Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Combined solar-heat pump systems for heating diesel power plants in standby mode
Submission Author:
Gabriel Pereira , SC
Co-Authors:
Gabriel Pereira, Bruna de Oliveira Busson, Victor César Pigozzo Filho, Júlio Passos, Alesson Itallo Ribeiro Dias da Silva, Luciano Barbosa
Presenter: Gabriel Pereira
doi://10.26678/ABCM.COBEM2023.COB2023-1201
Abstract
In the context of high penetration of photovoltaic (PV), which is heavily dependent on environmental conditions, dispatchability has become a very important characteristic of energy generation. Diesel power plants have the advantage of operating whenever they’re needed. To keep a diesel power plant in standby mode, there needs to be a constant source of heat to keep it at 63°C. This process usually burns diesel in auxiliary boilers. This paper considers the case of a power plant in the semi-arid region of Pernambuco, which uses diesel-fueled steam generators to provide hot water for their diesel engines to keep them in standby mode. This work analyzes the viability of using photovoltaic-thermal solar collectors and a heat pump to warm the engines and keep them in standby mode. Three configurations were modeled in the software TRNSYS. The parameter chosen for comparison was the thermal fraction, which represents the fraction of heat that was generated by the thermal collectors and heat pump. Configuration 1 is an array of photovoltaic-thermal solar collectors used as a source of heat and electricity. The solar panels heat the water from ambient temperature up to about 45°C. Then, the water is transported to a water-water heat pump, which is powered by the electrical energy from photovoltaic-thermal collectors, and is used to heat the water feeding the engine up to 63°C. Configuration 2 is an air-water heat pump used to heat the engine’s water up to 63°C. The heat pump is partially powered by PV modules. Configuration 3 is composed of solar thermal collectors used to directly heat the water that is feeding the engine. In all configurations, an auxiliary boiler is used in case the system can’t generate enough heat. Solar collectors were chosen as a cost-effective long-term alternative due to the abundance of excellent solar resources in the region and their independence from external fuel requirements. Preliminary solutions show that Configuration 1 offers the best thermal fraction, however, it is the most complex model and with more components. All configurations are viable alternatives to diminish the diesel usage in the power plant, especially in Configurations 1 and 2, which provide estimated yearly savings of US$ 52,731.87 and US$ 47,964.79, respectively. These configurations, however, may have a higher initial cost due to their need for more components.
Keywords
thermal photovoltaic system, diesel consumption reduction, combined solar-heat pump systems, diesel power plant
