Урок 2.9

Текст А

Solar heating components

The collector is the most important and one of the most expensive parts of a solar heating system. It must be long-lived and well insulated, yet its cost must be minimized. Collectors of primary interest for space and water heating are of two basic types: liquid and air. Liquids may be water, an antifreeze mixture or various hydrocarbon and silicone heat transfer oils. Air type collectors use air as the collector fluid. The absorber plate is that part of the collector which absorbs the solar energy and converts it to thermal energy. A portion of the thermal energy is carried to the building or thermal storage unit by the fluid which circulates through passages in the absorber plate. The absorber plates can be made of metal, plastic, or rubber compounds. The metals commonly used in order to decrease thermal conductivity are copper, aluminum, and steel. Plastics (polyolefins) and rubbers (ethylene propylene compounds) are relatively inexpensive, but due to their low thermal conductivity and their temperature limitations, they are suitable only for low temperature applications such as heating swimming pool water or for use with water source heat pumps. Other major components of a solar collector include: a) absorber plate coating -to enhance the heat transfer and protect the absorber plate; b) one or more transparent covers - to reduce thermal losses by radiation (using the "greenhouse effect") and by convection (wind, etc.). Spacings are nominally 2 in. or more.

Notes:

heat transfer oil масляный теплоноситель;

hydrocarbon гидрокарбон;

silicone силикон;

polyolefin полиолефин;

ethylene propylene compounds этиленпропиленовые соединения.

Ответьте на опросы к тексту:

1. What is the most important and one of the most expensive parts of a solar heating system?

2. What collectors use air as the collector fluid?

3. Why are plastics and rubbers suitable only for low temperature applications?

4. What low temperature applications do you know?

5. What is the absorber plate? What can it be made of?

6. What metals are commonly used to decrease thermal conductivity?

7. What do other major components of a solar collector include? What for?

Упражнение № 1. Переведите слова и словосочетания на русский язык.

Solar heating component; long-lived (adj.); well insulated, primary interest; space and water heating; basic type; antifreeze mixture; silicone heat transfer oil; air-type collector; absorber plate; convert (v.); thermal conductivity; copper (n.), aluminum (n.); steel (n.); relatively (adv.); inexpensive (adj.); temperature limitation; water source heat pump; include (v.); enhance (v.); protect (v.); transparent cover; thermal loss; radiation (n.) ; greenhouse effect; convection (n.).

Упражнение № 2. Переведите слова и словосочетания на английский язык.

С длительным сроком службы; система солнечного отопления; основные типы; теплопроводность; температурное ограничение; теплопотери; парниковый эффект; прозрачное покрытие; радиация; увеличивать; защищать; включать; превращать, преобразовывать.

Благодаря; или; более; как, в качестве; для; для того, чтобы; но; только.

Упражнение № 3. Сопоставьте слово А с его определением В.

А

1. green house effect;

2. thermal conductivity;

3. mixture;

4. transparency;

5. component;

В

1. a part or element of a larger whole, especially a part of a machine or vehicle;

2. a combination of substances that are put together;

3. the rate at which heat passes through a specified material, expressed as the amount of heat that flows per unit time through a unit area with a temperature gradient(перепад температуры) of one degree per unit distance;

4. the gradual warming of the air surrounding the Earth as a result of heat being trapped by pollution;

5. transmitting heat or other electromagnetic rays without distortion.

Упражнение №4. Переведите следующие предложения, обращая внимание на независимый причастный оборот без причастия.

1. With the heat transfer surface low, a fluid flowing through a heat exchanger can actually freeze at the surfaces.

2. Steam pressure high, fire tube boilers need large diameter shell.

3. With fluid velocities low, designer can maintain the pressure drop limitations.

4. Thermal conductivity low, collectors are suitable only for low temperature applications.

5. The online maintenance preferable, all kinds of online cleaning methods were developed.

6. Weather cold, collectors perform poorly.

Упражнение №5. Проанализируйте подчеркнутое в тексте предложение: выделите в нем подлежащее, сказуемое и второстепенные члены и укажите часть речи, которой являются эти члены предложения.

Упражнение №6. Задайте три вопроса к подлежащему или его определению, три альтернативных и три разделительных вопроса к тексту А.

Упражнение №7. Переведите следующие предложения и определите функции глаголов to be; to have.

1. A fouled heat changer has to be cleaned once in a while.

2. Before beginning each work activity involving where a new work crew or subcontractor is to perform the work, the contractor(s) shall prepare an activity hazard analysis.

3. The clear liquid doesn’t have colour and smell.

4. Peek temperatures may occur when fuel and air are not properly mixed.

5. When materials are exposed to cyclic loadings while operating at temperatures within their creep range, the creep reduces their fatigue life.

6. Mechanical properties such as ductility and toughness are required to be considered for boiler construction.

7. Every two years the boiler also has to be inspected and certificated.

8. Work will not begin until the activity hazard analisys for the work activity has been accepted by the Government Designated Authority.

9. Depending on their construction boilers can be divided into: fire tube boilers, water tube boilers.

10. The water they provide is heated from temperatures of 120ºC up to 180ºC, which means the water will have pressures up to 10 bars.

Текст B

Types of solar heat collectors

Major components of a solar collector include: c) insulation - one to three inches are used to reduce heat loss through the side and back of the absorber plate; d) collector box - to provide a rigid mounting to hold the components must be weatherproofed; e) gaskets and seals - to insure a weathertight seal between components while allowing thermal expansion of the components. Normally these seals remain ductile to accomplish their purpose.

Flat plate collectors are most suitable for low temperature applications such as domestic hot water and space heating. They collect both direct and diffuse radiation. It is not required that they track the sun thus initial cost and maintenance are minimized. A properly designed flat plate collector has a life expectancy of 10 to 25 years or sometimes longer. All copper and glass systems currently exhibit the longest lives. Using softened water will help. Tubes should be 1/2 inch in diameter or greater for low pressure drop and longer life. The better the attachment of tube-to-plate (such as by soldering) the better the heat transfer but the greater the manufacturing cost. Advances in collector cost reduction will probably be made in the direction of cheaper manufacturing processes. Some collectors not made from tube and sheet may not tolerate domestic hot water (DHW) line pressures.

Notes:

line pressures линейное давление

Ответьте на вопросы к тексту:

1. What collectors are most suitable for low temperature applications?

2. What kind of radiation do flat-plate collectors collect?

3. What does life expectancy have a properly designed flat-plate collector?

4. In what case is the heat transfer better?

5. What dimensions should tubes be in diameter for low pressure drop and longer life?

Упражнение №1. Переведите слова и словосочетания на русский язык.

Insulation (v.); absorber plate; collector box; provide (v.); rigid mounting; weatherproofed (adj.); gasket (n.); seal (n.); insure (v.); weathertight (adj.); thermal expansion; remain (v.); ductile (adj.); accomplish (v.); purpose (n.); flat-plate collector; domestic (adj.); diffuse radiation; initial (adj.); maintenance (n.); properly (adv.); life expectancy; softened water; attachment (n.); manufacturing process; sheet (n.); line pressure.

Through; both; all; and; in; but; thus; while.

Упражнение №2. Переведите слова и словосочетания на английский язык.

Плоский коллектор; потеря тепла; производственный процесс; падение давления; прикрепление; стойки против атмосферных воздействий; термальное расширение; эластичный, податливый; совершить, достигнуть; прокладка, уплотнитель; изоляция, защищенный от непогоды; пластинчатый солнечный коллектор, линейное давление; срок службы; смягченная вода.

Упражнение №3. Найдите перевод слов списка А в списке В.

А	В	А	В
component	обслуживание	suitable	выдерживать
collector	подходящий	application	достигать
maintenance	размеры	attachment	компонент
tolerate	коллектор	domestic	пластина
sheet	применение	dimensions	прикрепление
accomplish	расширение	expansion	домашний
include	требовать	initial	обеспечивать
remain	дешевый	softened	медь
provide	смягченный	insure	требовать
copper	гарантировать	cheap	начальный
ductile	ковкий	require	оставаться

Упражнение №4. Задайте 5 вопросов различных типов к тексту В.

Упражнение №5. Найдите в тексте примеры употребления слов one и that. Обратите внимание на их перевод.

Упражнение №6. Найдите в тексте предложение с оборотом the….. the. Переведите его на русский язык.