Parasitics |

| To view the Parasitics page, click Parasitics on the main window's navigation menu. Note that for the physical trough input pages to be available, the technology option in the Technology and Market window must be Concentrating Solar Power - Physical Trough System.
| Overview
The variables on the Parasitics page define electrical loads in the system. For each hour of the simulation, Solar Advisor calculates the parasitic load and subtracts it from the power cycle's gross electrical output to calculate the net electrical output.
| Input Variable Reference
Parasitics Piping thermal loss coefficient (W/m 2-K) The thermal loss coefficient that is used to calculate thermal losses from piping between receivers, crossover piping, header piping, and runner piping. The coefficient specifies the number of thermal watts lost from the system per pipe surface area, square meter of aperture area and temperature difference between the fluid in the piping and the ambient air (dry bulb temperature). The length of crossover piping depends on the row spacing variable on the Solar Field page, and the piping distance between assemblies on the Collectors page. Tracking power (W per collector) The amount of electrical power consumed by a single collector tracking mechanism. Solar Advisor only calculates tracking losses during hours when collectors are actively tracking the sun. The total field tracking power is calculated by multiplying this value by the number of loops in the field and number of assemblies per loop specified on the Solar Field page. Required pumping power for HTF through power block (kJ/kg) A coefficient used to calculate the electric power required to pump heat transfer fluid through the power cycle. Solar Advisor applies the coefficient to all heat transfer fluid flowing through the power cycle. The coefficient can alternatively be defined as the pumping power divided by the mass flow rate kW/kg-s, which is equivalent to the units kJ/kg. Required pumping power for HTF through storage (kJ/kg) A coefficient used to calculate the electric power consumed by pumps to move heat transfer fluid through the storage heat exchanger on both the solar field side and the storage tank side (for cases where a heat exchanger exists, specified on the Thermal Storage page). This coefficient is applied separately to the solar field flow and the tank flow. Fraction of rated gross power consumed at all times A fixed electric load applied to all hours of the simulation, expressed as a fraction of rated gross power at design from the Power Cycle page. Balance of plant parasitic (MWe/MWcap) A parasitic load that is applied as a function of the thermal input to the power cycle. Aux heater, boiler parasitic (MWe/MWcap) A parasitic load that is applied as a function of the thermal output of the auxiliary fossil-fired heaters. Applies only when the system includes fossil backup. See Modeling a Fossil-fired Backup Boiler for details. Design Point Total Tracking (W) A value displayed for reference indicating what the total tracking parasitic load would be if all collectors in the field were actively tracking simultaneously. Design Point Total Fixed (MWe) The value of the fixed parasitic load applied at all times. Design Point Total BOP (MWe) The value of the balance-of-plant parasitic load assuming design-point operation. Design Point Total Aux (MWe) The value of the auxiliary heater (for the backup gas boiler) parasitic load assuming the auxiliary heater is providing 100% of the thermal load required for the power cycle.
| Equations for Calculated Values
This section will describe equations for the calculated values on the Parasitics page. It is currently under development. For general descriptions of the variables, see Input Variable Reference. Tracking Fixed BOP Aux