.Buildings.Fluid.SolarCollectors.Controls.CollectorPump

Information

Pump on/off controller for a solar thermal system.

This controller outputs whether the pump should be commanded on or off based on the incident solar radiation, the collector inlet temperature, and the system parameters. The pump is commanded on when the incident solar radiation is greater than the critical radiation plus the offset delQ_flow, and it is switched off if the incident solar radiation is below the critical radiation.

The critical radiation is defined per Equation 6.8.2 in Duffie and Beckman (2006). It is

G_TC=(F_RU_L (T_In-T_Env))/(F_R(τα))

where G_TC is the critical solar radiation, F_RU_L is the heat loss coefficient, T_In is the inlet temperature, T_Env is the ambient temperature, and F_R(τα) is the maximum efficiency.

References

J.A. Duffie and W.A. Beckman 2006, Solar Engineering of Thermal Processes (3rd Edition), John Wiley & Sons, Inc.

Revisions

• November 7, 2022, by Michael Wetter:
  Corrected implementation to make comparison based on total irradiation on tilted surface rather than the direct normal irradiation. This required adding parameters for the azimuth, tilt and ground reflectance.
  Changed output from continuous signal to boolean on/off signal as the old implementation run the pump possibly at very small flow rates. Moved old model to Buildings.Obsolete package.
  This is for issue 3074.
• January 15, 2013 by Peter Grant:
  First implementation.