Bachelor's thesis Daniel Orth


Development of a method for the analysis of refurbishment measures for cold water supply systems regarding the part-load efficiency

This thesis focuses on the discovering how refrigeration machines (both existing and new installations) can operate more efficiently providing cooling energy while minimizing electrical energy consumption. To this end, a calculation tool is developed which is able to calculate the energy consumption of refrigeration systems using information provided by vendor in conjunction with appropriate assumptions. This tool is based on a simplified algorithm describing the thermodynamic cycle in particular for partial load situations of the machine. It is described how and with what restrictions such a tool can be realized at all and how exactly a reference machine can be imaged. In a second step the influence of various thermodynamic and component dependent parameters on the efficiency is shown using a particular type of machine. Therefore three different types of reference machines exhibiting three particular load profiles are introduced: industrial refrigeration, commercial refrigeration and building cooling. These machines and the associated load profiles are supposed to reflect different types of cooling consumers.

Over the course of a year each load profile has a different proportion of full load operation and thus affects the partial load performance of the refrigeration system. Based on these consumer types different optimization strategies are simulated. A simple method based on key figures evaluates the efficiency of measures to modernize the refrigeration machines. The modernization measures are subdivided into high and low cost measures, depending on whether the replacement of a high-priced investment component is necessary or not. These and other modernization measures are defined and analyzed using the algorithm in the context of this piece of work. This shows that already low cost measures, such as the cleaning of the evaporator or the supercooling of the refrigerant significantly improve the performance. High investment measures such as the exchange of the electrical motor are not necessarily beneficial for enhancing the SEER.