Work

Experimental and numerical assessment of a hybrid EAHE–HVAC system under sliding mode control for indoor temperature and CO2 regulation

Year: 2026

Type: article

Abstract: This study investigates the performance of an Earth-to-Air Heat Exchanger (EAHE) coupled with an Heating-Ventilation-Air-Conditioning (HVAC) unit in a small experimental building. A thermal and CO 2 model was developed and validated with three days of winter measurements from Sal´e, Morocco. A Sliding Mode Control (SMC) strategy was implemented to regulate indoor temperature and CO 2 simultaneously. The model reproduces the measured temperature within about ±0.9 °C and the CO 2 levels within roughly 10 ppm, which is inside the sensor accuracy. Three operating modes were analysed: EAHE alone, HVAC alone under SMC, and a hybrid EAHE + HVAC configuration. Compared to the HVAC-only baseline, the hybrid mode reduces heating demand by about 17% and peak power by around 22%, while maintaining temperature and CO 2 within comfort limits. These results show that combining a passive EAHE with a robust nonlinear controller can improve indoor comfort and reduce heating energy use in small laboratory buildings.

Source: Case Studies in Thermal Engineering

DOI: 10.1016/j.csite.2025.107637

Authors: Yasmine Tiouti, Soukayna Berrabah, Zineb Bouhssine, Kenza Oufaska, Radouane Ouladsine, Mohamed Bakhouya

Institution: International University of Rabat

Language: English

Topic: Building Energy and Comfort Optimization

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDGs: Climate action, Affordable and clean energy

Open Access status: gold

Estimated APC paid: $1,620