My VRF Origin Story

My VRF Origin Story

I can trace the trajectory of my career all the way back to a job walk in Pasadena.

Back in 2007, our sales manager suggested we take a look at an installation of a new type of heat pump. It was one of the first installations of its kind. It had the ability to connect multiple fan coils to a single outdoor condenser. It even had the ability to heat and cool different zones of the system at the same time. The system was called a Variable Refrigerant Flow system or VRF.

I was a young sales engineer at the time and I understood those words but my mind had a hard time comprehending how that could work. I went to the job site and took these few photos with my Sidekick 3. I didn’t know it at the time, but I ended up concentrating on and spending the majority of my career on VRF.

Back then, it was a new technology and even today in 2024, it still is considered “advanced” or “complicated” (at least in the United States). I’ve spent the last 10+ years selling, educating, and advocating the benefits of VRF and I can trace it all the way back to that job site visit.

Outside Air Ventilation for VRF Systems

Outside Air Ventilation for VRF Systems

One of the challenges when using VRF is integrating ventilation or outside air. There are different ways to bring in outside air.

The most straightforward way to bring in outside air through a dedicated outside air system, or DOAS. As the name implies, these are basically specialized rooftop packaged units whose only job is to bring in and temper fresh outside air. The main downside to this is that it will require its own ducting system and you’ll have to find a way to integrate it into the space; either mixing with the comfort cooling system, or by dumping it directly into the space.

Another way to do this is to do what I took of picture of here. Many cassette fan coils have a small perforated hole on the chassis that you can punch out and bring in a duct to introduce outside air.

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I always have to preface this by saying it is a SMALL amount of outside air, typically 3–5% of the nominal airflow of the cassette and it will be untempered and unfiltered. But in some cases, it makes sense. I saw this in a brewery in Oakland and it was close to an outside wall and in the Bay Area, the climate is generally mild.

I had to take a picture while enjoying a beer since it was the first time I saw the OA knockout being used.

On VRF’s modularity and scalability

One of the advantages of VRF systems is that they’re modular and scalable. From single modules starting at 6 Tons, and then combining modules to form systems up to 42 Tons, we have the ability to combine multiple systems allowing us to condition spaces all the way up to large professional sports arenas. Time for a story…

The year is 2017 and the Golden State Warriors finished the season with a 67–15 record. They steam rolled through the playoffs before meeting Lebron and the Cleveland Cavaliers for the third year in a row. They easily defeat the Cavs 4–1 and were 2016–2017 NBA Champions. A month later, I received plans for the largest, highest profile project I’ve been involved in: The job was called New Warriors Arena which was eventually named Chase Center.

From what I recall, the systems themselves were pretty simple. Each system consisted of water cooled condensing units with ducted fan coils and a few cassettes. But with the size of the arena, we needed over 60 of these systems. Everything was tied together with central controllers.

On March 5th, 2020, Steph Curry made his long awaited return after breaking his hand during the 2019 season. I had a neighbor who had season tickets to the Warriors and he invited me to a game, so of course I took him up on his offer. I distinctly remember going to the game because there were stories in the news about people getting sick and my wife urged me to wear a mask while I took BART to the game. Once I got there, I had to take a look up and I saw a ducted fan coil installed above me. It was cool to know that I had a part in getting that fan coil up there. Admittedly a VERY SMALL part, but a part either way.

P.S. It turned out that that was Curry’s only game at Chase Center that year. We all know what happened a week later.

VRF Installation Practices

VRF Installation Practices

A few years back, I was asked to look at a home with a VRF system that wasn’t working correctly. I showed up and found sagging refrigerant lines and Y joints that were improperly installed.

VRF is an amazing mechanical cooling technology that is efficient and quiet. However, it takes proper designing AND installation for the equipment to work as intended. When I showed up at this house in Reno, I went into the crawl space and found refrigerant lines that were sagging and Y joints that were installed incorrectly. They were vertical instead of horizontal.

Why are sagging refrigerant lines bad? In every air conditioning system, RTU, split system, VRF, mixed in with the refrigerant is some amount of oil. The oil acts as a lubricant where it lubricates the moving parts of the compressor, similar as in a car engine. If there are areas where the refrigerant lines sag, it can cause oil to collect and not make it back to the compressor. Not lubricating the compressor can lead to wear and early failure of the compressor. It’s important to always install refrigerant lines straight with minimal sagging.

And why can’t you install Y joints vertically? Short answer: Gravity.

If you install Y joints vertically, gravity naturally prevents refrigerant from going into that top branch. This means that any fan coils coming off that branch doesn’t get the refrigerant it needs to operate properly. And then THAT leads to under cooling/heating in that zone. They need to be installed horizontally so refrigerant can flow to both branches equally.

With any piece of equipment, it needs to be installed properly or else it won’t work as intended, or at the worst, lead to early failure of the equipment. There are trainings available for each manufacturer. If you need training, please reach out and I can direct you to where you need to go.

Three Reasons Why Building Owners Should Use VRF

Three Reasons Why Building Owners Should Use VRF

Variable Refrigerant Flow is THE best technology for mechanical cooling. Here are 3 reasons why:

Efficient

VRF is extremely efficient compared to older technologies such as rooftop packaged units and chilled water systems. How is this possible? VRF systems use variable speed compressors at the outdoor unit and fans with EC motors at the indoor fan coils. By using these, the compressor will only use the appropriate amount of energy to send the refrigerant to only the zones that need it and the fans will only move as much air as it needs to to hit set point.

Real world analogy: when driving, you wouldn’t floor the gas to reach driving speed, let go, floor it, let go, etc. to maintain 65 mph. It’s EXTREMELY inefficient. You would depress the pedal slowly and smoothly to reach 65 mph and hold it to maintain it. This is how variable speed compressors work.

Scalable

VRF technology is scalable, meaning you use it from small applications from an elevator room to large applications such as hotels and college campuses. We can do this because the equipment is modular. Using various size ODUs and combining them to form larger systems, and then grouping these systems and controlling them via a central controller allows us to tackle any size project.

We also have different styles of indoor fan coils, from wall mounted, ceiling cassette, ducted, and using PMV kits, we can use any 3rd party AHU, which means we have a solution that we can use in any space.

Cost Effective

Using VRF can be cost effective over the life of the equipment. Since the systems are very efficient, they use less electricity to operate saving the building owner thousands over the life of the equipment.

It also uses a small footprint compared to other systems. Refrigerant piping takes up a fraction of the space of the equivalent ductwork of a RTU system or CHW/HW piping of a chiller/boiler/cooling tower system. You are able to place the outdoor heat pumps on the roof and eliminate mechanical equipment rooms, or even entire floors dedicated to mechanical equipment and open it up to leasable space. More leasable space to rent out to tenants and generate more money for the building owner.

If you’d like to see if VRF systems are right for your application, please reach out to schedule a lunch and learn.

VRF 201: Connection Ratio vs. Diversity

In the second video of my VRF series, I cover the difference between connection ratio and diversity factor. I see a lot of people getting the two confused or treating them as the same thing. I go over the differences and how to use both to properly size an efficient VRF system.

VRF 101: An Introduction to Variable Refrigerant Flow Systems

My first video in my VRF lunch and learn series. I cover the basics of VRF, 2 pipe vs. 3 pipe, and heat pump vs. heat recovery.