1. Variable Refrigeration Flow Systems Overview 10/11/2016
Executed by

2. Data Power Technology Illinois
“Aggressively, relentlessly anticipating and exceeding our customer’s and client’s expectations every day, while always building trust.”
Thank you for your time today.
My name is Steve Blanchard and I am going to give you an overview of VRF systems and components today.
I have been working in the HVAC industry for a little over 17 years, with 10 of them on the contractor side of the business as an installer, service technician and project manager. After returning to school and obtaining a degree in CAD Design I began working with the LG VRF systems at DPT Mechanical, the Iowa Mechanical rep division of DPT Group, a sitter company of Data Power Illinois.

3. Agenda What is VRF VRF Components Application overview Ventilation Air
Condensing Units
Fan Coil Units
Branch Selector Boxes
Controllers
Specialties
Application overview
Layouts
Condensing Unit Options
Ventilation Air
Energy Efficiency and Savings
Today we are going to talk about a what a VRF system is, how energy is transferred in a VRF system and the components that make up these systems.
We will take a look at the refrigeration cycle and some of the different ways it operates to provide heat pump and simultaneous heat recovery operation.
We are going to take a look at how a VRF system can be applied and leave a little time for some questions at the end.

4. What is VRF “Air conditioning on a dimmer switch”
DC inverter driven compressor with load matching software algorithm that varies the output to match multiple fan coil unit capacity demands.
Pulse modulated electronic expansion valves control refrigerant flow through evaporator coil.
Branch controller unit changes flow of refrigerant based on the demands of the space.
Transfers energy through refrigerant allowing for heat recovery during simultaneous mode operation.
Extremely efficient in part load conditions.
VRF systems were invented in Japan in 1982 by the Dakin Company and have spread across the European markets and began to enter the US around 2005.
Based on DX refrigeration like mini splits, VRF systems are capable of connecting multiple Evaporator fan coil units to a series of condensing units.
Simply explained as Air Conditioning on a dimmer switch VRF systems use many components to control the refrigeration cycle to efficiently match the power consumption of the system to the changing load requirements of the spaces it serves.
These components include:
DC Inverter driven compressors that control the rate of compression by varying the speed of the compressor from 15 to 150Hz in 1Hz increments.
Pulse Modulated electronic expansion valves in the evaporators similarly vary their position to control the flow of refrigerant based on the conditions of space.
Branch Controller or HR Box units let the evaporators select the phase of refrigerant necessary to condition the space and allow heat recovery and simultaneous operation of heating and cooling within separate zones.

5. What is VRF? Heat Pump – 2 Pipe – All Heat or All Cool. Y branches
Headers
Heat Recovery – 3 Pipe – Heat or Cool.
Branch selector boxes
VRF Systems consist of 2 types-
Heat Pump systems –
2- pipe mains utilizing Y branches and Header pipes to connect fan coil units to the system main piping.
All units are in heating or cooling
Heat Recovery systems utilize a 3rd pipe and a branch selector/heat recovery box.
HR boxes are fed Liquid, Suction, and Hot Gas by the three pipe mains and distribute that energy to Fan Coils based on the demand in the space.
HR Systems also allow energy recovery transferring energy within the refrigeration piping network.

6. Components Condensing Unit Single, Dual, Triple frame Air Cooled
Water Cooled
V 3Phase
460V 3Phase
The Condensing Unit is the heart and brain of the system-
Sizes range from 6 tons to 42 tons –
Condensing unit chassis can be a single, dual, or triple chassis depending on the capacity required to condition the space.
Condensing units come in Air Cooled or Water Cooled chassis
, 3 Phase or Phase is available

7. Fan Coil Units Capacities from 0.5 to 8 Tons. Ducted. Non-Ducted.
Ceiling, Wall, Floor mounting.
Air Processing Ducted Units.
Ventilation Air.
Single Phase.
Fan coil units come in a multitude of sizes and types,
Ranging from ½ to 8 tons in capacity there are several configurations for ducted units with high and low static capabilities.
Fan Coil units also come in non ducted configurations including ceiling, wall and floor mounted evaporators. Capacities vary from ½ ton up to 4 tons depending on manufacturer and unit style.
There are also air processing units for introducing conditioned outside air into the space. These evaporators can be placed on a stand alone system or connected to the primary system depending on the application and manufacturer.
Fan coil units are Single Phase and have amp draw ranges between .16 to 5.2A and multiple units can be placed on a single circuit in zone configurations.

8. Heat Pump System
The illustration on the screen shows a 2 pipe heat pump configuration where all of the Fan Coil units are in heating mode.
On the left we have an air cooled condensing unit.
Lower Right represents a 4 branch header.
Upper Right represents 4 separate Fan Coil unit zones.
In the next slide we will take a look at a heat recovery system and break down the components.

9. Simultaneous Cooling Based
Here we have a heat recovery system operating in cooling based operation with one fan coil in heating mode.
We have added a 3rd pipe and replaced the 4 branch header with a 4 branch heat recovery branch selector.
On the left inside the condensing unit we have several components to the refrigeration cycle
#1&2: are the heart of our system the inverter driven compressors
#3 is our accumulator
#4 is the oil separator
#5 is the hot gas valve used to maintain suction pressure and temperature.
#6 is the High Pressure Sensor
#7 is the 4 way valve, this valve maintains flow through the compressor and changes flow to the fan coil units based on demand.
#8 is the Low Pressure Sensor
#9 is the condenser coil.
#10 is the Outdoor Unit Main EEV. This EEV controls Mass Flow of refrigerant in the heating cycle.
#11 is the sub cooling circuit used to maintain refrigerant temperature and subcooling in the cooling cycle.
#12 is the Sub Cooling EEV used to maintain flow in the sub cooling circuit
#13 is the Liquid injection valve used to control the discharge superheat if the compressor.
#14 represent the same fan coil units as before and #15 represents a 4 branch heat recovery box.

10. Simultaneous Heating Base
In this slide we have changed the position of the 4 way valve to show the cycle in heating based simultaneous operation.

11. Branch Selector Boxes Single Circuit Box Multiple Circuit Box
Home Run Multiple Circuit
There are several versions of heat recovery branch selector boxes depending on the manufacturer of the systems.
These configurations all have similar operation but can vary the layout of the refrigeration piping network depending on which configuration is chosen.
Single Circuit boxes are sized based on downstream capacity and can serve one or multiple fan coils within the capacity range of the box.
Multiple circuit boxes combine internal header piping and separate valve mechanisms to control flow to multiple fan coils placed in zone configurations.
Home Run Multiple Circuit heat recovery branch selectors are generally placed in a central location of the building and piped out fan coils throughout the building.
Home Run boxes only use 2 pipes between the condensing unit and the Branch Selector and also require condensate removal.

12. Controls Power consumption metering. Local- Room Controllers.
Central Controllers.
Integration Devices.
BACNet, Lon, Modbus.
Digital input/output controllers.
Dry Contacts.
Economizer control.
Occupancy sensors.
Auxiliary heat control.
Power consumption metering.
All VRF Systems come with a complete onboard controls system capable of reading and changing individual zone temperatures, controlling mode of operation and compression speed and temperature of the compressors discharge. These onboard control systems operate the entire system in the most efficient way possible.
Local room controllers come in a variety of configurations from very simple up down to touch screen digital programmable versions
Central controllers, (also touch screen) can be used to control one or multiple VRF systems in a building and control other 3rd party devices such as lighting or ventilation systems.
Integration devices can connect the VRF system to a 3rd party BAS system. They speak BACnet, Modbus and Lon.
Central Controllers and Integration Devices have the option of adding Digital Input and Output controllers for communication an control of other devices
A variety of dry contacts are available for Fan Coil Units
Additionally Power Consumption Metering devices are available for measuring and reporting energy consumption for an entire system down to a single zone.

13. Specialties Special purpose fan coil units Water Heating/cooling.
Domestic hot water (with 3rd party HX tank).
In Floor / sidewalk snow melt, radiator.
3rd Party AHU Integration
VRF Condensing unit connects to AHU coils providing capacity control.
Part of VRF system or stand alone.
Several Manufacturers have introduced special purpose fan coil units in recent years as they look to maximize the application spectrum and energy saving capability's of VRF Systems.
Hot Water/Chilled water fan coils use a refrigerant to water heat exchanger to add or remove heat from a water loop. This can include domestic hot water when applied to a secondary heat exchanger, in floor heat such a snow melt or radiant fan coils.
Discharge temps range from 43F in cooling mode to 176F in heating mode.
3rd party AHU Integration ties in the refrigeration circuit and controls of a 3rd party rooftop or central station air handler into the inverter driven VRF system.
There are 2 ways this can be done
#1 – The VRF system treats the AHU as part of the VRF network and controls operation based on return air temperature.
#2- The AHU uses the VRF condensing unit as a remote condensing unit. Digital Inputs and outputs from onboard AHU controller signal On/Off, Mode, and a 0-10 output controls the speed of the compressor to meet a desired leaving air temperature.

14. Application Overview Office Space 9,600 Sqft. 30 Zones.
Conference. Room.
Individual zone control.
Simultaneous heating and cooling.
The application we are going to cover is a single story office space consisting of 9,600 square feet.
The occupant requires 30 zones mixed of office and conference room space.
Individual zone control and simultaneous mode operation is required to meet the occupancy demands and heat loss and gain based on varying exposures.

15. RTU-VAV (5) Packaged RTU (30) VAV Gas Fired DX Cooling
SCR Electric Heat
One traditional approach to meet these demands would be a zoned rooftop VAV system using 5 packaged rooftop units with gas fired heat and dx cooling. The individual zones would use 30 VAV boxes with SCR electric heat.

16. VRF Cassette (30) 4-Way Ceiling Cassette Ventilation Air required.
Heat Recovery.
Independent zone control.
In this layout individual VRF 4 way cassettes were placed into each space.
An additional ventilation air processing unit will be required
This layout will be a heat recovery systems with independent zone control.
Next I am going to show how the refrigeration piping layout would look for Home Run, Single Circuit and Multi Circuit Heat Recovery systems.

17. Home Run Heat Recovery Centrally Located Branch Selector.
Rigid ACR from CU to HR/BS box.
Soft Copper Line Sets from HR/BS box to Fan Coil.
V 1Ph connections on HR/BS and IDU.
BS/HR Condensate drainage needed.
First we will look at a Home Run Heat Recovery system.
This system has a centrally located HR box and Sub HR box connected by 2 pipes to the condensing unit located on the roof.
Rigid ACR copper is run from the condensing unit down to the Branch Controller box.
Soft copper line sets then connect each fan coil back to the Branch Selector
HR boxes are powered by single phase and can be connected to the same circuit as the fan coils.
These boxes require condensate drainage.

18. Single Circuit Heat Recovery
Zone located HR/BS boxes.
Rigid ACR from CU to HR/BS box (3 Pipe)..
Soft Copper Line Sets from HR/BS box to Fan Coil.
V 1Ph connections on HR/BS and IDU.
BS/HR Condensate drainage NOT needed.
The Single Circuit Heat Recovery layout stretches out the location of heat recovery units to the zone they serve.
A combination of rigid and soft copper is spread out through the space interconnection each zone back to the main piping network with Y branch fittings.
single phase powers the HR boxes and can be zoned with fan coil unit electrical circuits.
No condensate is requited for single circuit heat recovery boxes.

19. Multiple Circuit Heat Recovery
Zone or Centrally Located HR/BS boxes.
Rigid ACR from CU to HR/BS box.
Soft Copper Line Sets from HR/BS box to Fan Coil.
V 1Ph connections on HR/BS and IDU.
BS/HR Condensate drainage NOT needed.
Multiple circuit heat recovery uses zoned or centrally located HR boxes interconnected to the main piping network with rigid and soft copper utilizing Y branches. Depending on the manufacturer and capacity the boxes can be piped through because of the internal manifold.
Multiple circuit heat recovery boxes are also powered by single phase and can be zoned with the fan coil units they serve.
These boxes also do not require condensate drainage.

20. Condensing Unit Options
Air Cooled
Ranges from -13°F to 65F° heating mode.
Cooling range from 14°F to 118°F.
Cooling down to -9.9°F with low ambient kit.
Capacity decreases in heating mode as outdoor ambient temperature drops below 14°F.
Requires defrost.
Can be placed in enclosure.
Most air cooled condensing units have operational ranges from -13 to 65F in heating mode without requiring any supplemental heat.
Cooling ranges between 14 and 118F with low ambient kits stretching this range down to -9.9F
It is important to keep in mind when designing a system that performance begins to decrease from nominal capacity around 14F. When a system is over connected this decrease in performance can be more dramatic.
Depending on your climate region condensing units may require defrost cycles to clear frost accumulation from condensing unit coils.
Condensing units can also be placed in enclosures.

21. Outdoor Placement- Air Cooled
Account for Snow Fall.
Access for maintenance.
Prevailing Winds.
When installed outdoors, air cooled condensing unit can be placed on rooftops or grade but it is recommended that they are elevated to provide clearance for snow accumulation and drainage.
It is also important to account for prevailing winds and in some cases hail damage.
VRF Manufacturers provide hail guard accessories that can be added to the condensing units to protect the coil from potential damage.

22. Placement in enclosures
Placing VRF air source condensing units within enclosures can mitigate risk associated with weather events and operational limitations based on outdoor ambient temperature.
There are two types of enclosures;
Partial enclosures- have at least one wall to block prevailing winds and a roof.
Today we are going to talk about full enclosures-
A full enclosure is exactly what it sounds like, 4 walls and a roof. This can be an old boiler/chiller room, old air handling unit room, a generator enclosure, even an upcycled shipping container.
Full enclosures, especially old equipment rooms have a relatively minimal conversion cost.
Lets take a look at some of the components necessary to retrofit an existing equipment room for VRF condensing units.
Outside Air intake louver with insect screen and actuated damper
Exhaust louver with insect screen and actuated damper
Plenum installed bypass/recirculation damper for recirculating air in low ambient outdoor air conditions.
Condensate drain pan under the heat pump.
Inlet and Outlet Louvers and Dampers with Bypass Damper System.

23. Water Cooled Condensing Unit
EWT Ranges down to 23°F.
Loss of nominal capacity with Glycol .
Closed Loop
Geothermal
Open Loop
HX Required
Indoor Installation
Water cooled condensing units can be applied in a variety of applications but must be installed inside the building.
Closed loop systems such as geothermal or boiler with a fluid cooler.
Open loop systems with a cooling tower will require a secondary heat exchanger.

24. Ventilation Air
Refer to ASHRAE Standard Ventilation for acceptable indoor air quality.
Ventilation air can be direct or decoupled from the VRF fan coil units.
Examples of Ventilation air systems
DOAS with an energy recovery wheel.
DOAS with an energy recovery core.
ERV/HRV.
VRF outdoor air processing unit.
Ventilation air is important to keep in mind when implementing VRF systems in a building design.
You can refer to ASHRAE Standard Ventilation for acceptable indoor air quality to find the calculation for the minimum outside air requirement for the space you are designing for.
Ventilation supply air can be either directly coupled or decoupled from the VRF system. Some fan coils have a built in connection for fresh air, others will require ventilation air to serve the space independently.
Some systems we typically see providing ventilation air to the space are:
Dedicated Outside Air System with gas heat, mechanical cooling and energy recovery wheel.
Dedicated Outside Air System with electric heat, mechanical cooling and energy recovery core.
Energy recovery ventilators, Heat recovery ventilators with electric preheat
VRF Outside air processing unit.

25. Energy Efficiency
Measured in IEER. AHRI Standard with Addendum 2
Integrated Energy Efficiency Ratio
Measured in EER, IEER, SCHE and COP for Heating.
Elimination of duct losses estimated at 10-20% airflow in some systems
Variable speed compressor spends most of it’s time between 40-80%
Estimated 30-35% savings in annual operation costs vs VAV systems
In 2010 AHRI released standard with addendum 2 to provide and official rating of the performance and energy consumption of VRF systems.
Integrated Energy Efficiency Ratio measures energy consumption and performance at part load conditions. AVG 23 – 38
EER is measurement of full load energy AVG
SCHE is Simultaneous Cooling and Heating Efficiency AVG
COP is coefficient of performance AVG 3.7 – 47, & 2.5 –
Because VRF systems transfer energy through small copper pipes rather than large ducts it is estimated that there is a 10-20% savings in energy expended through duct losses.
VRF systems are also said to be yielding an average savings of 30-35% in annual operation costs versus VAV systems.

26. Questions Thank you! Steven Blanchard Data Power Technology Illinois
8105 N University St, Peoria, IL 61615

27. Thank You
References
ASHRAE Journal. April Variable Refrigerant Flow Systems, By William Goetzler.