Van Dwelling/Heating & Cooling

Heating

How can you heat your vehicle on cold, wintry nights? There are several strategies

1. Heavily insulate your vehicle. The more your vehicle is insulated, the less heating it will require.
2. Bundle up. It's much easier to heat you alone, than it is to heat your whole vehicle. Multiple layers of clothing (t-shirt, sweater, jacket) are better than a one single layer of the same thickness. Each layer of clothing traps a pocket of air. The trapped air prevents heat radiated by your body from exchanging with the colder external air. Layers of clothing also allow you to remove clothing as you get warmer. This helps you to avoid sweating which can cause excessive cooling as the sweat evaporates.
3. Wear a hat. Roughly 30% of body heat is radiated through an unprotected head and neck.
4. Use the vehicles on-board heating. If you live in a temperate climate, and your vehicle is well-insulated, captured heat (from the on-board heater and solar radiation) may be sufficient to keep you warm enough to sleep throughout the night.
5. Build an air-to-air heat exchanger. This will allow you to vent the excess humidity and stale air from your living space without losing very much energy.
6. Store heat energy in a "thermal battery" such as a tank of heated water, Nalgene "piss jug", or a container of melted paraffin. According to Laren Corie, "...8.3 pounds of water (1 gallon) will only store 833 BTU for a 100°F rise. That is less than 1% of the energy density of propane..." Melted paraffin can store much more energy in a smaller space.
7. Set up a heat exchange circuit between your vehicles cooling system and your hot water system. Idle the engine for a while to charge your hot water tank.
8. Make a simple, vented, charcoal, or wood pellet heater, to mount on a wall, and either use it to heat the interior air, or to also put its heat into the heat storage, or both.
9. Sleep in your underwear - can be a problem in the event of a nighttime disturbance.
10. Personally, I think you don't need any of these methods if you have a good SLEEPING BAG - which is way more effective even than wearing a bunch of layers along with having a bunch of covers. I've been living the van life for 2 and a half years so far and have got it down to a science. - From anonymous vanman

You can also combine all of the above approaches. Here's how Laren Corie describes one potential setup:

At this point [all of the above] may not seem practical, but I can assure you that it was a very practical approach for my Centauri Van, which was a small diesel, box van. The walls were an insulated sandwich of aluminum surfaces, and 1 1/4" of urethane foam (approx R 8-10).

I figured that two 20 gal tanks (under the bed platform) plus the eleven gallons in the heat exchanger tank, would be enough to get me through an eight hour night of 0°F. It would not keep the van at 70°F but it would keep it warm enough for comfortable sleeping. On nights that only went down into the thirties, it would stay toasty. This also considered Reflectix covers over all of the windows. Fifty gallons of water weighs over 400 pounds, but you need to carry some water anyway. Paraffin containers, could be arranged to heat the bed platform, instead of the interior air, and would require a lot less storage, while you normal water storage could be used to heat the interior air.

A two liter bottle of paraffin (votive candle wax)heated to just over 130°F will give off about 400 BTU as it cools to body temperature. It will then give off another 100BTUs or so, as it cools down to the temperature that the van air will cool to.

Two liters of water will only give off about 4 1/3 BTU per °F, so maybe 80 BTUs as it drops from 130° down to 50°F.

A two liter bottle of melted wax will store about five times as much heat as a two liter bottle of water heated to the same temperature, and it will also weigh considerably less. Either one can be heated all the way up to the approx 180°F that the engine coolant gets to.

Just call these guys, they will keep you warm

• Northern Air Conditioning & Heating
• sci.engr.heat-vent-ac newsgroup

• Free online HVAC heat load calculator

Cooling

Cooling tends to be more difficult in general than heating. When you are cold you can add more layers, but it is more circuitous to cool off when warm. During the summer, most vehicles heat up due to the greenhouse effect. This is very unpleasant to wake up to.

• Block sunlight from entering the vehicle, preferably using white material on the outside of the windows.
• Experiment with some method to actively circulate air into the vehicle.
• Park in the shade
• Sleep outside the vehicle if possible
• Install a 12V fan. Check the power consumption
• Build or purchase an air conditioner that works by evaporating water such as a swamp cooler or evaporative cooler. Note that this works in inverse proportion to the relative humidity. Heat of vaporization is 5 calories per gram. It takes 5 times the amount of energy to vaporize water as it does to heat it from 0 to 100 degrees Celsius. So they are really effective. (It appears, however, that some swamp coolers output humid, cool air; which in most climates except exceptionally dry ones will not cool you because the water vapor will condense on you heating you up. You should run that humid air through a heat exchanger, exhaust the humid air, and blow the cool and less humid air over you.) Apparently, simply cooling your face has a large effect.
• Sleep in your underwear - can be a problem in the event of a nighttime disturbance.
• Use a peltier junction cooling device (such as found in 12V coolers). There is a product that cools just your neck, or you could circulate cooled water over you

Alternatives

Ground Source Heating

Ground source heating/cooling utilizes thermal energy from the earth to heat or cool a house. Unlike the temperature of air which fluctuates throughout the seasons, the temperature slightly below ground is consistent year round. A geothermal system utilizes this phenomenon to control the temperature of the house. The system consists of three elements: an underground piping system, a heat pump and a distribution system for the house. During wintertime, the temperature below ground is warmer than in the house. This heat is absorbed by the fluid in the underground pipes which circulates to the house. The heat pump utilizes refrigerants which extract this energy and distributes it through the ventilation system of the house. During the summer, this process is reversed. The heat pump extracts the thermal energy from the house where it gets sent below ground. In this configuration, the earth acts as a heat sink. A ground source heating/cooling system only requires a small amount of electricity to power the heat pump which is why it is so efficient. Unlike traditional systems, the heat is not created through a combustion process but simply extracted from the ground.

Thermoelectric Solid State Heat Pump

A thermoelectric (TE) solid state heat pump operates based on the Peltier effect, in which electrical energy is converted to thermal energy. A thermoelectric module consists of a thermoelectric material, typically semiconductors such as Bismuth telluride (Bi₂Te₃), sandwiched between two ceramic plates joined with electrical interconnects. When a voltage is applied to the device, heat is transferred from one side to the other, typically against the temperature gradient. The direction of heat travel depends on the sign of the voltage, and thus the device is capable of providing both cooling and heating. The term “solid state” refers to the fact that the device has no moving parts, thus enabling it to run fairly quietly and requiring minimal maintenance.

TE heat pumps operate purely on electricity, so precise temperature control can be achieved as we can directly measure and control the current flow into the system. To date, TE solid state heat pumps are primarily used in cooling applications, whether it’s for electronic components that require specific constant temperatures, or portable coolers for personal use as in furnace filters. Large scale applications however, in this case the heating and cooling of an entire residential house, are extremely rare or almost nonexistent, due to the potential cost and complexity of the overall system.

Relocate

Going to where the climate is nice is a surprisingly simple yet effective option.

One of the primary advantages of van dwelling is mobility. If one has the freedom with job and friends/family, they can simply drive to locations that are warmer in winter and cooler in summer. The cost of fuel should be considered of course; but it may be offset the by a reduction in the cost of fuel required to stay comfortable. Then there is the psychological boost of always being comfortable, and seeing new locations.