On 2022-05-12 08:46, Jacopo Valente via TRNSYS-users wrote:
I have to set the air flow rate of the heat pump. The pump works all year in both heating and cooling modes. I calculate the flow rate from the maximum hourly load that I have in my load profile, but having two different max values for heating and cooling i have two different air flow rate. So I would like to set the air flow rate to change when the system switches from heating to cooling.
Most residential heat pumps that I have seen don't modulate the air flow depending on whether the unit is in heating or cooling mode. The heat pump is sized to meet the larger of the heating or cooling loads, and then runs at the set fan speed; turning on and off by the signal for the thermostat. And that's exactly how Type 954 operates. The fan is fully on in heating or cooling mode, and then either fully on or fully off if there is not call for heating or cooling (depending on the fan control signal).
If you truly want to have two different air flows (one for heating and one for cooling), then you'll need to use two instances of Type 954 and turn one on in heating mode and one on in cooling mode.
Jeff -- Jeff W. Thornton President Thermal Energy System Specialists LLC 3 N. Pinckney Street, Suite 202 Madison WI 53703 USA (608) 274-2577 www.tess-inc.com