I plan to do extended (months) car camping this winter. I would like to be able to have things like fruit, vegetables, yogurt, OJ, PB&J, beer, etc. in the cooler between 34 and 50 F.
Coleman 58 Qt Cooler http://ift.tt/1Miiyk5
I have thought about solar on top of the roof box trickling to a 12v, but tossed it for cost and complexity. Makes no sense to convert DC to AC to run a heater in the cooler. DC thermoregulated heaters of the scale I needed are a rare bird. I found one, but never finished working out the particulars on the unit due to cost and complexity.
Ditto with the above for running a second battery on a switch off the alternator.
Current cheap thoughts are:
Passively heat the cooler when the car cabin is warmed by opening the lid.
Rotating water, food in for the thermal mass.
Sodium Acetate reusable heat packs.
I plan to have a digital thermometer attached to the cooler wall so I can follow temperatures inside it.
58 gallons = 220 liters. The volume will be divided between water (specific heat 4.2 kJ/kg *C) food (2 kJ guess), glass (0.75 kJ), air (1 kJ).
10 kg water
5 kg food
2 kg glass
1 kg air
So I would need ~ 435 kJ to raise the cooler 1 *C if I got that right.
Sodium acetate gives off about 270 kJ/Kg in crystallization. Great thing is the heat pack can be "reset" by boiling in water. Homemade sodium acetate heat pack video: https://www.youtube.com/watch?v=TkJhAxyXEdU Keep the sound on to remember 6th grade. Would use a dromedary bag. Would prefer to figure out the flexing a non ferrous metal to activate like wikepedia references. A 4 liter dromedary bag should hold 4 kg of the supersaturated sodium acetate (d=1.4 g/ml) so that potentially is 1,080 kJ.
Water would be placed on top of the heat pack for thermal regulation. I would want to feel good about the bag used in the heat pack over the course of the winter and why I looked at MSR dromedary bags. Ideally I would have 3 or 4 2 liter bags so I could have more control over the heat, but that is a bit pricey. Open to less expensive but reliable bag sources.
Keeping a cooler above freezing in winter
Coleman 58 Qt Cooler http://ift.tt/1Miiyk5
I have thought about solar on top of the roof box trickling to a 12v, but tossed it for cost and complexity. Makes no sense to convert DC to AC to run a heater in the cooler. DC thermoregulated heaters of the scale I needed are a rare bird. I found one, but never finished working out the particulars on the unit due to cost and complexity.
Ditto with the above for running a second battery on a switch off the alternator.
Current cheap thoughts are:
Passively heat the cooler when the car cabin is warmed by opening the lid.
Rotating water, food in for the thermal mass.
Sodium Acetate reusable heat packs.
I plan to have a digital thermometer attached to the cooler wall so I can follow temperatures inside it.
58 gallons = 220 liters. The volume will be divided between water (specific heat 4.2 kJ/kg *C) food (2 kJ guess), glass (0.75 kJ), air (1 kJ).
10 kg water
5 kg food
2 kg glass
1 kg air
So I would need ~ 435 kJ to raise the cooler 1 *C if I got that right.
Sodium acetate gives off about 270 kJ/Kg in crystallization. Great thing is the heat pack can be "reset" by boiling in water. Homemade sodium acetate heat pack video: https://www.youtube.com/watch?v=TkJhAxyXEdU Keep the sound on to remember 6th grade. Would use a dromedary bag. Would prefer to figure out the flexing a non ferrous metal to activate like wikepedia references. A 4 liter dromedary bag should hold 4 kg of the supersaturated sodium acetate (d=1.4 g/ml) so that potentially is 1,080 kJ.
Water would be placed on top of the heat pack for thermal regulation. I would want to feel good about the bag used in the heat pack over the course of the winter and why I looked at MSR dromedary bags. Ideally I would have 3 or 4 2 liter bags so I could have more control over the heat, but that is a bit pricey. Open to less expensive but reliable bag sources.
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