NOVELTY - The system (10) has thermal energy transport conduits (14) arranged within a thermal mass (12) e.g. concrete floor, and allowing passage of a heat transfer fluid e.g. water, through the conduits. The conduits deliver thermal energy to the mass and a phase change material (PCM). A heat exchanger is in communication with the conduits. An energy source (18) generates thermal energy, where the energy is transferred to the fluid by the exchanger. A controller (20) monitors operating and environmental parameters of the system. The energy source is a geothermal pond system.    USE - Optimized radiant heating and cooling system for heating or cooling interior space of building and public facility e.g. bus stop, train station and open areas, by building maintenance personnel for cooling and air conditioning applications by using geothermal green energy e.g. wind energy and solar energy.    ADVANTAGE - The system optimizes the energy requirements for heating and cooling the buildings, facilities and open areas using radiant heating or cooling effect of slabs or thermal mass. The system incorporates a control system to process inputs combined with thermal storage property of the PCM so as to optimize the system, thus reducing operational costs by using stored thermal energy to supplement real-time heating and cooling effect of the system during time of peak demand and/or recharging the PCMs at off-peak energy demand period or period with least energy cost, reducing total energy consumption, reducing equipment cost as the system no longer needs to remediate peak-loading and reducing total energy consumed by the system, and hence conserving valuable resources. The system includes metallic fillers or metal matrix structures that are used in combination with paraffin wax to improve thermal conductivity of the metallic fillers or metal matrix structures. The system utilizes an enhancement thermal conductivity matrix such as graphite matrix, to effectively dissipate heat in the PCM and to prevent occurrence of subcooling, thus protecting the PCMs from effectively dissipating and absorbing thermal energy as the PCM does not release or absorb thermal energy due to the phase change at melting temperature. The system includes a pump that runs during peak time, thus performing more efficient and cost-effective operation.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a heating and cooling system.    Optimized radiant heating and cooling system (10)    Thermal mass (12)    Thermal energy transport conduits (14)    Energy source (18)    Controller (20)