Experiments in Heat Loss | Experiments in Heat Gain


Experiments in Heat Gain

When the sun's light shines on things, it heats them up. They GAIN HEAT.


Words that Architects Use:

THERMAL MASS or THERMAL STORAGE: Thermal mean heat. Thermal storage is a material that can store heat. Water or pebbles make good thermal storage.


black and white cups

Experiment 8

For this experiment we use 4 plastic cups instead of the Energy House. You will learn how solar collectors work!

The Steps:

  1. Leave a jug of water stand overnight so it becomes room temperature.
  2. Paint the 4 plastic cups as shown in the pictures. Paint the lids too.
  3. Make sure the lids have a hole big enough to fit the thermometer in, so you don't have to take off the lid to take readings.
  4. Set the cups where they will receive equal, direct sunlight. Face the half-and-half cup with the clear side towards the sun.
  5. Fill each cup with the same amount of room-temperature water. Cover.
  6. Measure the temperature rise every 15 minutes.
  7. Graph the temperatures. Click here to see an example of one of these graphs.
clear and half clear cups

Things to Notice:

Which cup is the best collector of solar heat? Which is the worst? Why do you think there's such a difference?

How would this experiment help you to design a good solar collector?

Can you tell how the cups in the sun are acting like miniature Energy Houses?

experiment 9 diagram

Experiment 9

The sun can't heat up your house if it can't get in. The direction that a house faces is the important thing here. On the north side windows are needed only for view and some light, but not heat.

The Steps:

  1. Place the house in the sun, facing the door and the small window toward the sun.
  2. Measure the temperature rise every half hour and graph the results.

Things to Notice:

Compare this experiment to Experiment 10. This experiment goes hand in hand with a study of the sun's motions through the sky


experiment 10 diagram

Experiment 10

Here's the Greenhouse Effect demonstrated. When heat from the sun enters an enclosed area it can't easily get out, so heats builds up.

The Steps:

  1. Place the house with the large windows facing the sun.
  2. Measure the temperature rise.
  3. Graph the temperatures.

Things to Notice:

Did the windows fog up this time? Compare this experiment to the next one...

experiment 11 diagram

Experiment 11

Finally, this is the passively heated solar house in its basic form: well insulated; large windows toward the sun and small windows elsewhere; heat storage material placed to absorb heat.

The Steps:

  1. Place the black-painted pan in the house
  2. Fill with room temperature water.
  3. Place the house in the sun, with large windows facing the sun.
  4. Measure the temperature rise and graph.
  5. Block out the sun after 2 or 3 hours and keep taking readings as the temperature drops.
  6. Graph the temperatures.

Things to Notice:

Compare this experiment to Experiment 10. Does the house heat up faster or slower? Does it cool down faster or slower? (HINT: Check here for hints about the slopes of lines in graphs)

In this experiment, the sun heats the water, the water absorbs heat and releases it slowly. If you had heat storage in a real house, you could store the sun's heat during the day and let it out at night when it is needed. Even better, you could pull all the curtains at night to keep more heat in. Unfortunately this is not possible to do with the model without opening up the Energy House and disturbing the experiment.

experiment 12 diagram

Experiment 12

This experiment is about keeping the house cool in summer.

"The sun can't heat up your house if it can't get in." That's true in summer as well as winter. Awnings, louvers or shutters stop the sun before it gets into the house.

Shades, curtains or blinds work to help a room stay cool too, by reflecting some of the heat back out. But not so well as something like and awning that keeps the sun from getting in the first place.

The Steps:

  1. Make the awning and attach it to the house with push-pins.
  2. Place house with the large windows facing the sun. Try to do this on a day when the Energy House will get the same amount of sun as in Experiment 10.
  3. Measure and graph the heat rise.
  4. Graph the temperatures.

Things to Notice:

Compare your graph to Experiment 10 -- does the awning really work to keep the house cool? People use electricity to run air conditioners to take away the heat after the sun has heated up their house. Do you think it would be better and cheaper to prevent the house from heating up in the first place?

If you've done all the experiments, now you have a complete set of graphs.
What do they tell you about designing a real house?


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