Interesting mini split installation

[PT Doc]

Hi all. I just came from a commercial building complex and looked around quite a bit. The units that had no neighbor beyond the back wall had mini split units mounted either on the ground or on brackets on the back wall of the building. This is how I am used to see them installed.

Many of the these units are in buildings with neighboring units on either side as well as having a back neighbor. So there is no place to mount a mini split. Penetrating roof is not permitted here. Each unit has a rollup door or 2 and each has a man door on the front. Above the man door is a 12x12 grate that covers an opening into the building to allow fresh air. One owner cut this opening to approx 24”x24” and mounted the condenser unit with brackets to the inside of the unit. The fan side was somehow sealed against the inside wall so that the fan was blowing the air outward through this grate. I have never seen this type of install. Obviously, the unit is always outside when installed. In the install I saw today, if the fan is exhausting the air outside and the unit on the inside has fresh air fully around it, why is this type of install not what we see? What would fail if installed like I saw today? Thanks in advance for explaining.

 

[paranoid56]

any pics?

 

[Jackfre]

I’ve seen MS installed in all manner of locations. Some flat out would not work. The condensing units move a lot of air. If the air flow is sufficient and unrestricted then they run really well. Building them in is not good as they need to be serviced & one day repaired. If they cannot be easily serviced they do not get serviced.

 

[PT Doc]

I didn’t take a photo since this was in a guys shop.

Ill try to explain again and hopefully better this time. The condenser unit was installed inside this unit above the man door. The fan side of the unit was facing the wall and the concrete wall was cut so the fan could blow the air out. The unit was sealed to this concrete wall somehow. So from the inside, the install looks just like it would if installed on the outside of the building. This unit was not enclosed in any way, it’s 100% on the inside of the unit and just the fan faces the wall and is blowing through this cot out in the wall. From the outside of the building all you see is a grate above the man door.

Anyways, looks like a reasonable solution when you can’t install the unit outside. Time will tell how long it last.

 

[Two Door]

I didn’t take a photo since this was in a guys shop.

Ill try to explain again and hopefully better this time. The condenser unit was installed inside this unit above the man door. The fan side of the unit was facing the wall and the concrete wall was cut so the fan could blow the air out. The unit was sealed to this concrete wall somehow. So from the inside, the install looks just like it would if installed on the outside of the building. This unit was not enclosed in any way, it’s 100% on the inside of the unit and just the fan faces the wall and is blowing through this cot out in the wall. From the outside of the building all you see is a grate above the man door.

Anyways, looks like a reasonable solution when you can’t install the unit outside. Time will tell how long it last.

I can't imagine how that could work with both the hot and cold coils sharing the same envelope, AND the fan exhausting the conditioned air. Maybe this was actually in an outer room thermally separate from the rest of the shop.

Otherwise, after heat absorbed and discharged cancel each other out, it sounds like a complicated way to waste electricity.

 

[Innovate1]

Yeah. I don't get it either. Sounds like the outdoor unit pulls air from inside and blows it outside. But it's kind of hard to visualize...

 

[fitter30]

All equipment have clearances listed in their install manual. Tops have to be removable for controls, access to the coil for cleaning along with side panel and fan comes out the front.

 

[BernaldtotheSky]

It's difficult to picture this

 

[dscheidt]

I've seen a compressor mounted in a niche on a shipping container office, where they were clearly concerned about still being able to ship the containers by not changing external dimensions. They'd cut a section out of the end, and welded in a niche for the compressor and a panel for a shore power connection. I'd expect the compressor to not do well with no airflow over it, but who knows.

 

[Steve W.]

Yeah. I don't get it either. Sounds like the outdoor unit pulls air from inside and blows it outside. But it's kind of hard to visualize...

To me, it sounds like they re-purposed a mini-split into the concept of a portable air conditioner.

The biggest disadvantage I see there is the same as it is for the portable units, ... make-up air. It is taking inside (conditioned) air and pushing it outside. Replacement air has to come from somewhere.

.

 

[duneslider]

To me, it sounds like they re-purposed a mini-split into the concept of a portable air conditioner.

The biggest disadvantage I see there is the same as it is for the portable units, ... make-up air. It is taking inside (conditioned) air and pushing it outside. Replacement air has to come from somewhere.

.

I would be interested to see how they were actually "sealing" this. In my experience the outdoor unit has the coil on the end and the fan on the bigger "front" side. If they had both of those "ducted" to the outside I don't see why it would be a problem, it would all be "outside" air passing through the unit. Probably not the preferred way to go but it should work and it wouldn't be pulling conditioned air from inside and pushing it outside and you wouldn't need to worry about make-up air. You would have to have an intake and exhaust path for that to work though. Service wouldn't be easy, which means it likely doesn't happen...