Deck 3: Hydronic Heat Sources

Question 1

A boiler operates at _____ efficiency only when it is being fired continuously under nonvarying conditions.

A) steady-state
B) measurable
C) DOE-certified
D) manufacturer

Answer 1

A

Question 2

A ____ is a device for converting low-temperature heat into higher temperature heat.

A) thermal converter
B) radiating unit
C) flue gasket
D) heat pump

Answer 2

D

Question 3

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.

Answer 3

True

Question 4

It is not advisable to maintain water flow through the condenser whenever the heat pump is operating.

Question 5

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.

A) manufacturer recommended
B) DOE enforced
C) user-set
D) local fire code

Question 6

Most cast-iron sectional boilers are limited to use in ____ hydronic systems.

A) "bare-bones"
B) packaged
C) closed-loop
D) distributed

Question 7

Conventional gas- and oil-fired boilers are currently used in the vast majority of residential and light commercial hydronic systems in North America.

Question 8

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.

A) storage tank
B) water source
C) evaporator
D) closed-loop

Question 9

The heating capacity of the heat pump drops rapidly with increasing source water temperature.

Question 10

One type of boiler design surrounds the combustion chamber with a water-filled heat exchanger.This arrangement is called a ____ boiler.

A) hydraulic
B) condensation
C) steam
D) wet-base

Question 11

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.

A) 1/4 in./ft.
B) 1/2 in./ft.
C) 1/8 in./ft.
D) 1/16 in./ft.

Question 12

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.

Question 13

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 ____.

A) condensed within the boiler
B) expelled from the system
C) replenished regularly
D) minimized

Question 14

Many boilers currently used in North America were designed with the intent that flue gases would condense within the boiler.

Question 15

The cast-iron sectional boiler is currently one of the most common boilers used in residential and light commercial buildings in North America.

Question 16

Boilers with low thermal mass tend to have ____ cycle efficiencies due to lesser amounts of heat remaining in the boiler following burner shutdown.

A) lower
B) unpredictable
C) higher
D) dependable

Question 17

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 ____.

A) life cycle
B) thermal mass
C) efficiency factor
D) size

Question 18

In full storage ETS systems, all energy used during the subsequent on-peak period is purchased and stored during the peak cycle.

Question 19

The term "hydronic heat pump" always refers to a heat pump that delivers heat to a flowing stream of water.

Question 20

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.