Experimental study on the control of HVAC system

Abstract

This report presents on the experimental study that was done based on the aim of achieving accurate airflow measurement. Airflow measurement is a pre-requisite to achieve a balanced air flow system. Based on existing research, there been evidences to support that it is important to have a precise flow measurement to ensure that a balanced system in the air distribution system which will address thermal comfort, ensuring system efficiency and energy savings in the long run during operational days.

HVAC system is designed to achieve energy savings and to provide thermal comfort for the occupants. It is responsible for the significant proportion of the total energy consumption of the building and it plays an important role to ensure that the building is well-ventilated. It all narrows down to the sensors and the controls that are implemented in the system. The sensors will detect the physical quantities which will then be converted to an electrical signal, this signal will inform the system whether additional or a reduced in cooling is required to reach its setpoint. Challenges encountered by air balancing system are often found to be the precision of the airflow measurement and lack of a systematic balancing approach in HVAC system. Many of the air balancing approach are dependent on the measurement of flowrate in ductworks. Hence this shows the significance of having an accurate airflow measurement in the system.

The purpose of the experimental study is to verify that the k coefficient is constant and to determine the relationship between the airflow and the differential pressure. Data collection is performed on an existing air duct system in the laboratory via a series of algorithm in MATLAB to collect readings for both airflow rates and differential pressure readings for the respective damper angles. After the collection, another series of algorithm is created to analyse the set of data collected via linear regression.