Investigation of a new solar-wind energy-based heat pump dryer for food waste drying based on different weather conditions

Abstract

To date, many studies endeavors have been undertaken regarding the provision of energy necessary for heat pump drying systems utilizing renewable energy resources. Conversely, the contemporary heat pump dryers require both electricity and heat concurrently, whilst the sporadic availability of a particular renewable energy source throughout the day necessitates the utilization of a combination of multiple renewable sources as a prospective remedy to these predicaments. The present research aims to assess the practicability of integrating photovoltaic and thermal collectors with wind turbines for the purpose of meeting the energy demands of a food waste drying system. A study was conducted to evaluate the performance of a dryer with a fixed weight of 100 kg and a moisture removal rate of 71.42 kg/h under varying climatic conditions in the cities of St. Petersburg, Yekaterinburg, Yakutsk and Khabarovsk, Russia. The investigation took into account four key factors, specifically energy, exergy, economy, and environment, over a period of one year. The thermodynamic outcomes derived from economic considerations indicate that an increase in dryer usage leads to a decrease in energy efficiency and a rise in energy expenditure. According to the empirical data, the optimum utilization of the dryer was recorded in Khabarovsk urban center as a consequence of the favorable climatic milieu which facilitated an efficacious moisture extraction rate of 51850.92 kg/year. Conversely, the city of Yakutsk demonstrated the lowest utilization frequency of the dryer, attributable to the unfavorable atmospheric conditions which hindered an effective moisture extraction rate, recording a minimal usage frequency of 27996.64 kg/year. The production of clean electricity and avoidance of natural gas for heating purposes in the cities of Khabarovsk and Yakutsk resulted in the attainment of the most pronounced decreases in carbon dioxide emissions, as indicated by the recorded figures of 47.53 tons and 25.32 tons, respectively. Consequently, following an economic evaluation pertaining to optimal repayment time, based on an interest rate of 0.03 %, the cities of St. Petersburg, Yekaterinburg, Yakutsk and Khabarovsk demonstrate repayment periods of 12.9, 12.6, 18, and 9.6 years, respectively.