Saturday, March 7, 2015

The Kume Shade: Simple, Homemade, Low-cost Insulating Curtains

The Kume "family" in Chile has come up with a new design for thermal shades that I think is very interesting and may be a good solution for you if  you are looking for thermal shades.

The Kume shade if various states of rollup
The Kume shades fit in the window frame and roll up to stow in a built in catch at the top -- the rollup only takes a few seconds.

The shades use four layers to provide better insulating value.

Layer 1 is a front insulating (and decorative) material, 2 is a moisture barrier, 3 and 4 are wood batten spacers, and 5 is the back insulation panel.

IR picture shows the Kume shade in action

The shade materials are relatively cheap and the shade is easy to build.  The instructions are very complete.
Good, detailed build instructions

The room facing layer can be a decorative insulating fabric, so the shades can be very nice looking.

One thing this shade appears to address is the problem of condensation on the window and frame that can occur the room air is humid, the outside temperature is cold, and the shade does not prevent room air from circulating behind the shade.  This design's combination of fabric that seals against the window frame and a moisture barrier address this problem.

I'd be very interested in hearing from anyone who build these shades on how well they do.

The Kume "family" is a group of friends and relatives living in Chile who are working together on projects that will have a positive effect on climate change.

For complete details on the design and build ...

For lots more on other thermal shade and window insulating techniques...

March 7, 2015

Monday, January 19, 2015

Large DIY Serpentine Drainback Solar Space Heating Project

Tim, Doug, and Will provide a very detailed description of a unique solar space heating system along with quite a bit of design information.

The system uses solar to heat water, which is in turn used for space heating in a radiant floor system. One of the most unique features of the system is that the drain back solar collector uses serpentine path absorbers rather than the usual vertical riser tubes. This arrangement allows the entire south face of the building to be used as a collector, right up to the peak of the roof. In addition to providing more collector area and more heat, it has a very nice look.

View of the full wall drain back collector.

The absorber uses a serpentine arrangement of tubes to carry heat from the absorber to the tank rather than the more usual vertical riser tube arrangement.  This allows the absorber to cover the entire wall all the way up to the peak.  This makes for a very nice looking full glazed wall.

Shows the serpentine absorber being fitted to the wall.  

The entire south wall is glazed with greenhouse style twinwall polycarbonate.  The full glazed wall makes for a very nice looking collector.

Full wall collector with glazing in place.

The system also uses a unique heat storage tank design that is partitioned into a warmer and a cooler section.  The collector circuit pulls water from the cold side of the tank and returns it to the warm side, and the radiant floor circuit pulls water from the warm side of the tank and returns it to the cooler side.  The idea is to allow the collector to run cooler, and therefore more efficiently.

The partitioned solar heat storage tank under construction.

January 19, 2015

Wednesday, October 22, 2014

Progress on the Fuel Efficient Camper Conversion

As I described a while back when we are working on a fuel efficient and lower emissions RV-Camper Van.  Ours is based on a converting a RAM ProMaster  van into a self-sufficient camper.

Last time we gave an initial description of our thoughts and deeds so far on the conversion -- this is an update on what has been done since then -- its getting pretty close.

The electrical system has been completed except for the installation of the solar panel on the roof.

Overview diagram of the electrical system.

Nearly all of the electrical system -- batteries, inverter/charger, solar charge
controller, breakers and distribution panel.

Testing the solar panel (which will go on the roof) with rest of system.
The electrical system provides power as 12 volts DC or as 120 volts AC from the batteries, and provides for charging the batteries from solar, or the van engine, or shore power.

Floor and Paneling:
The floor and the paneling for the walls and the ceiling are completed.

The floor incorporates an inch of polyiso rigid board insulation and is finished off with some conventional kitchen flooring.

The finished floor

Insulation board and underlayment going in.

The wall and ceiling paneling are both hardboard paneling with insulation underneath.

Paneling going up 

Just about completed paneling with trim.
We added three windows.   Nothing like cutting big holes in the side of your new van!

Now with windows!

kind of breezy in this configuration.

Also completed or mostly done:

  • Furnace
  • Grey and fresh water tanks and plumbing
  • Roof ventilation fan
  • Galley, sink, stove.
  • High efficiency electric refrigerator 
Thanks to Gordon's post, we are probably going to go with a homemade composting toilet.

The grey water tank is a bit unusual in that its home made...

All the details on progress so far here...


Thursday, October 9, 2014

Solar Heated Stock Tank Does Well In Really Cold Climate

Its the time of year to think about doing a solar heated stock tank that will save a lot of ice breaking and electricity for tank heaters over the window.

Karolyn has worked  out a nice design for a solar heated stock than that performed well over the very cold winter last year in Minnesota.

South wall of tank is solar collector that heats tank.

Drinking opening with flaps provides improved freeze protection.

This design is rugged and provides good freeze protection.

October 9, 2014

Thursday, August 28, 2014

DIY Composting Toilet for RV's and Small Spaces

Gordon and Sue provide detailed information on designing, building, and successfully using a compact composting toilet that he built for their small RV.

Gordon's DIY composting toilet is based on a recycled plastic barrel that was used to ship olives.  

The toilet seat was salvaged from an RV toilet.

The box surrounding the barrel has all the supplies needed to keep the toilet running smoothly.

A small muffin fan (1.3 watts) continuously draws fresh air from the RV into the composting chamber and exhausts it to the black duct to the outside.  This keeps the composting process aerobic and eliminates any smell.

A picture of the small RV that the composting toilet is used in and the venting outlet for the toilet.

Probably even more valuable than the how to build it information is the how to successfully use the composting toilet so that it works well and produces no odor.  Between the RV and their tiny cabin, Gordon and Sue have many years of experience living successfully with various composting toilets.

For the full story on Gordon and Sue's composting toilet...

In addition to the material on Gordon's composting toilet, I've added a section on composting toilets for RV's and small spaces with some good info on compact commercial composting toilets and how to use them...

August 28, 2014

Tuesday, July 22, 2014

Small, Simple, Efficient RAM ProMaster DIY Camper Van Conversion

We have enjoyed RVing over the years, but lost our last RV in a highway crunch.

One thing we did not enjoy about RVing was the 10 mpg gas bills and the 2 lbs per mile of CO2 emissions. So, this project is about getting back into RVing with a smaller footprint.

The RAM ProMaster 1500, hi roof, 136 WB at start of conversion

Objectives for the new van conversion:

  •  Keep it simple 
  •  An open feel inside
  •  20+ mpg
  •  Comfortable beds for 2
  •  No need for hookups 
  •  Drives like a car
  •  Able to handle some back roads 

The RAM ProMaster we bought for the conversion is a high roof, 1500, 136 WB. This gives us an area to work with of about 10.1 ft long by 6.5 ft wide (behind the driver/passenger seats). The inside height is about 76 inches.  A really Tiny House :)

It was the smallest and lightest vehicle we could find that we think will also provide enough space  and stand up height.  

Just as an aside, it would be very interesting to see what could be done with an even smaller vehicle -- maybe something like the Ford Transit Connect -- a 30 mpg RV!

So, this is going to be a several month project, and I'm just going to be adding to it as things go along. 

I'd very much like to hear ideas, comments, and suggestions that we might be able to incorporate as things progress.

I've put up a new section on BuildItSolar with pages for each major part of the conversion: layout, insulation, paneling, flooring, electrical system, ...  The main page for the conversion is here...

Progress so far...


We have pretty much decided on this layout:

We did a very crude mockup of this layout in the van:

The two beds are in the back and make into a seating area during the day, galley is on right behind drivers seat.  There will be some more storage cabinets around the edge up high.  New windows will be added in 3 or 4 locations (about where the blue tape is).

We like this nice open feel of this and the high quality beds.

More on other layouts we considered...


Did the insulation of the walls and ceiling using spray foam polyurethane insulation.  I used one of the two component kits that provide the two pressurized bottles and spray nozzle and hoses.  

Had never used one of these kits before, but it worked out pretty well.

All the details on insulating here...


I've been working on the electrical system design.

Its a bit more complicated than I would like in that we want to be able to spend a couple days (or more) away from hookups.  It has a fairly large battery and the battery can be charged via solar (on the roof), the van alternator, or from shore power.

I've worked out a tentative list of components.

Would appreciate any comments on the design or the components.


Today's project is the floor.

I've put up a new section on BuildItSolar with pages for each major part of the conversion: layout, insulation, paneling, flooring, electrical system, ...  The main page for the conversion is here...

Gary July 22, 2014

Thursday, July 3, 2014

Solar Powered DIY RV Evaporative Cooler

Tom has come up with a very nice evaporative cooler for his RV. The cooler is effective, uses very little electrical power, and is inexpensive and relatively easy to build.

The finished cooler in position on the solar powered RV

The system uses fans to blow outside air through a porous wet cooling pad. Evaporation of water in the cooling pad cools the air, dropping the temperature by as much as 25 F.

The compact unit contains a water reservoir, water pump, aspen cooling pad, and circulation fans as shown in the diagram.
It runs on 12 volt DC power and is powered by the RV's solar panel and battery -- pretty cool :)

Diagram showing how the cooler operates.

The finished unit ready to install.

Tom uses this to cool his RV -- it uses only a fraction of the power that conventional coolers use and allows him to rely solely on solar power when camping off the grid.

The same sort of design could be used for all sorts of cooling applications -- cooling a living space or shop or greenhouse with no grid power, cooling when the power grid goes down, ... For this size cooler, the fans and pump only use about 18 watts at 12 volts -- so a modest size PV panel could direct drive the cooler. The design could be scaled up for larger spaces.

July 3, 2014

Friday, June 20, 2014

Dryer Heat Recovery and Dark Sky Lighting

These are two nice DIY projects from George Plhak's blog.

Dryer Heat Recovery Using a Furnace Filter

Venting clothes dryers to the outside is very wasteful.  It wastes the heat contained in the vented air stream, much of which could be recovered for space heating.  And, venting the air to the outdoors causes new air to be pulled into the house which then has to be heated to the house temperature by the furnace.  The energy wasted can be as much as 4 KWH per dryer load -- clearly one of the largest potential home energy savings available.

While there are various approaches to recovering dryer heat, the simplest one is to just vent the dryer air stream inside the house.  One problem with this is capturing the lint in the dryer stream so it does not end up in your house.  George has worked out a nice way to vent to the inside and to capture the lint using a furnace filter.  The furnace filter provides a lot of filter area, is easy to replace, and is inexpensive.

The dry vent filter box is on the wall next to the dryer.

The filter goes in a slot in the box.

Important Note: For some climates and some homes, venting the dryer inside can result in moisture problems, so if you go this way, be sure to monitor the situation after you starting venting inside.  Also, this is for electric dryers only -- gas dryers should never be vented inside.

A DIY Garden Light that Preserves Dark Sky

This is a very nice design that uses inexpensive and recycled parts to make a low energy use (LED) garden light that does not allow any upward light radiation that would pollute the night skies.
The light in action.

It uses a used stainless steel mixing bowl and a jelly jar to hold the LED and reflect its light downward toward the ground.  Makes a very nice light pattern on the ground.

The mixing bowl and jelly jar to house the light 

George's blog has a lot of interesting material, including his extensive work on a DIY concentrating solar water heating collector.

June 17, 2014

Monday, June 9, 2014

A Large Shop Thermosyphon Solar Air Heating Collector

This is Ivan's large shop heating thermosyphon solar air heating collector.
It is 6 ft high by 40 ft wide. This 240 sqft of collector will likely provide in excess of 40,000 BTU per hour on a sunny winter day.

The finished 6 by 40 ft collector

These collectors are very effective heaters and since they rely only on thermosyphoning to move air through the collector they do not need any fans, controls, or power. The only moving parts in the whole collector are the simple backdraft dampers that prevent reverse flow at night. At about $3 to $5 per sqft of collector, these are one of the fastest payback solar projects that it is possible to build.

This is the south wall of the shop before the collector was added:
Ivan just built the collector right over the windows.  This allows a nice, wide and simple collector. I think this will work quite well as the windows will still get quite a bit of light through the collector absorber (which is two layers of screen).  How to handle existing windows is a question that comes up quite a bit in adding collectors, and I think Ivan's method is definitely worth considering.

The collector frame is built right on the existing shop wall.  The upper and lower vents that connect the collector and the shop are visible in the picture.  After the frame is done, the back wall is covered with rigid insulation, painted black, and then the two screen absorber is added, followed by the outer glazing.

The glazing being applied to the collectors, which already have the absorbers installed.

This diagram shows how simple the collector is.  The solar heated absorber heats the air, which rises out of the collector and draws new air into the bottom.  No fans, no controls, no electricity, no maintenance.

June, 9, 2014

Saturday, May 31, 2014

The Simplest Solar Water Heater

Carl came up with this very simple and effective solar batch heater that heats up one bucket of water. You put the 5 gallon bucket into the glazed box, put it in the sun, wait a few hours, and then take the heated bucket of water to where you need it.

Perfect for a cabin, emergencies or just locations without running hot water.

Its mounted on a turntable, so its an and advanced tech, human powered tracking solar water heater!

A piece of foam cut to fit the bucket reduces heat loss from the water surface.

Very nice and very simple.

In one test, the bucket water heated from 53F to 122F over a 7 hour collection period.

More details on construction and performance here....

May 31, 2014
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