How to Make a Solar Water Heater From Beer Bottles

Solar water heaters use thermodynamic principles to heat and separate warm water from cool water. They are particularly effective in hotter regions with regularly clear skies.
By using empty beer bottles, you recycle the glass to use as the heating columns of your solar water heater -- a double benefit and cost-effective as well.
The two main risks for solar water heating systems are possible damage in freezing weather and overheated water during hot summers.

Things You'll Need

• 72 empty and clean 1 liter beer bottles (preferably green or brown glass)
• Wooden or metal frame (with back) and with interior dimensions 140 inches X 18 inches and 3 inch or greater sidewalls
• 2 support legs (material matching your frame) to hold frame at 20- to 40-degree angle
• 1 inch glass-cutting drill bit
• 1 inch plastic-cutting drill bit
• Power drill
• Epoxy
• 10 PVC 1 inch Tee sections
• 2 PVC 1 inch 90 degree elbows
• 5 feet of PVC 1 inch pipe cut into 24, 2.5 inch lengths
• PVC pipe cutter
• PVC primer
• PVC cement
• 40 gallon (or larger) high temperature plastic water tank
• 4 PVC 1 inch ports (may be threaded or not)
• Measuring tape
• 10 feet (or longer) dishwasher high temperature hose with 1 inch inner diameter
• 4 small hose clamps (for dishwasher hose)
• Safety glasses
• Ventilating fan

Instructions

Preparing the bottles

1. Using the glass-cutting 1 inch drill bit, carefully cut a hole centered in the bottom of each beer bottle.
   Wear safety glasses while performing this step.

2. With the ventilator fan blowing, use epoxy to glue the top of one beer bottle securely into the hole you drilled in another bottle. Epoxy the bottles into 6 columns of 12 bottles each and allow to dry thoroughly.
   Keep the ventilator fan blowing during each of the steps using epoxy, PVC primer and PVC glue.

3. Epoxy a 2.5 inch length of PVC pipe into the bottom hole of the bottom bottle of each column. Epoxy another length to the top of the top bottle of each column and allow to dry.

4. Apply PVC primer to the top of the PVC length on the tops of each bottle column. Prime the ends of the remaining PVC lengths and the inside ends of each of the PVC elbows and Tees.

5. Put a light coat of PVC glue inside one end of a PVC elbow and attach it to the PVC length on the top of one of the beer bottle columns. This is now the end column. Glue the other elbow to the bottom of the same column, ensuring it faces the same direction as the top elbow.

6. Use PVC glue to attach the center leg of 5 PVC Tee sections to the tops of the five remaining bottle columns. Then glue the other 5 PVC Tee sections to the bottoms of the columns, ensuring the bottom Tee sections are the same angle relative to each column as the top Tee sections.
   Allow glue to dry.

7. Place the end column (with the elbows) in the frame at the far end from where you will have the water tank. Glue a pipe length into the open end of the top elbow and one into the bottom elbow.

8. Set another bottle column into the frame next to the end column. Glue the top Tee section to the pipe length extending from the top elbow. Repeat for the bottom Tee section and bottom elbow.

9. Glue another pipe section into the open end of the second column's top Tee section and another into the open end of the bottom Tee section.
   Set another column in next to the second column and repeat the process until all six rows are in place and connected at the top and bottom.
   The open ends of the Tee sections on the sixth column should have PVC lengths glued into them to act as the bottom inlet port and top outlet port.
   Allow to dry thoroughly.

Preparing the tank

1. Measure a point 3 inches up the side of your tank from the bottom and drill a 1 inch hole. Drill a matching hole on the opposite side of the tank.

2. Measure a point 3 inches from the top of the tank and directly above one of the Step 1 holes, and drill a third hole. Repeat with a matching hole on the opposite side.

3. Use epoxy to securely attach the four PVC 1 inch ports into the holes you drilled. Allow to dry.

4. Cut your dishwasher hose into two pieces of equal length.

5. Slip a hose clamp over one end of a length of hose and clamp it onto the exposed PVC pipe length on the bottom of nearside bottle column. This will be the cool water inlet line to your solar heater.
   Clamp the other end of the hose to the lower tank port on the near side of the water tank.
   Repeat to connect the remaining hose between the upper tank port and the top of the nearside bottle column as the warm water outlet of the solar heater.

Using the system

1. Connect your cool water source to the lower water tank port. Add water to the tank as you use hot water out of the tank to keep the water level constant.

2. Connect the remaining port of the water tank to the point where you wish to use the heated water.

3. Face the bottle array to receive maximum exposure to sunlight.

4. Cool water from the water tank will flow into the bottom of the bottle array and the pressure will force it up through the columns and back into the water tank.
   As the sun heats the water in the columns, the warm water will rise and flow into the upper tank port, with cooler water in the tank settling to the bottom for flow into the lower end of the bottle array.

5. Monitor the water temperature at the upper outlet of the tank. In hot, clear weather this water may require mixing with cool water to avoid scalding.

Tips & Warnings

• Additional bottle columns may be added to increase the quantity of warm water available.

• Adding water level switches to the water tank and wiring them to a pump can give you an automatic system to optimize the tank level.

• In cold or overcast regions, pay special attention to your array. Electrical heating tape may be required to keep the array from freezing and the glass or PVC from breaking.

References

• Solar water heating basics
• Beer bottle solar water heater
• (pdf) Plans for solar heater made from bottles