ASHRAE Presentation: VRF Overview Mitsubishi Electric Presenter: email Phone number 2011 Mitsubishi Electric& Electronics USA, Inc. Agenda General overview of VRF Technology Review of Design Considerations
Benefits of VRF Variable Refrigerant Flow (VRF) Heat Pump versus Heat Pump with Heat Recovery Heat Pump Heat Pump
Outdoor Unit Indoor Units Controls System Heat Pump
Outdoor Unit Indoor Units Controls System Heat Pump Applications Restaurants
Lobbies Others? Churches Heat Pump with Heat Recovery Simultaneous Cooling & Heating Heat Pump with Heat Recovery Simultaneous Cooling & Heating
Outdoor Unit Branch Circuit Controller Indoor Units Controls
System Heat Pump with Heat Recovery Simultaneous Cooling & Heating Outdoor Unit Branch Circuit Controller
Indoor Units Controls System Heat Pump with Heat Recovery Applications Simultaneous Cooling & Heating Schools
Assisted Living Facility Others? Offices What is the purpose of each component? Outdoor Unit Controls compressor speed Controls condenser fan speed Controls pressure of refrigerant to maximize capacity and efficiency
Branch Circuit (BC) Controller Separates refrigerant into gas and liquid Ensures units in heating receive superheated gas Ensures units in cooling receive sub-cooled liquid Indoor Units Sense the space temperature Contain a Linear Expansion Valve (LEV) that automatically modulates Allow the precise amount of refrigerant through the heat exchanger
Filter and distributes air Controls System Integrated sequence of operation Takes input from the user and provides feedback to the system Recall What system type requires a Branch Circuit Controller? Which system type cannot provide cooling and heating simultaneously to connected units?
Is there any difference between the controls offered for Heat Pump Systems versus those offered for Heat Pump with Heat Recovery? VRF Design Considerations Equipment Layout Ceiling Space 20 Ton System Rectangular Ductwork (DX System) Round Ductwork (DX System)
Piping (4-Pipe System) Piping (VRF) 40 x 20 30 Round 3 CHWS&R, 3 HWS&R 13 /8 Gas 1 1 /8 Liquid
Rooftop Equipment Weight 80 Ton System 12,000 10,000 8,000 Equipment Weight (lbs) 6,000 4,000 2,000
0 VAV RTU w/ SS VRF 4-Pipe Fan Coil WSHP Vertical Stack WSHPs
Water-source VRF Piping Lengths There are piping considerations for: Total System Piping Length Intermediate Lengths Elevation Differentials Condensation Outdoor Units Consider location of unit Consider area drains and floor stands
BC Controller Drain pipe connection Indoor Units Drain pipe connections Some styles include standard condensate lift mechanism All styles include contact for condensate alarm/safety switch Diversity
3 Tons Morning 5 Tons Morning E N Solar Diversity
3 Tons Afternoon 5 Tons Afternoon What is the sum of the zone peak loads? S
W What is the block load? Occupant Diversity WORK ROOM 103 2 TONS 2 TONS
CONFERENCE 105 1 TON 4 TONS COFFEE 105A OPEN OFFICE 101
5 TONS 2 TONS Occupant Diversity WORK ROOM 103 2 TONS 2 TONS CONFERENCE 105
1 TON 4 TONS COFFEE 105A OPEN OFFICE 101 5 TONS 2 TONS What is the
sum of the peaks? What is the block load? Building Diversity HEATING Waste Heat COOLING
What equipment is running? Designing with Diversity Connected Capacity: Connect up to 150% of the outdoor unit capacity. Actual Capacity: The actual system capacity is the capacity of the associated outdoor unit.
A system cannot provide more than 100% of the outdoor units capacity. Contact your local representative when designing at greater than 110% connected capacity. Designing with Diversity Example: Indoor units totaling 14 tons can be connected to a 12 ton outdoor unit Connected Capacity = 14 Tons, 117%
Actual Capacity = 12 Tons, 100% The maximum amount of cooling that can ever be provided at a single instant is 12 tons Contact your local representative when designing at greater than 110% connected capacity. Ventilation Ventilation Duct required Outside Air (OA) directly to space or indoor unit
Always calculate entering coil temperatures Use Dedicated Outside Air System (DOAS), Energy Recovery Ventilator (ERV), or both to temper the air Adhere to local codes in designing ventilation Equipment Layout Diversity
Ventilation Heating Efficiency Heating Equipment Layout Diversity
Ventilation Heating Efficiency Special Considerations for Heating Utilize manufacturers design software Minimize connected capacity for colder climates Outside Air Consider Building Warm-up
Equipment Layout Diversity Ventilation Heating Efficiency
Efficiency Equipment Layout Diversity Ventilation Heating Efficiency
Efficiency INVERTER-driven compressor matches compressor speed exactly to load Simultaneous cooling and heating allows heat recovery between zones All efficiency values now available via AHRI Directory http://www.ahridirectory.org Equipment Layout Diversity
Ventilation Heating Efficiency Efficiency 20 Ton System System Type
Roof Top Units Air-Cooled Chiller Air-source VRF Water-source VRF
IEER 11.5 - 17.7 19.6 EER
9.7 10.3 10.9 10.5 IPLV -
14.2 - - SCHE - -
18.6 N/A Equipment Layout Diversity Ventilation Heating
Efficiency What are the benefits of VRF? Two-pipe System INVERTER Technology Multiple Indoor Units Variable Capacity System Zoning System Complete Control Offering
