Shikang Wen / 温世康

Shikang Wen / 温世康

Research in building energy, computational design, and intelligent built environments.

Terminal devices, thermal comfort, and ventilation uniformity

Published research May 2026

Overview

This field study compared how three terminal systems - fan-coil units, gravity cabinet units, and radiant surface systems - affect ventilation distribution and vertical temperature uniformity in an office building in Suzhou.

Floor plans of the three test offices marking five measurement points and the ventilation outlets, alongside photographs of the rooms.
The three test offices in Suzhou, showing measurement points and ventilation outlet positions.

Method

Measurements were conducted under summer cooling and winter heating conditions. Local air-change rates were derived from carbon-dioxide decay, while air temperatures were measured at multiple locations and heights to quantify ventilation uniformity and vertical stratification.

Schematic diagrams of a fan coil unit, a gravity cabinet unit in cooling and heating mode, and a radiant ceiling panel and radiant floor.
The three terminal devices compared: fan-coil unit, gravity cabinet unit, and radiant surface system.
Schematic of the shared HVAC system with pre-filter, mix box, coil, and heat pump, paired with a psychrometric chart of cooling and heating modes.
All three rooms share one air-handling system, so only the terminal device differs between cases.

Key findings

All three systems maintained ankle-to-head temperature differences below 2 °C in both seasons. Fan coils provided the most consistent year-round performance; gravity cabinet units produced the best thermal uniformity during cooling but the greatest stratification during heating; and the radiant system delivered the most uniform heating conditions, with weaker ventilation uniformity during cooling.

Air change rate profiles against height at five measurement points for each terminal system under winter heating, annotated with coefficients of variation.
Local air-change rates under winter heating; the radiant system holds the coefficient of variation below 5.5%.

Contribution

Conceptualization, data curation, methodology, software, visualization, and original-draft writing.