Pregunta 1
Pregunta
Conventional gas- and oil-fired boilers are currently used in the vast majority of residential and light commercial hydronic systems in North America.
Pregunta 2
Pregunta
The cast-iron sectional boiler is currently one of the most common boilers used in residential and light commercial buildings in North America.
Pregunta 3
Pregunta
If a cast-iron boiler is significantly oversized and experiences long off-times between firing cycles, much of the heat stored in the boiler's thermal mass can be carried up the flue by air currents passing through the combustion chamber.
Pregunta 4
Pregunta
Many boilers currently used in North America were designed with the intent that flue gases would condense within the boiler.
Pregunta 5
Pregunta
Condensing boilers are designed with large heat exchanger surfaces capable of extracting more heat from the exhaust gases compared to the heat exchangers in conventional boilers.
Pregunta 6
Pregunta
In full storage ETS systems, all energy used during the subsequent on-peak period is purchased and stored during the peak cycle.
Pregunta 7
Pregunta
The term "hydronic heat pump" always refers to a heat pump that delivers heat to a flowing stream of water.
Pregunta 8
Pregunta
The heating capacity of the heat pump drops rapidly with increasing source water temperature.
Pregunta 9
Pregunta
It is not advisable to maintain water flow through the condenser whenever the heat pump is operating.
Pregunta 10
Pregunta
The decision to use a wood-fueled boiler involves a time commitment much more demanding than for conventional heat sources operating on natural gas, propane, fuel oil, or electricity.
Pregunta 11
Pregunta
Most cast-iron sectional boilers are limited to use in __________ hydronic systems.
Respuesta
-
"bare-bones"
-
packaged
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closed-loop
-
distributed
Pregunta 12
Pregunta
The combination of metal and water weight gives cast-iron boilers the ability to absorb a significant amount of heat. Such boilers are said to have a high __________.
Respuesta
-
life cycle
-
thermal mass
-
efficiency factor
-
size
Pregunta 13
Pregunta
One type of boiler design surrounds the combustion chamber with a water-filled heat exchanger. This arrangement is called a __________ boiler.
Respuesta
-
hydraulic
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condensation
-
steam
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wet-base
Pregunta 14
Pregunta
Analysis of combustion processes reveals that significant amounts of heat can be recaptured from the exhaust stream if the water vapor it contains can be _________.
Pregunta 15
Pregunta
Boilers with low thermal mass tend to have __________ cycle efficiencies due to lesser amounts of heat remaining in the boiler following burner shutdown.
Respuesta
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lower
-
unpredictable
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higher
-
dependable
Pregunta 16
Pregunta
A boiler operates at __________ efficiency only when it is being fired continuously under nonvarying conditions.
Respuesta
-
steady-state
-
measurable
-
DOE-certified
-
manufacturer
Pregunta 17
Pregunta
A __________ is a device for converting low-temperature heat into higher temperature heat.
Respuesta
-
thermal converter
-
radiating unit
-
flue gasket
-
heat pump
Pregunta 18
Pregunta
A flow restriction or stoppage in the __________ can lead to rapid formation of ice crystals on the cold heat exchanger surfaces separating the water and refrigerant.
Respuesta
-
storage tank
-
water source
-
evaporator
-
closed-loop
Pregunta 19
Pregunta
In solar anti-freeze based combisystems, the outside heat dump provides a way for the system to shed excess heat. It is activated if the temperature of the thermal storage tank reaches a _________ upper limit.
Respuesta
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manufacturer recommended
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DOE enforced
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user-set
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local fire code
Pregunta 20
Pregunta
It is vital that the solar collectors and all exposed piping in a drain-back system be pitched a minimum of __________ toward the storage tank to allow complete drainage.
Respuesta
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1/4 in./ft.
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1/2 in./ft.
-
1/8 in./ft.
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1/16 in./ft.