G UNIT: Self test questions Flashcards
What is considered to be the core of a heat pump system?
The refrigeration cycle
What is the fourth component of a refrigeration system?
An evaporator
What is the term given to the additional heat that is required to raise the temp of the refrigerant above its saturation temp?
Superheat
Which component of a refrigeration system is responsible for absorbing heat from a source into the refrigerant?
The evaporator
Which component of a refrigeration system is responsible for “dumping” heat from the system to a load?
The condenser
In a cooling only scenario, what would be the vehicle responsible / would be mounted within the ductwork?
The evaporator
What component is responsible for allowing a heat pump to either heat or cool a load?
The reversing valve
What type of pump is most commonly used in homes in North America?
Air - to - Air
What is the term given to the pair of copper tubes that move refrigerant between the evaporator and compressor?
Lineset
What my be required if an Air- to Air heat pump can’t keep up with the building heat loss in very cold climates?
An auxiliary electric heater installed in the supply ductwork
What component will aid in keeping a cooling coil in a furnace’s supply duct from becoming plugged?
A high - quality air filter
What component, when installed with an air - to - water heat pump, eliminates the need for having to freeze - protect the entire distribution system?
A heat exchanger
If a heat pump pulls low temp heat from vertical loops installed in a well / transfers it to a coil in a forced - air furnace, what variety of heat pump is it?
Water - to - Air
A coil installed within a supply duct on a heat pump, intended to heat the air, would be an example of what component?
A condenser
A heat pump installed to heat or cool a building through a radiant floor system by using the heat from an earth loop would be an example of what type of heat pump?
Water - to - Water
What represents the heating efficiency of a heat pump?
Coefficient of Performance (COP)
What represents the cooling efficiency of a heat pump?
Energy Efficiency Rating (EER)
Water to water heat pumps in heating mode work best when…
the source temp is highest / load temp is lowest
What is one ton of cooling equivalent to?
12,000 BTUH
When determining a COP for the heating side of a heat pump, what are the units of measurement for the electrical energy input?
Watts
water - to - water heat pumps in cooling mode work best when…
The source temp is highest and the load temp is lowest
In order to keep the EER if a heat pump in cooling mode as high as possible, what is the max suggested flow rate through either the evaporator or condenser?
3 GPM
Why are earth (ground) loops considered to be a better heat pump source media than air?
Because the ground temp is more consistent year - round as compared to air temp year round
What is the piping material most commonly used in ground - source heating?
HDPE
At least how many GPM / ton would be required in a water - to - water or water - to - air heat pump?
3
When using open - loop systems, what are the characteristics of water that are of most concern?
Quantity and Quality
In an open loop system using lake water as the source, what is used to allow periodic replacement of the pump?
A sleeve on the intake line and a vault.
What two components of an open - loop well system are similar or identical to those found in a well system for a house?
A hydro - pneumatic tank + pressure switch
If a chain trencher is used, how many pipes can be buried in the trench?
1 or 2
What is the normal capacity of a 6” vertical borehole in feet per ton of capacity?
125 - 150
What is used in a borehole to increase the thermal conductivity between the tubing and the earth around it?
Sand and Bentonite
How are the manifolds piped in a vertical field?
In a reverse - return configuration
What is the material that is most commonly used for earth - loop piping?
HDPE
How is earth loop piping joined?
Using heat - fusion methods
If manifolds are installed inside a building, how many wall penetrations will there be?
Two for each field loop
What is not an advantage to installing manifolds within the building?
There are many pipe penetrations through foundation walls
What is not an advantage to installing vertical, rather than horizontal, earth loops?
Specialized well - drilling equipment / personnel is needed.
What is the accepted pressure / duration of the air test on all buried piping in earth - loop installations?
75 psi for 24 hours
What is power - purging?
Removing trapped air by using high - velocity water flows
What type of antifreeze solution was used in early versions of geothermal heat pumps field loops but is no longer the industry standard?
Calcium chloride - based (Brine?)
What type of heating system is best suited for use with geothermal heat pumps?
Radiant floor
The installation of what piece of equipment helps ensure that a heat pump in a multiple - zone heating system doesn’t short cycle when only one or two zones are calling for heat?
Buffer tank
What control component is used to maintain the temp of the water in a buffer tank and thereby eliminate the need for a mixing valve?
An outdoor reset controller
What is water that is taken to low temp / used for cooling known as?
Chilled water
What is moisture removal from interior air, for cooling / comfort purposes, known as?
Latent cooling
What is the most important consideration for cooling systems in order to avoid damage to the building
Condensate collection / removal
What is the condensate from a chilled water terminal unit considered to be?
Clear water waste
Besides being insulated, what other protection is needed to prevent piping / associated fittings from causing condensation issues?
They must be hermetically sealed
What variety of heat pump is most common for residential use in Canada?
Air - to - Air
What is a Desuperheater?
A heat exchanger
What is the min suggested rate of purging (flushing) in order to remove unwanted debris trapped air from earth loops / manifolds
2 ft / sec
What should be the min capacity of a purge barrel?
30 gallons
What component of an earth - loop system will remove dissolved air from the piping, just as it does when installed in a hydronic heating system?
A microbubble resorber
What is the median (average) % of glycol / water mixture used in antifreeze systems for heat pumps?
20% glycol / 80% water
Where is the lowest point (min water level) that liquid should be when using a purge barrel to flush or add glycol to the system, in order to prevent air from being drawn in with the liquid?
1” above the highest opening in the pump intake line
What components would have to be installed in any closed earth - loop system, to avoid issues caused by fluid temp variations?
An expansion tank
For calculation purposes, what is usually used as the water temp at time of filling the system?
50F –> 10C
What doesn’t have to be done routinely as part of regular system maintenace?
Dump, flush and refill all closed system piping
(Closed system have to remain closed)
What is the type of radiation that strikes that earth’s surface and is easy to reflect using mirrors?
Direct
What is the type of radiation that is reflected in every direction due to particles in the air / that cannot be easily reflected?
Diffuse
Which one of the following can be viewed as the position or change in the sun’s path across the sky in the different seasons?
Solar declination angle
Which one of the following is measured from true north in a clockwise direction, with the south pole being 180 degrees?
Solar azimuth angle
What is the difference between compass - indicated north/south and true (polar) north / south known as?
Magnetic declination
What describes the type of system that might use large south facing windows / bare concrete floors to absorb heat during the say and release it at night?
Direct - gain passive
What is the term known as whereby heat from the solar storage tank is lost to the collectors through convection currents?
Thermosiphoning
What is the term given to any system that uses a circulator to move a fluid through collectors
Active thermal
What type of finish on the tubes and sheets helps w/ the collection of heat by a flat plate solar collector?
Black matte
What type of solar collector is built somewhat like a thermos bottle?
Evacuated tube
What type of installation is well suited to the use of collectors that are of the unglazed, uninsulated flat plate UV stabilized polymer variety?
Swimming pool
What collector criteria is the result of an equation that factors in the collector inlet fluid temp, ambient air temp and solar radiation intensity?
Inlet fluid parameter
At what time of day is solar direct radiation the strongest, no matter what the latitude of the location?
12pm
What contributes to the most to achieving the best collector performance?
Low collector inlet fluid temp
What is the term given to a high-temp situation in the collectors that is caused by unusually high sustained direct radiation / low flow conditions?
Stagnation
What component prevents thermosiphoning of the heated water in the thermal storage tank?
Check valve
What component ensures that water won’t be circulated through the collectors unless there is enough heat there?
Check valve
What component is needed on an antifreeze system so that collector fluid and heat load fluid are kept separate from each other?
Heat exchanger
What condition would required the use of two circulators to introduce heated water to the thermal storage tank?
An antifreeze loop with an external heat exchanger
What uses a tank / properly - graded piping for freeze protection?
Drain-back system
What must not have a check valve in the collector supply piping nor an air vent at the top of the collector array?
Closed loop drain-back system
What critical component of device is necessary at the outlet of solar domestic hot water tank to protect users of system water?
A tempering valve
What principle ensures that the coolest water in the tank is fed to the collectors, thereby ensuring higher collector efficiency?
Stratification
Complete the following statement: The flow pattern through brazed plate heat exchangers
should be piped in a counterflow pattern between the two mediums
What is not a principle to be considered when using solar for space heating?
The need for cross connection control is never a consideration
Which space heating system is ideally suited to an active solar system?
Hydronic radiant floor
What is not used to ensure hydraulic separation between primary and secondary circulators in a hydronic system’s primary loop?
a 3 way mixing valve
What determines the system pressure in a closed loop drainback system?
The liquid level in the drainback tank
What does a drainback system contain?
a circulator
an air riser tube
a pressure relief valve
On a solar system suppling heat for a forced air system, what component prevents excessively hot water from reaching the coil in the furnaces supply plenum?
a 3 way mixing valve
What provides the hydraulic separation between the primary and secondary loops?
The hydrolink
What is the control strategy called that shuts off space heat when domestic water needs to be heated in a combi-system?
Priority
What is the control that is normally used to automatically adjust the water temp to a radiant floor system, depending on the temp outdoors but can also be used to monitor the water temp at the top of the thermal storage tank?
Outdoor reset
On which side of a hydronic system the radiant floor panels be found?
The load side
What is the single most important consideration in a solar thermal system?
The placement of the solar collectors
Between what hours of the day is potential shading of the collectors most critical?
9 am - 3 pm
What would be the issue of most concern when using an engineer - designed pedestal base to support a solar thermal array?
Support / protection of piping
What protection should also be installed along with insulation for supply / return piping?
Aluminum or plastic covers
What is the optimum azimuth angle for collectors installed in the northern hemisphere?
180 degrees
What is the optimal collector angle or “tilt” when used for domestic water heating?
The same as the local latitude
What is the preferred type of pipe or tube and joining method used in solar thermal systems?
Copper tube with pressed connections
What Canadian - based software program, developed to simulate / estimate the performance of a solar thermal system?
RETScreen
What is the term “solar fraction” used to describe?
The % of the month by month total energy load that is met by an active solar system
What would be the best storage tank w/ on or two internal coils?
An indirect storage - type heat exchange
What device should always be installed on the hot water outlet of any thermal storage tank that feeds the potable water system?
An anti-scald valve
What device contains “pete’s plugs” that allow a pressure differential to be read across it?
a circuit setter
Whenever a cross connection may exist between a potable water system and the solar thermal system, which one of the following would be considered the best choice for protection of the potable system?
An RPBA
