Soojuskoormuse

Soojuskoormus is the rate at which heat energy must be supplied to a building, system, or component to maintain a specified indoor temperature under defined outdoor conditions. It is expressed in units such as kilowatts (kW) or megawatts (MW) and reflects the instantaneous demand for heating.

The magnitude of soojuskoormus depends on heat losses and gains. Key factors include heat loss through the building envelope (walls, roof, windows) and through ventilation or infiltration, as well as heat gains from solar radiation, occupants, equipment, and lighting. Thermal mass and internal temperature setpoints, operating schedules, and outdoor weather conditions also shape the load, which varies over time.

Calculation approaches range from simple steady-state estimates to dynamic energy models. In a steady-state view, heat loss is approximated as Q = U · A · (T_inside − T_outside). More detailed methods use degree-day calculations or hourly simulations to capture changing outdoor temperatures, solar gains, and occupancy. These calculations yield design heat loads (peak needs) and hourly load profiles for system sizing and operation.

Applications include designing and sizing heating systems, evaluating energy performance (such as energy certificates), and planning district heating connections or retrofits. Reducing soojuskoormus is a central aim of energy efficiency measures, including improved insulation, airtightness, heat recovery ventilation, and shading to minimize solar gains in summer.

In Estonian contexts, soojuskoormus is a core concept in building physics, used to assess how much heating a building requires under specified conditions and to inform energy optimization and regulation.