A pressure governing approach for modelling of variable flow systems in Building Performance Simulation (BPS) tools

Heating and cooling distribution systems are the most common parts of heating, ventilation, air-conditioning and refrigeration (HVAC&R) systems, which account for a significant portion of energy used in HVAC&R systems. For instance, in office buildings, the distribution systems account for more than 20% and 30% of the energy consumption and CO2 emissions of HVAC&R systems respectively. Therefore, an accurate modelling of distribution systems is essential to achieve energy efficiency in HVAC&R systems. This study is to develop a model to enhance the existing simulation programs by introducing a simulation-real-time assessment of variable flow systems under a pressure governing regime. In addition, this research will introduce a mechanism for accurate modelling of variable flow systems that can be used to tune the system in design stage.
The aim of this study is to develop a new pressure governing approach for simulation of variable flow systems and integration of the model with the existing BPS tools. The research objectives to meet the aim are:
1. To develop a set of numerical models for simulation of the most influential components within the variable flow systems.
2. Integration of the newly developed components of variable flow systems into the existing BPS tools.
3. Verification of the proposed integrated model using a set of laboratory experiments.
The outcome of this study will be applicable to the design of a variety of HVAC&R systems regardless of type and combination of primary and secondary systems. In addition, the proposed simulation approach can be adopted by those involved in commissioning of HVAC&R systems to provide quantitative measures for the assessment of often ignored phenomena such as starving, over-flow and the lack of controllability of the control devices in variable flow systems.