Heating Ventilation and AIr Conditioning System Condition Assessment Methodology

The purpose of an HVAC system is more than just warming or cooling a space.Instead, it serves to improve indoor air quality and provide comfort for everyone inside a building.It contains a boiler, chiller, cooling tower, Building Management System (BMS), Environmental Monitoring System (EMS) and air handling unit, the system is used to control the temperature of a designated space with the control of moisture in the air, supply the area with fresh air by controlling the CO2 and oxygen levels.It also controls the contamination of airborne particles by regulating the movement of air.During inspection it was found that the differential pressure of the pre-filters, fine filters were out of the defined limit and so was the temperature and RH limit.After survey of all complete HVAC system, the following major problems were found:1) Frequency of blower assembled in AHU system was found low from VFD.2) Pre-filter was found clogged.3) Chiller providing chilled water to the AHU's was found tripping at irregular time intervals.4) Heaters assembled in AHU's to control RH were not set properly as per the RH requirements.After identification of cases, following solutions are proposed for above mentioned problems: 1) In-case the differential pressure is found out of limits due to blower frequency being low, the frequency needs to be set at a high Hz to provide a better air flow to maintain the differential pressure within limits.2) Pre-filters need to be cleaned as per the frequency and differential pressure shall be monitored on regular basis to avoid uncertain differential pressure failure.3) Due to no load on AHU, the chiller was found tripping unexpectedly.The chiller should have an average HVAC load of minimum 30% of its capacity to avoid chiller tripping issues.4) The heater controller must be set at lower value with respect to the required value for example if RH requirement is 50% then the controller must be set at 45% to get the desired RH.