NOVELTY - The panel (10) has an inlet tube and an outlet tube coupled to a heat exchanger to feed heat exchange fluid to and from the exchanger. Size of the exchanger is equal to size of a thermal mass unit. The exchanger is made of thermally transmissive material selected from a group of polymer, stainless steel, aluminum and copper. The unit is made from one of modular or in place formed concrete, cement, gypsum concrete and stone. An insulator panel is made from one of expanded or extruded polystyrene, icynene, urethane or isocyanurate.    USE - Modular thermal panel for mounting on a pedestal i.e. corner pedestal, to transfer solar generated heat on a flat surface e.g. rooftop patio and swimming pool patio, of a high rise building to heat domestic water in a domestic hot water system, or swimming pool water, and concurrently cool a patio surface or to transfer the heat into the patio for melting snow and ice on the patio surface. Can also be used for balcony, flat roofed building, terrace, low sloping roof, plaza, pavement and patio, and for heating stored water.    ADVANTAGE - The panel is modular to perform thermal transfer among multiple fluids and thermal mass with a simple connector between two modular units. The modular units can be nested with multiple pavers/slabs raised on the pedestal or easily disassembled and reassembled without causing damage to a set of components. The panel has a re-usable connector that does not cause harm to the tubes, thus allowing vertical movement between the modular units and allowing expansion and contraction between the modular units, while maintaining a redundant leak proof connection. The panel is practical to use, and can be manufactured in an inexpensive manner. The modular unit can be manufactured to match a desired size paver/slab/stone unit, and arrayed with other paver/slab/stone units to create highly efficient transfer of thermal energy among the fluids and thermal mass by using modularity of the panel. The modular units can be disassembled and re-assembled to allow easy repair of the panel and replacement of damaged or broken paver/slabs or to gain easy access to an area below a paver surface. The panel can be removed and replaced within a row of units without the need for removing an entire patio, where the panel functions as an invisible solar collector. The units are connected to a geothermal loop to remove excessive heat from the thermal mass in hot climate and to transfer the heat to the thermal mass in cold climate, thus making a paver/slab system to be compatible with a set of alternative energy sources. The panel transits chilled fluid through the system to create a comfortable walking surface in very hot climate.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a set of modular thermal panels arranged on a rooftop patio of a high rise building to absorb heat from sun and to heat swimming pool water.    Modular thermal panels (10)