The use of vertical axis wind turbines (VAWT) in Colombia could tackle the energy distribution difficulties as large parts of the territory are not connected to the electrical grid. The present research experimentally determines the wind resource available of a rural place known as Chicamocha’s canyon and selects the airfoil for a VAWT blade through CFD modeling. By using the mean wind speed of the location, the performance of the NACA0018 and DU06W200 airfoils is evaluated in terms of the lift and drag coefficients through a 2D CFD modeling using OpenFOAM and the “Spalart-Allmaras fv3” turbulence model. It is found feasible the use of wind energy at the location where the mean year density power is 485 [W/m2], and the DU06W200 airfoil is suggested for constructing the blades of a VAWT, as its aerodynamic efficiency (cl/cd) overcomes by 14% the commonly used NACA0018.

Buildings exhibit a high energy consumption compared with other economic sectors. While percentages vary from country to country, buildings are responsible for approximately 40% of the global energy demand. Most of this is consumed for achieving human thermal comfort. In Colombia, the government promotes policies for the adoption of efficient energy strategies in this sector. The earth to air heat exchanger (EAHE) can be used to reduce the cooling load of a building. Therefore, this study aims to evaluate the energy savings that can be obtained by installing an EAHE in a tropical climate in Colombia. To do so, a mathematical model is implemented in TRNSYS (Transient System Simulation Tool) to predict the thermal performance and the cooling capacity of the EAHE. The system is modeled as a function of pipe length, diameter, material, thickness and air mass flow. Moreover, soil, local atmospheric conditions and building features are taken into account. It is found that the air leaves the EAHE at temperatures between 20.9 °C and 24.1 °C, which are approximately 3 °C below ambient temperature. Furthermore, the economic feasibility of the project is verified. Thereby, it is demonstrated that the EAHE can be a competitive alternative to current HVAC systems.

The energy characterization of buildings can be done by bottom-up methods such as energy simulation models (samples or archetypes). A sample consists of the selection of real buildings and an archetype is a theoretical building that represents them. Nevertheless, both approaches have shortcomings for the creation of energy models. This work proposes to improve the sampling approach from the validation of input data, and calibration of models by individual adjustment processes. The studied category corresponds to multi-family buildings of median incomes from the Metropolitan Area of Bucaramanga (Colombia). This study presents the energy model of five existing buildings and an archetype, calibration results, energy characterization, and comparative analysis between both approaches. The sampling approach indicates that housing units and general services demand an average of 76.9% and 23.1% of consumed energy, respectively. The average energy consumption by housing units is 22.38 kWh/m2·year caused by appliances (85.3%), lighting (11.2%), and air conditioning (3.5%). The archetype presents similar results for the energy consumption of housing units (kWh/m2·year), but notable differences concerning a specific behavior of inner spaces, being the sampling approach more accurate to characterize to a building category.

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Combustion is the main method of converting biomass to energy, either by direct heating systems or by boilers. By means of CFD models, it is possible to optimize the behavior of those systems and improve significantly its performance, without incurring the economic and environmental cost of experimental studies. However, modelling of biomass combustion is a complex process that requires a large number of sub-models and computational resources for a detailed description, therefore, different approaches have been developed which depend on the system and simulation objective. In this work, a review of the state of art of modelling of solid biomass combustion in the last years is presented, including classification, description and analysis of several of the main models about the subject.