Guides
Frozen and chilled on the same run: what actually works
Half the round is at −18 °C and half of it wants +2 °C, and one refrigerated body holds one number. There are four honest answers to that, they cost different amounts, and the one most people reach for first is usually the wrong one.
The physics
There is no compromise setting, and that is the whole problem
People assume a middle number exists. It does not, and understanding why saves an argument at the loading bay.
A transport refrigeration unit has one thermostat. It reads the air coming back to the evaporator, compares it with the number you set, and runs until the two match. One sensor, one setpoint, one body of moving air. Nothing in that arrangement can hold two bands at once, which is why a single insulated box behaves like a single room rather than like a fridge with a freezer compartment.
Now put both halves of a mixed round inside it. Set the unit at −18 °C to protect the frozen goods and the chilled half freezes: lettuce collapses, yoghurt splits, and a pallet of medicines is written off because freezing damage does not show through the carton. Set it at +2 °C to protect the chilled half and the frozen goods start to soften from the outside in, which is the point at which ice cream is finished and boxed poultry begins to lose the argument.
Splitting the difference at −8 °C is worse than either. It is too warm to keep frozen product frozen and far too cold for anything chilled, so it ruins both halves instead of one. There is no setting that serves two bands, and any supplier who implies otherwise is describing a vehicle they do not have.
What this leaves you is four real options: carry the smaller half in insulated boxes, run the job twice, send two vehicles, or find a genuine multi-temperature body. The rest of this guide is how to choose between them.
The decision
Find the small half first
Every version of this problem is solved the same way: the body runs at the band of the larger, less forgiving half, and the smaller half travels inside something.
| Shape of the round | Set the body to | Boxed half |
|---|---|---|
| Mostly frozen, a few chilled crates | −18 °C | The chilled crates |
| Mostly chilled, a few frozen cartons | +2 to +5 °C | The frozen cartons |
| Roughly half and half | Neither | Two runs or two vehicles |
Count in crates or cartons rather than in value, because what matters here is how much space the boxed portion needs, not what it is worth. Twenty crates of frozen against four crates of dairy is a clear answer. Twelve against ten is not, and that is the round that should be split rather than forced.
Then check tolerance. Frozen product is forgiving of time and unforgiving of warmth: it sits at −18 °C with a large thermal buffer and will hold for a long while in a closed box. Chilled product is the opposite, with a narrow band and very little margin, and medicines in the 2 to 8 °C band have a floor as well as a ceiling, which is covered in the medicine and vaccine guide. If one half is medicines, that half decides the body setting and the other half goes in boxes, whatever the crate count says.
One more filter before you plan the boxes: the drop order. If the boxed half is delivered in the first forty minutes, a box will do it comfortably. If the boxed half is the last three stops of a four-hour round, it is the wrong half to box, and you should look at the setting the other way round.
Option one
Insulated boxes, and the four things that decide whether they hold
A box inside a refrigerated body is the cheapest answer by a wide margin, and it works far better than people expect as long as four things are right.
The first is conditioning. Gel packs have to be brought to the band they are meant to hold, overnight, in a freezer or a cold room, not pulled from a shelf an hour before loading. A pack that goes in at the wrong temperature is dead weight, and it is the single commonest reason a box arrives out of band.
The second is the ratio. There has to be enough cold mass for the volume and the hours, and the honest way to find that number is to test your own worst round with a logger rather than to guess it. A box packed to a ratio that works for a forty-minute hop in February will not hold the same load for three hours in August.
The third is separation. Packs conditioned to −18 °C sitting directly against chilled product will freeze whatever they touch, so they go against the walls and the lid with a layer between them and the goods. This is the same freezing risk that catches people inside a chiller van, just at a smaller scale.
The fourth is discipline at the doors. A sealed box works the entire time nobody touches it and stops the moment it is opened to check. Open it at the drop and nowhere else, and deliver the boxed portion early in the round.
Cold sources
Eutectic plates and dry ice, and when not to use either
Two things come up whenever this conversation goes past gel packs. One is genuinely useful on the right round. The other carries a risk that is worth stating plainly.
Eutectic plates are sealed panels of a solution that freezes at a chosen temperature. They are charged from mains electricity while the vehicle stands overnight, then hold their band through the day without the refrigeration unit running. On a short, high-frequency round with the engine stopping constantly, that is a real advantage, and it is why they turn up on milk and ice cream rounds. The trade is weight, wall space, and the fact that once the plates are spent they stay spent until the next charge.
Dry ice needs a warning rather than a recommendation. It does not melt, it sublimates straight into carbon dioxide gas, and that gas is heavier than air, so it sinks and displaces oxygen in exactly the low, enclosed spaces a load area provides. Published safety guidance is consistent: never carry it in an occupied compartment, keep the load space ventilated, do not leave it in a closed vehicle, and remember that a small quantity produces a large volume of gas. The symptoms build quietly, starting with headache and confusion.
Our position is simple: we do not supply dry ice, gel packs or eutectic equipment. If your process depends on any of them, tell us before you book and we will say honestly whether the vehicle and the round suit it.
Options two and three
Two runs or two vehicles: the arithmetic that decides it
When the halves are too close in size to box one of them, the choice is between doing the job twice with one vehicle and doing it once with two.
Two runs cost you the road twice and the pull-down twice. The vehicle has to come back, be brought to the second band, and go out again, and the body does not change instantly: a box that has been at −18 °C all morning needs a real part of an hour before it is fit for chilled work, which is dead time in the middle of the day.
Two vehicles cost you a second hire and a second driver, and buy back the whole morning. The tipping point is usually the round itself rather than the rate: if both halves have to arrive before a kitchen opens or a shop takes delivery, one vehicle cannot be in two places, and the second hire is not really a choice.
Two numbers make the comparison concrete. A driver is AED 250 for a day of up to nine hours, so a second run that pushes past nine hours is more expensive than it looks. And the mileage allowance is per hire, not per trip: a daily hire includes 150 km, which a repeated round eats quickly, while a weekly hire includes 1,000 km. Both are on the rate card.
There is a third shape worth knowing. Where one half is small but genuinely cannot be boxed, a 1-Ton Chiller Van alongside the main vehicle is usually cheaper than a second full-size truck, and it runs on an ordinary car licence, so your own staff can drive it.
Option four
What a real multi-temperature body is, and why hire fleets rarely have one
Vehicles that genuinely hold two bands at once exist. They are built differently, and that is exactly why they are hard to hire.
A true multi-temperature body is divided by an insulated bulkhead into two compartments, each with its own evaporator fed from the same unit, so each side has its own sensor and its own setpoint. Some are built with a movable bulkhead so the split can be changed; most are fixed where the operator wanted it.
The costs are structural. The bulkhead and the second evaporator take load space that you paid for, the compartment sizes are decided when the body is built rather than when you load it, and a fixed split that suits a supermarket round is the wrong split for yours. So they sit in the fleets of distributors running the same round daily, not in hire fleets where the next customer needs a different division.
We should be straight about our own fleet: our refrigerated bodies are single-compartment and hold one setting for the whole run, anywhere from −18 °C to +5 °C. The sizes are set out in the chiller truck sizes guide, and if your round genuinely needs two live compartments, we will say so rather than sell you a compromise.
Loading
Stacking a mixed load so the drops work
Once the setting is decided, the order things go in decides whether the plan survives contact with the round.
Boxes go where the air is not blasting. The discharge from the evaporator is colder than the number on the display, so an insulated box standing directly in that stream is being pushed towards the wrong band from the outside. Put boxes along a side wall, off the floor if you can, and leave the front of the body for product that wants the coldest air.
Load in reverse drop order, with one exception. Normally the first stop goes in last, nearest the doors. On a mixed run the boxed half keeps its own clock, so it goes early in the round whatever the geography says, and the route is built around that rather than the other way about.
Keep the two halves visibly apart. A frozen carton that ends up in the chilled stack is not found until someone opens it at a customer, and a chilled crate buried in the frozen block has already been damaged by the time it surfaces. A strap, a load bar or simply a gap is enough, as long as the driver can tell at a glance which is which.
Records
One vehicle reading does not evidence two bands
This is where mixed rounds fail an inspection even when the product arrived in perfect condition.
The unit records the body, and on a mixed run the body is only half the story. A printout showing a steady −18 °C says nothing about the chilled crates that travelled in a box, and a receiver who asks for evidence of the chilled band will not accept it. If the boxed half has to be evidenced, a logger travels inside the box with the goods, not on the bulkhead.
Say which half is which on the delivery note. When two bands leave on one vehicle, the paperwork should show what travelled at which temperature and by what method.
Rules follow the destination rather than the depot: a run into Abu Dhabi emirate answers to a different authority from one that stays in Dubai, which the Al Ain page covers. Ask the receiving business what it expects before you design the round.
Mixed load questions
Is there a setting that suits both?
No, and a middle number is worse than either extreme. At −8 °C the frozen goods are too warm and the chilled goods are frozen, so you lose both halves instead of one. Pick the band that the larger or less forgiving half needs and box the other half.
How long will an insulated box actually hold?
It depends on the box, the conditioning of the packs, the ratio of cold mass to volume, the ambient temperature and how often it is opened. That is too many variables for a number we could publish honestly. Test your own worst round with a logger in the box and use that figure.
Do you have a partitioned or dual-zone vehicle?
No. Every body we run is one compartment on one setting, anywhere from −18 °C to +5 °C. A multi-temperature body needs a bulkhead and a second evaporator, and the split is fixed when it is built, which is why they live in dedicated fleets.
Can I bring my own dry ice?
Tell us first. Dry ice sublimates into carbon dioxide, which is heavier than air and displaces oxygen in an enclosed load space, so it is not something to put in a body that opens at every drop without ventilation and a plan. We do not supply it, and on some rounds we will say it is not suitable.
Two runs with one van, or two vans?
If both halves must arrive in the same window, two vehicles, because one cannot be in two places. If the windows are far apart, one vehicle twice is cheaper, as long as you allow for the pull-down between runs and watch the nine-hour driver day.
What do I send you to get this planned properly?
The two temperature bands, roughly how many crates or pallets in each, the number of drops and the delivery windows. With those four we can say whether it is one vehicle with boxes, one vehicle twice, or two vehicles, and which costs least over a week.
Send us both halves of the round
Tell us the two bands, the rough split in crates, the drops and the windows. We will tell you which of the four answers fits, including the ones that do not involve hiring more from us.
Get in touch through the contact page or on WhatsApp. The vehicles themselves are under chiller van rental in Dubai and freezer van rental, and the difference between the two is explained in chiller van, freezer van or reefer truck.