Water. About two thirds of the world is covered with it. It’s amazing how some of the things that are the most plentiful in the world are the most useful. Kind of like using sand for bricks and mortar; trees for lumber and furniture; you know-the basic stuff.
I’ve been involved with HVAC for a long time now. 24 years ago, I had a new idea. Well, even a broken clock is right twice a day, and it was my time to be right. I was right about the geothermal HVAC being a technology that’s here to stay. And it uses water; water from the Earth.
As I got further along with geothermal HVAC technologies, I began to play around with shifting loads from one part of the building to the other. For example, I decided to take some of the waste heat from the air conditioning system and put it into the pool, and some into domestic hot water. We all know of desuperheaters or ECUs. They take a waste heat from a direct expansion refrigerant system typically, and they shed that waste heat into a useful place like a domestic hot water tank. With water source air-conditioning, the waste heat is channeled through the discharge condenser water from the air conditioner, and easily channeled into the geothermal pool heat pumps. One thing led to another, and we have continued to work toward perfecting this type of thermal advantage – load sharing with many different devices in the building. A piping circuit containing water makes this all possible.
Water has been used for a long time now to transfer BTUs from one place to another. Whether you’re talking about a nuclear power plant, a solar thermal installation, a chiller plant, or geothermal heat pump, water is what we use to move heat. So why do we need refrigerant? Good question. Simply put, chemical refrigerants do a great job through the process of phase change in absorbing or dissipating a lot of BTUs in a small area. And if you ask me, refrigerant should stay confined to a small area; like right inside the local equipment.
Refrigerant is expensive, it’s dangerous, it is finicky, and it’s elusive. There is one refrigerant that is the exception; R-718. It costs $0.00084 per pound. Pure, clear water.
Most refrigeration systems historically have been packaged, with perhaps a remote condenser here or there. Many installation use a fluid cooler, and keep the refrigerant inside the factory sealed unit, and pipe the hot or cold by-product to the outside. Then in the late 70s and early 80s, split systems really took off. The dependability of air-conditioning with these systems went down, partially because they depended upon a field service technician to properly prepare the refrigerant lines, evacuate the air and moisture, and ensure the integrity of the system. These are rarely installed to factory specifications; when was the last time you witnessed a technician run a steady flow of dry nitrogen through copper line set while brazing the copper joints?
Let’s get back to the energy recovery unit or desuperheater from years past; these were a great idea and worked well when installed correctly. But even with correct installations we ran into problems a few years down the road. The pumps seized up, the temperature sensors failed, the refrigerant-to-water exchangers leaked, and most people chose to decommission the units upon these failures by simply turning them off. Sure, the right thing to do would be to completely remove the desuperheater, but that would cost several hundred dollars because of the extensive refrigeration rework required to mend the hot gas line, the domestic water terminations, and the decommissioning of the electrical service to the unit. When the customer is told that this cost $900, he says, “no way”. Even with the warning that this could cause complete air-conditioning system failure under certain circumstances, the customer will typically choose to take his chances.
Big mistake. We all know what happens when a piece of equipment is left outdoors, decommissioned, especially with refrigerant and water inside of it. They will leak, and when they do it’s often at the expense of the main refrigeration system.
Let’s apply this scenario to a variable refrigerant job:
An owner of a small commercial office is very pleased that he has just installed a state-of-the-art variable refrigerant system. This customer has eight offices in a building that is 3000 ft.². Every single one of his offices has individual controls. Now let’s fast-forward to three years after installation, and evaporator is damaged while service man is running computer cables; the service man simply dropped his cordless drill on the top of the evaporator unit. It seemed harmless enough, except that the fan started vibrating. So they called the HVAC service company back out to repair the fan, and find that they aren’t able to get that exact fan; but they get one that will “do the job”. It’s louder and only works on single speed, but it will do…
At five years of age, that particular unit goes out again due to the same fan motor starting to rattle, and now they can’t get parts of any kind for this particular evaporator. So they try to buy a new fan coil unit, and find that the model is obsolete. On top of that, the next generation of refrigerant has been rolled out. They go ahead and purchase the new model evaporator, and the wiring protocol has changed. At this point, they have no choice but to buy an individual condenser for that particular evaporator. Two years later, basically the same thing happens again to another office; and they put another singular stand-alone mini split in that office, too.
The efficiency is terrible, because now they’re operating unmatched equipment that can’t even communicate with the original control system. By the end of 10 years, they have a mishmash of equipment that is so unlike what they purchased to begin with, that it’s not even recognizable anymore.
Have you ever felt like a 1973 Pinto with a short circuit in the blinker? Ka-Frickee-Boom.
We are in a society where habit seems to rule us all. I’m talking about general acceptance to appliances that no longer are repaired when something goes wrong. For example, when was the last time you tried to fix a hair dryer, a toaster, a DVD player, or microwave? If you have, you’re the exception rather than the rule. A few decades ago, we repaired just about everything. However we’ve grown accustomed to the new ‘rule’, and it’s convenient in some ways.
We are talking about the mechanical system for commercial buildings, and when we can no longer get parts needed to maintain and upgrade the mechanical system, that may be pushing “throw ways” too far.
Today, every time a customer with an R-22 system needs a major repair he has no choice but to replace the entire system with the newer R-410a matched products. R-410a is a transitional refrigerant that has been implemented while the industry comes up with “what’s next”. Are you seeing a trend here? You can’t mix different refrigerants in systems, but water will always be acceptable to use on as many watercooled refrigerant system as your heart desires.
25 years ago, I worked for a refrigeration company that sold commercial ice making and ice cream making equipment. We outfitted everything from restaurants to production facilities with this equipment. Almost every piece of equipment we sold and/or installed was watercooled. That was because the matter how many pieces of equipment were installed in the production facility, you could hook it in to a fluid cooler/cooling tower. And we sold those, too. Engineering was a cinch, and adding on was exceedingly easy. So why are we running refrigerant lines all over the place?
It’s dangerous, it’s expensive, it’s finicky, and it is not the right way to do things.
Say no to variable refrigerant systems. Say no to Ka-Frickee-Boom.
Say yes to R-718. Say yes to Water. You will never have to worry about “what’s next” in the refrigeration world.
Water. It does a building good.