SOLAR WATER HEATER, School Science Project

SOLAR WATER HEATER

PROJECT

You will construct a water heater with a collector and storage tank.

MATERIALS AND EQUIPMENT

Collector

1.       Z 10-inch (25-centimeter) square piece of galvanized

sheet metal (the thinnest available)

2.       Z 20-inch (51-centimeter) square piece of cardboard

3.       Z Flat black spray paint

4.       Z 10-inch (25-centimeter) square piece of insulation

(Styrofoam, corrugated cardboard, newspaper, or

batting) at least 3 inches (8 centimeters) thick

5.       Z 3-foot (1-meter) soft copper tubing, 3/8-inch to

1/2-inch diameter

6.       Z 16-inch (40-centimeter) square sheet of 3- or 4-mil

clear plastic

7.       Z Knife or box cutter

8.       Z Cellophane or masking tape

9.       Z Tubing bender (or have the copper tubing bent at

the hardware store)

Water Heater

1.       Z 1- or 2-pound coffee can with plastic lid

2.       Z 2 2-inch (5-centimeter) pieces of soft copper tubing,

3/8-inch to 1/2-inch diameter (must be same

diameter as the copper tubing used in collector)

3.       Z Thermometer

4.       Z Cardboard box, slightly larger than coffee can

5.       Z Insulation material (Styrofoam, corrugated

cardboard, newspaper, or batting)

6.       Z 100- to 200-watt soldering iron and acid-flux solder

RESOURCES

The copper and plastic tubing, tubing bender, box cutter, galvanized sheet metal, and plastic

PROCESS

Setting Up the Experiment

TO MAKE THE COLLECTOR

1.        Bend the copper tubing carefully into an S-shape using

  a tubing bender to avoid kinks.

2. Lay the copper tubing onto the galvanized sheet metal and solder it in place.

3. Spray the plate and tubing with the flat-black paint.

4.     Draw lines on the cardboard.

5.   Cut on the solid lines, and fold on the  dotted lines.

6.   Cut slots and holes in the cardboard to insert the collector (sheet metal with tubing).

7.        Fold and tape the cardboard to make a box.

8.        Put the insulation in the bottom of the box.

9.        Slide the collector into the box along the slots, and tape the

  slots tightly closed.

10.    Place the clear plastic sheet over the top and fold and tape it

Add caption

  down to make a tight but removable cover.

TO MAKE THE WATER HEATER

1.        Punch two holes on opposite sides of the coffee can. One hole must be   1 inch (2.5       centimeters) from the

top of the can and the other, 1 inch from the bottom of the can.

2.      Insert the copper tubing in both holes and solder the joints. The joints must be watertight.

3.      Cut holes in a cardboard box that will align with the

tubes in the can.

4.      Put the can inside the cardboard box, with the tubes

sticking out the holes in the box.

5.      Put insulation around the coffee can.

6.      Cut the plastic tubing into two pieces, one slightly larger

 than the other

WHAT DID YOU SEE?

What happened to the water level in the can when you first hooked up the system?

How hot did the water get in 20 minutes? In an hour?

Would the solar water heater work if the storage container was placed lower than the collector?

Will the solar water heater work in reverse on a cold night?

Can you detect the water flow in the system using chalk dust or food coloring in the water?

What was the highest temperature you recorded?

HOW SOLAR WATER HEATERS WORK

Solar water heaters use the sun to heat water in collectors mounted on the roof of a house. One type of solar

water heater is called a thermostatic system. As water in the collector heats, it becomes lighter and rises into the

tank above. Meanwhile, cooler water in the tank sinks down pipes to the bottom of the collector, causing

circulation throughout the system. This is known as thermosiphoning. The storage tank must be above the

collector for the thermosiphoning to work

Doing the Experiment

1.        Make a chart to record the following data:

  Water temperature before:

Add caption

  Water temperature after     20 minutes: Water temperature after 1 hour:

2.        Hook the collector and water heater together.

3.        Disconnect the plastic  tubing from the inlet.

4.        Run water through the tubes and the collector until all

the air is gone.

5.        Reconnect the tubing to the inlet, and fill

the coffee can with water to above the level

of the inlet.

6.        Measure and record the water temperature and replace the lid.

7.        Face the collector directly into the sun, placing the bottom of the

heater above the top of the collector.

8.        Measure and record the water temperature after 20 minutes.

9.        Measure and record the data every 20 minutes.