1. Adequately, 2. Inadequately, 3. Excessively, 4. Warm enough, 5. Coolest, 6. Much lighter, 7. Cool enough, 8. Hottest

A LOW-PRESSURE HOT WATER SYSTEM

1.

1. to replace water drawn-off from the system.

2. to the top of the cylinder. To effect circulation of water by convection

3. by not maintaining a temperature difference between the water in the primary flow and that in the primary return. In other words, by turning off the boiler.

4. the pressure due to the height of the water in the feed tank.

5. To prevent the formation of air locks.

6. The boiler could explode.

7. at the lowest part of the system, to drain it.

2.

1. It becomes less dense than the cold water in the highest parts of the system

2. The displacement of the heated water

3. the process of convection

4. A temperature difference is maintained between the water in the primary flow and that in the primary return,

5. the height of the water in the feed tank.

6. it collects at the top of the storage cylinder.

7. a pipe which allows air to escape from the system

8. a reduction of pressure in the boiler

9. If the draw-off point is opened

SOLAR WATER HEATERS

1.

a) insulation, b) absorber box, c) cover, d) absorber or heat exchange

2.

1. absorber box, 2. absorber, 3. insulation, 4. cover

SPACE COOLING

1.

3, 6, 1, 8, 4, 2, 7, 5

2.

1. give out heat

2. Because the absorber must reject heat to the environment, it must be located in a cooler place than the collector.

HOT-WATER SYSTEM.

1. Soluble salts in the ground cause hard water.

2. Scaling is caused by deposits made by hard water when it is heated.

3. The temperature of the water

4. Scale is a bad conductor of heat.

5. Heat is prevented from passing through the walls of the boiler.

The efficiency of the boiler is reduced.

The boiler walls may overheat

The boiler plates may burn out causing leaks.

6. To be able to de-scale the inside of the boiler

THE EFFECTS OF THE SURFACE ARE/VOLUME RATIO IN THE ARCHITECTURE

1. The higher the ratio between surface are and volume, the faster the rate of heat transfer.

2. The lower the ratio between surface are and volume, the slower the rate of heat transfer.

3. The smaller the size of the building, the more quickly it gains or loses heat.

4. The larger the size of the building, the more slowly it gains or loses heat.

5. The thicker the insulation of a building, the slower the rate of heat transfer

6. The more compact the shape of a building, the more it retains heat.

7. The less compact the shape of a building, the less it retains heat