variable speed inverter compressors Various sizes and styles of indoor units Daisy chain communication Heat pump (2-pipe) or Heat Recovery with SIMULTANEOUS heating and cooling (3-pipe) 8

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10 System Operation 10

11 Heat Pump (2-pipe) 2-way Heat Pump System ACR Soft Copper (Insulated) Ball Valves Condensate 18ga 2W(S) 18ga 2W(S) 11

12 VRF Heat Pump Operation 8 Ton Compressor Capacity = 3T EEV Load 3T Nom 1T Load 3T Nom 1T Load 2T Nom 0T Load 2T Nom 1T Load Fan Heat Recovery (3-pipe) 12

13 3-way Heat Recovery System (Simultaneous Heat/Cool) ACR Soft Copper (Insulated) 18ga 5W Ball Valves Condensate 18ga 2W(S) 18ga 2W(S) Different types of VRF piping systems 13

14 Heat Balance Control - Heat Recovery DCV1,2:Open SCV1,2:Close ALL I/U COOLING A C D C 8 ton Cooling 2Tons Cooling 2Tons Cooling 1Ton Cooling 1Tons Cooling 2Tons Heat Balance Control - Heat Recovery DCV1,2:Close SCV1,2:Open ALL I/U HEATING A C D C 8 ton Heating 2Tons Heating 2Tons Heating 1Ton Heating 1Tons Heating 2Tons 14

15 DCV1:Open DCV2,SCV1, 2 :Close COOLING:4Tons>HEATING:1Tons Comp. Capacity=Cooling Capacity=4Tons O/U Heat Ex. Capacity=Cooling-Heating=3Tons 4Tons A C D C 3Tons 8 ton Cooling 2Tons Cooling 2Tons Heating 1Ton DCV1,2:Close SCV1,2:Open HEATING:6Tons>COOLING:2Tons Comp. Capacity=Heating Capacity=6Tons O/U Heat Ex. Capacity=Heating-Cooling=4Tons 6Tons A C D C 4Tons 8 ton Heating 2Tons Heating 2Tons Heating 1Ton Heating 1Tons Cooling 2Tons 15

16 DCV1,2,:Close SCV1:Open SCV2:Open HEATING:4 Tons = COOLING:4 Tons Comp. Capacity=Heating Capacity=4Tons O/U Heat Ex. Capacity=Heating-Cooling=0Tons 4PS A C D C 8 ton Heating 2Tons Heating 2Tons Cooling 1Ton Cooling 3Tons STOP VRF Applications Zoning / Variable Occupancy Schools Office Buildings High End Residential Historic Buildings Mid and High Rise 16

17 Example Midwest Installations CHA Kenmore 600 W. Van Buren Belmont House IIT Food Safety Lab Thornton High School Addition Winnetka Village Hall Roseland Hospital VA Hines Offices JF Ahern Mechanical Madison Children s Museum United Airlines Loading Bridges Historic 1800s Stone Farmhouse Indiana Harbour Belt (IHB Office) WEBINAR REMINDERS 17

18 System Cost Consider Total Building Cost Energy usage Installation labor vs. ductwork Building Automation System Electrical switchgear and electrical service Natural gas service not needed Usable space Ceiling height Mechanical rooms Duct and pipe chases System Comparison Rooftop / VAV plus controls controls included 18

19 System Comparison Chiller / VAV plus controls controls included Economic Performance 19

20 Efficiencies of Typical Equipment Types Cooling Small Split System SEER ( COP) Large DX Split or RTU EER ( COP) IEER ( COP) A/C Chiller EER ( COP) IEER ( COP) Does not include distribution (pump/fan) energy VRF Cooling? Heating? Heating Electric Heat 1.0 COP Gas Furnace or Boiler 80-97% AFUE or TE Approx COP Gas RTU 80-82% TE COP Heat Pump 7-13 HSPF deg outdoor 20

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22 AHRI VRF Terminology AHRI System Types HMSV-A-CB (heat pump, air-to-air) HMSV-W-CB (heat pump, water-to-air) HMSR-A-CB (heat recovery, air-to-air) HMSR-W-CB (heat recovery, water-to-air) AHRI VRF Terminology Energy Efficiency Ratio (EER) Full load cooling 95db OA Note COP = EER / Integrated Energy Efficiency Ratio (IEER) Part load cooling efficiency IEER = (0.020 A) + (0.617 B) + (0.238 C) + (0.125 D) A = EER at 100% capacity B = EER at 75% capacity C = EER at 50% capacity D = EER at 25% capacity Coefficient of Performance (COP) Heating efficiency at 47db/43wb OA Heating efficiency at 17db/15wb OA Heating efficiency at 68db loop temp (water-source units) Excludes supplemental heat 22

23 AHRI VRF Terminology Simultaneous Cooling and Heating Efficiency (SCHE) Only applies to Heat Reclaim systems Ratio of total capacity (heating and cooling) to the effective power when in heat recovery mode 50% heating and 50% cooling Tested at 47db/43wb outdoor Units are BTU per watt hr, same as EER and IEER COP during Heat Recovery Operation Heat Balance Point 23

24 Sample AIR-SOURCE VRF Efficiencies in Directory Sample WATER-SOURCE VRF Efficiencies in Directory 24

25 VRF AIR-SOURCE Cooling Efficiencies in

26 VRF WATER-SOURCE Cooling Efficiencies in 90.1 VRF WATER-SOURCE Cooling Efficiencies in

27 VRF AIR-SOURCE Heating Efficiencies in VRF WATER-SOURCE Heating Efficiencies in

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29 Modeling VRF Technology and performance are proprietary Hard to model bin data for load sharing VRF modules/wizards now available in: EnergyPro (5 brands built in) EnergyPlus equest Carrier HAP Trane TRACE Cold Climate Heat Pump Application Tip Locate outdoor unit inside building Single supplemental heater in mechanical room instead of every zone Simplifies heater fuel choices Optimal room setpoint around 0 degrees depending on utility costs Need condensate system 29

30 ASHRAE 15 Refrigerant Safety Yes, ASHRAE 15 is applicable to these systems What is the smallest zone? What is the charge of the system? Refrigeration Concentration Limit (RCL) per circuit RCL defined by ASHRAE 34 and referenced by ASHRAE lbs per 1,000 ft3 for R-410a 12.5 lbs for institutional occupancies Exemptions for equipment with less than 6.6 lb total charge Exemptions for laboratory spaces ASHRAE Journal July 2012 Stephen W. Duda of SSPC-15 30

31 ASHRAE 15 Tips for VRF Remove the smallest zone from the VRF system and use a dedicated unit for that zone (PTAC, DFS, etc.) Use a common ducted indoor unit to serve the two smallest rooms Use above ceiling unit so the ceiling cavity can be included in the calcs Use multiple, smaller VRF systems to serve the building Interconnect spaces with permanent openings Consider what spaces the pipes are routed thru, not just the rooms that have the indoor units installed Case Study #1 ASHRAE Headquarters (Atlanta, GA) Building renovated in 2008 and rated LEED NC Platinum VRF conditions spaces on 1 st floor, GSHP on 2 nd floor, and ventilation DOAS serves both Energy performance data collected from 2011 to

32 Case Study #1 ASHRAE Headquarters (Atlanta, GA) GSHP (2 nd floor) Avg. system heating COP = 3.3 Avg. system cooling EER = 14.2 Space energy use 1.5 kwh/ft2-yr Services mostly offices VRF (1 st floor) Avg. system heating COP = 2.0 Avg. system cooling EER = 8.5 Space energy use 2.7 kwh/ft2-yr Serves mostly offices and infrequently used meeting rooms Note: indoor fan speed control was sub-optimal A Case Study #1 ASHRAE Headquarters (Atlanta, GA) 32

33 Case Study #2 University Crossing (Madison, WI) Ground-source VRF with cooling EER of 22 Six miles of piping in perimeter ring borefield 250-ft. deep bores were used (instead of 400 ft.) because site location is in a city wellhead protection zone No supplemental heating system Energy performance data collected from 2013 to 2015 Case Study #2 Seventhwave (Madison, WI) DOAS for ventilation air GSHP with enthalpy ERV wheel Airflow modulates with CO2-based DCV in densely occupied spaces and lighting system s motion sensors in select zones Driving decisions to use VRF Geo included: energy savings, mechanical room space, and maintenance Seventhwave occupies half of 3 rd floor 3 condensing units mechanical room Fan coil zones throughout space Sub-metered by Madison Gas & Electric Live publically available data monitoring 33

34 Case Study #2 Seventhwave (Madison, WI) Case Study #2 Seventhwave (Madison, WI) 34

35 Ryan R. Hoger, LEED AP Special Thanks to those who allowed me to use their slides or graphics today Ryan R. Hoger, LEED AP

36 This concludes The American Institute of Architects Continuing Education Systems Course 36