The concept of caravanning implicitly and also habitually evokes associations with the freedom to travel, the absence of barriers, in the simplest terms, freedom. In this view, a season in which the cold forces you to wear a winter hat and the weather might not be so sunny should not be a limitation.
A 4-season recreational vehicle is a vehicle that is prepared for difficult terrain and weather conditions. And just as water tightness is an absolute requirement for any vehicle, not all of those on our roads or offered by manufacturers deserve to reap laurels for suitability in winter caravanning. Several design factors determine whether you take a camper or campervan for a ski trip or North Cape (Nordkapp), which can be covered by one key term – heat retention. It is also about thermal insulation, which is the total insulation and thermal design of any unit, including a building. Heating is one of the elements that, along with the design concept, constitutes an interconnected system in the term “4-season vehicle”. However, this is only part of the system that guarantees comfort and safe travel. A radiator alone is not enough….
Balance and equilibrium
The secret of good heating lies not so much in the answer to the question of how to provide heat but how to maintain it for as long as possible. The nature in which we live has its own rules – being subject to the laws of physics like everything else around us, it strives to maintain a balance. If it were not for human interference with the natural resources of the environment, we would enjoy a predictable climate or we would observe well-functioning but now endangered animal species in the ecosystem. Balance is not only the talent of a circus performer that manifests itself in the ability to balance on a beam and juggle bowling pins at the same time… On a global scale, for example, it is the cause of winds, when air masses move between centres of different atmospheric pressures. In the end, balance is – unfortunately – any attempt to take away our accumulated warmth by nasty and bitter cold. Whether under a jacket or in a sleeping bag, or inside a camper, caravan, or any recreational vehicle (RV). The guarantee of thermal comfort will thus not only be effective heating but, just as importantly, a barrier to protect the interior from the loss of heat, which, after all, we need for efficient functioning but also for the important feeling of peace and comfort.
Where is the energy?
There is a belief, quite popular in caravanning circles, of innate perversity of gas-powered heating systems, which is expressed in the exhaustion of the gas supply only at night. Indeed, there is something in it, as the percentage of travellers who have experienced this “poltergeist attack” on caravanning is really high. And indeed, the gas in heating systems, especially during the cold seasons, likes to run out just when you least expect it. Well, when the difference between the temperature inside and outside increases and in the comfort of the camper the temperature becomes pleasant, the heating system works with more power and thus consumes more fuel and going outside to change gas cylinders is then associated with extreme measures. Undoubtedly, energy is then spent on additional activities and we can feel first-hand how important it is to conserve, maintain and accumulate it.
Naturally, heat is also energy, so if the temperature inside the living area drops during camping, we can talk about a loss of energy. The aim of good camping management, and good practice in conserving resources such as either diesel fuel or propane-butane or propane gas will be to isolate as much as possible from external factors – humidity, temperature, wind. And this is where the basic component of the term “good heating” comes in. A component because, as we mentioned, it is not only the choice of efficient heating that is the secret, but also where we will “store” the heat produced. So, how was your RV body designed? If your RV is a semi-integrated motorhome where the cab has been covered with a blanket in the hope of getting warm, the effect will be as “good” as an attempt to heat a cinema with a lighter. If, on top of this, the vehicle is not a 4-season vehicle, the heating will be running continuously, compensating for losses and leading to a rapid exhaustion of fuel. There will also be the side effect in the form of an uneven temperature inside the vehicle. We then turn up the already highly engaged thermostat, our sense of comfort decreases and we overheat the interior. The latter is not difficult in caravanning, as it is very pleasant to feel warm as soon as you enter the vehicle from a frosty yard. It is then easy to be fooled and set the temperature higher than it actually needs to be. We should bear in mind that the optimum temperature is 20℃, or even less, close to 18℃, if we like to stay in the RV in a sweatshirt or sweater. This range is almost ideal to maintain in vehicles that are specifically designed for winter tourism. Azimoo comes up with a proposal that is common among leading manufacturers in the caravanning market, offering a container based on the DEQRE SHIELD wall construction. The sandwich-like construction of the walls and floor used is based on insulation technology using XPS foam and aluminium cladding, which – in addition to its insulating value – is also a storage value, aiming to give the wall the highest possible heat capacity. So it accumulates thermal energy. Why is this so important?
Collect the heat
Suppose we had a really nightmarish night behind us, we were tormented by insomnia, and when we finally managed to fall asleep we were in turn tormented by nightmares about being late for the last tram to school before our school-leaving exam was about to start. When you wake up, the small interior of the vehicle needs to be aired out from the fumes of sleep, and the temperature outside has just covered the trees with rime. The dilemma of “to air out or not to air out” is a big one in this case but the decision should be both simple and hygienic if our vehicle is made of heat storage materials. The decision to change the air in the camper by forcing the draught by opening the windows, even at sub-zero temperatures, will not make the interior colder. The walls will keep the heat in and the temperature will quickly even out thanks to the already mentioned natural balance rule. This is because its essence is clear from the definition – heat is thermal energy that flows from the higher-temperature system to the lower-temperature system. So the better the insulation and accumulation properties of the walls, the better the heating we have.
However, this is only the base, the foundation of warmth in winter caravanning of any type. This does not deviate fundamentally from building standards, in which the avoidance of thermal bridges and the durability of combinations of surfaces determine the quality of the building. Here we can also see by the example of Azimoo how important a conscious container design concept is for ensuring thermal comfort and safety. It is, by the way, not only a matter of protecting against heat loss but also a matter of insulating against the loss of coolness in hot weather. The isothermal value is ensured by a structure that is glued finger-over-finger, covered with aluminium lagging, riveted and reinforced at the joints.
If we called thermal bridges the inward penetration of the cold at surface joints, the windows could be called the real Golden Gate of this problem. Therefore, the use of insulated linings to insulate the indoor window surfaces is an integral part of winter caravanning. Here, there are different schools of thought – thick, down-filled lining to absorb cold penetration or heat shielding cladding which, in turn, prevents “heat transfer to the window pane” that is impossible – naturally – to heat.
We have deliberately not mentioned the heating systems used in caravanning so far, because in order to work properly, be effective and efficient, the parameters described above should be ensured in the RV, or at least taken into account. The higher the significance of your trip the more details based on the principle of the weakest link can cause problems. So if good insulation is combined with the best heating system, you can expect a vehicle ready for a Siberian winter. Unfortunately, the price of the system determines the properties. The most expensive heating systems on the market and at the same time considered the best are produced by Alde, based on the use of a hydraulic system. So here we have heaters and piping operating in a similar way to a detached house. The heat accumulated by the liquid medium circulating in the system is maintained for a long time, so proportionally little energy is needed to keep it at the set temperature. A small thermostat buffer will allow gentle, imperceptible temperature fluctuations due to accumulated thermal energy. The Alde system is so well designed that the residential heating system allows it to be integrated into the cooling circuit of the engine, so that the heat produced during driving can be dissipated directly in the vehicle body, automatically disconnecting the dedicated generator from operation. The heaters enable installation in places that are suitable for air circulation.
The lulling sound of waves
Not to mention the fact that there is no noise! It is said that those who have once tried Alde heating in their vehicle will not swap it for a forced air heating system again. The sound detail, in the form of the noise of the air coming out of the heating vents, becomes acceptable after a while and is barely audible afterwards. We get used to that sound, just as residents of housing estates located near the airport get used to the fact that a plane to Amsterdam takes off at 11:15 a.m. However, it is not the air noise that is the secret of the lower price and lower performance of systems by companies such as Truma or Webasto. Spiritus Movens here represents a lack of good thermal energy storage, as the heat generated is transferred immediately to the indoor air, which in turn forces the heating coil to operate more frequently or forces it to operate continuously at lower power. While it is true that there is no problem in placing the air duct outlets anywhere in the vehicle body to achieve proportional and even warm air coverage, underheated zones or overheated zones with African-like temperatures do occur in vehicles with complex interior design. In such a situation, one thermostatic sensor is clearly not sufficient for the entire vehicle, especially that inlet ducts also vary in lengths and thus have a unique cooling level. The cardboard tube does not accumulate heat and cools down instantly. This does not mean, naturally, that it is a bad system – just a different one, based on a different management of resources, in this case also fuel for heating.
Going from the general to the specific, we have made our journey through the exterior walls, the microclimate of the vehicle body, the air ducts and the heating coil to the gas cylinder or diesel tank – let’s stop here for a moment. When considering how to manage good, efficient winter caravanning, it is important to mention that the choice of right gas to supply the heating system and the choice of burners for a gas stove are of considerable importance. The choice is between pure propane or propane-butane. The difference in use between the two gases is nonexistent for the average caravanner who is fascinated by summer trips. This difference only appears when the temperature drops below zero degrees. The boiling point of both gases plays the leading role here. Propane changes from liquid to gas in really severe frosts, as the temperature would have to drop to around -40°C for this to happen. It is unlikely in European realities, so we can be certain about the effectiveness of this gas. This means that we will most likely use up all the filled-up gas. On the other hand, the boiling point of the propane-butane mixture is also responsible for its low suitability for winter activities. This mixture changes its state of aggregation from liquid to gas already at -0.5°C, while still in the cylinder. Moreover, below 0°C, propane evaporates from this gas mixture. Consequently, butane alone is left for heating, causing complete radicalisation of the heating parameters and performance. Specialists in stationary hot air heating systems further point out an interesting, and rarely mentioned, argument for using pure propane. It turns out that the efficiency of this gas is higher than that of the mixture even at positive temperatures, as it allows much higher temperatures to be reached in the heating system. So why not fill the gas cylinder with propane alone? Exactly… A million dollars for whoever manages to find a petrol station or a distribution point where they can buy this gas without any problems. There is no problem with this in Europe. When it comes to Poland … well, we can only wait for a change, or…
…install large gas tanks, Truma Dual Control systems when using two cylinders, gas cylinder meters, electronic scales designed for installation in a compartment for gas cylinders or use backup heating systems in the form of electrical radiators. This, however, remains to be used on an ad-hoc basis. The best way to avoid running out of gas where we cannot simply buy it is… heating powered by fuel from the vehicle’s tank. This is a rather abrupt answer, but we have to admit that systems running on diesel oil are easier to control, as we simply use the fuel gauge on the car’s dashboard as a consumption monitor. And as long as we have fuel with additives to counteract the release of paraffin from the oil due to low temperatures, this will be the safest formula for supplying the heating. We can buy diesel fuel around the globe, from Yakutsk to Havana.
It is useful to keep a few simple rules in mind to support the heating in winter, remembering about maintenance of energy and the use of factors that support the heating system. If we have the opportunity to park in a location that will be favourable to the operation of the solar panels, the shell of the housing capsule will also benefit from this by taking in the heat of sunlight. Naturally, efficient isothermal insulation will not allow too much of heat to get inside, but built-in windows will allow more sunshine, and thus heat, to get inside the vehicle. Positioning the vehicle in an area with little exposure to the wind or facing the wind will also be beneficial for thermal management. When leaving the vehicle for a few hours or so, the interior temperature should be reduced to the minimum temperature at which the vehicle will not cool down nor will the accumulated energy be lost. When airing the vehicle in frosty conditions, do it quickly and efficiently, forcing a draught so that the air exchange can take place quickly without cooling the interior. Open windows, skylights and doors wide to allow air to circulate more quickly. Do this with the heating off, but also do not turn it on as soon as the windows are closed. Allow the temperature to normalise so that the thermostat has a chance to correctly assess interior conditions.
Enjoy the winter and at the same time enjoy caravanning. Vehicles used all year round will certainly thank us!