A comparison study of HVAC load and energy consumption by varying wall materials of a residential building

Abstract

HVAC system is the most prominent system responsible for utilization of energy in any household. This operation of HVAC costs massively for overall energy consumption of a residential building. However, with preliminary study on design factor of any residential building that accommodates for less HVAC load and can result in less economic burden for operation can help for lessening HVAC load and overall cost of energy. Model house with all the floor plans and elevation view has been created in Autodesk Revit. Autodesk Revit is a modelling software for designing buildings and various infrastructure used by architects, mechanical engineers, and structural engineers. In this case study of residential building, wall material varied twelve times with widely used wall material in the context of Nepal during preliminary study of design of this building. Mixed type of wall material has been used in this study. Common brick wall with variation as AAC block, CLC block, ply board and Cement board is used. HVAC system used for the building is ASHRAE package terminal heat pump. HVAC load for each type of wall material of the building has been calculated with Radiant Time Series Method defined by ASHRAE in Autodesk Revit. Also, the gbxml file of this model has been extracted and run for energy simulation using Green Building Studio. Equipment and furniture inside of the house has been considered for this calculations. Energy consumed by these equipment and heat produced by light has been considered. HVAC load of building for each kind of wall material has been calculated from the Autodesk Revit itself. Likewise, energy consumption by the building for each kind of wall material has been calculated from simulation feature of Autodesk DOE-2.Eventually energy cost has been calculated. So the final results suggests mixed wall type of brick with 8 inch CLC block wall as inner wall material most accommodates for less HVAC load in the residential building which resulted in least energy consumption and finally least energy cost. HVAC heating load with this combination was found to be 18,938 Watt and cooling load was found to be 6273 Watt. The annual energy consumption was 61.1 % of total energy use. Also, energy cost of this combination was found to be Rs. 253848.7 which is least of all the combination. Hence with use of eight inches CLC block as wall material one can benefit from least energy consumption and energy cost.