Thermal simulation and cooling energy sensitivity analysis of a typical shophouse in Jakarta, Indonesia

In this paper, the results of simulating the cooling energy demand of a reference shophouse in Jakarta, Indonesia are presented. The building reference is a two-storey shophouse, of which ground floor is used as a shop and upper floor as a dwelling. The simulation and visualization tool used was DesignBuilder v.1.8 (www.designbuilder.co.uk, 2008), an Energy Plus based dynamic thermal simulation engine. First of all, a reference building was simulated, in order to obtain its cooling energy demand. The parameter setting for building envelope of this reference building was based on the data provided by the planner, PT. Jaya Real Property, Tbk. Subsequently a sensitivity analysis was done with the aim of obtaining the parameters that contribute significantly to the decrease of annual cooling energy demand. The parameters investigated were roof construction and insulation, building orientation, SHGC value, the value that represent the glazing’s effectiveness in rejecting solar heat gain, and operating time and power of the cooling device. The simulation results show that building facing to the south gives the lowest annual cooling energy demand than other buildings which have north orientation, north-east orientation and south-west orientation, that is 3.65% less cooling energy demand than the reference building which has north orientation. SHGC of the glass will also contribute to the decrease of the annual cooling energy demand. By decreasing 50% of SHGC value will reduce annual cooling energy demand by 8.3%. It is also found that for a ventilated sloping roof construction, applying roof insulation has no significant effect on the reduction of annual cooling energy demand, except for the case that the schedule of the air conditioning in the upper floor is 24 hours always on. In the case of flat roof construction, insulated flat roof will give approximately the same effect as sloping roof. By limiting the power of the cooling device to 2kW which means reducing the investment cost, will reduce annual cooling energy demand by 2.07% of the building without roof insulation.