Low-energy opportunity for multi-family residences: A review and simulation-based study of a solar borehole thermal energy storage system

• Published in: Energy (Oxford) Vol. 204; p. 117870
• Main Authors: Elhashmi, Rodwan, Hallinan, Kevin P., Chiasson, Andrew D.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2020; Elsevier BV
• Subjects: Boreholes; Carbon; Computer simulation; Construction; Cost analysis; Cost control; Energy; Energy conservation; Energy efficiency; Energy storage; Ground heat exchanger; Heat exchangers; Heat pumps; Life cycle analysis; Life cycle costs; Multi-family building; Optimization; Residential buildings; Retrofitting; Solar collectors; Solar energy; Thermal energy; Thermal energy storage; Water demand; Water heating; United States > US; Thermal energy storage; Ground heat exchanger; Energy; Multi-family building
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2020.117870

The multi-family residential building sector is the least energy efficient in the United States, thus allowing for ample opportunities for significant cost-effective energy and carbon savings. In the present study, we propose a district solar borehole thermal solar energy storage (BTES) system for both retrofit and new construction for a multi-family residence in the Midwestern United States, where the climate is moderately cold with very warm summers. Actual apartment interval power and water demand data was mined and used to estimate unit level hourly space and water heating demands, which was subsequently used to design a cost-optimal BTES system. Using a dynamic simulation model to predict the system performance over a 25-year period, a parametric study was conducted that varied the sizes of the BTES system and the solar collector array. A life-cycle cost analysis concluded that is it possible for an optimally-sized system to achieve an internal rate of return (IRR) of 11%, while reducing apartment-wide energy and carbon consumption by 46%. Both a stand-alone and solar-assisted ground-source heat pump system were designed and simulated for comparison to the BTES system, and found to be less economically favorable than the solar BTES system. Thus, the promise for district-scale adoption of BTES in multi-family residences is established, particularly for new buildings. •Multi-family dwellings have few options or incentives for improving energy efficiency.•A district BTES system utilizing solar heat was proposed for a multi-family dwelling.•Parametric system simulations used actual heating loads derived from utility data.•All heating and hot water loads can be met without the need of a heat pump.•A solar-BTES appears economically viable in a moderately cold climate.