UNIT 30 Upgrading Heating, Ventilation

and Air Conditioning (Part II)

Read, translate the following text and be ready to fulfil the tests:

Fabrication of Ducting. The fabrication of HVAC ducting should incorporate energy efficient measures such as turning vanes at 90° bends and smooth transitions between ducting and components of different sizes or sections. Galvanic corrosion between galvanized steel and stainless steel should be prevented by isolating them from each other; this will save on duct / component replacement costs.

Diffusers and Grilles. The supply and extraction of the air to the rooms / offices can be made more efficient by using modern diffusers and grilles and improving airflow control. These ensure that the optimum amount of air is admitted and extracted from the rooms, promoting more uniform room temperatures.

Heating and Cooling Methods to Upgrade HVAC. Hot or cold air is supplied to the building by the fans that draw the air through coils in the air handling unit. Large commercial buildings use hot water as supplied by a furnace to circulate through the coils producing hot air and cold water from chillers being used for the air conditioning. Both these methods have been in use for some time, but modern appliances have seen efficiency rise by 20%, therefore the modern furnaces and chillers should be examined. One of the biggest energy efficiency savings in heating and cooling can be achieved by using a heat pump. In the hot air mode, refrigerant gas is circulated around the coils of the heat pump condenser located in the AHU. When the fans draw the air over the coils. the refrigerant condenses to a liquid, giving up its heat to the air. The fans then discharge the hot air to the building. In the air conditioning mode the system is reversed by a reversing valve; the coils in the AHU act as an evaporator, with liquid refrigerant being circulated through the coils this time. The air is drawn over the coils by the fans, evaporating the refrigerant and converting it back to a gas. This removes the heat from the air before being discharged by the fans to the building.

This system can be made even more efficient by the use of geothermal energy in the form of a geothermal heat pump, which is suitable for large buildings provided there is the ground-space to locate the buried pipe loops. Vertical loops take up less space, but these are more costly to install than their horizontal counterparts. During the winter months, the heat pump uses the heat from the underground loops to evaporate the refrigerant. This heat from the refrigerant gas is transferred to the air that is then used to heat the building. In the summertime the heat pump is used to cool the air by dissipating the heat from the building back into the ground through the geothermal loops. Heat pump components for use in commercial buildings are continuously being upgraded. For instance, modern screw or scroll compressors are much more efficient than the standard reciprocating ones.

Control Systems. Modern HVAC management control systems can also improve the efficiency of the system. The control system constantly monitors the temperatures and pressures of the air at strategic points throughout the HVAC system. Ducting static air pressure monitoring and control are fulfilled through automatic adjustment of circulating fans / dampers, (also detects air leaks).

Electronic Programmable Thermostats. These automatically control pre-set, comfortable temperatures both during working hours, and when building is unoccupied, reducing energy and increasing overall plant efficiency.

Zone sensors. These are sensors for control of air quality and quantity supplied to the different zones or areas of the building, e.g. offices, rest rooms, conference rooms, executive suites, canteens, and cafeterias.

Read and memorize the active vocabulary to the text:

Active Vocabulary

1. fabrication производство, изготовление, монтаж, сборка

2. measure единица измерения, мероприятие, мера

3. to prevent предотвращать, препятствовать, предупреждать

4. replacement замена, замещение

5. supply подача; подвод; питание |

6. to ensure обеспечивать; гарантировать

7. to admit допускать, поступать

8. furnace котёл (центрального парового отопления)

9. appliance прибор; приспособление; устройство

10. mode режим (работы)

11. condenser конденсационный аппарат, испаритель

12. AHU air handling unit - агрегатная вентиляционная или воздухоприготовительная установка

13.to discharge подавать; нагнетать (жидкость или газ)

14. to convert превращать, переводить (из одного состояния в другое)

15. counterpart копия, дубликат, аналог, эквивалент

16. dissipating рассеивание

17. scroll спиральный

18. reciprocating возвратно-поступательный

19. leak утечка

20. pre-set заданный, заранее установленный

21. unoccupied пустой, свободный (о территории, жилье и т. п.)

22. executive suites комплекс административных помещений

CONTROL TESTS

TEST I

Decide whether these statements are true or false:

1. a). The fabrication of HVAC ducting should incorporate air circulating fan electric drive motors.

b). The fabrication of HVAC ducting should incorporate energy efficient measures.

c). The fabrication of HVAC ducting should incorporate electronic programmable thermostats.

2. a). Galvanic corrosion between galvanized steel and stainless steel should be prevented by constant monitoring of the temperatures and pressures of the air.

b). Galvanic corrosion between galvanized steel and stainless steel should be prevented by duct / component replacements.

c). Galvanic corrosion between galvanized steel and stainless steel should be prevented by isolating them from each other.

3. a). Hot or cold air is supplied to the building by the fans that draw the air through coils in the air handling unit.

b). Hot or cold air is supplied to the building by a heat pump located in the AHU.

c). Hot or cold air is supplied to the building via operable windows, louvers, or trickle vents.

4. a). In the air conditioning mode the system draws the air through heating/cooling coils.

b). In the air conditioning mode the system can be made more efficient by using modern diffusers and grilles.

c). In the air conditioning mode the system is reversed by a reversing valve.

5. a). Heat pump components for use in commercial buildings should be replaced with modern, more efficient units.

b). Heat pump components for use in commercial buildings are continuously being upgraded.

c). Heat pump components for use in commercial buildings are automatically adjustable or fixed, directing the air into the return ducting.

TEST II

Match words in columns A and B (synonym match):

A B

1. fabrication a). foundation b). differentiation

c). operation d). manufacture

2. measure a). arrangement b). length

c). installation d). cladding

3. transition a). prefabrication b). conversion

c). welding d). alignment

4. replacement a). preassembly b). framing

c). substitution d). shaping

5. mode a). standard b). profile

c). position d). regime

6. transfer a). shift b). section

c). result d). accuracy

7. discharge a). barrier b). connection

c). outflow d). formwork

8. to convert a). to weld b). to turn into

c). to brace d). to align

9. to monitor a). to span b). to enable

c). to withstand d). to control

10. adjustment a). regulation b). composition

c). compression d). application

TEST III

Select the best possible answer out of the choices from the list to the statements (multiple choice):

1. Large commercial buildings use hot water …

a. obtained by geothermal energy in the form of a geothermal heat pump.

b. produced by the heat from the underground loops.

c. as supplied by a furnace to circulate through the coils producing hot air and cold water.

2. The optimum amount of air is admitted and extracted from the rooms, …

a. promoting more uniform room temperatures.

b. thus solving health problems of employees working in the environment.

c. conserving the building’s structure: steel, composites, and wood.

3. One of the biggest energy efficiency savings in heating and cooling can be achieved …

a. by using ducting static air pressure monitoring.

b. by using a heat pump.

c. by using zone sensors.

4. The supply and extraction of the air to the rooms / offices can be made more efficient …

a. by utilizing suction and discharge filters.

b. by employing electric motors.

c. by using modern diffusers and grilles.

5. Zone sensors are sensors for control of …

a. air quality and quantity supplied to the different zones or areas of the building.

b.temperatures and pressures of the air at strategic points throughout the HVAC system.

c. galvanic corrosion between galvanized steel and stainless steel.

TEST IV