ASHRAE Presentation VRF Overview Mitsubishi Electric Presenter email Phone number 2011 Mitsubishi Electricamp Electronics USA Inc General overview of VRF Technology Review of Design Considerations ID: 769317
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ASHRAE Presentation: VRF Overview Mitsubishi ElectricPresenter:emailPhone number ©2011 Mitsubishi Electric& Electronics USA, Inc.
General overview of VRF Technology Review of Design Considerations Benefits of VRF Agenda
Variable Refrigerant Flow (VRF)
Heat PumpversusHeat Pump with Heat Recovery
Heat Pump
Outdoor Unit Indoor Units Controls System Heat Pump
Heat Pump Outdoor Unit Indoor Units Controls System
Heat Pump Applications Restaurants Lobbies Others? Churches
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
Heat Pump with Heat Recovery Outdoor Unit Branch Circuit Controller Indoor Units Controls System Simultaneous Cooling & Heating
Heat Pump with Heat Recovery Applications Schools Assisted Living Facility Offices Others? Simultaneous Cooling & Heating
What is the purpose of each component?
Controls compressor speed Controls condenser fan speed Controls pressure of refrigerant to maximize capacity and efficiency Outdoor Unit
Separates refrigerant into gas and liquid Ensures units in heating receive superheated gasEnsures units in cooling receive sub-cooled liquidBranch Circuit (BC) Controller
Sense the space temperature Contain a Linear Expansion Valve (LEV) that automatically modulatesAllow the precise amount of refrigerant through the heat exchangerFilter and distributes air Indoor Units
Integrated sequence of operation Takes input from the user and provides feedback to the system Controls System
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? Recall
VRF Design Considerations
Equipment Layout
20 Ton System Ceiling Space Rectangular Ductwork (DX System) 40” x 20” Round Ductwork (DX System) 30” Round - Piping (4 Pipe System) 3” CHWS&R, 3” HWS&R 3 / 1 / 8 Piping (VRF) 1 8 ” Gas 1 ” Liquid
Rooftop Equipment Weight 80 Ton System
Vertical Stack WSHPs
Water -source VRF
There are piping considerations for:Total System Piping LengthIntermediate LengthsElevation Differentials Piping Lengths
Outdoor UnitsConsider location of unit Consider area drains and floor standsBC ControllerDrain pipe connection Indoor UnitsDrain pipe connections Some styles include standard condensate lift mechanism All styles include contact for condensate alarm/safety switch Condensation
Diversity
E Solar Diversity W 5 Tons Morning 3 Tons Morning What is the sum of the zone peak loads? 5 Tons Afternoon 3 Tons Afternoon N S What is the block load?
OPEN OFFICE 101 WORK ROOM 103 CONFERENCE 105 5 Tons 2 Tons 1 Ton 2 Tons 4 Tons COFFEE 105A 2 Tons Occupant Diversity
OPEN OFFICE 101 WORK ROOM 103 CONFERENCE 105 5 Tons 2 Tons 1 Ton 2 Tons 4 Tons COFFEE 105A What is the sum of the peaks? 2 Tons Occupant Diversity What is the block load?
Cooling HEATING What equipment is running? Waste Heat Building 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 unit’s capacity. Designing with Diversity Contact your local representative when designing at greater than 110% connected capacity.
Example: Indoor units totaling 14 tons can be connected to a 12 ton outdoor unitConnected 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 Designing with Diversity Contact your local representative when designing at greater than 110% connected capacity.
Ventilation
Duct required Outside Air (OA) directly to space or indoor unitAlways calculate entering coil temperaturesUse Dedicated Outside Air System (DOAS),Energy Recovery Ventilator (ERV), or both to temper the airAdhere to local codes in designing ventilationVentilation
Heating
Utilize manufacturer’s design software Minimize connected capacity for colder climatesOutside AirConsider Building Warm-up Special Considerations for Heating
Efficiency
INVERTER-driven compressor matches compressor speed exactly to loadSimultaneous cooling and heating allows heat recovery between zonesAll efficiency values now available via AHRI Directory http://www.ahridirectory.orgEfficiency
Efficiency System TypeRoof Top Units Air-CooledChiller 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 --18.6N/A 20 Ton System
Two-pipe SystemINVERTER TechnologyMultiple Indoor UnitsVariable Capacity System Zoning SystemComplete Control OfferingWhat are the benefits of VRF?