Environmental Progress and Sustainable Energy, vol.42, no.6, 2023 (SCI-Expanded)
Combined heat and power (CHP) systems, an effective way of meeting high energy demand with high efficiency, were adapted to existing large service buildings in most studies. Because of the large daily and seasonal fluctuations in energy and electricity demands of the buildings, optimization problems have come into view and have been studied. This study propounds a holistic design solution for the CHP systems' inadequacy to meet varying consumer energy demands in residential and the excessive electricity demand created by cryptocurrency mining. In addition, the study defines the possible high efficiency and sustainability for residentials producing and consuming heat and electricity by themselves. An energy-conservative three-block residential and a CHP system were projected together by a holistic view balancing the residencies' peak thermal demand to the thermal output capacity of the CHP system. The investment return rate of the CHP system was maximized by optimizing the thermodynamic efficiencies and maximizing the electric generation for cryptocurrency mining. The energetic efficiency increased from 40% to an energy utilization factor of 83%, and exergetic efficiency increased from 39% to 42%. The waste-exergy ratio decreased from 61% to 58%. The engine's environmental effect factor was 1.56 and reduced to 1.38 with the CHP system. The exergetic sustainability index was improved from 0.64 to 0.72. The benefit–cost ratio was estimated as 1.6, with an internal return rate of 79%. Holistic designs considering common values should be considered to improve sustainability.