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.

Summer:

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.

Winter:

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