Passive versus Active energy systems while Trekking

A Passive Solar Energy Device

When trekking we take advantage of both active and passive temperature control and other systems. Of course simple conservation is the best passive system to use, in my opinion. By practicing this hot water and energy requirements are reduced. Judicious approaches to cooking also reduce energy requirements, even if propane or other fuels are used. Solar power has a significant advantage over other energy sources if plentiful sunlight is available. This is particularly true for those planning on spending long periods in the camper or RV with a preference not to be "plugged in". However, solar power is not "free." The solar energy collection and storage systems had to be built, have to be maintained and they do have a finite lifespan. There is a cost for that and while it is possible that some of the systems will have a 10 year lifetime or even longer, some approaches will not. In other words, all solar and battery systems are not equal.

The sun sail in the photo above is an example of a "passive" solar system. It doesn't use energy nor does it rely upon mechanical devices. The awning on the side of the vehicle can shield most of that side from the heat of the sun. Reflectix reflective bubble pack in windows is another. The screen on the rear door is a third example of passive temperature control. These things, when used together can assist in regulating the interior temperature.  By orienting the vehicle to the sun and using these techniques, the interior temperature can be improved in both hot and cold weather.

Of course, many of our homes also use passive systems such as insulation, south facing windows for winter solar heat and so on.

Other passive approaches used when RVing include simple orientation of the vehicle to the sun's solar radiation (infrared energy). In the summer this includes parking the vehicle in the shade to reduce interior temperatures. In the winter, parking it in the sun and allowing entry of sunlight through windows is a method to increase interior temperatures. This is effective because the infrared energy from the sun is converted to heat on striking an object. Certain colors absorb more infrared than others. Black, for example is an excellent energy absorber while white or highly reflective surfaces absorb less energy. Infrared which is reflected is not converted to heat, so to maximize heating we attempt to reflect as little sunlight as possible. For minimum heating we do just the opposite and reflect as much sunlight as possible.

Active systems include the use of electrical energy from a variety of sources. These include the 50A or 30A, 120VAC shore power connectors on RVs and the solar panels many come equipped with and the battery systems. The solar panels, controllers, batteries and inverters are active systems because they collect and store that solar energy, and then later convert it for use in heating, cooling, cooking and so on.

An Active Solar Energy Device

Solar on Full Sun

Of course, if the vehicle is equipped with roof top solar panels, then it may be a necessity to park in the sun to take maximum advantage of the solar energy which is available and to avoid depleting the batteries. So, there are trade-offs with such active systems. Some get around that with smaller portable solar panels which can be set up 10 or more feet from the vehicle and oriented as desired. This approach has the advantage of allowing the vehicle to be parked in the shade for cooling, while energy is collected and stored by the solar panel(s) which are in the sun. Of course, portable solar panels can't collect energy while stored in the vehicle and rooftop collectors can. So there are trade-offs to all approaches. Of course, one can use both rooftop and portable solar collectors and get the best of both worlds.

Further passive temperature control in the vehicle can be accomplished by opening widows or door(s). With the vehicle in the shade, the windows and/or doors open and good airflow, the interior temperature will be the lowest possible and will approach the outside temperature. If in the sun, with a sun sail properly positioned and the awning extended the interior temperature will be lower than it would otherwise be in full sun.  Vehicle color also plays a part. Certain colors such as black generally absorb more infrared energy while white reflects more energy.

Cooking is another opportunity for use of passive systems. Simply cooking outdoors will lower the interior temperature of the vehicle. It will also lower the relative humidity. Boiling liquids creates steam and that may lead to discomfiture and even water on cooler surfaces. There are also a variety of solar cookers on the market. If the desire is to reduce consumption of energy in the vehicle, then cooking over a wooden fire is always an option, assuming suitable firewood is available. People have been making "solar tea" forever; all it takes is a glass jar and a tea bag. If the vehicle has sufficient batteries and solar collectors, then an inductive cooktop can be used inside or outside the vehicle.

Even active system benefits can be improved and extended by use. For example, most vehicles which have coach batteries include an inverter. The inverter may also be used to control the charging of the batteries while the vehicle is on shore power (120VAC) or the vehicle engine or generator are running. However, the primary purpose of the inverter is to convert 12VDC from the batteries to 120VAC at 60 hertz (Hz). Unfortunately, using an inverter will more rapidly deplete the stored energy of the batteries because inverters are not 100% efficient. During the inversion, some DC is used, or lost, primarily as heat. That heat may also be transferred to the interior of the vehicle. So, to maximize battery power available, it is best to use 12VDC devices and avoid the inverter all together. Many plug-in devices such as laptops, or cellphones and other electronic devices can run or be charged on 12VDC. For additional interior "cooling" there are 12VDC fans available, and even for refrigerator compartment cooling a 12VDC fan is frequently used.

Using passive systems may require a shift in one's thinking and approach to some activities. It may require a change in awareness, and an inquiry into "what am I hoping to accomplish here and how can I reduce the energy required?" However, a lot of this becomes habit after a while. For example, on cool mornings we generally cook indoors and use that heat to increase the interior temperature. Later, when the outdoor temperatures are at their peak, we may cook outside to maintain interior comfort levels. This approach is necessary for other tasks such as water consumption. True, there are passive water sterilization techniques and ground campers and backpackers use them all the time. However, there is a limited capacity to the grey and black water tanks. One needs to determine just how much of a "camping" experience their trekking is to be. Many of us want it to be less camping and more like home. Simultaneously we prefer to minimize the use of shore power, generators and extend the time until the grey and black tanks are full. If so, that desire becomes a driving force for better and more flexible energy sources in our trekking vehicles. It also provides a motivation to be better trekkers.

The "Mini-Ship" has landed

We hear a lot about "the mother ship" in RV circles, However, because I've added a sun sail I have decided to call our little home on wheels a "mini-ship." Why  "mini?" No it isn't an automobile. The choice was dictated by the PC norms here in the U.S. in which midgets, dwarfs and other small people are denigrated if we use such terms. As of today, the term "mini" has not yet been relegated to the dustbin of racism or whatever, and so I will use it. I know, to call my little home on wheels a "mini" is neither poetic or awe inspiring. and that's the way I prefer it to be. Remember, this journey is about "A life of moderation."

So we arrived at our "tiny home on wheels" and set up the sun shade (I did it myself; rather easy, actually) and then I prepared a teriyaki ribeye steak while G made a salad of lettuce, cucumber, daikon root and onion with a splash of ranch dressing.

Sun Sail

The sun sail was a stunning success. It took three tent poles, one 4 ft wooden dowel and a 9 ft triangular sun sail. However, after two days of use we decided that it made a significant improvement in comfort.

We've been at a number of camp grounds or areas where there is limited afternoon shade. If the vehicle is pointed into the sun, even with Reflectix in the window the interior temperature at the front of the vehicle can become very warm. Last year, in Texas heat, the front of the vehicle was so warm I couldn't open the engine compartment without burning my hand.

The sail is held in place with two carabiners. This allows quick removal in the event of a storm. The poles and guys can be left up at night, or when storms move through, as they are this evening. So I lowered two of the poles, unclipped the shade and then folded and wrapped it, and put it in the storage compartment for the night, with our folding chairs.

Keeping the Mud Daubers Out

Screen held in place with magnets

One of the issues during the warm weather months is mud daubers, those industrious, solitary wasps that build nests made of mud.

They build these in all sorts of places, reportedly in RV furnaces and hot water heaters.

Recently, I've had ants attempt to set up in the water and shore power compartment of the Roadtrek. I now keep the power cable off of the ground. Then there is a red squirrel family that likes to hop around on the RT at about 4:30am or so. I heard the "thumps" again this morning and parted the curtain to look out of the rear window. And there, about 6 inches away and sitting on the spare tire was that red squirrel. We were eyeball to eyeball for a few seconds and then is scurried away. Is it going to set up shop in the heat pump/AC compartment?

Currently I'm dauber proofing the hot water heater, furnace and refrigerator compartments. These are "spare time" chores and the sun sail took precedence. Weather also interferes. We've had a lot of rain recently and I haven't found the access to the shop which is hidden somewhere in this Roadtrek.

I had purchased about $8 of aluminum screening at the local hardware store. This I've used to make a passenger window screen. I also intended to use this for the furnace and the hot water heater, which is why I purchased aluminum screening, rather than plastic. The furnace and hot water heaters have exterior steel covers and so attachment with magnets is easy. I purchased some 3/4 inch diameter x 1/16 inch neodymium high strength magnets. These are being used for securing aluminum screening to the passenger window, furnace and hot water heater. All three of these areas are steel and so the magnets stick easily. I'm epoxying steel washers to the interior of the Dometic refrigerator vents. Magnets will then be able to attache the aluminum screening.

Fastened this way, all of these are readily removable, which was a requirement.

I'll post more photos in a few days, weather and time permitting.

West Coast Trek - Lighthouses - Cape Meares

During our West Coast Trek we stopped at many lighthouses from Cape Meares in Oregon to Point Reyes in California.  This post will be the first in a series on those lighthouses.

Lots of seabirds:

Next on the itinerary: Oceanside Beach

Adding a screen to the vehicle passenger window

Trekking in my view is to be living a life of moderation. This is consistent with other aspects of my life.  To that end, using nature's breezes and ambience is far superior to air conditioning, etc. That's my opinion and my quest.

Our Roadtrek came with optional screens for the rear and side entry door. These are a good thing. The screen in the rear entry work well, because we don't enter or exit from those doors. I only need to unzip the screens for access to the storage below the rear king-sized bed/sofa.

However, the screen for the side entry is another issue. We enter and exit frequently via this door. I'd say it's obvious that a plastic screen with zipper won't survive long in that location. So we haven't used it.

However, to get good cross-ventilation we need a goodly sized front entry or exit point for those breezes. The side entry window includes a screen and the window pivots on a vertical hinge, and opens about 1/2 inch. This area isn't sufficient for the air movement we need. It is also a problem if the weather turns inclement.

The front of the vehicle also gets a lot of sun (infrared) load if it's pointed that way. In other words, the front of the vehicle gets hot. We really like the heat pump/air conditioner in the rear, but the front of the vehicle remains warm.

So I decided to improve the airflow. To that end I fabricated and installed a screen on the exterior of the passenger side window. With such an arrangement, we can open one of the rear doors with the screens attached and we'll get the cool breezes we love, sans insects.

This was easier than might be imagined. In fact, I'd suggest that Roadtrek offer this as an option for buyers. The screen rolls and is easily attached to the exterior with magnets. The thick black edging in the photos is not used to adhere the screen to the vehicle. Magnets at 8 points will be used.

To construct this I used aluminum screen, but it would be easy to do the same with a plastic screen. I purchased the aluminum to bug-proof the refrigerator and hot water heater ventilation.  I may post on that in the future.

This is a photo of the screen, temporarily held in place with 8 pieces of electrician's tape. Magnets will be used to do this in the future. The 2 inch black edging is "duct tape" which provides a thin surface for magnetic attraction and also seals the edge of the aluminum screening. I installed the black duct tape in two layers "back to back" with the aluminum screen sandwiched between.  However, about only 1 inch of the screen is sandwiched between the tape. The electric window can open and close while the screen is in place.

When not in use (when the vehicle is travelling, etc.) the screen is rolled for storage:

If I were wanting to get "fancy" I'd purchase tape which more closely matches the exterior color of the Roadtrek. I leave that for Roadtrek to offer!

Here's a photo of the screen while being constructed. If one wanted ultra-precision, I'd suggest the old trick of taping newspaper together to fit the area and then using that as a template. My parents did that to purchase a pre-cut linoleum floor back in 1955 or so. It worked then and it will work now.

After installing this, I asked G what she thought about it. She said it was a real improvement. Mission accomplished!

Add an external 120V receptacle

Every motor home or camper van may seem to be deficient a feature or two. I purchased a Roadtrek 210P and I've made a few improvements to tailor it to my personal "tiny home on wheels" lifestyle.

One thing the 210P does not have is an exterior 120VAC receptacle. This may not be a problem if the site one rents has a meter with both 30A RV power connector and 120VAC ground fault receptacle. In such a case, all that is required is an outdoor rated extension cord and we can power up lighting, an induction heat plate or even a boom box. However, if the campsite has only a 30A RV power receptacle then we face a dilemma. The only way to get power to an exterior device or extension cord is to leave a door open and use one of the ground fault protected 120VAC receptacles.

That solution was not acceptable to me, and so I decided to add an exterior 120VAC receptacle. The following video shows how this was done without violating the integrity of the RT body and fiberglass shell.