Outdoor Test Cell Modelling with Modelica

Abstract

The experimental setup implements a simplified PASSYS test cell construction, which is combined with a detailed simulation to reduce measurement effort. To analyze the cell’s dynamic behavior, the test cell was closely monitored with thermal sensors, and different static and dynamic heating modes were applied during a three-week calibration period. Co-heating tests were performed for steady-state measurements and cyclic heating periods account for the transient behavior of the test cell. The cells response was compared to the results of transient simulations with the software packet Modelica. The equation based Modelica framework allowed a detailed transient thermal simulation of the test cell’s dynamic to be set up that shows close agreement with the measurements. In addition, the flexibility of Modelica allowed unforeseen events affecting the experimental setup to be replicated, thereby ensuring an uninterrupted heat flow history of all surfaces. More than 96% of the predicted air temperatures (1 min resolution) match the experimental values within an error band of ±1.5 K, and 90% of all predictions are within ±1.0 K.

An Innovative Façade Element with Controlled Solar-Thermal Collector and Storage

“…Other than the ventilated DSFs evaluated in previous research [8,10,11], the SEBF is not actively ventilated or used for active energy production, e.g., for hot water or room heating. An accurate transient heat flow model of the façade element shall be developed and validated by comparison against measurements on a test cell [12]. The effect of solar energy use and solar thermal storage are evaluated by annual simulations under the climatic conditions of four locations in Europe.…”

“…The performance of the SEBF with and without thermal storage (SEBF w and SEBF a ) was evaluated assuming an attached test cell [12]. The cell's south-facing wall was completely replaced by a side-by-side installation of either two SEBF water or two SEBF air elements.…”

“…The test cell is equipped with an HVAC unit, modeled with a rated power of 1000 W in heating and cooling mode. Due to a lack of documentation, the device's control schedule was modeled based on the observed operation in the test cell [12], as illustrated by Figure 8. The HVAC unit has a dead band of about ± 1.5 K to the set point ( 22• C in the model).…”

“…Together, the two elements form the south-facing wall of a test cell [12]. The cell comprises an 8.6 m 2 conditioned space and a 6 m 2 maintenance room.…”

“…The SEBF elements were equipped with digital thermal sensors (DS18B20 from Maxim Integrate, USA, on a one-wire bus). The manufacturer specifies an accuracy of +/− 0.5 K. Sensor response was corrected for offset and slope [12]. Vertical solar irradiation was recorded by an ISO Second Class Pyranometer (Kipp & Zonen SMP3-V).…”