In-Situ Energy Performance Analysis of A Hybrid-Fuel Heating System in A Net-Zero Ready Duplex

Abstract

The growing global population and increase in energy usage have led to a rise in greenhouse gas (GHG) emissions. The residential sector in Canada accounts for 17% of total secondary energy consumption and 14% of GHG emissions. To reduce energy consumption, operational costs, and GHG emissions, there is a need to promote the use of renewable energy and energy-efficient heating systems. One potential solution is a hybrid-fuel space and domestic hot water heating system that combines a conventional air-source heat pump (ASHP) with a natural-gas tankless water heater (TWH). This system can operate alternately between the ASHP and the TWH or use both based on system efficiency and time-sensitive energy cost, offering benefits such as a reduction in peak electric power demand on the grid and improved resilience during power outages. While laboratory experiments in existing literature have shown the advantages of this system, there is a lack of in-situ performance evaluations. Moreover, software tools for energy performance of buildings and their systems such as HOT2000 rely on default software values, such as system operation schedule. As a result, the prediction may not reflect in-situ performance and has not been reported in literature. This study presents an analysis of the in-situ energy performance of a duplex and their hybrid-energy heating systems, covering building energy consumption assessment, system space heating hourly output, lessons learned about building operations, and heating performance of the system. The study proposes an economical control strategy based on in-situ data or manufacturers specifications. Using the ANN model, the study proposes an approach to compare the energy performance between in-situ results and HOT2000 simulations. The life-cycle costs and energy performance of the hybrid energy heating system with other conventional heating systems are also compared. The study presents a comprehensive study of a hybrid-energy heating system and the results show potential for improvement in the system's energy efficiency.