We have seen a lot over the past 12 years with portable refrigerated trailers. As the name implies there really are two key elements involved here, the refrigeration and the trailer. We have seen some folks get part of it right while most fail at both aspects when designing and building a small refrigerated trailers.
Let's start with the trailer. This is the foundation of everything we do. The regular cargo- enclosed trailer industry has changed over the years so much and they are cutting out the strength and durability we require for refrigerated trailers. It is important not to just get a trailer off the lot and try this at home like so many we see out there today.
Quality built refrigerated trailers should have:
1. Single Piece Aluminum roof
2. 16 "OC steel tube walls
3. Steel tube roof
4. Steel tube framed rear doors (not plywood w / aluminum skin)
5. Triple tube tongue
6. LED lights
7. Sub floor for superior insulation with aluminum underbelly
8. Load D or greater tires for better stability
9. No wood framing or wood walls / ceiling (lighter & stronger with no mold or mildew issues)
10. Reinforced front nose for refrigeration unit
11. Extended tongue with mounts for generator
12. Should be specifically built to be refrigerated trailers and built with strength and durability in mind. Please check out how important it is to use a trailer made of steel tube instead of z-post or hat post.
We have even seen people taking walk in coolers and putting them on a flat bed trailer. Be careful as many of these structures are not DOT approved and you can be fined or even worse injure someone. Use common sense, walk in coolers are great for sitting inside or outside a building but they are not designed for the rigors of the road going up and down and side to side, they offer no structural support.
The refrigeration is just as important and you definitely want to get this part right. The ideal solution for businesses is a unit that can be used as either a cooler or a freezer. Please make sure that even if you are purchasing a cooler that the refrigeration system has a defrost capability and preferably hot gas defrost. I mention this because so many folks find out the hard way that if you want your trailer to stay at 35 degrees then your evaporator has to be 12- 15 degrees cooler than that to maintain your temperature. Well it may take 12 hours or 24 hours but ever you are going to get an ice build up on your coil and you will need a way to defrost it or else lose your product.
Standard refrigeration units that have hot gas defrost are the most effective and fast way to defrost a system. The use of standard refrigeration will save you a bundle in repair and maintenance cost alone. We also recommend modifying your refrigeration system for transportation and do not use copper to connect the evaporator coil to condenser coil. Copper is a soft metal and will break easily. Hopefully these tips serve you well in your search for refrigerated trailers to purchase or rent.