A modular wall system having a plurality of evacuated air spaces to provide a thermal break, the system comprising: a plurality of thermally-broken interconnected units, each unit having a top end plate, a bottom end plate, a convex exterior sidewall, an interior sidewall, and an interior void within a columnar tubular member defined by the top end plate, the bottom end plate, the convex exterior sidewall, and the interior sidewall, each unit configured to form at least a portion of the thermal break; a horizontal connector between horizontally adjacent units, wherein, the columnar tubular member has a longitudinal axis, the modular wall system is structurally self-supporting, each of the convex exterior sidewall and the interior sidewall is made of glass, the convex exterior sidewall has a focal point along the longitudinal axis, each of the sidewalls extends vertically between the top end plate and the bottom end plate, and each of the units includes a solar energy collection rod extending axially within the interior void, characterized in that a vertical connector is arranged between vertically adjacent units, and in that each horizontal connector includes at least two linearly-extending sealing components that cooperate with and are symmetrical to each other, wherein each of the components includes a base securely bonded to outer layers and inner layers of the sidewalls, a projection extending away from the base, a receiver on a distal end of the projection relative to the base, and an abutment strip received by the receiver, the abutment strip abutting the horizontally adjacent units, and wherein each vertical connector forms a seal between the vertically adjacent units. a plurality of thermally-broken interconnected units, each unit having a top end plate, a bottom end plate, a convex exterior sidewall, an interior sidewall, and an interior void within a columnar tubular member defined by the top end plate, the bottom end plate, the convex exterior sidewall, and the interior sidewall, each unit configured to form at least a portion of the thermal break; a horizontal connector between horizontally adjacent units, wherein, the columnar tubular member has a longitudinal axis, the modular wall system is structurally self-supporting, each of the convex exterior sidewall and the interior sidewall is made of glass, the convex exterior sidewall has a focal point along the longitudinal axis, the columnar tubular member has a longitudinal axis, the modular wall system is structurally self-supporting, each of the convex exterior sidewall and the interior sidewall is made of glass, the convex exterior sidewall has a focal point along the longitudinal axis, each of the sidewalls extends vertically between the top end plate and the bottom end plate, and each of the units includes a solar energy collection rod extending axially within the interior void, characterized in that a vertical connector is arranged between vertically adjacent units, and in that each horizontal connector includes at least two linearly-extending sealing components that cooperate with and are symmetrical to each other, wherein each of the components includes a base securely bonded to outer layers and inner layers of the sidewalls, a projection extending away from the base, a receiver on a distal end of the projection relative to the base, and an abutment strip received by the receiver, the abutment strip abutting the horizontally adjacent units, and wherein each vertical connector forms a seal between the vertically adjacent units.