Testing and Validation of Simulation Tools of Hvac Mechanical Equipment including Their Control Strategies Part Ii: Validation of Cooling and Heating Coil Models

This paper presents detailed information about testing and validation of cooling and heating coil models. The work has been carried out under Subtask D of the International Energy Agency’s SHC Task 34/ECBCS Annex 43 (Testing and Validation of Building Energy Simulation Tools). The goal of this Subtask (Mechanical Equipment and Control Strategies) was to develop and test methods that would help evaluating, diagnosing and correcting HVAC mechanical equipment simulation software. INTRODUCTION As a basis for all studies in the context of this project cooling and heating coils have been used that have been installed in an air conditioning system serving several test rooms in a laboratory building. Figure 1 Schematic plot of AHU system with measuring points The laboratory building is located in Ankeny, Iowa, U.S. The air-conditioning system as well as the two hydronic systems (heating and cooling) supplying the coils is equipped with many sensors that allow collecting minute-by-minute data of all relevant parameters. Finally, three sets of data have been collected: one for the heating coil and two for the cooling coil covering a total time period of 30 days. Data has been collected in 2005 and 2006. Due to maintenance services at the HVAC system operating conditions of the system have been slightly changed which has to be taken into account for the model validation. These modifications are for instance in terms of physical properties of chilled water and calibration of sensors. Figure 2 shows the concentration profile of Propylen-Glycol percentage of chilled water and periods of chilled water tests I and II. Figure 2 Historical to current ERS Chilled Water System Concentration METHODOLOGY The procedure of developing validation test methods was the same for both heating and cooling coil: In a first step information from the manufacture submittal has been assorted and pre-processed allowing a user to generally set up and configure a coil model. The information is related to geometry and materials the coils consist of as well as nominal coil performances. Doing it this way basic input and parameter requirements of different types of simulation programs could be satisfied. In a second step quasi-steady state performance data derived from the data collected on-site during the experiments have been used to further characterize coil performance at different part load conditions. Both data coming from the manufacturer as well as data derived from measurements can be used for model calibration. The following section will give some more insight into the type of data available. Eleventh International IBPSA Conference Glasgow, Scotland July 27-30, 2009