Alternative Energy Sources

An easy do-it-yourself fountain, shown in below, is made of two separate halves of oak barrels. Here’s how the fountain works: In sunlight, the upper reservoir fills slowly. When the sun goes behind a cloud, the fountain maintains flow by draining the upper reservoir. When the upper reservoir gets too full, water drains through the overflow spout. You can close the lower valve and save water in the upper reservoir for use later, such as when you go to bed or when you’re having a dinner party with friends. Water trickling sounds come from three sources: the valve, the overflow spout, and the pump tube. It’s interesting to note the different sequences of sounds you get from various weather conditions and time of day. A solar well pump system works on the same principles. During sunlight hours, well water is pumped into a reservoir located above a house. On sunny days, the reservoir fills up, but it has enough capacity to work even through a few cloudy days. Water runs into the house by simple gravity feed, with well-regulated pressure — at least until the reservoir drains.

 

 

 

 

 

 

 

 

 

 

 

Parts list

You generally want to build the reservoir parts of the fountain before selecting a pump, so buy the materials in two stages. Here’s what you need to build the basic structure of the fountain:

• Two halves of an oak barrel: These cost $20 and up per half at big nurseries.
• Nice barrels from wineries cost more, but they’re very good quality and usually look better for a lot longer. They’re not easy to cut in half, so buy them precut. 
•  Clear silicon sealant: Seal cracks and leaks with clear silicon sealant, sold at all hardware stores. 
•  A completely reliable support structure: Use heavy, rigid concrete blocks or bricks to support the upper reservoir, with the bottom around an inch higher than the top of the lower — it can get very heavy. Keep the upper reservoir as level as possible. The lower barrel can sit on the floor, with the back edge supporting the upper reservoir. The upper reservoir can weigh upwards of 200 pounds if you’re using big barrels. If you don’t get it set with integrity, it can come crashing down. Always use concrete or mortar or glue whenever possible. If you need to, make the structure rigid enough so a kid can climb onto it without mishap. 
•  A valve (faucet): For $8 you can get a good brass faucet. Even better, gift shops often sell fancy faucets made of copper (green patina). Faucets made for outdoor hose systems come with male-threaded mounting ports, so you can screw the faucet into the barrel after you drill a hole.  
• One copper tube, around 4″ long, between 1?2″ and 3?4″: Copper tubes are stock items in plumbing departments. Or you can use a decorative valve that matches the other one as your overflow spout. Just open it up all the way and leave it like that.

After you build the basic fountain (see the next section) and before you buy the next set of materials, determine how much flow you need. Bring a hose over to the finished fountain, along with a 1-gallon container, and do the following:

1. Place the hose in the 1-gallon container and adjust the water flow so that the hose fills the container in 1 minute. 
2. Set the hose in the upper reservoir of your fountain and find out what kind of flow 1 gallon per minute results in. If this is fine, buy a 1-gpm pump.
3. If you’re not satisfied with the result in 2, readjust the flow either up or down and measure the container fill time once again. Use the formula: 1/fill time in minutes to get the flow rate.
4. Reapply to the fountain and determine whether the new flow is correct. The smaller the cheaper, but pumps can also wear out over time, so don’t cut it too close. Many pumps have a flow adjustment valve; they’re worth the extra money.

You’re then ready to buy some of the more mechanical parts of the fountain:

A 12VDC submersible pump, at least 1?2 gpm (gallons per minute) flow with 2 feet of head pressure: Head pressure is a pump spec, usually in feet, which tells you how much vertical height the pump will be able to force water. You may want bigger and faster, which makes more noise and moves more water. Most retail outlets for pumps assist their customers in choosing the best pump for the particular application. Use this free resource, if possible. Otherwise, the best bet is to look on the Internet.

Four feet of tubing that connects with the pump: Clear plastic is the best choice because it’s less visible. Buy matching tubing when you buy the pump. 

 A 5-watt or larger PV module with 12VDC output: How much power? Ask the pump experts, and they’ll tell you how much flow you’ll get for how much power. Keep in mind this flow is going to happen only under the best conditions. For $50 you can buy a complete kit with PV module, pump, wiring, and tubing. You don’t get much flow, but it works just fine if you like subtlety. 

 A mounting scheme for the PV module: You can lay a PV module directly on the ground or rocks or gravel, and it’s not harmful. But in general, it does better the higher you can get it. Rooftop is best if you want a steady flow because you get sunshine all day without contending with shadows. If you want variation, plan to mount it in a place where shadows change over the course of the day.

 Wire from the PV module to the pump: Tell the hardware store clerk how big your solar module is in watts at 12VDC, and he should be able to give you the wire you need. Direct burial cable used for household 120VAC systems is a good option because you can simply dig a trench, lay it in, and then cover it back up with the dirt. Your hardware store has a variety of wire splicing kits; when you’re ready to do the wiring, make a diagram of where the pump and switch and PV module are; measure the distances in feet. Get both the wire you need and the proper splicing kit at the same time because they’re one and the same. 

An SPST (single pose, single throw) switch, electrical box, and faceplate: The cheapest switch is an off/on light switch for a house. You can buy one for $1, and it’s easy to wire. Buy a matching electrical box and faceplate; many styles are available. The most convenient boxes come with nails ready embedded into the plastic housing; hold it up to a post and pound the nails in, and you’re hard mounted with integrity.

Assembly and operation

Before you begin, get your first set of parts ready (see the preceding section for a list of what you need to build the fountain structure). Then follow these steps:

1. Prepare the oak barrels and install the valve and overflow spout. Seal any cracks and leaks in the barrels with clear silicon sealant. In one of the halves (the upper reservoir), drill a hole near the bottom for your valve (faucet) and install it. If your faucet has a male-threaded mounting port, you can twist it right in by hand (use clear silicon sealant very liberally and wipe away the excess after you have the valve in). In the same half, drill a hole for the overflow spout about an inch from the top, not directly over the valve but a couple of inches away. Angle the hole with a slightly downward tilt so when water drains through the spout, it’ll pour outward. 
2. Finish the reservoir parts of the fountain. Put the top and bottom reservoirs into place, setting the upper reservoir on its support structure with mortar, concrete, or glue. 
3. Determine how much flow you need and purchase the appropriate pump, tubing, and wiring (see the preceding “Parts list” section). 
4. Install the solar pump system and put the tubing in place. The pump goes at the bottom of the lower reservoir, as low as possible. The PV module goes into sunshine, and the tubing connects the pump to the upper reservoir. 
5. Complete the wiring, connecting the PV module to the switch and the switch to the pump. Use your wire splicing kit. Make all wiring runs as short and direct as possible, and make excellent connections everywhere. A shoddy connection is like a weak link in a chain; it defines the overall quality. Bad connections don’t last long outdoors, in the elements. If you don’t do a connection right, you’ll be redoing it soon and suffering performance anxiety in the meantime. 

Here’s how to operate: With the switch off and the valve closed all the way, fill the upper reservoir one-quarter of the way. Fill the lower reservoir an inch from the top, and then flip the switch on. Adjust the valve so that the upper reservoir fills slowly on a sunny day.

You can have fun and discover a lot about solar by experimenting with all the different variables. A lot of subtle physics is at work — gravity, pumps, sunlight, weather, evaporation, balance, fluid flow, energy storage, power, and so on. For example, you can face the solar panel east or west to change the time of day you want to run your fountain the strongest. If you like to wake up to a fountain, face the module due east. If you like to come home in the afternoon to a peaceful waterfall, face the PV module into the southwest. You can even use two PV modules connected in parallel to cover both early morning and late afternoon (when you buy the PV modules, make sure to tell the sales staff so they can get you the right kind to do this with). On the other hand, if you want your fountain to change a lot over the course of a day, put the solar module in a partly shaded backyard where shadows are constantly evolving.