ZeroBuild Journal

Volume 4, Issue 2 of ZeroBuild Journal brings together four studies that address building energy performance from complementary perspectives: high-efficiency HVAC technologies, occupant-centred control, passive architectural design, and ventilation-related energy losses.

The issue opens with a review of water-source variable refrigerant flow (VRF) systems and their potential contribution to net-zero energy buildings. By comparing water-cooled and air-cooled configurations, the study highlights the higher coefficient of performance achievable with water-source systems, their reported energy-saving potential, and the opportunities offered by seawater- and lake-water-source applications. It also draws attention to the limited number of studies directly examining these systems within net-zero building projects.

The second article introduces a methodological pathway for psychology-sensitive HVAC devices. The proposed framework combines mood assessment, facial thermal measurements, wearable sensing, and adaptive HVAC control. By incorporating the Profile of Mood States (POMS) and real-time physiological data, the study extends thermal comfort research beyond conventional environmental and personal parameters and points towards more individualised, responsive, and energy-conscious indoor climate control.

A third contribution examines window position as an orientation-dependent passive design parameter. Using OpenStudio and EnergyPlus, thirty-six scenarios are analysed while window area and geometry remain constant. The findings show that relocating a window within the same façade has a limited effect on total annual energy use but can substantially alter solar heat gains and cooling demand. The study therefore underlines the importance of evaluating window position together with façade orientation, glazing properties, shading, and the seasonal heating-cooling balance.

The final article evaluates the effect of the area-specific ventilation air flow rate on the heating and cooling performance of an educational building using the TS 825:2024 calculation framework. The results demonstrate that excessive or uncontrolled air change increases annual energy demand, particularly during the heating season. Rather than reducing the necessary fresh-air supply, the study emphasises airtightness, controlled ventilation, demand-based operation, and heat recovery as appropriate energy-efficiency strategies.

Collectively, the papers in this issue demonstrate that progress towards zero-energy buildings requires the coordinated consideration of system efficiency, occupant needs, building-envelope design, ventilation control, and standards-based performance assessment.