1.1. System and operation concept The system concept is shown in Fig. 1. The core components are the reversible adsorption machine which can be operated as a thermally driven chiller or heat pump and the borehole system that is used as heat rejection system for the chiller mode as well as the low temperature heat […]

The heat and mass transfer model for the desiccant wheel used below is based on the analogy method with heat transfer that occurs in the sensible heat regenerator. It was first introduced by Banks [3] and Maclaine cross [4] then Jurinak [5] and Stabat [6] improved the model. The following assumptions are considered: • The […]

The data acquisition system consists of internally integrating heat meters with matched Pt100 type temperature sensors. The integrator has a sampling rate of 1s and calculates cumulated energy amounts and mean temperatures and powers. This internal sampling rate assures a correct collection of energy data for the highly dynamic temperature patterns characteristic of adsorption systems. […]

The experimental installation presented in section 2 is used to validate the above presented model. Different inlet conditions were considered with temperature varying form 25°C to 38°C and humidity ratio from 10 to 15 g/kg and for different regeneration temperature (55°C, 60°C 65°C, 70°C and 80°C). The figure 2 [9] plots the temperature error versus […]

The results presented here correspond to the operation period from June 4th, 2007 to December 1st, 2007. From these 180 days the system was in operation during 108 day. The days without operation were either weekends or days without monitoring data due to a lightning stroke into the data acquisition system. Within these 108 days […]

4.1 Results Experiments have been conducted on the desiccant wheel with the parameters (e. g. outside temperature, outside humidity ratio, regeneration temperature and regeneration humidity ratio) varying in the range defined in the section 2. The complete DOE of 4 parameters operating between 2 levels needs 24=16 experiments. When a combination of the studied parameters […]

Performance of the chiller In order to evaluate the performance of the chiller a comparison of experimentally measured cooling capacities and COPs with expected values from calculations is shown in Fig. 2. The experimental values were selected according to the following criteria: 1. a continuous operation during the whole hour as well as in the […]

A detailed full dynamic simulation model of the installed system which considers the electricity consumption of all installed components (fans, pumps, etc.) has been developed by zafh. net in the simulation environment INSEL [5]. The simulation model is used to analyse the effect of different storage charge and discharge options. A very small time step […]