Mississippi Solar Examination

For a typical residential solar swimming-pool heating system, which collector type is preferred and why?

• AUnglazed polymer collectors, because pool water is only a few degrees above ambient and u…
• BEvacuated-tube collectors, because pool water must routinely be heated above 160°F
• CConcentrating tracking collectors, because pool heating requires high-temperature steam
• DPhotovoltaic modules, because they convert sunlight directly into heated pool water

In a solar pool-heating loop that uses the existing filter pump, where should the solar collectors be piped relative to the filter?

• AOn a dedicated raw-water suction line that bypasses the filter
• BDownstream of the filter so only filtered water enters the collectors
• CBetween the skimmer and the pump strainer
• DOn the pool-return line after the chlorinator, so sanitizer flows through the collectors…

What is the preferred compass orientation for solar pool-heating collectors in Mississippi?

• ATrue north, to avoid summer overheating
• BTrue south, to maximize daily solar exposure
• CDue east only, to capture morning sun exclusively
• DMagnetic west only, because afternoon sun cannot be used for pool heating

A rectangular pool measures 16 ft by 32 ft. Using the FSEC season-extension guideline of collector area equal to 50 percent of pool surface area, how much collector area is required?

• A128 square feet
• B256 square feet
• C384 square feet
• D512 square feet

An unglazed solar pool array has 400 square feet of collector. Using the FSEC/industry design flow of 0.10 gallons per minute per square foot, what collector-loop flow is required?

• A4.0 gpm
• B10 gpm
• C40 gpm
• D400 gpm

Which single measure most reduces the heating load of an outdoor swimming pool before solar collectors are sized?

• AAdding extra return fittings on the deep-end floor
• BUsing a pool cover to cut evaporative heat loss
• CPainting the pool interior white to reflect sunlight out of the water
• DRunning the filter pump 24 hours per day year-round

How does a differential temperature controller operate a solar pool-heating system?

• AIt starts collector flow when the collector sensor is warmer than the pool sensor by the…
• BIt runs the pump whenever the pool water is below 104°F, regardless of collector temperat…
• CIt opens the solar valve only at solar noon based on a time clock
• DIt heats the pool whenever wind speed exceeds 10 mph

Why is a check valve required in a solar pool-heating loop?

• ATo increase filter backwash pressure
• BTo prevent nighttime reverse thermosiphon that would cool the pool through the roof colle…
• CTo add chlorine residual in the collectors
• DTo raise the pool water to steam temperature

What is the function of the automatic three-way diverting valve used on most residential solar pool systems?

• AIt mixes city water into the pool to control TDS
• BIt sends filtered water either through the collectors or straight back to the pool, based…
• CIt isolates the pump from the skimmer during vacuuming only
• DIt is the pool’s main drain hydrostatic relief valve

Why is reverse-return (first-in, last-out) piping used on a bank of parallel solar pool collectors?

• AIt lets one collector run at twice the design flow while others are starved
• BIt equalizes path length so each collector receives approximately the same flow
• CIt is required so collectors can be piped in series at pool-heating temperatures
• DIt eliminates the need for a filter

Which piping material is commonly used for unglazed solar pool-heating supply and return lines?

• AUninsulated Type K copper only, because pool water exceeds 250°F
• BSchedule 40 PVC rated for the temperature, pressure, and outdoor exposure of the installa…
• CGalvanized steel water pipe without dielectric isolation
• DFlexible natural-gas CSST

For winter-biased solar pool heating, FSEC tilt guidance is closest to which rule?

• ATilt equal to the site latitude plus about 15 degrees
• BTilt equal to the site latitude minus 45 degrees, even if that is below horizontal
• CAlways mount collectors vertically on a north wall
• DTilt is irrelevant because unglazed collectors only use diffuse radiation

A west-facing roof is the only available location for solar pool collectors. What design adjustment does FSEC practice call for compared with a true-south array?

• AReduce collector area to 25 percent of the pool surface because afternoon sun is stronger
• BIncrease collector area, commonly toward about 75 percent of pool surface, to offset the…
• CReplace the unglazed collectors with PV modules
• DOmit the filter because west arrays run at lower flow

How are unglazed solar pool collectors commonly protected from freeze damage in a mild but occasionally freezing climate such as Mississippi?

• AFill the collectors with automotive ethylene glycol and leave them connected to the pool
• BDrain the collectors automatically or manually so they do not hold water during freezing…
• CKeep the pool heater firing at 180°F whenever the outdoor temperature is below 50°F
• DRely on residual chlorine to lower the freezing point of the water

A 16 ft by 32 ft pool will be heated with 4 ft by 12 ft unglazed collectors. If the design collector area is 75 percent of the pool surface, how many of those collectors are required?

• A4 collectors
• B6 collectors
• C8 collectors
• D12 collectors

Where should an air vent or vacuum-relief device be installed on a rooftop solar pool-heating array?

• AAt the lowest point of the buried return line only
• BAt the high point of the collector bank so air can leave and water can drain
• COn the pump strainer lid, replacing the strainer basket
• DInside the chemical feeder

A solar pool array is flowing 40 gpm with a 5°F temperature rise across the collectors. Using the water heat-rate approximation Q = 500 × gpm × ΔT, what heat is being delivered?

• A10,000 Btu/h
• B20,000 Btu/h
• C100,000 Btu/h
• D200,000 Btu/h

A new solar pool array shows only a 1°F rise at a measured 70 gpm through 400 square feet of collector. What is the most likely hydraulic problem?

• AFlow is far above the 0.10 gpm/ft² design, so dwell time is too short and pump energy is…
• BFlow is far below design, so the collectors are overheating
• CThe pool cover is causing the small temperature rise
• DThe three-way valve is stuck in full bypass, so 70 gpm cannot be going through the collec…

Where should the collector temperature sensor be mounted on a solar pool-heating system?

• AOn the coldest shaded edge of the roof, away from the array
• BAt the collector outlet or on a collector near the array outlet, so it reads the warmest…
• CInside the chemical feeder
• DOn the pump motor housing

Which collector type is the usual choice for a residential solar domestic-hot-water system?

• AUnglazed polymer pool mat
• BGlazed flat-plate collector
• CBare black garden hose coiled on the lawn
• DBuilding-integrated PV shingles with no water passages

What is an integral collector-storage (ICS) solar water heater?

• AA passive unit that combines the absorber and a storage tank in one rooftop collector
• BA PV-powered heat-pump water heater with no solar thermal collector
• CA closed-loop glycol system with a separate heat exchanger tank in the garage
• DA drainback system that uses a ground-level reservoir and a circulating pump

For a thermosiphon solar DHW system to circulate, where must the storage tank be located relative to the collectors?

• ABelow the collectors so the pump can lift the water
• BAbove the collectors so heated water can rise into the tank and cooler water can fall back
• CIn a separate building at least 100 feet away
• DInside the collector header, replacing the absorber plate

How does a drainback solar DHW system provide freeze protection?

• AIt leaves water sitting in the collectors and relies on pipe insulation alone
• BWhen the pump stops, collector fluid drains by gravity into a reservoir below the collect…
• CIt mixes swimming-pool water into the potable tank
• DIt uses only ice-maker rated PEX on the roof and never drains

Which solar DHW system is the most appropriate default in a climate that has hard freezes?

• AOpen-loop direct circulation of potable water through unprotected roof collectors
• BICS batch heater with no freeze valve
• CClosed-loop system using a non-toxic antifreeze heat-transfer fluid and a heat exchanger
• DThermosiphon system with the tank in an unheated attic below the collectors

If an antifreeze heat-transfer fluid is used in a solar DHW collector loop, which fluid is preferred for potable-water systems?

• AAutomotive ethylene glycol mixed with stop-leak
• BFood-grade propylene glycol formulated for solar use
• CUninhibited methanol
• DUsed engine oil

A solar DHW array has 80 square feet of glazed collectors. Using the FSEC design flow of approximately 0.01 gpm per square foot, what collector-loop flow is required?

• A0.08 gpm
• B0.80 gpm
• C8.0 gpm
• D80 gpm

A solar DHW system has 80 square feet of collector. Using the common storage rule of 1.5 gallons of storage per square foot of collector, what minimum tank volume should be provided?

• A40 gallons
• B80 gallons
• C120 gallons
• D240 gallons

For year-round solar domestic water heating, the preferred collector tilt is closest to which value?

• AThe site latitude
• BLatitude plus 45 degrees
• CZero degrees (dead flat) in every climate
• DNinety degrees, mounted as a south wall

Using the common Sun Belt collector-sizing rule of 20 square feet for each of the first two occupants and 8 square feet for each additional occupant, what collector area is indicated for a family of four?

• A28 square feet
• B40 square feet
• C56 square feet
• D80 square feet

Why must a thermostatic mixing (tempering) valve be installed on a solar DHW system?

• ATo raise stored water from 80°F to pasteurization temperature at every fixture
• BTo limit the temperature of water delivered to the fixtures so occupants are not scalded…
• CTo replace the T&P relief valve
• DTo add glycol to the potable distribution piping

Per the IPC, which statement about a water-heater temperature-and-pressure (T&P) relief valve is correct?

• AA shutoff valve may be installed between the T&P valve and the tank for easy service
• BA T&P relief valve is required, and no shutoff shall be placed between the valve and the…
• CThe T&P valve may be omitted if an expansion tank is installed
• DThe T&P valve may discharge into a sealed connection on the building sewer

Under IPC 504.2, which solar storage tanks require a vacuum relief valve?

• AOnly rooftop ICS units
• BBottom-fed water heaters and bottom-fed tanks connected to water heaters
• CEvery tank that has a mixing valve
• DOnly tanks larger than 120 gallons

A solar storage water heater is supplied through a check valve on the cold-water line. What additional protection does IPC 607.3 require?

• ANo additional device; the T&P valve is allowed to drip daily to control expansion
• BA thermal-expansion control device, typically a listed expansion tank, connected on the c…
• CA second check valve piped in series
• DRemoval of the T&P valve so pressure can back-feed the street main

Under the Uniform Solar Energy Code, when a heat-transfer fluid is toxic, how must potable water be protected at the heat exchanger?

• AA single-wall coil is acceptable if the installer labels the tank
• BA double-wall heat exchanger that will reveal a leak, or another method approved for toxi…
• CThe toxic fluid may be piped directly through the potable fixtures if it is dyed
• DNo heat exchanger is allowed in any solar DHW system

What minimum continuous slope is commonly required on drainback collector piping so the array will empty when the pump stops?

• ALevel piping is acceptable if the pump is oversized
• BAbout 1/4 inch per foot back to the drainback reservoir, with no sagging traps
• C2 inches per foot toward the collectors so they stay full
• DA reverse slope that holds a water trap at each collector

Where are the two temperature sensors placed on a typical pumped solar DHW differential control?

• ACollector outlet (or absorber near the outlet) and the lower portion of the storage tank
• BBoth sensors on the mixing-valve body
• COne sensor in the attic air and one on the T&P discharge pipe
• DBoth sensors on the backup water-heater flue

A solar DHW differential control is typically set so the circulating pump starts and stops in which pattern?

• AStarts when the collector is about 8 to 20°F warmer than the tank and stops when the diff…
• BStarts whenever the tank is below 180°F, even at night
• CRuns 24 hours a day on a time clock
• DStarts only when the collector is colder than the tank

Why are isolation valves and unions installed on both sides of a solar DHW circulating pump?

• ATo allow the pump to be removed for service without draining the entire system
• BTo replace the T&P relief valve
• CTo increase collector stagnation temperature
• DTo convert the system from closed-loop to open-loop automatically

What problem does a check valve in a pumped solar DHW collector loop prevent at night?

• AScale formation in the mixing valve
• BReverse thermosiphon that would carry stored heat back to the cold roof collectors
• CUtility backflow into the street main
• DLoss of anode-rod protection

Which installation meets IPC 504.6 for T&P relief-valve discharge piping?

• AFull-size pipe that drains by gravity, is not trapped, is not valved, and terminates thro…
• BA pipe reduced two sizes and tied directly into the sanitary sewer under the slab
• CA valved hose that can be capped so the utility room stays dry
• DA pipe that runs uphill to a roof drain

What is the difference between SRCC OG-100 and OG-300 ratings?

• AOG-100 rates a collector; OG-300 certifies a complete solar water-heating system
• BOG-100 is a PV inverter listing; OG-300 is a battery listing
• COG-100 applies only to unglazed pool mats; OG-300 applies only to PV modules
• DThey are OSHA fall-protection labels

What is the principal freeze-related risk of an open-loop (direct) solar DHW system?

• APotable water circulates through the roof collectors, so a freeze can burst the absorber…
• BThe glycol becomes too thick to pump
• CThe drainback reservoir cannot be located indoors
• DThe mixing valve will freeze before the collectors

A copper solar DHW line is connected to a steel tank fitting. What fitting detail is required to limit galvanic corrosion?

• AA dielectric union or isolating fitting listed for the potable-water connection
• BA steel-to-copper solder joint with no isolation
• CA hose-clamp connection on bare steel
• DLeaving the joint unconnected so the metals cannot touch

Two 32-square-foot glazed collectors are piped in parallel for DHW. Using 0.01 gpm per square foot, what flow should each collector receive if the total array flow is split evenly?

• A0.16 gpm per collector
• B0.32 gpm per collector
• C0.64 gpm per collector
• D3.2 gpm per collector

Jackson, Mississippi, is at about 32°N latitude. What collector tilt best matches a winter-biased solar DHW design?

• AAbout 17 degrees
• BAbout 32 degrees
• CAbout 47 degrees
• DAbout 90 degrees facing north