A. The boiler must be big enough for the job it has to do.

B. The pipes should be of a size sufficient to convey the volume of water required to give up the needed heat.

C. Pipe runs should be as direct as possible.

D. A system should be planned to provide enough heat in the worst possible conditions.

E. The occupants of rooms should be given a means of controlling the heat output in the room by means of valves.

From a point of view of heat control, one valve only is needed and this can be fixed on either pipe; although in practice it is usually fitted to the return or lower pipe where it is out of the way. It is useful to fit a valve on each pipe so that radiators can be taken out for repair without having to run off the whole of the water in the system.

1. Ответьте на вопросы к тексту. Ответы переведите на русский язык:

1. What is a gravity system of heating?
2. Why is it so important the rapidity of circulation in a heating system?
3. When will rapid circulation be evident in any heating system?
4. What is used by the occupants of rooms to control the heat output in the room?
5. Why is useful to fit a valve on each pipe?

Контрольная работа N 3

Вариант 3

I. Определите время и залог глагола-сказуемого и переведите предложения на русский язык

Much is being done in southern California, one of the world’s largest known reservoir of geothermal power.

A plant based on this principle has worked for some year in South Africa, where it purifies water being used in uranium processing.

Because concrete has a low resistance to the passage of heat, it is conducted into the interior.

The values used for sizing and performance of hot-water equipment do not produce accurate results.

II. Переведите предложения, обращая внимание на разные функции слов it”, “that”, “one”

South Africa is one of the countries in the world most suited for solar heating.

Water mains are those pipes which distribute the water from the reservoirs.

Composition pipes are lighter than those made of cast iron.

Protecting the roof from the sun prevents it from expanding.

III. Переведите предложения, обращая внимание на разные функции глаголов “to be”, “to have”

When this power station is completed it will produce about 800 mln kilowatts hours a year

Domestic heat pumps have only recently started to penetrate the residential market and the number of units is very small.

Most of the apartments with access to electricity have to use electric geysers or water heating.

Houses in hot-dry climate are to have compact layouts (расположение) due to the high solar radiation.

IV. Переведите предложения, обращая внимание на функции Ving форм и инфинитива

To support normal farming in Iceland, fruits, vegetables and flowers are grown in large green houses heated with natural steam or hot water.

Workers in the utility industry, consulting engineers and manufacturers are meeting with difficulty in developing new equipment and more efficient systems, as well as in analyzing existing systems.

Categories of dwellings are defined according to the materials to be used for walls and roof construction.

Such solar batteries are very useful in supplying current for rural telephone

Systems

V. Прочитайте текст и выполните упражнение после текста.

DOMESTIC HOT WATER HEATING IN SOUTH AFRICA

Domestic hot-water heating is an important component of energy consumption in the residential sector. For example, in the USA hot water is second in energy demand only to space heating. Reliable information on domestic hot-water consumption is limited and the available information is dated. The values used for sizing and performance of hot-water equipment do not produce accurate results when compared to measured data. Workers in the utility industry, consulting engineers and manufacturers are meeting with difficulty in developing new equipment and more efficient systems, as well as in analyzing existing systems.

2. In South Africa, however, hot water consumption and not space heating is the largest user of energy in the domestic sector, the reason being the very mild climate. Estimates vary, but figures are as high as 40 to50% of the monthly electricity use of an average middle-to-upper income level household.

There are 8.7 million dwellings in South Africa which 348,000 are apartments. Categories of dwellings are defined according to the materials used for walls and roof construction. The main materials are bricks or cement blocks for the walls and concrete slabs, corrugated iron, tiles or asbestos for roofs.

Five methods are generally used for heating of how-water in apartments, namely: solar heating, heat pumps, gas heating and electrical elements. Although South Africa is one of the countries in the world most suited for solar heating, an insignificant number of apartments are fitted with solar water-heating systems. The reason for this is the high capital cost and the low cost of electricity. Domestic heat pumps have only recently started to penetrate the residential market and the number of units is very small. Unlike many countries in the world natural gas is not readily available and is therefore not distributed to an apartment via pipelines. Therefore, gas in pressurized bottles is usually only used in rural areas where electricity is not available. Most of the apartments with access to electricity use electric geysers or water heating. The geyser consists of a how-water storage tank and an immersed electrical resistant element.

1. Ответьте на вопросы к тексту. Ответы переведите на русский язык:

1. What is an important component in energy consumption in the residential buildings?
2. Why is hot water consumption and not space heating the largest user of energy in the domestic sector in South Africa?
3. What are the main materials used for walls and roof constructions?
4. Why are solar water-heating systems not often used for domestic heating?
5. Where is natural gas used for heating in this country?
6. What is the electric geyser?

Контрольная работа N 3

Вариант 4

I. Определите время и залог глагола-сказуемого и переведите предложения на русский язык

There has been a steady and significant improvement in water quality.

A new international research programme is being carried out for safely dispersion of wastes of higher radioactivity.

Calculations done by these scientists were correct.

Air filters will be located in the centre and they will remove dust from the air.

II. Переведите предложения, обращая внимание на разные функции слов it”, “that”, “one”

The other problem, that of land subsidence can be controlled.

There is one apparent drawback to a tidal-power station – its intermittent operation.

3. The big advantage of a tidal-power station is that it will never lack water for its operation because of (из-за) drought or fuel shortage.

Among the negative factors that result in disfunction of ecological systems are the air and water pollution.

III. Переведите предложения, обращая внимание на разные функции глаголов “to be”, “to have”

Average concentration of smoke in the air has fallen by 80 per cent for the last 30 years.

Smog kills hundreds of people and is the cause of serious illnesses for many thousands peoples.

The cocks are used when the system is being filled with water.

Sanitary fitting are those appliances which have to be used in the collection and disposal of human and domestic waste materials.

IV. Переведите предложения, обращая внимание на функции Ving форм и инфинитива

1. The evaporator (испаритель) consists of cooling coils made of copper with aluminium fins(радиаторная пластина). They are designed to absorb the maximum amount of heat.

The air filters are acted as filters removing dust from the air.

It is a good idea to turn rubbish into energy by burning it.

To avoid stiffness, the air should be given a certain amount of motion.

V. Прочитайте текст и выполните упражнение после текста.

WATER FROM THE OCEANS

Every day the world shortage of fresh water increases. No matter how many dams are built or wells drilled or rivers tapped, all our efforts do not provide enough of this essential raw material. This shortage has led scientists to study the possibilities of using sea water.

The oceans contain many salts that make sea water unfit for drinking, agriculture, and industry. When the sun evap­orates water from the sea, it leaves these salts behind. The pure water vapour condenses to form clouds and returns to the earth as rain. And so the problem of making sea water usable is simply this: how can we imitate the purifying pro­cess of nature? Ocean-going ships have been solving that problem for about half a century: using the heat of their engines, they boil sea water and condense the steam from it. Even though the cost of this process is around $ 8 per 1000 gal­lons, ship-owners find that it pays, because the space once occupied by fresh-water tanks can be used for freight.

On land, however, such a cost would be too high. What is needed is a technological breakthrough that would bring the cost down to, say, 50 cents per 1000 gallons. With the efforts now being expended on research in the United States and Europe, there is every likelihood of achieving success within a few years. If we want to boil water, the right way to do so is under reduced pressure, for this lowers the boiling point and so reduces the amount of heating required. (This is the reverse of the pressure-cooker principle, where the boiling point of water is raised by increasing the pressure.) Water-purifying plants work on this principle. Their main use is to convert undrinkably salty water (about 35,000 parts of salt per million parts of water) into fresh water.

There is another technique that may soon prove an econom­ic way to purify waters whose salt content is much lower— say, 10 parts per million, or about a tea-spoon to 10 gallons. This technique relies on the fact that all dissolved salts tend to break down into positively and negatively charged atoms or groups 'of atoms called ions. When we pass an electric current through the water, the positive ions migrate to the negative electrode, and vice versa. The water, being electrical­ly neutral, passes through undisturbed and emerges purified of its salts.