Techno-Economic Assessment of a Hybrid Gas Tank Hot Water Combined Heat and Power System

Brent B Skabelund,Ryan J Milcarek,Joseph Elio

doi:10.3390/su132313040

Abstract

Combined heat and power (CHP) systems with an integrated solid oxide fuel cell (SOFC) is a promising technology to increase overall efficiency of traditional residential combustion systems. One potential system is gas tank hot water heaters where partial oxidation of the fuel serves as a means of fuel reforming for SOFCs while producing thermal energy for heating water. In this study, a residential hybrid gas tank hot water heater with an integrated SOFC model was developed and a thorough techno-economic analysis was performed. Fuel-rich combustion characterization was performed at equivalence ratios 1.1 to 1.6 to assess synthesis gas production for the SOFC. The effect of fuel utilization and operating voltage of the model SOFC stack were analyzed to provide an in-depth characterization of the potential of the system. CHP and electrical efficiencies over >90% and >16% were achieved, respectively. The techno-economic analysis considers the four major census regions of the United States to evaluate regional savings based on respective utility costs and hot water demand. The results show the hybrid system is economically feasible for replacement of an electrical water heater with the longest payback period being approximately six years.

Highlights

The use of combined heat and power (CHP) systems is expected to increase in popularity worldwide with an estimated global capacity increase from 864.2 GWe in 2018 to1051 GWe by 2025 [1]
CHP systems benefit from the ability to provide greater energy independence and lower energy costs, making them more economically competitive compared to stand-alone systems
The performance of the hot water heater was dependent on the operating conditions including the fuel-rich combustion equivalence ratio, the operating voltage of the FFC, and the fuel utilization of the FFC

Summary

Introduction

The use of combined heat and power (CHP) systems is expected to increase in popularity worldwide with an estimated global capacity increase from 864.2 GWe in 2018 to1051 GWe by 2025 [1]. The use of combined heat and power (CHP) systems is expected to increase in popularity worldwide with an estimated global capacity increase from 864.2 GWe in 2018 to. Known as cogeneration systems, CHP systems produce electricity while supplying thermal energy for heating purposes. The combined electrical and thermal energy generation in a CHP system results in an overall efficiency of 65–85% compared to 45–55% when the two devices are separated [3]. CHP systems benefit from the ability to provide greater energy independence and lower energy costs, making them more economically competitive compared to stand-alone systems. The capacity of these installations varies depending on the industry sector implemented in, from kilowatts up to a gigawatt [2].

Methods

Results

Conclusion