Re-heat systems (CAV/RH)
Heating coil (reheat) inserted in the zone supply. O
Fixed supply airflow rate as well as heating and cooling coil temperatures. Capacity controlled by terminal reheat coil.
Cooling coil lowers Tsa to set point. Reheat coil adds heat to satisfy thermostat. Typical temperatures for cooling coil are 13°C (55°F). Reheat temperature for full load is 13°C (55°F), when reheat turns off For this process energy is wasted by overcool & reheat.
Preheat coil raises Tsa to set point. Reheat coil adds heat to satisfy thermostat. Typical temperatures for preheat coil are 13°C (55°F), and reheat under full load are 38°C (100°F). No wasted energy.
Posted in Fundamentals of Heating. Ventilating, and Air-Conditioning