Hach L., Katoh Y., Murata H.
Bibliographic info:
24th AIVC and BETEC Conference "Ventilation, Humidity control and energy", Washington D.C., USA, 12-14 October 2003

Many recently developed energy-reducing strategies with respect to heat loads in residential interiorsincluded in simulation programs possess extensive capabilities in handling these loads (gains orsinks) for each zone - spatial unit designed for maintaining moist air thermodynamics there.We have taken up procedure, which was primarily dedicated to the influence of the sensor positionsof a room model. In the study were proposed some important hints regarding the most desirablesensor locations, which in turns enables to set up mathematical model of the room accurate enough to be usable testing tool for room controllers (thermostatic control). Up to this point was ourmethodology analogous : with the model components, yielding local values of heat transfercoefficients (radiative and convective) on room-faced wall surfaces, an assessment was made aboutheat load and (vertical) temperature profile out from handful checkpoints. The proposed techniqueretrieves a portion of desired (local) air velocities PS and draft risk PD, while solvingNavier-Stokes equations (NSE) at meridian surface cross cut area of occupied space in twodimensional (2D) analysis and turns them immediately as input variables into three-level-decisioncontrol algorithm in order to reduce spatial heating (cooling) energy.Summarising the results, time-consuming numerical calculation of NSE does not retrieve dataon-time, such as turbulence intensity and indoor air velocity components in 2D-calculations overthe meridian cross-area within the occupied space, Fig.3, both needed in either empirical ortheoretical models (PMV, PPD) with sufficient accuracy. Rather, including them into controllersinput signals can contribute in reducing heating loads. This would happen, when for inst. convectiveheat transfer occurs along adjacent air layers onto colder wall surfaces (outside walls) in contrary tobuoyancy force. Managing slower their movement means certain boost in thermal resistance andoverall U-value, eventually. Therefore, purported goal of operative switching of guarded qualitiesthroughout occupied space to a zone singled out from the occupied space could still benefit forheating energy reduction.