VRF / VRV manufactures require that you use their proprietary software to design the refrigeration piping for the installation of their VRF systems. You or your engineer will need to have a cooling and heating load to import or use with the VRF piping design software. Using energy modeling software is great for Heat Recovery Systems and optimizing zoning layout. Below you will find a list of links to each of the Manufactures free VRF Piping Design Software. Here is what you can expect to receive.
VRF Piping Diagram
The VRF manufactures software will provide a schematic piping diagram showing all the outdoor & indoor units along with any accessories. The schematic piping diagram will also show the pipe sizes and lengths that were used in the calculation. There will also be model numbers for the equipment and accessories with the schematic. All fittings and valves are converted to an equivalent length of pipe when calculating piping and system size.
Of course you will be asked to enter the lengths of piping unless your VRF sales representative has agreed to do it for you based on a set of plans and specifications. The software will automatically indicate whether the design has exceeded the allowable lengths as dictated by the VRF manufacture.
The VRF Piping Design Software should give you the following as shown in the Piping Diagram above;
- Model # and Size of the Outdoor Unit
- Pipe Sizing from outdoor Unit to Branch Selector or Indoor Unit
- Pipe Lengths for each section
- Model numbers of all “Y”-Branch Fittings and where they are located.
- Model # of all Branch Selector Boxes
- Pipe Sizing from Branch Selector Boxes to Indoor unit
- Pipe Lengths for each section
- Model # of all Indoor Units and its Cooling & Heating Capacity
- Thermostat or controller Model #
Looking at the above VRF piping diagram you can see everything is drawn with a single line, but that there are three dimension (3-Pipe System) for the pipes leaving the Outdoor Unit, and two dimensions (2-Pipes) leaving the branch Selector Box going to the Indoor unit. This makes the drawing is easier to read.
VRF Electrical & Control Wiring Diagram
The VRF manufactures will provide a schematic of the electrical and control wiring diagrams showing how all of the components of the system are powered and controlled. The schematic will indicate the power and control wiring size and type.
The VRV Design Software should give you the following as shown in the Wiring Diagram above;
- Power Wiring for Outdoor units
- Power Wiring for Branch Selector Boxes
- Power Wiring for Indoor Units
- Control Wiring from Controller to Indoor Units
- Control Wiring between Indoor Units
- Control Wiring from Indoor Units to Branch Selector Box
- Control Wiring between Branch Selector Boxes
- Control Wiring between Branch Selector Boxes and Outdoor Units
- Control Wiring between Outdoor Units
- Control Wiring to Main Controller if used.
Bill of Materials
The VRF Piping Design Software will provide a bill of materials for the project which should include the following at a minimum;
- Equipment Model Numbers & Capacity
- Accessories: Branch Selector Boxes, Y-Branches, Headers, etc.
- Piping sizes and lengths
- Controls, thermostats
- Factory refrigerant charge & additional refrigerant charge required
The VRF/VRV Design software will generate equipment schedules that can be used on your CAD design drawings. This will save you time and money from not having to make this yourself.
The software will generate an estimated quantity of refrigerant that you will be required to supply to meet the required capacity of the system. The outdoor unit should come pre-charged with an amount for the system excluding the piping. The amount of refrigerant charge should be indicated in the report.
VRF System Sizing Diversity Factor
This is known by the various names that each VRF manufacture uses to describe the ratio of Indoor Unit Capacity to Outdoor Unit Capacity. There are two formulas often used to express system/load diversity. The first involves the total peak load of all the indoor units divided by the total capacity of the outdoor units that they’re connected to.
Indoor Unit Capacity (Btuh) Total of Peak Loads / Outdoor Unit Capacity (Btuh) = Diversity Ratio.
Cooling Load diversity occurs when the engineer provides zoning of the indoor units with different peak load times. Outdoor units serving a block load contains zones that peak on different days at different times, allowing for the outdoor unit to be smaller than the sum of the peak loads of each indoor unit. This is often achieved by combining zones with different solar exposures onto the same outdoor unit. The second formula involves the total Block Load divided by the Total Capacity of the Outdoor units.
Block Load Capacity / Total Outdoor Unit Capacity = Building Load Diversity
VRF Piping Design Software Links
Unfortunately some of the VRF manufactures have several divisions throughout the globe with differing links and names for their software. Here are a few.
What you will need to get started
- Heating & Cooling Loads with zoning requirements.
- General layout of equipment components in building.
- Lengths of piping between pieces of equipment
- Type of Ventilation system
- Type of Indoor Units for each space.
The VRF Manufactures representative will often provide the above information free of charge with the hopes that they will be able to sell you the equipment and accessories. Contact your local VRF/VRV supplier for information on the above VRF Piping Design Software.