An Optimal Battery-Free Approach for Emission Reduction by Storing Solar Surplus in Building Thermal Mass

2026-03-30

AI Summary

This study addresses the lack of carbon-aware objectives in existing building demand-side management and the environmental, economic, and durability challenges associated with battery-based energy storage. To overcome these limitations, the authors propose a novel battery-free, carbon-aware optimization strategy that leverages building thermal mass as a passive energy storage medium. By dynamically adjusting indoor temperature setpoints within thermal comfort constraints, the approach stores surplus photovoltaic generation as thermal energy to enable load shifting. The method integrates grid carbon intensity forecasting with model predictive control and is validated through simulations using a multi-zone thermal mass building model developed in TRNSYS. Results demonstrate that the proposed strategy significantly reduces grid electricity consumption across three building types, effectively enhances renewable energy utilization, and lowers carbon emissions.

Abstract

Decarbonization in buildings calls for advanced control strategies that coordinate on-site renewables, grid electricity, and thermal demand. Literature approaches typically rely on demand side management strategies or on active energy storage, like batteries. However, the first solution often neglects carbon-aware objectives, and could lead to grid overload issues, while batteries entail environmental, end-of-life, and cost concerns. To overcome these limitations, we propose an optimal, carbon-aware optimization strategy that exploits the building's thermal mass as a passive storage, avoiding dedicated batteries. Specifically, when a surplus of renewable energy is available, our strategy computes the optimal share of surplus to store by temporarily adjusting the indoor temperature setpoint within comfort bounds. Thus, by explicitly accounting for forecasts of building energy consumption, solar production, and time-varying grid carbon intensity, our strategy enables emissions-aware load shifting while maintaining comfort. We evaluate the approach by simulating three TRNSYS models of the same system with different thermal mass. In all cases, the results show consistent reductions in grid electricity consumption with respect to a baseline that does not leverage surplus renewable generation. These findings highlight the potential of thermal-mass-based control for building decarbonization.

Problem

• emission reduction
• battery-free
• thermal mass
• solar surplus
• building decarbonization

Innovation

• thermal mass
• battery-free
• carbon-aware optimization
• load shifting
• building decarbonization