Comparison of Heating and Cooling Loads of a Typical Building with TRNSYS and eQUEST

Abstract

The energy performance of buildings can be estimated using various software which use different models for this simulation. It is important to know the value of heating and cooling loads of buildings in order to design the optimum system in every case for minimize the cost and the fuel or electricity consumption. In this study, the loads of a typical building are calculated by two different software, TRNSYS and eQUEST. These programs have different strategy in the loads calculation fact that makes this comparison important in order to validate the results.

A one-zone building of 100 m² area with four external insulated walls directed in the four orientations is analyzed. All the external walls include double glass windows except from the north wall. The building is located in Athens, where there are average heating loads and great cooling loads. Internal loads from lighting, people and equipment are taken into consideration in order to create a typical building. Simultaneously, this building is parametrically examined by changing the windows area, the infiltration rate, the building orientation and the insulation thickness of the external walls. The calculation of the loads in eQUEST are indirect and are become with the use of the coefficient of performance. Also the strategy for the lighting is different because of TRNSYS controls the outside irradiation and the eQUEST use inside controllers. The final results show that TRNSYS gives greater loads about 5 % in the study case and in the most cases of the parametrical analysis TRNSYS gives greater loads. Moreover, a monthly comparison is presented which proves that the results are close to each other.