A Cogeneration System for a Heavy-Snow fall Zone Based on Aquifer Thermal Energy Storage

Abstract

A combination of a cogeneration system and an aquifer thermal energy storage method, known as Co-Gene ATES, has been investigated numerically, based on the performance of fundamental elements of the system as obtained experimentally in previous investigations in a heavy-snowfall zone. The results obtained were as follows: (1) The yearly total coefficient of performance of Co-Gene ATES was estimated at 3.04, and the energy cost was a quarter of that of a conventional system. (2) In a comparison of Co-Gene ATES with conventional equipment, a financial break-even point of 6.3 years was estimated from an economic feasibility study, taking the recovery factor in the charge well as 60% and the increase in fuel cost as 1%, which in turn led to a 3% increase in the cost of electricity. (3) We proposed a method that estimated the optimum condition of system by the life gain. When the lifetime of Co-Gene ATES is 15 years, the optimum condition is that the proportion of snow-melt road area to total road area is 100%, and that of snow-melt roof to total roof area is 0%; financial break-even point of 3.3 years and a life gain of 9 hundred million yen were estimated.