Hycool - Deliverable 3.2: First design of the modular hybrid heat pump

This document is the deliverable "D3.2 - First design of the modular hybrid heat pump" in the European project "HYCOOL - Industrial Cooling through Hybrid system based on Solar Heat" (hereinafter also referred to as "HYCOOL", project reference: 792073). This document contains the first system image of a cascade chiller as part of the research project - "HYCOOL". The system presented forms one of the core elements of this project. A novel, two-stage cascade connection is the focus of the investigations. Driven by hot water, an adsorption unit represents the warm stage of the cascade. The adsorption process provides cold water at a low thermal level. The colder stage of the modular hybrid heat pump is based on a compression refrigeration unit. Both working principles are combined. The cold water from the adsorption plant will be used to dissipate heat in the condenser of the lower stage. In this way, the temperature lift between evaporator and condenser of the compression circuit is reduced and consequently energy efficiency is increased while compressor power consumption is reduced. First, the cascade system is analysed to get a first general impression of systems elements to be examined. The current state of research is included. Subsequently formulated boundary conditions and assumptions are consistent with the intended application area and location of the modular hybrid heat pump. Furthermore, the use of the conventional solution for cooling requirements is taken into account using a mathematical analysis as a basis for comparison. The internal calculation tool of FAH is used to identify the operating characteristics of the adsorption unit. An online calculation tool from GEA Bock confirms the energetic balance of the compression refrigeration part. Using the data publicly available from weather stations, the weather conditions at the planned installation site are sufficiently well represented. All results are processed and evaluated with Microsoft Excel. A laboratory scaled hybrid heat pump is designed based on the operating characteristics of the reference system. The calculation results of the cascade system with a cooling capacity of 19 kW show significant performance savings in operation. This configuration has a positive effect on the cooling capacity. Increases in cooling capacity over the entire operating range are included. An electrical power saving of 14 % is combined with an increase in cooling capacity of 9 %. Moreover, an increase in nominal EERof 26% is achieved in the investigated area compared to conventional system solutions. As a result, the main components of the experimental modular hybrid heat pump are identified and a first system image in form of the Piping & Instrument diagram is developed. Furthermore, it is pointed out that the declared assumptions for the calculation of the hybrid heat pump only provide a good approximate result. However, a more efficient operation is expected as part-load conditions have not yet been taken into account due to a lack in perfomance data. Therefore, the operation of the entire system has to be tested. The electrical power savings of the compressor are continuously compromised using a larger re-cooling unit and a larger number of circulation pumps. On the other hand, intelligent partial load operation holds further energy saving potential. Following, the first layout of the modular hybrid heat pump is designed, and all other system components are identified. Within the task T3.3 the realized hybrid heat pump will be installed and tested at CNR lab. The results will be crucial to do the final layout of the hybrid system.