Session: HVAC Technologies

Transcription

1 Session: HVAC Technologies What s VRF? Mira Vowles Bonneville Power Administration August 10, 2016 Rhode Island Convention Center Providence, Rhode Island

2 Why should I care about VRF? VRF systems: can be very energy efficient can improve comfort and IAQ can be cheaper to install in existing buildings 2

3 How is VRF different? Outdoor units condition multiple zones Uses refrigerant to transfer heat Good part load, and cold climate performance Provides cooling and heating Some can provide hot water and ventilation Some can provide simultaneous heating & cooling 3

4 What kinds of VRF systems are there? VRF systems can be: 1. air source, 2. water source or 3. ground source VRF system types: 1. VRF heat pumps and 2. VRF with heat recovery (HR) simultaneous heating and cooling 4

5 What are the components of VRF systems? DOAS Dedicated Outside Air System 5

6 VRF Integration 6

7 How much energy will a VRF system save? Fan savings Good part load efficiency and Eliminates electric resistance heat due to good cold climate performance difficult to verify savings! 7

8 How much do VRF systems cost? Installed costs range between $10 and $22 per square foot Incremental costs range between $0 and $12 per square foot Utility incentives range between $100 and $800 per ton, based on incremental costs and energy savings Costs vary a lot! 8

9 Who s installed VRF? Washington State Utility HQ s VRF system with HR and DOAS Existing building retrofit Replaced packaged rooftop heat pumps $12 per square foot incremental cost Energy models predicted 25,000 kwh per year of savings 56 ton VRF HR system with DOAS Retrofit occurred at night; so no need to re located occupants Lessons Learned: Train more than one person Integrate control of VRF and DOAS Install maintenance software for remote diagnostics Design indoor units for condensate drainage Remotes get lost 9

10 Who s installed VRF? Oregon Multi Family Building VRF system with HR and DOAS New building with 35 apartments, a community room and office space Energy models predicted 80,000 kwh per year of savings Lessons Learned: Don t let the refrigerant manifold be accessible to tenants. Check the VRF model hourly reports to ensure the results are reasonable. VRF systems offer flexibility, save space and don t require large ducts. The wall hung indoor units and an innovative ventilation solution allowed higher ceilings and bigger windows, eliminating the costs associated with a dropped ceiling. The indoor and outdoor units are very quiet. 10

11 Who s installed VRF? Washington State Office Remodel VRF system with DOAS $9.75 per square foot cost LEED Platinum building EUI of 21 Very low fan power Lessons Learned: Integrated design reduced building loads and VRF system size. 11

12 Who s installed VRF? Washington State Office Remodel VRF system with DOAS $14 per square foot cost EUI of 26 Lessons Learned: Integrated design reduced building loads and VRF system size. 12

13 Who s installed VRF? (VRF = Variable Refrigerant Flow ) Oregon College Building New building with classrooms, offices and common areas VRF with HR and DOAS $3.50 per square foot incremental cost 9 VRF systems, totaling 120 tons 5 year payback Lessons Learned: VRF system eliminated amount of required ductwork, freeing up ceiling space for other utilities. VRF system difficult to integrate with building energy management system. 13

14 VRF systems promise Energy savings, Cost effective, flexibility, Demand response potential, and Quieter, better comfort and IAQ VRF systems are very promising, but only with good design and operation. 14

15 Questions? VRF = Variable Refrigerant Flow 15