Закончите следующие предложения, которые описывают, как работает система горячего водоснабжения на низком давлении.

1. Water in the boiler is heated with the result that …
2. … is caused by the dense cold water sinking.
3. As a result of … water rises up the primary flow and is replaced by water descending the primary return.
4. …. thereby continuing the process of convection.
5. The pressure at a draw-off point is due to …
6. Hot water has a lower density than cold water. Consequently …
7. The formation of air locks in the system is prevented by …
8. The operation of the safety valve results in …
9. …. The system will drain

Контрольная работа 4

Вариант 4

I. Переведите предложения, обращая внимание на инфинитивные конструкции.

If a pipe leaving the top of the boiler allowed to circulate around the room and return to the bottom of the boiler, a rapid circulation would be evident.

A tall building is known to be relatively less expensive than a low building.

Green plants are considered to be very important, because they clean the air, reduce its contamination and so improve living conditions.

Because of the smog hanging over many large cities sunrise appears to come half an hour later than usual.

II. Переведите предложения, обращая внимание на зависимый и независимый причастные обороты.

The research being easy, the students conduct it themselves.

Water being heated in the boiler consequently becomes less dense than the cold water in the higher parts of the system.

Having been located above the air filters the evaporator was designed to absorb heat from the air.

When designing a heating system for a large building it is usual to ensure sufficient heating.

III. Переведите предложения, обращая внимание на условные предложения.

The fire will not cause much structural damage if the builders use fireproof materials.

If one pipe were connected to the top and the other to the bottom of a boiler, a slow circulation would be found to exist.

3. No circulation would take place provided the boiler connections were on the same level.

IV. Прочитайте тексты и выполните задания после текста.

SOLAR WATER HEATERS

Solar water heaters consist of a solar collector and a well-insulated tank. The function of the collector is to absorb solar radiation during the day and transfer heat to the water. The tank serves to store the water with little temperature loss until it is required. Various types of absorber units are found, but the relatively simple flat-plate collector is most commonly used. The collector normally consists of the following components: an absorber or heat-exchange element, insulation, cover and absorber box.

1. Прочитайте описание следующих частей коллектора и назовите их:

An absorber 2) heat-exchange element 3) insulation, 4)cover 5)absorber box.

a) a thick layer of material with a low U-value коэффициент теплопередачи; коэффициент теплоусвоения) placed behind the unexpected side of the collector plate.

b) A waterproof container made of wood, metal, or plastic

c) Two flat sheets of transparent glass or plastic.

d) A sheet of flat material constructed so that channels are formed through which water can circulate. It is painted black.

А сейчас соотнесите следующие функции с этими частями коллектора

1. to prevent rain from affecting the insulation and to provide a support for the transparent cover.
2. to absorb the maximum amount of radiation and to prevent the minimum amount of radiation being re-radiated.
3. to reduce heat losses to the rear to a minimum.
4. to reduce convection and low-temperature radiation heat losses from the absorber surface.

SPACE COOLING

Space cooling can be achieved by use of the heat obtained from the sun directly, to drive an absorption refrigerator. This is essentially the same machine as the domestic gas or paraffin (kerosene) operated refrigerator.

Запишите предложения в правильном порядке, чтобы получилось описание работы холодильного шкафа с абсорбционной холодильной машиной. Полученные предложения переведите на русский язык

1. Heating by solar radiation (or any other means) will expel some of the refrigerant (охладитель; хладагент) from the solution.
2. The warmed refrigerant gas is re-absorbed in the carrier fluid.
3. It operates on the following principles:
4. The liquid refrigerant will then enter the evaporator through a throttle valve
5. (дроссельный клапан), it will rapidly evaporate, cool, and take up heat from
6. the environment.
7. This solution will then be pumped back into the solar heater.
8. The refrigerant (e.g. ammonia) is more soluble in the carrier fluid (e.g. water) at low temperatures.
9. This process is also exothermic, thus the absorber will also reject some heat to the environment.
10. When this high pressure heated gas condenses, it will dissipate heat to its environment.

Контрольная работа 4

Вариант 5

I. Переведите предложения, обращая внимание на инфинитивные конструкции.

The direct hot-water system is considered to be liable to “scaling”.

2. The vent pipe (вытяжная труба) is a pipe which allows air to escape from the system.

The coefficient of thermal conductivity is known to calculate the rate at which a material conducts heat.

Many building codes require brick basement walls to be 4 in. (дюйм) thicker than the walls above.

II. Переведите предложения, обращая внимание на зависимый и независимый причастные обороты.

Hot water having a lower density than cold water, it collects at the top of the storage cylinder.

The material being in deposited in a boiler is a bad conductor.

The highest temperatures in the system occur in the boiler, the largest amount of scale being deposited there.

In some cases the plates may even burn out, causing leaks.

III. Переведите предложения, обращая внимание на условные предложения.

The measurements were always correct if the necessary instruments were used.

Unless the temperature rises the speed of the motion of the molecules will not increase.

If the information had been received in time, we should have used it in our calculations.

 

IV. Прочитайте тексты и выполните задания после текста.

HOT-WATER SYSTEM.

Its Disadvantage

One disadvantage of the direct hot-water system is that it is liable to “scaling”. Scaling is caused by deposits made by hard water when it is heated. Hard water occurs in areas which have soluble salts in the ground. Because the highest temperatures in the system occur in the boiler, the largest amount of scale is deposited there. Since the deposited material is a bad conductor, heat is prevented from passing through the walls to the water and the efficiency of the boiler walls may overheat, and in some cases the plates may even burn out, causing leaks. Because of this, boilers often have removable plates so that the inside can be de-scaled.

1. Соотнесите вопросы и ответы на них. Ответы переведите на русский язык.

1. What is the effect of soluble salts in the ground?
2. What is the cause of scaling?
3. Which factor determines the amount of scaling?
4. What is a property of scale?
5. What are four possible effects resulting from a property of scale?
6. What is the function of removable plates in boilers?

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

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.

Soluble salts in the ground cause hard water.

The temperature of the water

Scale is a bad conductor of heat

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

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

The relation between surface area and volume has many effects on the performance of buildings. For example, the rate at which a building gains or losses heat through its walls depends on its surface area and inversely proportional to volume. Thus, a building with a proportionately large surface area, such as a one room house, will lose or gain heat relatively rapidly. Conversely, a building with a large volume in relation to its surface area, such as a block of flats, will retain more heat.