Overheating analysis in a Healthcare Facility: enhancing thermal comfort and energy efficiency

At Praxis Resilient Buildings, we conducted a detailed thermodynamic simulation to evaluate the summer performance of a multi-storey healthcare building.

Overheating analysis in a Healthcare Facility: enhancing thermal comfort and energy efficiency.

A thermodynamic simulation-based approach.

At Praxis Resilient Buildings, we conducted a detailed thermodynamic simulation to evaluate the summer performance of a multi-storey healthcare building. The study aimed to identify optimal glazing specifications together with natural and mechanical ventilation design strategies to mitigate overheating and ensure comfort without excessive reliance on mechanical cooling.

Mejora del confort térmico y análisis de sobrecalentamiento en un edificio sanitario: un enfoque basado en simulaciones termodinámicas

Climate File and Simulation Tools

The analysis used the IWEC II climate file for Barcelona (ASHRAE), providing reliable long-term hourly data. The simulation was carried out with DesignBuilder v7.1 and EnergyPlus v9.4.

Base Case and Model Assumptions

Key features of the thermal envelope:

  • High-performance façade insulation (U = 0.157 W/m²·K)
  • Low-emissivity double glazing with solar control (Ug = 1.40, g = 40%)
  • Air tightness: n50 = 3.0 ACH
  • Active cooling with fan-coil units and an air-to-water heat pump
  • Constant air volume (CAV) mechanical ventilation with 70% heat recovery and a cooling coil

Cooling setpoints:

  • Weekdays: 24 °C (day) / 28 °C (night)
  • Weekends: 28 °C (all day)

Simulation Variants

The study explored five summer scenarios:

  1. Base Case
  2. Solar-control glazing and skylights
  3. Natural ventilation in the atrium
  4. Cooled ventilation air supply to the atrium
  5. All combined strategies

Additionally, two façade glazing types were compared:

  • Low-e glazing (g = 57%)
  • Low-e + solar control glazing (g = 40%)

Key Findings

  • Combined passive strategies reduced peak temperatures in circulation and waiting areas on the 3rd and 4th floors by between 7 and 9°C.
  • Solar control glazing alone reduced solar gains by 40%, making differentiated glazing by façade unnecessary.
  • The best performance was achieved with solar-control glazing + natural ventilation + cooled ventilation supply air to the atrium.

Glazing specification

Based on the simulation outcomes:

  • Façade windows: Double glazing, low-e + solar control: Ug = 1.40 W/m²·K, g = 40%
  • Skylights: Double glazing with solar control: Ug = 1.80 W/m²·K, g = 18%

Conclusion

The thermodynamic simulations demonstrate that a strategic combination of solar control glazing, natural ventilation, and cooled ventilation supply air can effectively manage overheating in summer. These findings support smart, passive-first design decisions in healthcare environments, reducing HVAC loads while enhancing occupant comfort.