Optimized operation method for an active chilled beam with VAV system

Abstract

The chilled beam system is a popular energy saving system and it has been applied in Europe, the United States, and other countries for many years. There are two main types of chilled beams, such as the active chilled beam and passive chilled beam. The active chilled beam operates on the primary airflow, which induces airflow from the space through the cooling coil. This provides much more cooling capacity than a passive chilled beam working on a natural circulation flow. The efficient operation of the primary air unit is important to save the energy consumption from the fan and cooling capacity of the primary air unit. In this study, energy efficiency and efficient performance of the active beams with variable air volume (VAV) system was studied by simulation of the optimizing variable control parameters; the chilled beam efficiency difference was discussed considering the ratio between a primary air capacity and a chilled water capacity.

Nomenclature

tw2	=	temperature of water leaving the coil (°C)
tp	=	primary airflow temperature (°C)
Cpw	=	specific heat of water (kcal/kg°C)
mi	=	mass flow rate of induced air (kg/s)
Cpa	=	specific heat of air (kcal/kg°C)
ti2	=	induced air temperature leaving the coil (°C)
QT	=	total cooling capacity of an active chilled beam (W)
Qa	=	cooling capacity of a primary air unit (W)
mpv	=	volume flow rate of primary air (m3/s)
mp	=	mass flow rate of primary air (kg/s)
tr	=	average room air temperature (°C)
mw	=	water mass flow rate (kg/s)
tw1	=	temperature of water entering the coil (°C)
ti1	=	induced air temperature entering the coil (°C)
Kin	=	induction coefficient
Qw	=	cooling capacity of a chilled beam (W)
mwv	=	volume flow rate of chilled water (m3/s)

Additional information

Notes on contributors

Changhoon Kim

Changhoon Kim, is a PhD Student.

Jinho Lee

Jinho Lee, PhD, is a Professor.

Daehui Lee

Daehui Lee, PhD, is a Researcher.

Sunho Choi

Sunho Choi is a Manager.