Thermoelectric fridge

K

killick

Well-Known Member
Joined
19 Sep 2011
Messages
75
Location
Durban South Africa
Visit site
I have,so far, gotten along quite well on a 5 liter block of ice in my boats coolbox but am now considering using a thermoelectric cooling system. Power is not a problem as the boat is on its mooring,with mains power,every night.What I require is something similar to the camping coolboxes.As I have no experience of such an system any advice will be greatly appreciated
 
We have a Halfords one, the biggest they do I think, runs on mains or 12 volts. It runs constantly, no thermostat, and generates a great deal of condensation. Works perfectly well but consumes far too much power to be used on batteries alone. When on 12 volts with the engine running you need to be aware that they are drawing 4 amps, so a cigarette plug and socket can get very hot. I burnt myself on mine.
 
Vyv, are 12v cigarette sockets normally that bad?

Anyway, back to camping fridges. I have never seen the point of these, even for camping, because (unless you have access to 240v or run your car engine continuously) you will flatten a car battery in about 24 hours or so (or less!) and car batteries do not take kindly to this. For shorter periods, you are better off with an insulated box (or bag) plus ice. Also, the fridge probably doesn't have a thermostat and so, depending on ambient temperature, the fridge might not run cool enough or could freeze its contents.

I assume you are planning to go sailing every day and return to the mooring each night? in this case a thermoelectric fridge could do the job (especially if it has a thermostat) but I would still prefer either to use ice or get a compressor type fridge.

Rather than a block of ice, I have used fruit juice bottles (about 1 litre) left in the freezer (with room for expansion), easier to handle and no spilled liquid.
 
I've bought a 60W Peltier plate to experiment with fitting it to my boats under seat coolbox, or to make a small galley locker into an even smaller fridge cabinet. The plan is to have it cooled using a fan to dissipate heat from it to the cool side of the plate and a closed fresh water cooling circuit on the hot side which will transfer heat to the sea.
I've bought all of the components, together with a 5A rated thermostat to prevent constant running, and the box will have its own 12v battery which will be recharged from a suitably sized solar panel.
All of this is going to cost about £100+ which is a lot more than any of the proprietary camping style boxes, but I don't really have the space for one of them, and the alternative of a much more efficient compressor/evaporator/condenser fridge is too noisy and bulky for my tastes.
One of these days I might actually get the time to get this project underway!
 
There is another option: for around £150 you can get a reasonably large top-loading absorption camping fridge which works on 12v/240v/gas. Working on 12v they are just as impractical power-wise as the thermoelectric type; but on 230v, and as long as they are level, they work well and are thermostat controlled. I use mine on gas when anchored or on a mooring, but I do have a permanently installed external flue and I ensure adequate ventilation.

Whatever type, always worth ensuring the insulation is the best you can realistically provide.
 
Earlier this season I bought a mini compressor fridge from Argos for less than £80 to replace my thermoelectric coolbox; the fridge consumes much less power than the thermoelectric types, it is bigger, silent and it has a freezer compartment too; there is no comparison.
 
Where I live it gets hot and a Peltier type cool box just does very little at all when it is hot. If you can't get by with a bottle of ice in an insulated box then go for a compressor type fridge freezer. My preference is to run the fridge as a freezer with frozen food in it. Use a cool box then with frozen stuff that needs to be defrosted to keep the box cool. We have done extensive camping touring holidays in the car using this method very successfully. By contrast we rented a camper van in New Zealand witha Peltier cool box. It was run anytime the engine was running and when on power over night and was useless. To Pauljs I wish him luck. The set up should give him the very best efficency out of the Peltier but I thinki he will still be dissapointed. goo0d luck olewill
 
Thank you all.I think the thermoelectric system will be shelved and I will start looking for the smallest compressor unit I can find. If fitted in the cabin will the ventilation be enough?
 
I have a Waeco cf-18.
These are compressor boxes basically but very efficient.
Only 18lyrs capacity.
They have a thermostat and 2 levels of battery protection.
IIRC they ate about 30w or say 4a when running but run about 20% each hour typically.
Not cheap.
About the size of a large coolbox.
The only thing that works for me on a small boat with limited battery capacity
 
killick said:
Thank you all.I think the thermoelectric system will be shelved and I will start looking for the smallest compressor unit I can find. If fitted in the cabin will the ventilation be enough?
Click to expand...
I use both types ( a peltier and a chest compressor) pros and cons for both. Consider a small mains chest ......much cheaper than 12v and you can always use an inverter when no mains. Always a certain amount of heat expelled to be considered.
 
VicMallows said:
There is another option: for around £150 you can get a reasonably large top-loading absorption camping fridge which works on 12v/240v/gas. Working on 12v they are just as impractical power-wise as the thermoelectric type; but on 230v, and as long as they are level, they work well and are thermostat controlled. I use mine on gas when anchored or on a mooring, but I do have a permanently installed external flue and I ensure adequate ventilation.

Whatever type, always worth ensuring the insulation is the best you can realistically provide.
Click to expand...
I have an absorption fridge, used when I go camping. Two problems: first, as noted above, they like to be level and I use a spirit level to set mine up. Presumably some types are more demanding than others in this respect. No problem when camping but not ideal for a boat!
And: gas. Problems with gas in a boat are described above. Some fridges have a flame-failure device to cut gas supply off when flame goes out (I think - check!). But even with this, I would get nervous with gas in a boat. The other problem is cost: the cost of Camping Gas seems to be spiralling up out of control and the cost of running such a fridge is likely, after a year or two, to exceed the purchase cost of a compressor fridge.
 
2 alternatives - convert a locker on board the boat and fit a proper compressor unit or buy an external fridge with compressor.
ASU-Isotherm are probably best for the first and Waeco offer both.
I would not waste my time, energy or money on the Peltier/thermoelectric route as they're less efficient than your current practice.
If you are converting a locker, just insulate it well, at least 4" preferably more.
The power draw of a reasonably efficient cold compartment is about 40ah/12v/24hrs for a 90l unit @ 38C.
 
Peltier coolers have a limited effect and will only draw down a fixed number of degrees below ambient (I've got a figure of 20 degrees in my head but may be wrong), they can be cascaded but then the power consumption goes up and the efficiency per cascade goes down. If you were to go a hybrid route, a peltier cooler and plenty of insulation would make the ice last a lot longer and could be run from a cheap timer to reduce the duty cycle.

Rob.
 
I have found after using a few different types of Peltier coolboxes:
a. I found the amount of condensation that just drips into the cool box and ends up with a pool of water if running for a few days.
b. Most are 16/18c below ambient temperature so if it is warm day they will struggle to keep things cool and won't be fridge temperature (4/5c).
c. Most will consume about 4.5/5 amps so your battery won't last long when there is no battery charging.
d. They run all the time & noisy fan.

BUT there are some that solve the problems above, I got the Waeco Tropicool T35 CoolBox which is a great improvement.
a. No condensation inside the cool box.
b. 30c below ambient temperature, so in the UK it would have to be approx. 35c (rare) to start being a problem.
c & d. It does draw 4.5 amps but it has thermostat (adjustable) and it does not run that often once down to the right temp, it also stops the fan when you open the lid to reduce cool air lost, lastly very quiet.

So if you are going to get a peltier type I would recommend the Weaco range, although more expensive - worth it.
 
Last edited:
I was after the same, and after a long decision making process also went with the waeco tropicool TC35. So far I have only used it on mains, but I have been very pleased with the cooling of the unit, especially as it is variable.

Initially I wanted to buy a compressor box, but they were too expensive. I initially had my eye of a fridgerite FR35. Its a budget Waeco box I believe. It was on Amazon at £285, when I decided a couple of days later to buy it, sods law, it went up in price to £360.

I then found a bargain Tropicool 35, paid £170 for it ( I think it was an error on the website, because after I bought it, it went up.) You can find these for £190 inc delivery and I think it is a good compromise.
 
You must log in or register to reply here.

Share this page

Top