• Energy Research

Resumen A partir de modelos inmobiliarios vigentes, se analiza la posibilidad de construir viviendas que abastezcan demandas energéticas propias y provean energía excedente (Plus-Energy House),. Para ello se revisa un catastro de tipologías y estadísticas de consumos, seleccionando un caso representativo en el que se proponen alteraciones de diseño pasivo y se ejecutan simulaciones energéticas integrando tecnologías activas en las que se determina una producción factible frente a las demandas. Se despliegan tecnologías solares en integración arquitectónica BIPV, BISTw, BIPVTa y BIPVTw individualmente o combinadas buscando maximizar la capacidad de producción para autoconsumo, comparándose temporalmente con demandas características para identificar déficits y excedentes característicos promedios de días representativos de verano, invierno y de épocas interestacionales. Por último se obtiene el balance anual, el cual refleja un abastecimiento de aproximadamente el 174 % al desplegarse solamente tecnología BIPV y 251 % al integrar tecnologías híbridas térmicas fotovoltaicas con fluido líquido y fluido aire (BIPVTw) (BIPVTa).

Abstract The photovoltaic solar potential in an urban sector and the effects produced by the electricity input into a low-voltage grid are determined, the analysis is performed for one year. First, the generation profiles are estimated, assuming the incorporation limits of typical silica panels and using photovoltaic (PV) tiles on roofs as an architectural alternative. Then, the consumer class demand is estimated. Production-demand matching is performed at the load point level to avoid impacts on the grid. A scenario incorporating a new load, induction heating cookers (IHCs) for all residential users, is posed, the use of which coincides with high-radiation hours. Finally, electrical storage is assumed to maximise the PV supply. A 16% coverage with silica PV panels, or 33% with PV tiles, would supply 46% or 39% of the consumption, respectively. With massive incorporation of IHCs and storage, the supply is increased to 73% and 59% of the consumption with silica panels and PV tiles, respectively. An annual consumption reduction of 16 Tn of liquefied petroleum gas is attained in the cases studied. Additionally, it is necessary to redirect the current subsidies for hydro dams and the overall energy sector towards promoting distributed microgeneration.

Ecuador, like every country in the world, urgently requires a conversion of transportation to electric power, both for economic and environmental reasons. This paper focuses on the technical and economic feasibility of a solar-powered electric charging station equipped with battery storage in Cuenca, Ecuador. By reviewing current literature, we assess the environmental impact of electric mobility and its potential to reduce fossil fuel dependence and generate energy savings. The analysis encompasses various factors, including EV energy consumption, solar energy system sizing, energy production, and battery storage capacity. Key findings indicate that integrating solar PV systems with EV charging stations efficiently supports a reliable and sustainable energy supply. Simulation results reveal seasonal variations in solar generation, highlighting the importance of proper system sizing to maintain charging supply reliability and manage surplus generation. The economic analysis of three scenarios underscores the financial viability of implementing PV systems without battery storage, yielding a positive Internal Rate of Return (IRR) and Net Present Value (NPV). However, scenarios with battery storage present negative NPV and long investment return periods, impacting economic viability negatively. These insights underscore the need for a balanced design to ensure sustainability and economic feasibility in the transition to electric mobility.

The energy requirements for dwellings in tropical equatorial climates are significant and ongoing throughout the year. Fortunately, significant and stable irradiation exists. We propose the redesign of a local-style, single-family home with a layout for a typical family of four. The methodology consists of real data on the electricity consumption of an existing case of a typical family, which is considered the source of the energy requirements to determine improvements. Once the house is characterized, it is redesigned. Its energetic behaviour is simulated with virtual tools such as ArchiCAD from Graphisoft and DesignBuilder to introduce passive strategies. Photovoltaic (PV) electrical self-supply of the building is integrated, and the inclusion of electric vehicles is considered. The house is virtually built as a dwelling with similar functions, but solar passive and active strategies are integrated to achieve high energy performance. The roof envelope configuration is the main energy source, and interior overheating is the cause. An initial reduction of 36.97% in energy requirements with only passive strategies and a double-ventilated roof is estimated. When simulating PV capability with the System Advisor Model software, nine standard PV 380 Wp panels are sized for the roof to meet the estimated power requirements, and nine additional units are needed to supply electric transportation sufficient for a single family. A model that can scalably integrate PV in accordance with demand is proposed.

Transportation consumes approximately 29% of the world's energy and is responsible for approximately 25% of CO2 emissions worldwide. In Cuenca, Ecuador, fossil fuels for transportation represent 59.9% of total energy consumption. Ecuadorian legislation has specified gradually replacing traditional public bus transport units with electric units. Because the relevant costs include those associated with replacing equipment and improving route networks, alternatives that prioritize incorporating the first units on the best routes are being sought. This work establishes a methodological process with a set of tools to prioritize the gradual migration from conventional to electric buses according to the characteristics of each route. The Preference Ranking Organization Method for Enrichment of Evaluation (PROMETHEE) multicriteria technique is used to detect the best routes according to technical, social, environmental, economic and location criteria. A final rank of routes is obtained using Visual PROMETHEE software. After the values defining each criterion and its corresponding weight were processed, the final ranking makes it possible to prioritize one route before others. Given 23 lines and 475 bus units, the method enabled us to determine that in an initial phase, 68 electric buses are required to be used on five lines to reduce fuel consumption. The factors that most influence decision making are the number of passengers served, the length of the trip and the energy required by the route.

Un outil de simulation populaire pour prédire la performance solaire thermique (ST) est le modèle F-chart, qui n'a pas été validé pour les conditions dans les pays à climat équatorial. Dans ce travail, la performance de deux systèmes ST (collecteurs à tubes sous vide (ETC) et collecteurs à plaques plates (FPC), largement utilisés pour l'alimentation en eau chaude sanitaire (ECS) a été évaluée et comparée aux résultats de simulation du diagramme en F. Les besoins en énergie ont été simulés en planifiant les rejets d'eau chaude et en mesurant les besoins en énergie de secours pour répondre aux besoins en eau chaude sanitaire. Ensuite, la différence entre la fraction solaire calculée à l'aide du modèle F-chart et la fraction solaire mesurée a été obtenue. Les mesures et les simulations ont montré que les systèmes ETC fonctionnaient mieux que les systèmes FPC dans une ville située sur les hauts plateaux équatoriens avec des conditions climatiques distinctes. Les résultats ont montré que les systèmes ETC sont, en moyenne, jusqu'à 18,5 % plus efficaces que les systèmes FPC. Une analyse économique comparative a été réalisée en considérant que les systèmes de chauffage de l'eau domestique sont soutenus par du gaz de pétrole liquéfié (GPL) ou de l'électricité, avec et sans subventions de l'État. Cependant, en raison du coût plus élevé de la technologie ETC par rapport à la technologie FPC, et malgré l'efficacité plus élevée de l'ETC par rapport aux FPC, seulement 0,34 USD par mois peut être économisé en moyenne en raison de l'impact des subventions énergétiques. Ainsi, la technologie FPC semble plus rentable, dans les conditions mentionnées, en raison de ses coûts d'investissement plus faibles. Avec des systèmes de secours alimentés par de l'énergie non subventionnée, les deux technologies sont presque comparables. La technologie ETC ne semble convenir que dans le scénario de l'électricité non subventionnée. La nouveauté de cette recherche est que de vrais systèmes ST installés dans des conditions similaires sont intégrés, le fonctionnement des technologies ST pour DWH est simulé et les différentes inclinaisons et orientations des capteurs solaires sont prises en compte. Les résultats sont comparés aux simulations du modèle F-chart, et chaque système est évalué économiquement. Una herramienta de simulación popular para predecir el rendimiento solar térmico (ST) es el modelo de gráfico F, que no se ha validado para las condiciones en los países de clima ecuatorial. En este trabajo, se evaluó el rendimiento de dos sistemas ST (colectores de tubos de vacío (ETC) y colectores de placa plana (FPC), ampliamente utilizados para el suministro de agua caliente sanitaria (ACS) y se comparó con los resultados de la simulación del gráfico F. Las demandas de energía se simularon programando descargas de agua caliente y midiendo los requisitos de energía de respaldo para satisfacer las necesidades de ACS. Luego, se obtuvo la diferencia entre la fracción solar calculada utilizando el modelo de gráfico F y la fracción solar medida. Tanto las mediciones como las simulaciones mostraron que los sistemas ETC funcionaron mejor que los sistemas FPC en una ciudad ubicada en el altiplano ecuatoriano con distintas condiciones climáticas. Los resultados mostraron que los sistemas ETC son, en promedio, hasta un 18,5% más eficientes que los sistemas FPC. Se realizó un análisis económico comparativo considerando que los sistemas domésticos de calentamiento de agua están respaldados con gas licuado de petróleo (GLP) o electricidad, tanto con como sin subsidios estatales. Sin embargo, debido al mayor costo de la tecnología ETC en comparación con la tecnología FPC, y a pesar de la mayor eficiencia de ETC que las FPC, solo se pueden ahorrar US$ 0.34 por mes en promedio debido al impacto de los subsidios energéticos. Por lo tanto, la tecnología FPC parece más rentable, en las condiciones mencionadas, debido a sus menores costes de capital. Con sistemas de respaldo alimentados por energía no subsidiada, las dos tecnologías son casi comparables. La tecnología ETC parece adecuada solo en el escenario de electricidad no subsidiada. La novedad de esta investigación es que se integran sistemas de ST reales instalados en condiciones similares, se simula el funcionamiento de las tecnologías de ST para DWH y se consideran las diferentes inclinaciones y orientaciones de los colectores solares. Los resultados se comparan con las simulaciones del modelo de gráfico F, y cada sistema se evalúa económicamente. One popular simulation tool for predicting solar thermal (ST) performance is the F-chart model, which has not been validated for the conditions in equatorial-climate countries. In this work, the performance of two ST systems (evacuated tube collectors (ETCs) and flat plate collectors (FPCs), widely used for supplying domestic hot water (DHW) was assessed and compared with F-chart simulation results. The energy demands were simulated by scheduling hot water discharges and measuring the backup energy requirements to fulfil DHW needs. Then, the difference between the calculated solar fraction using the F-chart model and the measured solar fraction was obtained. Both the measurements and simulations showed that the ETC systems performed better than the FPC systems in a city located on the Ecuadorian highlands with distinct climate conditions. The results showed that ETC systems are, on average, up to 18.5% more efficient than FPC systems. A comparative economic analysis was carried out considering that domestic water heating systems are backed up with liquified petroleum gas (LPG) or electricity, both with and without state subsidies. However, due to the higher cost of ETC technology compared to FPC technology, and despite ETC's higher efficiency than FPC's, only US$0.34 per month can be saved on average because of the impact of energy subsidies. Thus, the FPC technology seems more profitable, under the mentioned conditions, because of its lower capital costs. With backup systems powered by unsubsidized energy, the two technologies are nearly comparable. The ETC technology appears suitable only under the unsubsidized electricity scenario. The novelty of this research is that real ST systems installed under similar conditions are integrated, the operation of ST technologies for DWH is simulated, and the different inclinations and orientations of solar collectors are considered. The results are compared with simulations from the F-chart model, and each system is economically assessed. إحدى أدوات المحاكاة الشائعة للتنبؤ بالأداء الحراري الشمسي (ST) هي نموذج المخطط F، والذي لم يتم التحقق من صحته للظروف في البلدان ذات المناخ الاستوائي. في هذا العمل، تم تقييم أداء نظامين ST (مجمعات الأنابيب المفرغة (ETCs) ومجمعات الألواح المسطحة (FPCs)، المستخدمة على نطاق واسع لتزويد المياه الساخنة المنزلية (DHW) ومقارنتها بنتائج محاكاة المخطط F. تمت محاكاة متطلبات الطاقة من خلال جدولة تصريفات المياه الساخنة وقياس متطلبات الطاقة الاحتياطية لتلبية احتياجات DHW. بعد ذلك، تم الحصول على الفرق بين الجزء الشمسي المحسوب باستخدام نموذج المخطط F والجزء الشمسي المقاس. أظهرت كل من القياسات والمحاكاة أن أنظمة ETC كان أداؤها أفضل من أنظمة FPC في مدينة تقع على المرتفعات الإكوادورية ذات الظروف المناخية المتميزة. أظهرت النتائج أن أنظمة ETC، في المتوسط، أكثر كفاءة بنسبة 18.5 ٪ من أنظمة FPC. تم إجراء تحليل اقتصادي مقارن مع الأخذ في الاعتبار أن أنظمة تسخين المياه المنزلية مدعومة بغاز البترول المسال أو الكهرباء، مع دعم الدولة وبدونه. ومع ذلك، نظرًا لارتفاع تكلفة تقنية ETC مقارنة بتقنية FPC، وعلى الرغم من كفاءة ETC الأعلى من FPC، لا يمكن توفير سوى 0.34 دولار أمريكي شهريًا في المتوسط بسبب تأثير دعم الطاقة. وبالتالي، تبدو تقنية FPC أكثر ربحية، في ظل الظروف المذكورة، بسبب انخفاض تكاليفها الرأسمالية. مع أنظمة النسخ الاحتياطي التي تعمل بالطاقة غير المدعومة، فإن التقنيتين قابلتان للمقارنة تقريبًا. تبدو تقنية ETC مناسبة فقط في ظل سيناريو الكهرباء غير المدعوم. حداثة هذا البحث هي أن أنظمة ST الحقيقية المثبتة في ظل ظروف مماثلة متكاملة، ويتم محاكاة تشغيل تقنيات ST لـ DWH، ويتم النظر في الميول والاتجاهات المختلفة لمجمعات الطاقة الشمسية. تتم مقارنة النتائج مع عمليات المحاكاة من نموذج المخطط F، ويتم تقييم كل نظام اقتصاديًا.

Cities are human creations requiring large amounts of materials and energy. Constant consumption of resources exerts pressure on the environment not only due to its exploitation, but also because once processed, the resources produce waste, emissions or effluents. Cities are responsible for more than three quarters of the emissions of greenhouse gases. It is anticipated that the urban population will increase by up to 80% by the mid-21st century, which will make the current energy model unsustainable, as it is based on the intensive use of fossil resources. A change in urban planning is required to meet the energy requirements of cities. Several studies mention that renewable energy must be used in cities, but they do not identify the resources and technologies that can be used to promote circular urban metabolism. A review of the literature establishes that there are eleven renewable technologies with different degrees of maturity that could reduce the import of energy resources, which would contribute to changing the metabolic linear model into a circular model. However, the applicability of the different possibilities is conditional upon the availability of resources, costs, policies and community acceptance.

The use of photovoltaic (PV) technology in urban areas is an appropriate way to optimize the use of solar energy, since the energy conversion system is located in the same place as the demand. Thus, the losses caused by distribution networks and even technology costs are reduced; in addition, less space is required for energy production in the countryside. Energy can be produced in neighbourhood dwellings located in the periphery in low-density areas that contribute to supplying electricity to high-density urban centres. The performance of a solar system largely depends on the integration capacity of solar panels in building roofs or facades to maximize production. This research has analysed the integration of this type of system in the roofs of new types of housing in developing countries and its adaptability attributable to the geometry of solar panels with regular-sized mono- and polycrystalline cells. This research is based on 32 sloped roof typologies built since 2010. The main results indicate that an average of 36% of the roof surfaces are not useful because of their irregularity; in addition, the small solar panels show more adaptability, although less than expected with respect to large-format PV panels.