Урок 3.8

Упражнение 1. Прочитайте слова.

[µ] one; ton, function; pump, bulb; other; result; comfort; just.

Упражнение 2. Сопоставьте слово с переводом и соответствующей ему транскрипцией.

1) quantity; 2) equal; 3) equivalent; 4) duty; 5) magnitude; 6) to cause;

1) ['Å∙ÑÍIË(j)u:Ì]; 2) ['Ìju:ti]; 3) ['i:ÐÆqÎ]; 4) [I'ÐÆiÈ(q)ÎqnË]; 5) ['ÐƸÍËqËI]; 6) ['и:Ê];

1) эквивалент (равный по величине); 2) величина; 3) вызывать; 4) количество; 5) равный; 6) производительность (зд.).

Текст А

Cooling towers

A cooling tower (Figure 3.17) is a heat rejection device, installed outside of the building envelope, through which condenser water is circulated. Refrigerant in the refrigeration cycle is condensed in a refrigerant to water heat exchanger. Heat rejected from the refrigerant increases the temperature of the condenser water, which must be cooled to permit the cycle to continue. The condenser water is circulated to the cooling tower where evaporative cooling causes heat to be removed from the water and added to the outside air. The cooled condenser water is then piped back to the condenser of the chiller. A cooling tower is a latent heat exchanger, where the magnitude of heat flow is a function of the quantity of water that is evaporated which is primarily a function of the relative humidity of the outside air. Cooling Towers for HVAC duty are usually described by their tons of cooling capacity. The cooling capacity indicates the rate at which the cooling tower can transfer heat. One ton of cooling is equal to 12,000 BTUs (British thermal units) per hour, or 200 BTUs per minute. The heat rejected from an air conditioning system equals about 1.25 times the net refrigeration effect. Therefore the equivalent ton on the cooling tower side actually rejects about 15,000 Btu/hour (12,000 Btu cooling load plus 3,000 Btu’s per ton for work of compression). Cooling tower capacities at commercial, industrial, or institutional facilities typically range from as little as 50 tons to as much as 1,000 tons or more. Large facilities may be equipped with several large cooling towers.

Figure 3.17 Cooling tower.

Ответьте на вопросы к тексту:

1. What is cooling tower?

2. How does it work?

3. What is the magnitude of heat flow?

4. How are HVAC duty usually described?

5. What does the cooling capacity indicate?

6. How do the cooling tower capacities at commercial, industrial, or institutional facilities typically range?

Упражнение 3. Переведите слова и словосочетания на русский язык.

Heat rejection device; install (v.); outside (adv.); building envelope; refrigeration cycle; reject (v.); permit (v.); evaporative cooling; cooling tower; latent heat exchanger; relative humidity; cooling capacity; equal (adj.); equivalent (n.); net refrigeration effect; ton (n.); facility (n.); typically (adv.); range (v.); equipped with.

Through; which; therefore.

Упражнение 4.Переведите слова и словосочетания на английский язык.

Охлаждающая башня; отвергать, отводить; относительная влажность; охлаждающая вода в конденсаторе; варьироваться, изменяться в пределах; указывать, показывать; охлаждающая способность, производительность холодильной установки; расход холода (тепловая нагрузка); производительность системы ОВиК (Отопление, Вентиляция и Кондиционирование).

Упражнение 5. Сопоставьте слово (A) с его определением (B).

(А)

1. to permit;

2. cooling capacity;

3. to indicate;

4. cooling tower;

5. to reject;

6. to pipe;

7. to range;

(В)

1. to send a liquid or gas through a pipe to another place;

2. is the measure of a cooling system's ability to remove heat;

3. to point out, show;

4. a tall, open-topped, cylindrical concrete tower, used for cooling water or condensing steam from an industrial process;

5. to dismiss as inadequate, unacceptable, or faulty;

6. to allow (someone) to do something;

7. to vary or extend between specified limits.

Упражнение 6. Переведите письменно термины и дефиниции, используемые в производстве охлаждающих башен (градирни), используйте словарь при необходимости.

1. BTU (British thermal unit) - BTU is the heat energy required to raise the temperature of one pound of water one degree Fahrenheit in the range from 32°F to 212°F.

2. Cooling Range - The difference in temperature between the hot water entering the tower and the cold water leaving the tower is the cooling range.

3. Approach - The difference between the temperature of the cold water leaving the tower and the wet-bulb temperature of the air is known as the approach.

Establishment of the approach fixes the operating temperature of the tower and is the most important parameter in determining both tower size and cost.

4. Drift - Water droplets that are carried out of the cooling tower with the exhaust air. Drift loss does not include water lost by evaporation. Proper tower design can minimize drift loss. The drift rate is typically reduced by employing baffle-like devices, called drift eliminators, through which the air must travel after leaving the fill and spray zones of the tower.

5. Heat Load - The amount of heat to be removed from the circulating water within the tower. Heat load is equal to water circulation rate (gpm) times the cooling range times 500 and is expressed in BTU/hr. Heat load is also an important parameter in determining tower size and cost.

6. Ton - An evaporative cooling ton is 15,000 BTU's per hour. The refrigeration ton is 12,000 BTU’s per hour.

7. Wet Bulb Temperature (WBT) - The lowest temperature that water theoretically can reach by evaporation. Wet-Bulb temperature is an extremely important parameter in tower selection and design, and should be measured by a psychrometer.

8. Dry-Bulb Temperature - The temperature of the entering or ambient air adjacent to the cooling tower as measured with a dry-bulb thermometer.

9. Pumping Head - The pressure required to pump the water from the tower basin through the entire system and return to the top of the tower.

10. Makeup - The amount of water required to replace normal losses caused by bleed off, drift and evaporation.

11. Bleed off - The portion of the circulating water flow that is removed in order to maintain the amount of dissolved solids and other impurities at an acceptable level. As a result of evaporation, dissolved solids concentration will continually increase unless reduced by bleed off.

Упражнение 7. Переведите предложения, обращая внимание на условные придаточные предложения. Определите тип предложений.

1. If the temperature in the boiler rose to dangerous values, in that case the pipes of the boiler could melt down.

2. It will be very harmful for the boiler if it contains too little water.

3. If peek temperatures occur during combustion, NOx will be formed.

4. The air is cooler and drier if there is an air conditioning system in the room.

5. If unrealistically low allowable pressure drops were imposed, the designer would be forced to use lower fluid velocities to maintain the pressure drops limitations.

6. If the air is cooled directly by passing it over an evaporator, the process is known as direct expansion.

7. If customers did not understand HVAC design aspects, the engineer would guide and advise the customer on the best option.

8. If comfort is to be provided for occupants, a zone requires separate control.

9. If the longest duct run had been less than 200 feet from the heat source, furnaces would have provided effective heating in smaller buildings.

10. In general local heating system is a plus if majority of areas remain unoccupied and if the people preferences require different temperatures or they disagree about the most comfortable temperature.

Упражнение 8. Переведите предложения, обращая внимание на функцию герундия.

1. Evaporative cooling causes heat.

2. The field of heating and ventilation is a science and practice to provide health and comfortable interior conditions for occupants.

3. Sometimes the air is cooled directly by passing it over an evaporator.

4. The control of cooling, heating, and moisture provide the foundation for key HVAC system design and components.

5. Humidifier is a device for keeping the atmosphere in a room moist.

6. This unit works by moving heat from one area to another.

7. Employers and supervisors are responsible for reporting all injuries to the government authority.

8. An air solar system does not suffer from corrosion or freezing.

9. Deformation is the action or process of changing in shape or distorting, especially through the application of pressure.

10. Absorptance of solar radiation by the collector can be increased by using glass that has low iron content.

11. The drift rate is typically reduced by employing baffle-like devices.

12. Comfort cooling is almost always accomplished by cooling air and then distributing the air into the space.

13. This unit works by moving existing heat from one area to another.

Упражнение 9. Переведите предложения, обращая внимание на формы с суффиксом –ing.

1. Glass is a transparent solid substance used for making windows, bottles etc.

2. All kinds of online cleaning methods were developed.

3. Electroplated black nickel, black chrome, copper oxide or anodized aluminum are common types of selective coatings.

4. The contractor is responsible for obtaining appropriate medical and emergency assistance.

5. Local systems may be totally shut off in the unused spaces providing potential energy savings.

6. The burning of fuel takes place inside an enclosed metal container.

7. Furnaces provide effective heating in smaller buildings.

8. The ventilating of a kitchen uses ductwork and fans with a hood.

9. The exhaust gases including carbon-mono-oxide are vented to the exterior of the building.

10. All these surroundings have a uniform compjsition.

Упражнение 10. Задайте 5 различных типов вопросов к тексту А.

Текст В