hydronic Final Study
One way that heat loss of bare copper tube can be evaluated is when the length of the copper tube in feet divided by the flow rate in gallons per minute exceeds _________ ft./gpm, there will be a greater temperature drop along the tube from inlet to outlet.
20
An increase in pressure from the inlet to outlet port of an operating circulator is the "evidence" that ____ has been added to the fluid. Select one: a. head energy b. more volume c. antifreeze d. thermal dynamics
A
Heat flow from a basement or slab-on-grade foundation is determined by complex interactions between the building, the surrounding soil, insulation materials (if present), and the ____. Select one: a. air temperature above grade b. depth of the foundation c. orientation of the structure d. planned usage of the room
A
Heat is our perception of atomic vibrations within a material. Our means of expressing the intensity of these vibrations is called ____. Select one: a. temperature b. harmonics c. tuning d. cellular reaction
A
In addition to conduction losses, heat is also carried out of buildings by uncontrolled air leakage. This is called ____ heat loss. Select one: a. infiltration b. anti-thermal c. environmental d. insulation
A
Once the____ price of the fuel options has been calculated, a simple multiplication determines the estimated seasonal heating cost in dollars. Select one: a. unit b. advertised c. estimated d. effective
A
The circulators used in hydronic systems are technically classified as ____ pumps. Select one: a. centrifugal b. rotational c. pressurized d. nominal
A
The heating load is ____ of heat flow from the building to the outside air. Select one: a. a rate b. the quantity c. the cost d. one unit
A
The proper approach is to perform a heat load calculation ____. Select one: a. for each room b. factoring seasonal requirements c. for the entire building d. based on the owner's usage
A
A flow-check valve, or spring-loaded check valve, needs to be installed in each piping circuit anytime multiple circulators are installed ____. Select one: a. in half unions b. in parallel c. in series d. proportionally
B
An air separator is designed to separate air from water and eject it from the system. The process is ____ the water is heated. Select one: a. not affected if b. enhanced as c. unnecessary if d. more difficult if
B
Buildings with hydronic heating systems have shown ____ heating energy use compared to equivalent structures with forced-air heating systems. Select one: a. unquantifiable b. lower c. equal d. higher
B
In single-loop systems, the ____ prevents hot water in the boiler from slowly circulating through the distribution system when the circulator is off. Select one: a. off switch b. flow-check valve c. diaphragm d. thermosiphon
B
When designing a piping system, select a circulator that delivers up to ____ more head than required at the desired flow rate. Select one: a. 25% b. 10% c. 50% d. 5%
B
Early hydronic systems did not have circulators. Instead, they relied on the ____ of hot water to move water between the boiler and the heat emitters. Select one: a. hydraulics b. thermonics c. buoyancy d. molecular attraction
C
Heat emitters that use fans or blowers to force air through a heat exchanger are usually called fan coils or air ____. Select one: a. wavers b. tunnels c. handlers d. blowers
C
The U-value of any material or assembly is simply the reciprocal of the ____ of that material or assembly. Select one: a. temperature b. exposure c. R-value d. heat load
C
The circulator must first be filled with water and purged of most air before it can operate properly. This is called ____. Select one: a. volumizing b. purging c. priming d. compressing
C
The most common method of connecting a circulator to piping is with bolted flanges. A special type of flange, known as an isolation flange, contains a built-in ____. Select one: a. thermometer b. impeller c. ball valve d. water pump
C
The net positive suction head available (NPSHA) is a precise description of the state of the fluid, within a specific piping system, as it enters the circulator. It includes the effects of temperature, pressure, velocity, and the fluid's ____ into a single number. Select one: a. flow b. compressibility c. vapor pressure d. hydraulic equilibrium
C
To estimate the annual space heating cost provided by an electrically operated heat pump, its average COP must be factored in. What does COP stand for? Select one: a. capacity of production b. calculation of price c. coefficient of performance d. correlation of parts
C
Water has many characteristics that make it ideal for a hydronic system. It is readily available, nontoxic, nonflammable, and has one of the highest ____ storage abilities of any material known to man. Select one: a. vapor b. molecular c. heat d. space efficient
C
A modern hydronic system is almost exclusively a(n) ___ system, force circulated by a pump or circulator.
Closed
A given volume of water can absorb over ____ times more heat as the same volume of air for the same temperature change. Select one: a. 30 b. 340 c. 300 d. 3400
D
All building surfaces that separate heated space from unheated space. (walls, windows, ceilings, doors, foundation, etc.) are called the ____ of the building. Select one: a. thermal qualifiers b. heat load variables c. resistance factors d. thermal envelope
D
All hydronic heating systems will inherently attempt to find a point of ____ and remain in operation at that point. Select one: a. even hydraulic flow b. customer comfort c. level capacity d. thermal equilibrium
D
An object's thermal ____ can be defined as its thickness in the direction of heat flow divided by its thermal conductivity. Select one: a. reciprocity b. reactivity c. reproduction d. resistance
D
For a liquid at a given temperature, cavitation occurs anywhere the liquid's pressure ____ its vapor pressure. Select one: a. is in equilibrium with b. exceeds c. is compressed by d. drops below
D
In an ideal application, the rate of heat production by the heat source would ____ the rate of heat by the heat emitters. Select one: a. remain lower than b. depend on c. exceed d. exactly match
D
One common method of factoring local weather conditions into estimates of heating energy use is based on heating ____. Select one: a. prognostication b. thermometers c. historical records d. degree days
D
To reduce the number of circulator models needed and still cover a wide range of performance requirements, most circulator manufacturers now offer wet rotor circulators capable of operating at ____ different speeds. Select one: a. many b. four c. five d. three
D
When the rate at which a circulator adds head to the fluid in a piping system equals the rate at which the piping system dissipates this head, the system is in hydraulic equilibrium, and flow rate will ____. Select one: a. fluctuate only slightly b. steadily increase c. occasionally decrease d. remain constant
D
At elevated system water temperatures, a lower cold fill pressure could be necessary to properly pressurize a system. T/F
False
Ideally, the water in a hydronic heating system is replaced in the system every year. Select one: True False
False
It is relatively easy to assess the location and magnitude of all the air leakage paths in a typical building. Select one: True False
False
Maintaining comfort is simply a matter of supplying heat to the body. Select one: True False
False
Most circulators used in smaller hydronic systems are designed to be installed with their shafts in a vertical position. Select one: True False
False
Not every heating system consists of devices that convert one form of energy into another. Select one: True False
False
One can assume that individual room heating loads are proportional to room floor area. Select one: True False
False
Providing comfort is the secondary objective of any heating system designer or installer. Select one: True False
False
The R-value of a material is not directly proportional to its thickness. Select one: True False
False
The fluid's mechanical energy content is increased as it is accelerated toward the inner edge of the impeller. Select one: True False
False
The number of heating degree days that accumulate in a 24-hr. period is the difference between 72 F and the average outdoor air temperature during that period. Select one: True False
False
The system head loss curve that describes head loss versus flow rate in a specific piping system is not very dependent on fluid properties and temperature. Select one: True False
False
Thermal radiation is probably the least understood mode of heat transfer. Select one: True False
False
Generally, on small systems where the pumps do not produce more than 12' of head, pump ___ may not be important.
Location
A(n) _______ system can be a gravity system or a pumped system.
Open
As pressure drops occur within a system, dissolved gases are released and can form bubbles when the HTF reaches a low ____.
Static Pressure
Air can exist in ___ distinct forms within hydronic heating and cooling systems.
Three
A boiler, furnace, or small space heater operating on the same fuel, at the same assumed conversion efficiency, would produce the same estimated annual heating cost. Select one: True False
True
A properly designed and installed hydronic system can operate with virtually no detectable sound levels in the occupied areas of a home. Select one: True False
True
Always install the circulator so that its inlet is close to the connection point of the system's expansion tank. Select one: True False
True
Auto air vents can be used on air elimination systems. T/F
True
Circulators with "flat" pump curves should be used when the objective is to maintain a relatively steady pressure differential across the distribution system over a wide range of flow rates. Select one: True False
True
Each time water is added to a hydronic system, additional air enters the system as entrained air and dissolved gases.
True
For a liquid at a given temperature, cavitation occurs anywhere the liquid's pressure drops below its vapor pressure. Select one: True False
True
Heat is lost through all building surfaces that separate heated space from unheated space. Select one: True False
True
Hydronic heating systems use water (or water-based solutions) to move thermal energy from where it is produced to where it is needed. Select one: True False
True
In single-loop systems, the flow-check valve prevents hot water in the boiler from slowly circulating through the distribution system when the circulator is off. Select one: True False
True
Knowing how many MMBtu a building requires over a typical heating season is not of much use to most owners. Select one: True False
True
Many residential and commercial buildings have concrete floor slabs rather than crawl spaces or full basements. Downward heat losses are relatively small from interior areas of the floor slab. Select one: True False
True
Properly designed hydronic systems control both the air temperature and surface temperatures of rooms to maintain optimal comfort. Select one: True False
True
The U-value of any material or assembly is simply the reciprocal of the R-value of that material or assembly. Select one: True False
True
The design heating load of a building is an estimate of the rate at which a building loses heat during the near minimum outdoor temperature. Select one: True False
True
The motor of a wet rotor circulator is totally cooled and lubricated by the system's fluid. Select one: True False
True
The pump curve for two identical circulators connected in parallel is obtained by doubling the flow rate of a single circulator at each head value. Select one: True False
True
The simplest hydronic system can be described as a loop or piping circuit. Select one: True False
True
When two identical circulators are connected in series, the resulting pump curve can be found by doubling the head produced by a single circulator at each flow rate. Select one: True False
True
Within the hydronics industry, the terms pump and circulator are used interchangeably. Select one: True False
True
Most panel radiators are made of steel. Some are built of ____________ welded together at their perimeter.
aluminum sheets
Many types of fan-coils will produce some noise due to the _______________.
blower operation
To prevent corrosion, steel panel radiators should only be used in _________ systems.
closed-loop
Hydronic system designers must select and size heat emitters for a given project, so that ____________ are achieved in all areas of the building.
comfort and control
A typical finned-tube baseboard convector consists of sheet metal enclosure containing a ________ tube fitted with aluminum fins.
copper
The heat output of finned-tube baseboard is expressed in Btu/hr./ft. of active element length. The active length of the element is the length of pipe _______.
covered with fins
The heat output of a fan-coil is approximately proportional to the temperature difference between the ______________.
entering air and entering water
As a rule, convectors are well suited for rooms with high ceilings.
false
Panel radiators typically require much more wall space than fin-tube baseboard sized for equivalent heat output and operating conditions.
false
The rate of heat transfer depends on either the temperature difference or the flow rate.
false
Hydronic fan-coils have two common components --- a(n) _______ heat exchanger (often called the "coil") through which system fluid flows and a blower or fan that forces air to flow across the coil.
finned tube
Air leaving a compression tank and the water going into the tank will set up ___ circulation between the system and tank and cause the tank temperature to approach that of the system.
gravity
Preliminary lengths of finned-tube baseboard can be selected by basing the __________ of each baseboard on the average temperature of the fluid in the piping circuit.
heat output
Finned-tube baseboard convectors operate on the principle that ___________ due to its lower density.
heated air rises
One of the most practical methods for connecting baseboards into parallel circuits in residential and light commercial systems is called a ____________.
homerun distribution system
When baseboards are connected _________, each receives water at the temperature supplied to the manifold.
in parallel
A(n) ____________________ is designed to be used for air elimination systems for heat sources and chiller installations that cannot use the standard dip tube fitting.
inline air separator
Operating panel radiators at ______ water temperatures increases the percentage of radiant versus convective heat output from the panel.
lower
Increasing the fluid flow rate through the coil will _______ increase the heating capacity of the fan-coil.
marginally
Low-temperature heat sources such as condensing boilers and hydronic heat pumps are becoming increasingly common in ________ hydronic systems.
modern
Whenever air is used to transport heat, __________ movement can become a problem.
moisture
The term fan-coil applies to units that are mounted within __________________. Some fan-coils use a propeller-type ____________ by a motor to create airflow across the coil.
occupied spaces, fan driven
Every hydronic heating system attempts to establish operating conditions that allow the distribution system to current rate of heat output from the heat source. This state is known as ___________.
thermal equilibrium
A rule of thumb is to allow twice the linear footage of baseboard compared to typical residential finned-tube baseboard.
true
Finned-tube baseboard convectors operate on the principle that heated air rises due to its lower density.
true
Parallel piping methods allow independent flow rate adjustment for each baseboard.
true
Reverse return piping encourages equal flow rates and equal supply temperature to each radiator.
true
The balance between convection heat transfer and radiative heat transfer can significantly affect the comfort achieved by various heat emitters.
true
The heat output of a fan-coil is approximately proportional to the temperature difference between the entering air and entering water.
true
When rooms lack the wall space needed to mount finned-tube baseboard, one alternative is to use a hydronic fan-coil or air handler.
true
The head loss of radiant baseboard can be determined by considering each baseboard to be a tubing circuit approximately _______ as long as the baseboard extrusion.
twice
