A. natural B. executed C. technology
D. subdiscipline E. interrelated F. vehicular
G. industrial H. estimate I. specify
J. fabricate K. air L. replacing
1. HVAC (heating, ventilating and air conditioning) is the …… of indoor and vehicular environmental comfort.
2. The invention of the components of HVAC systems went hand-in-hand with the …… revolution.
3. HVAC system design is a …… of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer.
4. Ventilating is the process of "changing" or …… air in any space to provide high indoor air quality.
5. Methods for ventilating a building may be divided into mechanical / forced and …… types.
6. The three central functions of heating, ventilating, and air-conditioning are …….
7. The means of air delivery and removal from spaces is known as room …… distribution.
8. HVAC is …… in individual buildings or other enclosed spaces.
9. For very small buildings, contractors normally …… the capacity, engineer, and select HVAC systems and equipment.
10. Specialty mechanical contractors …… and commission the systems.
.
UNIT 27 Heating
Read, translate the following text and be ready to fulfil the tests:
Heaters are appliances whose purpose is to generate heat (warmth) for the building. This can be done via central heating. Such a system contains a boiler, furnace, or heat pump to heat water, steam, or air in a central location such as a furnace room in a home, or a mechanical room in a large building. The heat can be transferred by convection, conduction, or radiation.
Central heating unit. Heaters exist for various types of fuel, including solid fuels, liquids, and gases. Another type of heat source is electricity, typically heating ribbons made of high resistance wire. This principle is also used for baseboard heaters and portable heaters. Electrical heaters are often used as backup or supplemental heat for heat pump systems. The heat pump gained popularity in the 1950s. Heat pumps can extract heat from various sources, such as environmental air, exhaust air from a building, or from the ground. Initially, heat pump HVAC systems were used in moderate climates, but with improvements in low temperature operation and reduced loads due to more efficient homes, they are increasing in popularity in other climates.
Water / steam. In the case of heated water or steam, piping is used to transport the heat to the rooms. Most modern hot water boiler heating systems have a circulator, which is a pump, to move hot water through the distribution system (as opposed to older gravity-fed systems). The heat can be transferred to the surrounding air using radiators, hot water coils (hydro-air), or other heat exchangers. The radiators may be mounted on walls or installed within the floor to give floor heat. The use of water as the heat transfer medium is known as hydronics. The heated water can also supply an auxiliary heat exchanger to supply hot water for bathing and washing.
Warm air systems distribute heated air through ductwork systems of supply and return air through metal or fiberglass ducts. Many systems use the same ducts to distribute air cooled by an evaporator coil for air conditioning. The air supply is typically filtered through air cleaners to remove dust and pollen particles.
Dangers. The use of furnaces, space heaters, and boilers as means of indoor heating may result in incomplete combustion and the emission of carbon monoxide, nitrogen oxides, formaldehyde, volatile organic compounds, and other combustion byproducts. Incomplete combustion occurs when there is insufficient oxygen; the inputs are fuels containing various contaminants and the outputs are harmful byproducts, most dangerously carbon monoxide, which is a tasteless and odorless gas with serious adverse health effects. Without proper ventilation, carbon monoxide can be lethal at concentrations of 1000 ppm (0.1%). However, at several hundred ppm, carbon monoxide exposure induces headaches, fatigue, nausea, and vomiting. Carbon monoxide binds with hemoglobin in the blood, forming carboxy hemoglobin, reducing the blood's ability to transport oxygen. The primary health concerns associated with carbon monoxide exposure are its cardiovascular and neurobehavioral effects. Carbon monoxide can cause atherosclerosis (the hardening of arteries) and can also trigger heart attacks. Neurologically, carbon monoxide exposure reduces hand to eye coordination, vigilance, and continuous performance.
Read and memorize the active vocabulary to the text:
Active Vocabulary
1. heater отопительный агрегат; отопительный прибор
2. conduction теплоперенос
3. baseboard опора, опорная поверхность
4. backup вспомогательный, резервный
5. moderate умеренный
6. gravity-fed самотечный
7. surrounding близлежащий, соседний; окружающий
8. coil змеевик
9. to mount устанавливать; монтировать;
10. hydronics гидроника (применение жидкостей для охлаждения и нагрева)
11. auxiliary вспомогательный, добавочный, запасной
12. exchanger теплообменник
13. ductwork system система воздуховодов для распределения и удаления воздуха
14. fiberglass стекловолокно
15. evaporator испаритель
16. pollen particles частицы пыльцы
17. combustion горение, сгорание, сжигание
18. volatile organic compounds летучие органические соединения
19. byproduct побочный продукт
20. contaminant загрязнитель, загрязняющее вещество; отравляющее или заражающее вещество
21. adverse неблагоприятный
22. exposure воздействие
CONTROL TESTS
TEST I
Decide whether these statements are true or false:
1. a). Heaters are appliances which start their cycle in a gaseous state.
b). Heaters are appliances whose purpose is to generate heat (warmth) for the building.
c). Heaters are appliances which can use very little energy.
2. a). Heaters exist for various types of fuel, including solid fuels, liquids, and gases.
b). Heaters exist as systems including a reversing valve that switches from heating in winter to cooling in summer.
c). Heaters exist as systems controlled by a humidistat or de-humidistat.
3. a). Warm air systems distribute heated air through ductwork systems of supply and return air.
b). Warm air systems can extract heat from various sources.
c). Warm air systems can produce carbon monoxide with lethal concentrations.
4. a). The air supply is typically filtered through air cleaners to remove dust and pollen particles.
b). The air supply is typically provided by an air handler.
c). The air supply typically provides cooling and humidity control for all or part of a building.
5. a). Most modern hot water boiler heating systems remove excess moisture from ventilation air.
b). Most modern hot water boiler heating systems can usually be manipulated by adjusting the opening of the vent.
c). Most modern hot water boiler heating systems have a circulator.
TEST II
Match words in columns A and B (synonym match):
A B
1. appliance a). equilibrium b). device
c). gravitation d). stress
2. transfer a). limit b). manner
c). transmission d). technique
3. distribution a). dissemination b). assessment
c). tension d). shear
4. to supply a). to deliver b). to oppose
c). to prevent d). to optimize
5. auxiliary a). compressive b). dense
c). hyperstatic d). subsidiary
6. dangerously a). rapidly b). riskily
c). accidentally d). especially
7. output a). capacity b). resistance
c). enclosure d). substrate
8. harmful a). grout b). translucent
c). transparent d). detrimental
9. adverse a). identical b). unfavourable
c). prevalent d). adhesive
10. to remove a). to perforate b). to laminate
c). to eliminate d). to support
TEST III
Select the best possible answer out of the choices from the list to the statements (multiple choice):
1. The heat can be transferred by …
a. direct drive fans.
b. convection, conduction, or radiation.
c. trickle vents.
2. Heat pumps can extract heat from various sources, such as …
a. furnaces and geothermal energy.
b. space heaters and boilers.
c. environmental air, exhaust air from a building, or from the ground.
3. Incomplete combustion occurs …
a. without proper ventilation.
b. when there is insufficient oxygen.
c. when the air supply is not filtered through air cleaners.
4. The heated water can …
a. supply an auxiliary heat exchanger to supply hot water for bathing and washing.
b. circulate through the supply and return ducting.
c. have antibacterial / ultraviolet treatment against the growth of bacteria/organisms in the water storage tray.
5. Electrical heaters are often used …
a. as backup or supplemental heat for heat pump systems.
b. with fans, ducts, dampers, and control systems.
c. with an evaporator / condenser supplying the hot medium.
TEST IV
