Heat pump – тепловой насос, обратная тепловая машина 


Мы поможем в написании ваших работ!



ЗНАЕТЕ ЛИ ВЫ?

Heat pump – тепловой насос, обратная тепловая машина



heat source – тепловой источник

heat sink – теплоотвод

reversible-cycle – обратимый цикл

chiller – охладитель

cryocooler – криогенный охладитель

to achieve – достигать

to apply – использовать, употреблять

to extract - вытаскивать, извлекать; fraction – доля, часть

to require – нуждаться (в чём-л.); требовать (чего-л.)

properties – свойства

state – состояние

a heat exchanger – теплообменник

a device – устройство, прибор

capillary tube – волосная трубка, капиллярная трубка

 

essential – важнейший; необходимый; основной

to prevent – предотвращать, предупреждать

energy efficiency – кпд по энергии, энергетический кпд, выход по энергии, энергетический выход)

unit of input – единица затрат

HVAC – отопление, вентиляция и кондиционирование воздуха

to include – включать в себя, содержать в себе

a reversing valve – реверсивный клапан, реверсивный гидро- или пневмораспределитель

to optimized – оптимизировать

to switch – переключать

to deliver – доставлять

to swap – менять, обменивать

mode – способ

 


V. Find the Russian equivalents for the English ones:

temperature difference, working fluid, a ground-source heat pump, reversible-cycle heat pump, temperature differential, the discharge side of the compressor, to preheat, thermal comfort, input energy, a pressure-lowering device, to operate in reverse, a work-extracting device

 

VI. Find the English equivalents for the Russian ones:

Отопительная система, газообразное состояние, реверсивный клапан, водяной охладитель, реверсивный тепловой насос, регулирующий вентиль, нагреватель воды, физические свойства, отвод теплоты, теплопоглощение, конденсат, перепад давлений

 

VII. Translate the following sentences into Russian:

 

1. Most heat pump technology moves heat from a low temperature heat source to a higher temperature heat sink.

2. Heat pumps can essentially be thought of as heat engines operating in reverse.

3. A heat pump requires work to move thermal energy from a cold source to a warmer heat sink.

4. For the heat pump the amount of energy deposited at the hot side is greater than the energy taken from the cold side by an amount equal to the work required.

5. On the discharge side of the compressor, the now hot and highly pressurized gas is cooled in a heat exchanger.

6. The expansion valve passes the low pressure, barely liquid refrigerant to another heat exchanger.

7. The pressure difference must be great enough for the fluid to condense at the hot side and still evaporate in the lower pressure region at the cold side.

8. The reversing valve switches the direction of refrigerant through the cycle and therefore the heat pump may deliver either heating or cooling to a building.

9. The efficiency of a reversible heat pump is typically slightly less than two separately-optimized machines.

10. Both the heat extraction and addition capabilities of a single heat pump can be useful, and typically results in very effective use of the input energy.

 

VIII. Fill in the blanks with appropriate words:

 

1. A heat pump uses … to move heat.

2. A heat engine allows energy to flow from a hot … to a cold heat ….

3. The working fluid is … through the system by a ….

4. In the … the hot highly pressurized gas condenses into a high pressure, moderate temperature ….

5. In the evaporator the refrigerant … into a gas via ….

6. The energy efficiency decreases with increasing … difference.

7. A ground-source heat pump has a very small ….

8. The reversing … switches the direction of … through the cycle.

9. A heat pump is sometimes used to … water for swimming pools.

10. A heat pump normally refers to … device.

 

IX. Translate into English, using the active vocabulary:

 

1. Тепловой насос – это устройство, которое перемещает теплоту из одного положение в другое.

2. Теплота не может самопроизвольно переходить из холодного места в более горячее в соответствии со вторым законом термодинамики.

3. Тепловой насос работает, используя физические свойства конденсата.

4. Рабочая жидкость в газообразном состоянии циркулирует в системе при промощи компрессора.

5. После конденсора охладитель проходит через регулирующий клапан или капиллярную трубку.

6. Чем больше перепад температуры, тем больше перепад давлений.

7. Энергитический выход уменьшается с увеличением перепада температур.

8. Реверсивный клапан может изменить направление теплового потока.

9. Эффективность реверсивного теплового насоса достаточно небольшая.

10. Тепловой насос можно использовать для нагревания воды.

 

X. Answer the questions:

 

1. What is a heat pump?

2. What devices use a heat pump?

3. What physical law is the heat pump work based?

4. What is the difference between a heat engine and a heat pump?

5. What does a heat pump exploit in its work?

6. In what state is the working liquid circulated through the system?

7. What does the refrigerant pass through after the condenser?

8. What kind of refrigerant does an expansion valve pass to the evaporator?

9. What does the energy efficiency depend on?

10. Is a ground-source heat pump efficient?

11. How can the direction of heat flow be reversed?

12. What may the heat pump do using the reversing valve?

13. What is the efficiency of the reversible heat pump?

14. What is the heat pump used in plumbing applications?

 

XI. Skim through the text and say in a few sentences what the message of the text is. Answer the questions which follow.

 

When comparing the performance of heat pumps, it is best to avoid the word "efficiency" which has a very specific thermodynamic definition. The term coefficient of performance[6] (COP) is used to describe the ratio of useful heat movement to work input. Most vapor-compression heat pumps utilize electrically powered motors for their work input. However, in most vehicle applications shaft work, via their internal combustion engines[7], provide the needed work.

In cooling mode a heat pump's operating performance is described as its energy efficiency ratio[8] (EER) or seasonal energy efficiency ratio (SEER), and both measures have units of BTU/(h·W). A larger EER number indicates better performance. The manufacturer's literature should provide both a COP to describe performance in heating mode and an EER or SEER to describe performance in cooling mode. Actual performance varies, however, and depends on many factors such as installation, temperature differences, site elevation, and maintenance.

Heat pumps are more effective for heating than for cooling if the temperature difference is held equal. This is because the compressor's input energy is largely converted to useful heat when in heating mode, and is discharged along with the moved heat via the condenser. But for cooling, the condenser is normally outdoors, and the compressor's dissipated work is rejected rather than put to a useful purpose.

For the same reason, opening a food refrigerator or freezer heats up the kitchen rather than cooling it because its refrigeration cycle rejects heat to the indoor air. This heat includes the compressor's dissipated work as well as the heat removed from the inside of the appliance.

* * *

1. What does the term coefficient of performance mean?

2. What does a vapor-compression heat pump utilize for its work input?

3. What is EER? What unit does it have?

4. What does a COP / an EER or SEER describe?

5. What factors does actual performance depend on?

6. What is a heat pump more effective for heating or cooling? Why?

 

XII. Scan the text for details. Tell about the difference between air-sourced and ground-sourced heat pump. Ask some questions to your partner.

 

Heat pumps can be air-sourced or ground-sourced (geothermal heating).

The technologies are developing rapidly: COPs (coefficient of performance) have risen from COP=3 to COP=4 or even COP=5 over the last five years. Heat pumps are now becoming popular choices for home-heating as well as for cooling — especially in areas with less severe winters.

Those buying air-source heat pumps should look closely at its COP, the outside temperature range in which that COP is effective, the cost of installation, how much heat it can move, and how much noise it generates.

Air-source heat pumps do not work well when temperatures fall below around −5°C (23°F).

Ground-source heat pumps typically have higher COPs than air-coupled heat pumps, because they draw heat from ground or groundwater, and this is at a relatively constant temperature all year-round below a depth of about eight feet (2.5 m). The tradeoff for this improved performance is that a ground-coupled heat pump is usually more complicated due to the need for wells or buried coils, and thus is also usually much more expensive to install than an air-coupled heat pump.

 

XI. Tell about the heat pump.

 

UNIT 9

 

I. Read and translate the text:

 

History of air conditioning

While moving heat via machinery to provide air conditioning is a relatively modern invention, the cooling of buildings is not. The ancient Romans were known to circulate aqueduct water through the walls of certain houses to cool them. As this sort of water usage was expensive, generally only the wealthy could afford such a luxury.

Medieval Persia had buildings that used cisterns and wind towers to cool buildings during the hot season: cisterns (large open pools in a central courtyards, not underground tanks) collected rain water; wind towers had windows that could catch wind and internal vanes to direct the airflow down into the building, usually over the cistern and out through a downwind cooling tower. Cistern water evaporated, cooling the air in the building.

In 1820, British scientist and inventor Michael Faraday discovered that compressing and liquefying ammonia could chill air when the liquefied ammonia was allowed to evaporate. In 1842, Florida physician Dr. John Gorrie used compressor technology to create ice, which he used to cool air for his patients in his hospital in Apalachicola, Florida. He hoped eventually to use his ice-making machine to regulate the temperature of buildings. He even envisioned centralized air conditioning that could cool entire cities. Dr. Gorrie died in 1855 and the idea of air conditioning faded away for 50 years.

Early commercial applications of air conditioning were manufactured to cool air for industrial processing rather than personal comfort. In 1902 the first modern electrical air conditioning was invented by Willis Haviland Carrier. Designed to improve manufacturing process control in a printing plant, his invention controlled not only temperature but also humidity. The low heat and humidity were to help maintain consistent paper dimensions and ink alignment. Later Carrier's technology was applied to increase productivity in the workplace, and The Carrier Air Conditioning Company of America was formed to meet rising demand. Over time air conditioning came to be used to improve comfort in homes and automobiles. Residential sales expanded dramatically in the 1950s.

In 1906, Stuart W. Cramer of Charlotte, North Carolina, USA, was exploring ways to add moisture to the air in his textile mill. Cramer coined the term "air conditioning," using it in a patent claim he filed that year as an analogue to "water conditioning". He combined moisture with ventilation to "condition" and change the air in the factories, controlling the humidity so necessary in textile plants. Willis Carrier adopted the term and incorporated it into the name of his company. This evaporation of water in air, to provide a cooling effect, is now known as evaporative cooling.

The first air conditioners employed toxic or flammable gases like ammonia, methyl chloride, and propane which could result in fatal accidents when they leaked. Thomas Midgley, Jr. created the first chlorofluorocarbon gas, Freon, in 1928. The refrigerant was much safer for humans but was later found to be harmful to the atmosphere's ozone layer. The blend most used in direct-expansion comfort cooling is an HCFC known as R-22. Several non-ozone depleting refrigerants have been developed as alternatives, including R-410A, known by the brand name "Puron".

Innovation in air conditioning technologies continue, with much recent emphasis placed on energy efficiency and for improving indoor air quality. As an alternative to high global warming refrigerants, such as R-134a in cars' and R-22, R-410A in residential air conditioning, natural alternatives like CO2 (R-744) have been proposed.

ACTIVE VOCABULARY

 


aqueduct – акведук, водопровод

cistern – цистерна, бак; ёмкость, резервуар (для хранения воды)

to envision – представлять себе, предвидеть

to fade away – исчезать

to improve – улучшать; совершенствовать

humidity – влажность, степень влажности

moisture – влага

to condition – кондиционировать помещение

evaporative cooling – охлаждение испарением

to employ – применять, использовать

flammable – огнеопасный; легковоспламеняющийся

to leak – давать течь; подтекать

harmful – вредный, губительный;

blend – смесь

innovation – нововведение, новшество

indoor – комнатный

air quality – качество воздуха

to propose – предлагать

 


 

II. Say whether these sentences are True or False:

1. Ammonia could chill air when the liquefied ammonia was allowed to evaporate.

2. Air conditioning and the cooling of buildings are modern inventions.

3. Ammonia was much safer for humans.

4. Ice-making machine may regulate the temperature of buildings.

5. Cisterns were large open pools in a central courtyards or underground tanks.

6. R-410A is the most used blend in direct-expansion comfort cooling.

7. Carrier’s invention controlled not only temperature but also humidity.

8. Internal vanes of the wind towers directed the airflow down into the building.

9. He combined moisture with ventilation to "condition".

10. "Puron" is the brand name of several non-ozone depleting refrigerants.

 

III. Make up sentences and translate them into Russian.

1. air, gases, the, flammable, first, employed, conditioners.

2. technology, ice, create, was, compressor, to, used.

3. was, the, to, aqueduct, through, houses, water, of, circulated, them, walls, cool.

4. air, the, was, modern, in, invented, first, conditioning, 1902, electrical.

5. collected, rain, the, in, water, cisterns, was.

6. atmosphere's, to, layer, Freon, the, is, ozone, harmful.

7. homes, comfort, to, conditioning, in, improve, came, air.

8. continue, technologies, in, conditioning, air, innovation.

9. the, cooling, cistern, evaporated, air, water.

10. effect, provides, of, in, a, air, evaporation, water, cooling.

 

IV. What do the following numbers refer to?

1928, 744, 1906, 134, 1820, 410, 1842, 22, 1902

 

V. Ask different kinds of questions about heat according to the pattern. Work in pair or group.

 

I group (Yes/No-questions)

Is air condotoining a modern invention?

 



Поделиться:


Последнее изменение этой страницы: 2017-02-09; просмотров: 533; Нарушение авторского права страницы; Мы поможем в написании вашей работы!

infopedia.su Все материалы представленные на сайте исключительно с целью ознакомления читателями и не преследуют коммерческих целей или нарушение авторских прав. Обратная связь - 3.88.16.192 (0.047 с.)