Publication

Abstract : This thesis comprises the study of existing ‘Clivet’ type Heating, ventilation, and air conditioning system (HVAC) used in the industry to improve the performance of existing HVAC system. In commercial sector for air conditioning system 50 - 65% of the electrical energy is used in the HVAC system. Part of the energy is used for useful operation whereas remaining is lost as a heat. So the optimization of energy in this system plays a vital role. To optimize the energy the existing ‘Clivet’ type HVAC systems duct network is drawn using Solid works 2012 software and the air flow analysis in the existing network through flow simulation is carried out to know the performance of the existing system. From the air flow analysis through solid works flow simulation software it is clearly stated that the simulation results are more or less equal when compared to existing systems performance. Then the actual air velocity at each diffuser outlet is measured in the industry by using anemometer device and the total air volume is calculated. By comparing the designed air volume of the existing unit and the actual volume of the air flow through the duct network, it is evident that the amount of air volume in particular room is higher than the required level. The flow simulation analysis is continued for the existing system by varying the design parameters like duct bend radius, cross sectional area of the duct. The energy loss may occur when the duct bend is sharp so the design modification at the duct bend is varied by 5mm from 150mm – 165mm (existing system 150mm) and the results are evaluated. From this result the mass flow rate of the air through the duct network is increased by increasing the bend radius. So the amount of air volume entered through the zone is also increased which can be controlled by adjusting the damper. And thereby the collision of the air molecules at the duct bend is reduced. The energy loss occurred in the duct network is because of the friction of the air molecule at the inner surface of the duct network. This friction loss will cause the energy loss in the duct network. In order to minimise the energy loss the existing systems bend radius can be varied and found that the increasing in the bend radius can reduce friction loss and suggested that the radius of 154-155 mm can be suitable to minimise the energy consumption. Then the heating and cooling load calculations are carried out. From the calculations it is found that the motor, pump, and fan in the air handling unit consume more energy. From the calculation of fan coil unit and pumping unit it is consuming Rs 2728 and Rs 4960 respective per month. To reduce the energy cost the air cooled condenser can be replaced in place of water cooled condenser which can produce hot water that can be used for heating purpose and reduce the energy used for fan coil unit. The required modifications, replacements and the necessary steps required to operate the air handling unit is discussed and the proper maintenance and controlling of the existing HVAC systems air handling unit is suggested to the industry to save the energy.