Datalogging in Science

Attic insulation - - - how effective is it ?

Background
To keep houses warm in winter we need to heat them. This involves converting energy from fossil fuels like coal, or oil, or gas or electricity, which has been generated using one of these fossil fuels. Minimizing the wastage of energy is important for our own cost of living and also for the environment. To do this, we can insulate our houses. In this experiment we explore how effective attic insulation can be in reducing heat loss.

Overview
In this experiment, a box will serve as a model of the house, with a low voltage lamp inside it producing heat. Two similar boxes are used, both insulated on the base and walls, but only one has the inside of the lid insulated. The diagram below shows how an inverted plastic cup can be used to hold the temperature probes above the box. Both bulbs can be supplied by the same power supply.

Apparatus


1. Datalogger.
2. Temperature sensors (x2)
3. Large box with a lid.
4. Low voltage lamp.
5. Low voltage power supply for the lamp.
6. Insulating materials.

Notes
The use of a light bulb to heat the house is convenient.
A 12 V car brake-light and a 6 volt torch bulb were used when testing this work.
The main difference is rate of heating that happens.
Selecting the size of the house carefully can control this.
A 6 volt lamp was used to produce the sample result published below.
The house was a small, corrugated cardboard packing box 15 x 12 x 12 cm.

Procedure

1. Assemble the apparatus as shown in the diagram. The box is used to represent the enclosed space and the bulb represents the heating system. Place one of the temperature probes inside the box and the other near, but not touching, the outside of the box.

2. Launch the Graph software and set it to record temperature in Real Time.

3. Start datalogging.

4. Turn on the light bulb.

5. After 5 minutes, switch off the bulb and continue to log the data for a further five minutes or until the recording finishes.

Results

Analyse the results and present outcomes in a brief report.

Extension

1. Is the effect of insulation more evident on a windy day?
Try using a fan to simulate the wind.

2. Try the effects of increasing the thickness of insulation, and using different materials.

3. Find out the cost of cavity wall, loft insulation, and double-glazing.
Which is the most cost effective way of insulation?

4. If the box is placed on its end, we have a two-storey house. Investigate the effect of heating only the ‘ground floor’ or only the ‘first floor’.

5. Try adding a ‘window’ to your box & evaluate the use of single and double-glazing.

Data Harvest users

1. Connect the sensor to the datalogger and the logger to the computer
2. Then click the Set Up icon to the right of this message.
3. When the software opens, click the Play button.