NOVELTY - The panel (32) has hollow parabolic-trough mirror reflectors located between an upper layer of a glazed heating-tube and a lower layer of unglazed cooling-tube. Rising or sinking air flowing past the reflectors and the glazed heating-tube is accelerated through venturi like openings of each reflector for blowing the rising or sinking air around the unglazed cooling-tube to cool the reflector during day or night. The lower layer of the cooling-tube is located beneath the upper layer of the heating-tube when the panel is inclined at an angle facing sun.    USE - Double layer coaxial tube passive thermosyphon collector-array panel for use in a solar liquid-heating-and-cooling system (claimed) on a roof of a building for absorbing thermal energy from sun or coolness from surrounding environment during day or night.    ADVANTAGE - The panel absorbs the thermal energy from the sun or coolness from the surrounding environment in an improved and efficient manner. The solar liquid-heating-and-cooling system exhibits improved performance when marginal solar radiation occurs. The panel reduces refill rate for a hot-liquid storage-tank to lengthen interval between discharges through expansion spray tube atop adjustable pressure-relief expansion valves, thus reducing cumulative total liquid discharge. The panel is covered with a suitable netting or mesh so as to prevent insects i.e. mosquitoes, from breeding in the panel or birds from nesting in the panel. The panel provides molded roof flashing edges and side gutters to prevent rain water from entering an interior space.    DETAILED DESCRIPTION - The panel utilizes semi-permeable membrane material selected from a group consisting of Gore-Tex (RTM: waterproof/breathable fabric), Sympatex (RTM: lightweight, ultra-thin, non-porous polyester membrane), Triple-Point Ceramic (RTM: multi-layer microporous coating), Omni-Tech and H2NO (RTM: waterproof/breathable fabric) Storm HB. The heating-tube is a coaxial structured heating-tube. The cooling-tube is a coaxial structured cooling-tube. An INDEPENDENT CLAIM is also included for a solar liquid-heating-and-cooling system.    DESCRIPTION OF DRAWING(S) - The drawing shows a partially cut away perspective view of a solar liquid-heating-and-cooling system.    Hot-liquid storage-tank (22)    Coaxial heating-and-cooling-tubes (24, 96)    Double layer coaxial tube passive thermosyphon collector-array panel (32)    Long span roof (102)    Building (104)