| 摘要 |
A highly effective modular passive solar energy heating unit for heating an enclosed space employs phase change heat storage material, which is optically transparent to visible light when in high-stored-energy liquid state enabling a viewer to see through clearly and which is translucent milky white when in low-stored-energy solid state for providing pleasant illumination to the enclosed space when first illuminated by sunlight in the morning. This phase change material, in a sealed container having two opposite surface areas transparent to sunlight, is polyethylene glycol having a heat of fusion of about 33 to 37 cal./gm. (4,170 to 4,670 Btu's per cubic ft.), a melting point of about 13 DEG to 25 DEG C. (55 DEG F. to 77 DEG F.), a specific gravity of about 1,125 at 20 DEG C., and desirable isotropic freezing and melting characteristics with only very modest volume change during phase change. A dye soluble therein may be included for increasing solar-energy-absorptivity when translucent and for decreasing glare and direct penetration of sunlight into the space when transparent. The unit additionally contains at least one clearly optically transparent glazing layer facing the sunlight, preferably including an insulation layer to transmit short wavelength solar radiation while blocking longer heat rays for retaining thermal energy within the enclosed space. In preferred embodiments, there are two layers of closely spaced parallel transparent glazing near the sealed container, these layers being between incident solar radiation and the container.
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