Until the end of the midterm period the main conducted work involved the modelling, sizing, development and testing of the separate components by the respective partners and the preparation of the site for the experiments of the coupled system in the premises of the National Technical University of Athens (NTUA). The adsorption chiller, developed by Fahrenheit GmbH, was sized in such a way to deliver 10 kW cooling power at the 50% load point based on the Eurovent standard RS/6/C/003-2015. In terms of the sorption material, the results of a series of comparative studies revealed that the optimal performance, by means of higher SEER, for the considered application was achieved with zeolite AIPO-5 as the adsorptive material, which enhanced significantly system’s performance in respect to other conventional types of zeolite or silica gel. The overall system will be driven by vacuum tube collectors that were manufactured by AkoTec GmbH. Based on the experimental results, the vacuum tube collectors’ efficiency was significantly higher than other commercial products.
In parallel to the manufacturing process, a Life Cycle Analysis has been conducted to assess the impact of the system in comparison to a conventional heat pump.
The demo site was evaluated for operation on both cooling and heating mode in the period August 2019-February 2020. The results of the measurements came in agreement with the preliminary results of the design simulations. During August, the system was driven continuously within the day solely on solar adsorption module with COPs close to the nominal of the sorption chiller and daily EERs as high as 10, reducing thus significantly the need for the use of the conventional heat pump. Similarly, on heating mode capacities as high as 30 kW were reported, however, the reduced solar availability resulted in the conclusion that the industrial design of the system should have a slight increase in the solar field per produced from the chiller cooling kW. The respective economic analysis that used the results from the demo site concluded that the system can be economically competitive in regions with high solar irradiance as in the southern Mediterranean, a performance which can be further improved by taking advantage of the different financial instruments provided per country for renewable heating and cooling applications.
