Heat/cool for a real trailer

Solid_Fuel_Man

Customer of mine has a food truck, but is building an enclosed trailer to serve bbq out of year round. This will need heat 24/7 in the winter to prevent freezing. I've wired shore power at his house, and he has 240volts available where he travels as well. Trailer will be insulated to at least R10. 

I'm thinking this is perfect for a mini-split, but are there any which are rated for this? Being attached to a moving vehicle (while not running) and then being energized immediately after becoming stationary again. 

I'm going to install a small electric wall heater in there as well. 

72 square feet, 504 cubic feet total. 

hot_rod

All sorts of options in the RV industry for trailers that size. I see mini splits on tiny homes and expedition RVs all the time.
These are built near me and I see mini split condensers on the rear bumpers.
https://www.globalxvehicles.com

I built a 20' tiny home, put radiant floors and a 6,000 window AC unit. I used a Thermal 2000 electric boiler, needed a 30A 240.

Diesel and LP combi heaters are available also.
https://truma.net/heating-systems

pecmsg

Mini on a food truck with all that grease?

Budget a new one every year!

Zman

I winterized a food trailer a few years ago. The sides and lid had an inch or so of insulation stock. Since the trailer never traveled much, we sprayed a few inches of closed cell insulation on the underside and the tanks.

The thing you need to keep in mind is that the type 1 hood will pull ~300 CFM per lineal foot all the time. Unless you have a MUA unit, you cannot close the doors and windows when cooking or the pressure will go negative and you won't be able to open them.

We just installed a small electric unit heater to keep it from freezing at night and to provide a little heat for the counter person. With all that cold air whipping through, you really cannot maintain a steady temp in the trailer.

I think the best setup would be a radiant heater at the service window.

GroundUp

I set up a food trailer (mmmm, tacos) with radiant floors heated via an electric water heater a couple years back and have done a number of ice houses and a couple RVs the same way. As Zman mentioned, the exhaust hood can become an issue when they have the serving window open but for the most part there's not a lot of smoke/fumes to exhaust in the case of the taco wagon. They set that unit up with a roof AC from an RV for summer months as well, and last I heard they've been loving it.

Solid_Fuel_Man

pecmsg said:

Mini on a food truck with all that grease? Budget a new one every year!

No cooking happens in there. He smokes all the meat in a wood smoker at his house every night. Serves/assembles sandwiches etc. in the truck. 

No exhaust hood or frying happens. Just need it to not freeze all winter as it gets used every day. He said the aluminum floor truck turns into an ice rink. 

This is a personal friend and I'm helping with the whole project. 

We are planning on 1.5" of blueboard sandwich floor, with plywood on top cover with a commercial vinyl floor. 

1.5 - 2" of blueboard aeverwhere else covered with either stainless sheets, diamond plate aluminum, or FRP depending on location. He currently uses a 6,000 btu window shaker for A/C in the summer and his LP serving equipment heats somewhat in the winter. It regularly reaches -30F here. 

ratio

With an open serving window, radiant might be a more comfortable choice, maybe even hydronic as @GroundUp mentioned. Also, I think I'd stay with the window shaker (or a larger one if the 6k isn't enough) for the replaceability of it—it'd be a lot more expense to replace a mini split head & I do believe as @pecmsg, that it'd be a greasy mess after a while.

Zman

With no cooking, the mini split system sounds like a good solution.

Solid_Fuel_Man

Yes, so does anyone have any knowledge of a mini-split which is listed/tolerant of being attached to a vehicle? That's the real question. Or will any of them work? I can reach out to my rep, but wanted anyone's first hand experience. 

Solid_Fuel_Man

After talking to a couple of suppliers, they all said there would be no issues with a mini-split traveling around while not energized, in fact they echoed what @hot_rod said. Many units on tiny houses, demo trailers, even RVs, no issues!

Ordered a 9,000btu unit. The owner opted to have the entire trailer spray foamed (walls/roof, and under floor) so the stationary heatloss will be very small. When the window is open, well, it will be what it will be. 

bio_guy

9000 sounds like a lot of capacity unless the number of people packed in there calls for that much cooling or low temperatures make it necessary for heating.

Solid_Fuel_Man

Thinking about the open serving window. Also -30F here.

retiredguy

@ Solid Fuel Man, you used the term "shore power". I wonder which branch of the military you served in.