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Chapter 6 part 2
Passive Solar Space Heating
Active Solar Space Heating
Thermal Energy Storage
Summary
Energy in the News
Direct Gain Space Heating
Why is thermal mass important? (Thermal time constant of building?) Why did medieval lords live in stone castles? Are these best for dry or wet climates?
Performance of a Passive Solar Building
What is the range of interior building temperatures? RangeOf outside temperatures? No auxiliary heat is used in this building,Located in Concord, New Hampshire.
Trombe Wall
Heat stored withinConcrete wall
Vents closed atNight. Wall radiates heat.
Solar Greenhouse (Indirect Gain)Can grow plantsIn greenhouse.
Reduces air Dryness in winterWhy?
Active Solar Hot Water System
What additional features are required in an activeSolar system compared to a conventional water heatingSystem? (European vs American hot water heating systems)
Hot Air Flat Plate System
Thermal mass providedBy rock bin.
Solar collector uses air,not water. Hot air movedBy fan to rock bin or directlyTo rooms of house.
Water preheated in rock bin.
Good for humid climate.Not as efficient as waterBased solar system. Why?
Optimum Solar Collector AngleWhy does theOptimum collectorAngle vary as a functionOf the season?
How Big Should a Solar Collector Be?
Q = I * epsilon * AWhere Q is the heatI is the average solar insolation at the siteEpsilon is the efficiency of the solar collectorA is the surface area of the solar collector
Thermal Energy Storage
Q = m*c* delta T
Where Q is heat, m is mass, c is the specific heatOf the substance and delta T is the change in temperature.
What is better for thermal energy storage, a substanceWith a high specific heat or a substance with a low specificHeat? Why?
How does mass affect the thermal energy storage of aSystem?
Heat Capacity
Heat capacity = specific heat * density
Storing Energy in Phase Changes
Why are phase changes a very effective method of energy storage? (think of changing water to steam)
Components of Solar Heating Systems
Solar Collector
Thermal Energy Storage
Distribution System
Active Systems: have pumps or fans
