Thermal Storage Solar heating of a house ismuch more efficient if there is a way to store the thermal energycollected during the day to warm the house at night. Suppose onesolar-heated home utilizes a concrete slab of area 14 m2 and 21 cmthick.
A) If the density of concrete is 2400 kg/m3, what is the mass ofthe slab?
Express your answer to two significant figures and includeappropriate units.
b)
The slab is exposed to sunlight and absorbs energy at a rate of1.7 ×107J/h for 10 h. If it begins the day at 25 ∘C and has aspecific heat of 750 J/(kg⋅K), what is its temperature atsunset?
c) Model the concrete slab as being surrounded on both sides(contact area 28 m2) with a 1.7-m-thick layer of air in contactwith a surface that is 5.0 ∘C cooler than the concrete. At sunset,what is the rate at which the concrete loses thermal energy byconduction through the air layer?
D) Model the concrete slab as having a surface area of 24 m2 andsurrounded by an environment 5.0 ∘C cooler than the concrete. Ifits emissivity is 0.93, what is the rate at which the concreteloses thermal energy by radiation at sunset?
