A Project to Produce and Store Heat, Energy, Water, and Food, by T.S.

We all know that we can’t survive very long without water, food, and heat. Because we live in uncertain times, the benefits gained by this project would more than offset the initial cost. In a grid down situation, the extra heat, stored water, energy, and food production would be invaluable.

The list of benefits include but are not limited to:

  1. Heat production to help heat the house.
  2. Water storage plus heat storage.
  3. Solar energy production and storage.
  4. Food production.

Three years ago on a sunny winter day, I went out on our south (well, more like a southwest facing) porch, to enjoy the winter sun. It was a cold day, but without any wind sitting in a chair was warm and cozy. Then it dawned on me that I could enclose this porch with a wall of windows and it would be quite warm on a sunny day even if there was a wind. That’s where this all started, and in the process the porch project has evolved into much more than just a sun porch. Having a strong desire to increase our self-sufficiency as well as provide for my family, this has been an ongoing process that will return many benefits in the future.

In this article, I will share with you the process that will enable you to do all of the above plus more. I was fortunate in that there was already a reinforced concrete slab on which to build and a roof over the porch. The slab is 9-10 inches thick, which according to an architect friend is enough concrete to support the weight of both the wall of double pane windows and 50-gallon water barrels used to store heat and water. If you don’t already have a slab to build on, you will have to have one poured. Make sure it’s reinforced and thick enough for your purposes.

Constructing the Wall of Windows

The area that I had to work with was 29 ft. x 9 ft. On the 29 foot length, I built a wall of double pane windows, including four 32” x 74” and three 45” x 74”. These were purchased at a discount from a local building supply store that specializes in over runs, odd lots, et cetera, saving a lot of money. The ends of the porch are enclosed with 2×4 studs, and each end has a door and a small window to allow for air flow in the warmer months. The east end also has a 32” x 74” double pane window to take advantage of the morning winter sun.

In building this wall, I broke it down into three sections with two of the 32” windows with one of the 45” windows in the middle. The frames were 2×6, doubled in-between the windows, giving me roughly a 4×6 for stability and a single 2×6 on the top and bottom. The frames were first built on the slab, the existing porch header jacked up, the old porch post removed, the frame slid in, a 4×6 post inserted, and the header lowered on top of the frame and 4×6 post. (Don’t forget to seal the bottom of this frame before you set it in with silicone; otherwise, rain and snow melt will leak in.) After the frame was set, the windows were added. The bottoms of the windows are 10” off of the concrete floor to lessen the possibility of rain or snow leaking in. The process is repeated for the next set of three windows, leaving a single 45” x 74” window on the end. There was approximately three feet left on the east end to accommodate batteries and electronics for a simple solar installation.

All the walls were insulated and covered with OSB board, and siding was added to the outside.

Heat Production

In each window I hung corrugated tin five feet long by 26” wide that was painted flat black on one side. I put one piece in the smaller windows and two pieces in the larger windows, leaving space on all sides to let in a little light. These are hung with a small chain, leaving about 5” space between the tin and glass. You don’t want to hang the tin too close to the window; the heat produced might damage them.

Now you have a solar collector that gets so hot when the sun is shining on the tin it will burn your hand if you hold on to it for more than a few seconds. Initially I had tin in all the windows, and the temp on the enclosed porch would get up to 110 degrees in late February with the outside temp at 23 degrees. So, what do we do with all this heat?

Located in the Midwest in growing zone 5, this house is seven years old with 2×6 walls and about three feet of blown insulation in the attic, so it’s well insulated. With 1,600 sq. ft., the furnace thermostat is located approximately in the middle of the house in a hallway. On the enclosed porch end, there are two bedrooms; one has a door leading out to the porch, while the other bedroom has a window that opens onto the porch. I just opened the bedroom door leading to the porch and put a window fan in the window of the other bedroom, creating a circulating flow.

I wanted to get some of that heat to the rest of the house, so I placed a fan in the hallway to move some of that warm air to the other part of the house. On a sunny day in the winter, this will raise the temp on the thermostat by about five or six degrees. If the sun is shining in the fall, winter, or spring, the furnace rarely comes on. As an example, on a sunny day on March 3rd last year, the outside high was 21 degrees and the temp shown on the thermostat ranged from 68 to 73 degrees without the furnace running.

To distribute this hot air into the rest of the house more efficiently, I have added a bathroom exhaust fan with a 4” flue pipe in the attic to move the hot air deeper into the center of the house. This fan is 110v wired into a thermostat mounted on the ceiling of the porch that turns the fan on when the temperature reaches 85 degrees. These thermostats are commonly used in greenhouses to cycle fans to get rid of excess heat. As a plus, the money that you save on your heat bill could be spent on other essential items.

In a grid down situation, I have on backup two 12v Attwood Turbo 4000 Quiet Blower bilge fans that I will switch out to provide air flow, but for now I’m using the bathroom exhaust fan. The Attwood fan is noisier than the bathroom exhaust fan, but it can be quieted down by encasing it in Great Stuff insulating foam. This would be a big help in keeping the house warm if the power was out.

Water storage + heat storage

In addition to the black painted tin, four 50-gallon food grade, plastic barrels that are painted flat black for water storage plus heat storage have been added. I purchased these barrels from a local soda bottling plant for $10 each; they also have 30- and 15-gallon barrels available.

You will need a bung wrench to remove the bungs and rinse the barrels well, because there is always a residue of soda syrup in them. You will first need to paint the barrels with a primer so the black latex paint will adhere. The black paint keeps algae from forming and gathers solar energy. Paint every surface, even the bottom. I cover the top bungs with a small piece of black cloth to keep light out. In the winter, the water in the barrels will stabilize at about 85-90 degrees, releasing this heat slowly during the night. In the summer, I shade them with an automobile windshield reflector. If they aren’t shaded, the water will get as hot as 105 degrees, which is a good start on hot water if you want. It would take less energy to heat that 105 degree water to boiling for cooking or sanitizing.

This is like a Trombe wall using water barrels to absorb and store heat instead of a masonry wall. For now, I’m storing tap water instead of rain water and changing it out every six months, but I have a backup rain harvesting system if needed.

In placing these four barrels in the windows, a platform was built to get them up to the same level as the bottom of the windows. This gets them off of the concrete floor and helps to distribute the weight more evenly. The platform is made of 2×10’s with a ¾” plywood top and painted flat black with three cross pieces under the barrels where they meet, lined up on the platform. This provides stability and strength; you don’t want this platform collapsing. Again, I can’t stress enough to make sure your concrete slab will support the weight, since we’re talking about 1600 lbs. of water alone plus the weight of the windows. In planning the platform, a 1/2” of space was added between the barrels to allow for expansion, once the barrels are filled.

These barrels are thick and sturdy enough to install a water spigot about 5” off the bottom to avoid draining off any sediment that may collect and make it easy to attach a hose. The spigots were placed so that they are not sticking out over the edge of the platform in order to avoid them from being damaged by accidental impact. In mounting the spigots, use a ¾” hole saw and brass spigots, not plastic, with a ¾” pipe thread. Carefully screw the spigot into the hole, making sure it’s oriented straight; the spigot threads will cut threads into the thick plastic (about ¼” thick). Remove the spigot and put about three layers of Teflon tape on the threads, screw it back in, remove, and apply three more layers. Screw it back in almost all the way, stopping with the spigot in a position where it’s easy to thread on a hose with just enough length to be able to fill a bucket. Usually, the Teflon tape will seal it. If there is a slow drip, put down something to catch the water, and the drip should seal itself within a day. If it doesn’t seal itself, tighten the spigot a little more, being careful not to bottom out on the flange; you might strip the threads.

These barrels have two threaded caps on the top across from each other that cover access holes/bung holes. The barrels were oriented so the holes are lined up on the outer and inner edges relative to the windows. This allows for easy access for filling. These caps have a ¾” pipe thread hole in the center that I drilled out on the side facing the window. A ¾” pipe thread plastic L with a tubing fitting on the end was inserted in each of the caps. T’s were added on the other barrels and clear tubing was run to each of the barrels to allow them to “breathe”, as the barrels and water/air heat and cool. Be sure to cover the end of this tube with a screen or cloth to keep insects out.

For now, I have four of these water barrels, which is about 200 gallons of stored water, and I haven’t had any problems in the two years that the barrels have been full. It’s a good idea to have extra barrels on hand as well as spigots and washers. I’m considering adding more barrels to increase the heat storage capacity as well as water.

Solar electrical energy production and storage

Starting out simple, solar yard lights were placed in the parts of the windows that were not being used for heat production. I have picked them up at yard sales and auctions for as little as 25 cents apiece with batteries. These are very useful for minimal lighting for hallways, rooms, used as a small flashlight, and even to charge batteries for use in communication and other electronics. The bigger solar yard lights take a AA battery and are easy to remove. If it comes down to it, it’s a good idea to remove these solar lights from the window for OPSEC before the sun sets.

In working my way up to a larger solar installation, I purchased a Renogy 30w RNG 30D solar panel that is stored in a metal trash can along with two charge controllers to protect against an EMP. This solar panel was tested in one of the windows, and it does a very good job of charging a 12v battery that, should the need arise, would be useful for running the 12v bilge blower to move heat off of the sun porch. The battery’s charge status can be checked with a digital voltage meter available online or at an auto parts store. This unit will be a backup to a 200w system that I’m installing in the near future that I won’t get into because there is a lot of info on solar systems available online. One thing I might add is that batteries perform better when they are warm, which they are on the solar heated porch.

Food production

This past winter I planted spinach and radishes on top of the water storage barrels. Using round planters set on plywood with foam blocks under the plywood to get them up off the barrels a little, they did very well. The pots were set on turntables that were turned ¼ turn a day to even the light exposure to the plants. Car windshield reflector material cut and glued to foam core placed to reflect light back to the plants from the side away from the windows provided even more light for growing, essentially creating a mini greenhouse. The barrels provided plenty of heat at night, so freezing was not a problem. In staggering the planting, there is a somewhat steady supply of fresh greens. Speaking of which, radishes and their greens provide an excellent source of vitamin C. Radish leaves contain almost six times the vitamin C content of their root and are also a good source of calcium. Red Globes also offer a very good source of the trace mineral molybdenum and are a good source of potassium and folic acid.

Closer to spring, we got a head start on the tomato plants.

Since this porch is oriented more southwest than south, it gets more direct sunlight at all times of the year resulting in an excess of heat at times. In the summer, the tin panels are turned around so the shiny side is facing out and reflects some of the heat generated. In the late summer and fall, this excess heat (up to 110 degrees) is used at this ideal time of garden surplus to dehydrate fruits and veggies. I built a dehydrator out of an old metal kitchen storage cabinet and painted it flat black on the back and sides. To provide ventilation, a hole was cut in the side near the top and one on the bottom opposite side. The holes were covered to keep out insects, and shelves and racks were added. Placed in one of the windows, the heat generated creates its own airflow that can be increased as needed by adding a 110v exhaust fan. In adding an exhaust fan, I’ve found it helpful to vent it to the outside with flue pipe to keep the humidity down on the porch to speed drying.

To recap what has been an ongoing process to provide more self-sufficiency, I am continuing to find more uses for this project that I started.

We can’t live without water. Heat in the winter is both welcome and necessary to maintain health and morale, and fresh food is a plus. I’m sure you can come up with more uses for this seemingly simple project as time goes by, so use your God-given talents and expertise to expound on the possibilities. I believe that we are facing difficult times ahead, and whatever means we can take to overcome these difficulties need to be taken as soon as possible.

I have found the extra space to be useful for storage of necessary items, cleaning and maintenance of survival tools, or as the case may be to soak in a sauna on occasions.

Even if you don’t have a south facing porch or can’t afford to enclose it, you can still partially heat your house by hanging the tin, painted flat black, in your south or even west facing windows.

Disclaimer: I have no interest, nor any incentive by mentioning any products in this article. I will not be held responsible for any damages that may result in undertaking this project, so do your own research to make sure that, in your construction, usage of the information in this article applies to your conditions. Your results may vary depending on your location and other factors.