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System modeling: Fan coils

Objectives

The purpose of this study is to determine:
  • the ability of the fan coils to meet the IWs sensible loads
  • the impact of the fan coils’ control strategy on energy consumption and thermal comfort (fan speed, water flow rate, water temperature, indoor setback and set point temperatures, unoccupied/occupied scenarios)
  • the switching from heating to cooling and cooling to heating to make sure that the control system is stable
  • the time response (time between the controller’s signal is issued and when the temperature requirements are met, especially when switch between unoccupied and occupied period)



Accomplishments

Building energy simulation can be carried out as simulation mainly of the building envelope with simplifying assumptions regarding operation of the fan coils, or as, a detailed transient simulation of the building envelope and the fan coils, the ventilation unit and their control.
The detailed approach is used in this study to assess the impact of the control system on the energy consumption of the fan coils and the ventilation unit and their effect on the thermal comfort in the IWs. This simulation enables realistic prediction of space conditions and the reduction in annual heating and cooling energy costs dependent on the control strategy, the temperature of the energy source and the characteristics of the fan coils and the ventilation unit. We have been creating the models for the space, fan coil, and controllers.
 
 
Next Steps

First, the default settings of the Siemens controller - i.e. the proportional, integral and derivative gains - should be tuned.

Then, TRNSYS simulations needs to be ran in order to determine :
  • the ability of the fan coils to meet the IWs sensible loads
  • the impact of the fan coils’ control strategy on energy consumption and thermal comfort
  • the switching from heating to cooling and cooling to heating to make sure that the control system is stable
  • the time response (time between the controller’s signal is issued and when the temperature requirements are met, especially when switch between unoccupied and occupied period)  



People

Sophie Masson