Cooling control cabinet - Mike Holt's Forum

It appears like the suggestion to look at vortex coolers might make sense for your application.

HOWEVER, be aware they have some issues that can be problematic,

1. A lot of air supplies have oil or water in them. You will want to have some kind of device at the cabinet to remove the oil and water from the air before it enters the cabinet. Otherwise the inside of the cabinet will become slimy. be aware of where the air intake for the compressor comes from as well.

2. Compressed air is very expensive. Make sure you include a thermostat and solenoid valve so the air is only on when needed.

Cabinet air conditioners do not bring outside air into the cabinet being cooled, but do require some ongoing maintenance. They are available in type 4X design that may be suitable for your environment.

Here is a brand we use regularly. Figure out how many BTUs/hour you need and get one with that capacity.



There are also air to air heat exchangers that don't bring in any outside air to the cabinet. They can work OK if you want to reduce the energy costs of running the cooling device and the ambient temperature works out. Obviously, if the temperature outside the cabinet is 100 deg F, you will not be able to cool the inside below 100 Deg F.

One other thing to consider. You might be able to get by with just adding a stirring fan inside the cabinet. Moving the air around inside the cabinet gets rid of hot spots and promotes better cooling through the walls of the enclosure. This can work well if the ambient temperature outside the cabinet makes this option practical.

The important thing is to run the numbers and not wing it. Most of the time industrial control equipment can readily handle at least 40 deg C. It may be a little warm but the equipment will not care much.

You could also get a cooling plate that works with chilled water if you have chilled water available. pretty cost effective.

New control cabinet roughly 6ft x 6ft x 2ft deep is getting hot inside . We want to add a cooling system to the cabinet due to the heat , humidity in the area , and electronics inside the cabinet . We have a concern about just getting any type of cooling system as this is in a anodizing area with all kind of different tanks . We have ventilation in the room but this doesn't exhaust 100% of the fumes . Can anyone recommend cooling system that would not pull in fumes from outside the cabinet to cool the inside ?

What do you have inside the enclosure and how much heat is generated (in terms of watts) in the enclosure?
What is the worst-case temperature outside of the enclosure?
What is the temperature that you want to maintain the enclosure at?

Please take a look at the below link, closed-loop thermoelectric panel coolers with cooling capacity ranges of 130 BTU to BTU.

https://www.thermoelectric.com/air-conditioners/ I once did a vortex cooler system for some enclosures with PLCs inside that were above "pot lines" in an aluminum smelter, so VERY hot ambient air. For a 24x20x12 enclosure, the vortex cooler required what turned out to be 10HP worth of compressed air! They had no other viable choice so we had to use that, but as mentioned, that little detail is often overlooked when evaluating them.

I too like the Thermal Edge air conditioners, I've used them several times. But really most of the industrial brands like McLean (Hoffman), Rittal, Ice Cube etc. are all decent products. If you are in a humid area you will have to deal with condensate draining, another detail that is often missed.

The basic rule-of-thumb on heat exchangers is that the maximum ambient must be at least 10deg C LOWER than the maximum internal temperature. So for example if you must maintain 40C (104F) max. inside of the box, you must have NO HIGHER than 30C (86F) ambient, otherwise it will not work.

I really like the idea of Thermo-Electric (Peltier effect) cooling, but ho boy, the pricing (last time I checked) was a non-starter compared to conventional industrial air conditioners.

I once did a vortex cooler system for some enclosures with PLCs inside that were above "pot lines" in an aluminum smelter, so VERY hot ambient air. For a 24x20x12 enclosure, the vortex cooler required what turned out to be 10HP worth of compressed air! They had no other viable choice so we had to use that, but as mentioned, that little detail is often overlooked when evaluating them.

I too like the Thermal Edge air conditioners, I've used them several times. But really most of the industrial brands like McLean (Hoffman), Rittal, Ice Cube etc. are all decent products. If you are in a humid area you will have to deal with condensate draining, another detail that is often missed.

The basic rule-of-thumb on heat exchangers is that the maximum ambient must be at least 10deg C LOWER than the maximum internal temperature. So for example if you must maintain 40C (104F) max. inside of the box, you must have NO HIGHER than 30C (86F) ambient, otherwise it will not work.

I really like the idea of Thermo-Electric (Peltier effect) cooling, but ho boy, the pricing (last time I checked) was a non-starter compared to conventional industrial air conditioners.

Well, I guess This could fall in the Show Your Stuff Section. However, It is a bit off-topic. I have seen electrical cabinets that were either open loop cooling or closed loop cooling. All my builds to date have been open loop cooling with filter screens. Most Commercial machines however are closed loop. That said has anyone built electrical cabinets with closed loop cooling? If so did it make it more maintenance-free? Or did it become more trouble than it was worth? Also, I am talking about any air-to-air or liquid-to-air type heat exchangers. I know that some commercial types have used active refrigeration systems. That said I don't use my equipment when it feels like 110 degrees F. in my garage.

There should not be much condensate unless the cabinet doors are open. Once the little bit of humidity inside the cabinet is gone there is not much going to find it's way back in from the outside as it is pretty well sealed up.

I was referring to the condensate on the outside. Most use an evaporator, but in really humid areas (like Florida) I have seen those not be able to keep up and there is a constant pool of water on the floor under the A/C unit, which in some industrial areas is a real hazard.

Years ago when Hoffman used to give out those free CDs with the cooling calculation program on it, I would use it to keep increasing the enclosure size until it told me I no longer needed an A/C unit. I was in the Pacific NW at that time though, so I could base it on cooler ambient than I would be able to use down here now in California. But sometimes it would get ridiculous; I once had to put a 75HP VFD in a NEMA 4 sealed box, where they would not consider using an A/C. The box ended up being 120" wide, 90" tall, 24" deep and had to be in 100% shade at all times, so they had to build a lean-to for it. The A/C unit would have been cheaper. Before doing cooling, first consider alternatives. Three huge heat sources are transformers, drives, and DC power supplies. The first step is get the heat out of the cabinet. Many VFDs are offered in flange mount. So with a simple trim panel the heat sink (usually NEMA 4X aluminum) sticks out the back. You can buy epoxy encapsulated transformers that are nonvented. Just put the whole thing outside the panel with conduit connections. Or just separate things. You have a huge panel. Put say a fused disconnect and the DC power supply outside the cabinet in its own smaller and much more easily cooled cabinet. Plus it often moves arc flash out of the cabinet.

Also if you are outside in sun make sure you put up an awning or attach heat shields first. This also applies inside. Aluminum has roughly an emissivity of 0.05. It absorbs relatively little heat. So simply placing a layer of cheap “tin” siding on 1” standoffs in front of a heat source blocks something like 95% of radiated heat. On kilns we can reduce 800 degrees down to 100.

Also if you are still using CVTs, why??? Simple Islatrol filters and/or electronic power conditioners do everything the CVT does without all the disadvantages. A CVT is essentially a giant heavy panel heater. It runs a transformer in saturation so that it puts out square waves then uses a heavy resonant filter to pick the 50/60 Hz out. This is clearly highly inefficient and generates tons if heat.

I prefer thermoelectric coolers when it makes sense. The pluses are they are sealed…no exchange of air between outside and inside. They actually cool. And other than the two fans there are zero moving parts. They last up to ten years in really bad environments. Those are the good points. The negatives are they don’t scale up well so W of cooling is a realistic upper limit. They aren’t as efficient as air conditioners/heat pumps.

Next up is the stratus air to air heat exchangers. As long as ambient is ok which it usually is these are simple and work incredibly well at very low power.

I would consider true air conditioners/heat pumps last. Expensive, high power, and they don’t work long. Bard, Hoffman, many others. I’ve tried them all. They all suck. But if you need a lot of cooling and fans and the above doesn’t cut it, this is your best choice.

As with others, the biggest advantage of vortex cookers is they are cheap. It costs roughly 8 watts to make 1 watt of cooling. They spew oil all over everything. And they are usually too tiny to be effective.

Before doing cooling, first consider alternatives. Three huge heat sources are transformers, drives, and DC power supplies. The first step is get the heat out of the cabinet. Many VFDs are offered in flange mount. So with a simple trim panel the heat sink (usually NEMA 4X aluminum) sticks out the back. You can buy epoxy encapsulated transformers that are nonvented. Just put the whole thing outside the panel with conduit connections. Or just separate things. You have a huge panel. Put say a fused disconnect and the DC power supply outside the cabinet in its own smaller and much more easily cooled cabinet. Plus it often moves arc flash out of the cabinet.

Also if you are outside in sun make sure you put up an awning or attach heat shields first. This also applies inside. Aluminum has roughly an emissivity of 0.05. It absorbs relatively little heat. So simply placing a layer of cheap “tin” siding on 1” standoffs in front of a heat source blocks something like 95% of radiated heat. On kilns we can reduce 800 degrees down to 100.

Also if you are still using CVTs, why??? Simple Islatrol filters and/or electronic power conditioners do everything the CVT does without all the disadvantages. A CVT is essentially a giant heavy panel heater. It runs a transformer in saturation so that it puts out square waves then uses a heavy resonant filter to pick the 50/60 Hz out. This is clearly highly inefficient and generates tons if heat.

I prefer thermoelectric coolers when it makes sense. The pluses are they are sealed…no exchange of air between outside and inside. They actually cool. And other than the two fans there are zero moving parts. They last up to ten years in really bad environments. Those are the good points. The negatives are they don’t scale up well so W of cooling is a realistic upper limit. They aren’t as efficient as air conditioners/heat pumps.

Next up is the stratus air to air heat exchangers. As long as ambient is ok which it usually is these are simple and work incredibly well at very low power.

I would consider true air conditioners/heat pumps last. Expensive, high power, and they don’t work long. Bard, Hoffman, many others. I’ve tried them all. They all suck. But if you need a lot of cooling and fans and the above doesn’t cut it, this is your best choice.

As with others, the biggest advantage of vortex cookers is they are cheap. It costs roughly 8 watts to make 1 watt of cooling. They spew oil all over everything. And they are usually too tiny to be effective.

Back in the day, we used Kooltronic AC units in an industrial setting without issues. The key was to throw away the supplied washable filters and refit with disposable. Our plant was really dirty so we had someone assigned to go through the plant and replace the filters every Monday morning.

The oil discharge problem with vortex is largely due to a neglected or improperly designed plant air system.

Air conditioning is often one of the prime considerations when dealing with commercial or residential buildings. Whether you are renovating your house, or drawing up plans for your new dream home, you will inevitably be faced with the choice between a ductless system and a ducted one.

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This can quickly become a daunting task.

Both ducted and ductless heating or cooling systems come in multiple types under several brands. In this guide, we will be covering all the basics about these two systems, along with the advantages and disadvantages of each. By the time you’re done reading this, you will be able to make a more informed decision about which system is best for your home.

Ducted Air Conditioning Systems

As the name suggests, ducted air conditioning provides heating or cooling through a system of ducts spread out all over your home or commercial space. A central unit, consisting of a condenser, compressor, and an air handling unit, is usually located in the basement, attic, or garage. It provides cool or hot air, which is then distributed throughout the building through a series of ducts and vents, providing the appropriate climate control.

Types of Ducted Air Conditioning Systems

Ducted systems are also called central air conditioning systems. They can be broadly segregated into two types, i.e., Split central air conditioners and packaged central air conditioners.

Split Central Air Conditioners

These systems are by far the most common type of central air conditioning system currently being used. They consist of the condenser and compressor placed outside in a metal cabinet in one package. A separate evaporator is placed indoors within a segregated container, usually located in a closet or the attic. The outdoor unit provides the refrigerant to the evaporator, which then cools the air and pumps it down the network of central air ducts through an air handling unit.

Split central air conditioners are usually three times the size of an equivalent packaged central air conditioner. Splitting them in two makes the size much more manageable. Despite their size, split systems have higher SEER ratings than packaged air conditioners. In many split-system air conditioners, the indoor cabinet also contains a furnace or a heat exchanger of a heat pump. Moreover, split systems are an economical choice for homes that already have a furnace but no air conditioner as they can utilize the same furnace ductwork.

Packaged Central Air Conditioners

On the other hand, in a packaged central air conditioner, all the components, including the condenser, compressor, and evaporator, are in one single unit. You can either have these installed on a concrete slab next to your house or the roof.

This system is best suited for commercial buildings, or already built homes, where space can often be limited indoors. Central air ducts then circulate the air from the air handling unit into the room and move it back to the unit. These systems can be coupled with heating coils or furnaces to provide heating facilities too.

Packaged central air conditioning systems generally provide lower efficiencies than split systems but have the advantage of not taking up any space inside your home.

Before going for packaged central systems, be careful to check out your outdoor space well in advance. These systems can be heavy, so the roof should be able to handle the load adequately. Or, if you’re placing it on the ground, concrete emplacements need to be dug in beforehand.

Another important consideration while choosing ducted air conditioners is the ductwork. Regardless of which type of ducted air conditioning system you choose, central air ducts will take up a significant amount of space in your home. So it’s important to keep that in mind and see if a ducted system matches your home’s layout and design.

Types of Ducts for Ducted Heating or Cooling

Ducting makes up a major component of central air conditioning systems. Like with the main units, central air ducts also have various types based on the material used in their making. There are two central air duct types currently used:

1. Flexible Ducting

These AC ducts are tube-like structures with a large diameter. They consist of a metal framework surrounded by flexible plastic and insulation. This type of ducting is often cheaper and easier to install. It is best suited for confined spaces, where rigid structures can often be hard to install. It’s also useful for connecting rigid ductwork to the air outlet. An important point to remember while installing flexible ducting is ensuring that there are no kinks or bends, which might hamper airflow.

2. Rigid Ducting

As the name suggests, these central air ducts are fixed structures that distribute air across an internal space. They are usually made of metal, making them sturdier and more durable than flexible ducts, but at the same time, harder to install. They are also much noisier since metal ducts can carry the racket of a blower much better than plastic ones.

The use of fiberglass insulation around the metal can help reduce the sound of air conditioning. But it has the disadvantage of being a potential health hazard, where deteriorating and old fiberglass lining can release particles into the air. Inhaling these particles can irritate the lungs. They can also end up causing skin irritation.

Pros and Cons of Ducted Air Conditioning

Now that we’ve had a general overview of central or ducted air conditioning systems, let us go over the pros and cons of them:

Pros Cons According to the EIA, 91% of homes built in the US since have central ducts included. So chances are, you’ve already got a duct network within your property. If that’s the case, opting for a ducted air conditioner is a no brainer. This will also radically decrease the installation costs. Ducted air conditioning usually have   higher installation costs, especially if installation is being performed in an already installed property where duct space has to be made. The vents used in ducted air conditioning systems give out an unobtrusive and discrete outlook. So if you are one for aesthetics, these systems are for you. These air conditioners on the average, present lower efficiency ratings, called Season Energy Efficiency Ratios (SEER), for the same cost as their ductless peers. Leaks or damages to the ducts can further reduce the efficiency of the system, resulting in even higher operating costs. Ducted air conditioning removes humidity at a much greater rate than its ductless counterparts. So, if you live in a humid environment where maintaining an ideal humidity level is a priority, these systems come out on top. These systems are generally maintenance intensive, with ducts requiring regular upkeep and monitoring. According to the EPA, up to 30% of the air is lost through leaks, holes, and improperly installed joints within the AC ducts. If your target space is a large room with many people inside, such as a restaurant or workspace, then ducted systems provide enhanced airflow than ductless systems. A greater rate of air flow ensures it never gets too stuffy, and you are constantly provided with fresh air circulation. Mold in AC ducts can accumulate over time, and also serve as a breeding ground for insects. Such contaminants, when introduced to the room along with air, can result in allergies and diseases.

Ductless Air Conditioning Systems

Ductless Air Conditioning systems do not require ductwork to move air around your house. Instead, ductless units blow cooled air directly into the living space, which makes them highly efficient. Ductless air conditioning systems have two main components: an outdoor unit and an indoor air-handling unit with an evaporator coil and fan. A copper conduit housing the power cable, condensate drain, refrigerant tubing, and suction tubing, links the outdoor and indoor units.

Types of Ductless Air Conditioning Systems

Ductless air conditioners are gaining popularity due to their multiple advantages. There are various types of ductless air conditioning systems and heat pumps in the market. These are normally conventional, but more modern smart varieties are also entering the market. While smart air conditioners can be costly, you can make any standard ductless AC smart using a smart AC controller.

Let’s go over some of the major types:

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Wall Mounted Mini Splits

Wall-mounted mini-splits go on any wall that has enough space outside it for the outdoor compressor unit. These go high up on the wall to keep the circulation of air effective (remember, cold air sinks!).

These wall-mounted ductless air conditioners are fairly easy to install and quite cheap, making them a popular choice among consumers. Furthermore, these air conditioners provide the flexibility of zone control, allowing the user to set the climate of each room individually. In addition, advancement in this technology allows these mini-split units to work as reversible heat pumps, supplying heat in the winter months.

Wall-mounted mini-splits can be single zone or multi-zone:

• Single Zone Mini Splits

Ductless single-zone mini-split air conditioners consist of an indoor unit and an outdoor unit placed outside. Both the units connect via a small pipe bundle, consisting of piping for the refrigerant, condensed water, and a power cable. This bundle of pipes, placed in a copper conduit, passes through a small hidden hole in the wall.

• Multi-Zone Mini Splits

These systems are very similar to single-zone mini-split air conditioners. The notable difference is that instead of one outdoor unit powering one indoor unit, the outdoor unit connects to multiple indoor units. The basic principle is the same, but a larger outdoor unit is necessary to meet the added needs of the numerous systems connected to it.

Window Units

Instead of having a separate indoor and outdoor unit, the evaporator and condenser are packaged into one housing and installed on a window. The interior air is cooled by the evaporator, while the absorbed heat gets pushed outside. Multiple units may be installed within a large home, one in each room, to provide adequate cooling.

Portable Air Conditioners

With all the components housed in one package, portable air conditioners are similar to window air conditioners. However, the notable difference is that you can set up a portable ductless air conditioner anywhere, as required. The unit is usually on wheels or sufficiently lightweight so that you can move it around easily. These units have a hose that can be extended and placed outside to provide an outlet for the heated air venting from the condenser.

Ducted Mini-Splits

Ducted mini-splits, or concealed mini-split, provide the perks of both a ducted and a ductless air conditioning system. A mini-split unit connects to ducts that transport cooled or warmed air throughout your space. The mini-split duct connects to grills or registers that are barely visible in your room.

Floor Mounted Mini-Splits

As the name suggests, floor-mounted mini-splits have an indoor unit placed either on the floor or very close to it. These units are ideal for rooms with low-hanging ceilings or slanted walls. They’re also great for rooms with large windows that don’t leave enough space for wall-mounted units.

Cassette type Air Conditioners

Cassette air conditioners are usually recessed within the ceilings of the room, leaving your walls empty and not ruining the aesthetic of your room. Like other split units, they have an outdoor unit that transports the refrigerant to the indoor air handling blower via a conduit. They provide ample airflow from the four openings on each side of the unit. Therefore, they are best suited for larger rooms, such as shopping stores or workspaces.

Ducted Mini-Splits

Ducted mini-splits, aka concealed mini-split, provide the perks of both a ducted and a ductless air conditioning system. A mini-split unit connects to ducts that transport cooled or warmed air throughout your space. The mini-split duct connects to grills or registers that are barely visible in your room.

Pros & Cons of Ductless Air Conditioning

Now that we’ve had a general overview of ductless air conditioning systems, let us go over their pros and cons to help you make the best decision between ducted vs ductless air conditioning:

Pros Cons Ductless AC systems leave a much reduced footprint in the house than ducted ones. This is due to the absence of any ducting or a large condenser/air handling unit. This makes them ideal when renovating a space, where there is minimal room for ducts. Ductless AC systems require a unit to be placed within the room. These can often be obtrusive and an eyesore. Mini-splits can give freedom to create multiple temperature zones. Each room’s temperature can be individually altered as per need, without changing the whole homes’ temperature. Even though you also have this option with ducted systems, they are usually expensive. These systems have a higher initial installation cost than ducted systems. This can be recovered over their lifetime, but it depends on specific geographical conditions and AC usage. Due to their higher efficiencies, an increasing number of electric utility companies are now providing rebates and financial incentives to homeowners to install mini-splits. They generally do not provide the large levels of air flow which are observed with ducted systems. If you’re looking to put in large volumes of air in a large space, then ducted systems are the better option. An increasing number of electric utility companies are now providing rebates and financial incentives to home owners to install mini splits, due to their higher efficiencies. Inverter technology incorporated inside ductless systems enables the compressor to speed up or slow down as per demand, resulting in decreased energy usage. Better air quality is obtained through the use of ductless systems. Absence of ducts removes any potential for dust and contaminants. Filters can be easily removed and cleaned, with newer models having air purifying technology built in.

When Should You Opt For Ducted Air Conditioning

While both options have their perks and downsides, different systems are suitable under variable circumstances. Here’s when a ducted air conditioning system would be best for you when compared to a ductless unit.

1. Your space has existing ducts: If your home has existing ductwork in a workable condition, it would be wiser and more cost-efficient to make use of them.
2. You live in a humid space: Ducted air conditioning systems control humidity better. These systems will save you the trouble of getting a dehumidifier if you live in a moist region.
3. You need improved airflow: They provide better air circulation since the central air ducts move air more efficiently throughout your space.
4. You want a discreet solution: Everything is hidden away out of sight with ducted air conditioning systems, save for the registers. This system is ideal for people who want a cooling or heating solution that doesn’t ruin their home’s aesthetic.
5. You want a low-maintenance solution: You only need to perform occasional cleaning and maintenance with ducted air conditioning systems. These systems have fewer components and therefore can require less upkeep. Ductless units are present in each room and all require separate maintenance.

When Should You Opt For Ductless Air Conditioning?

In certain circumstances, ducted air conditioning solutions might not be best for you. Here are all the times when a ductless air conditioning system would suit your needs:

1. You have no room for ducts: If you live in a compact space where installing ductwork isn’t an option, or you don’t want to give you high ceilings up, a ductless air conditioning system would be ideal for you.
2. You are adding to an existing space: A ductless system would be a cheaper option if you’re adding an extra room or are looking for additional heating/cooling in your grow room or shed.
3. You don’t want dust in your space: Ductless air conditioning systems push air directly into your living space, which reduces the chances of them passing through dusty ductwork.
4. You want multiple zone temperature control: You can have separate air handlers for all the rooms in your home and can control the cooling and heating settings for each one individually. This feature makes ductless systems great for people living in shared spaces, with everyone having different temperature preferences.

Going for Both Ducted and Ductless Systems

Ducted vs ductless is one debate, however there is also a middle ground. You can opt for ducted ductless cooling to benefit from the best of both worlds!

The ultimate goal is comfort, efficiency and convenience and opting for a combined ductless and ducted HVAC system can provide just that. You can easily add air conditioning in additional rooms such as a new shed, your garage or attic where it may be difficult and costly to install new ducts in a pre-built home.

Hot and cold spots in your home can be covered with a ducted ductless solution and if your house is prone to thermostat wars, a combination of both systems can provide individualized comfort!

Zoning and integrated controls for HVAC are other modern solutions to provide ultimate flexibility with a combination of ducted and ductless systems.

Ducted vs. Ductless Air Conditioning : Which Is Better?

There is no hard and fast rule about when to go for a ducted air conditioner or ductless. HVAC systems are a complex piece of engineering, with many considerations that need pondering over. The final choice boils down to your specific needs. Whether you are installing the system in an already built property or do you wish to build from scratch? What is the area of the space you are heating/cooling? What is your budget? Whether you want individual zonal control or not? All these questions, and many more, need to be answered before going out and buying a suitable air conditioning system. Happy hunting!

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