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Waste-heat driven refrigeration technology represents a promising alternative for food preservation on-board, that could help reducing pollutant emissions and, at the same time, limiting fuel consumption. Aim of the present work is the assessment of possible benefits arising from the use of thermally driven systems, with focus on two technologies: absorption and adsorption. A dynamic simulation of the whole waste heat recovery system and the sorption refrigerators has been performed. For the modelling of the thermally driven chillers, experimental data from two prototypes have been employed. The results show that, for a cooling load typical of the Italian fishing fleet, fuel savings up to 1600 kg/y can be achieved, corresponding to 3 ton/ y of avoided CO 2 emissions. Moreover, for bigger vessels with 10 kW cooling load needed, up to 7 times higher fuel savings can be obtained.

A B S T R A C TThe selection of the proper device for space heating and domestic hot water for a building is crucial to achieve good energy and economic performances. For a single-family house, the most common heating device is the condensing boiler. Solar systems, electric heat pumps and gas driven sorption heat pumps represent suitable alternatives for improving the efficiency. Although the performances of each technology are well known, their ability to operate efficiently in bivalent heating plants depends on several variables and the choice of the most suitable heating system for a specific building is not straight-forward. The aim of this paper is to compare, under conditions typical of the European region, the seasonal performances of six system configurations that are obtained by combining the most commonly used heating technologies. The comparison is carried out in terms of primary energy consumption for three climatic conditions, changing the quality of the building envelope and the emission system typology. Although the results are sensitive to the primary energy factor for electricity, electric heat pumps generally result the most promising technology for conditions with low thermal lift, while gas heat pumps have the higher performances at high lift. Additionally, the systems are compared in terms of yearly CO 2 emissions and economic feasibility, finding scattered results among countries, due to large differences in the local energy mix and energy prices.

Energy efficiency in buildings is a crucial topic to reduce the worldwide energy consumptions and fight the climate change. A key aspect is the assessment of the heat transfer through the opaque elements of the building envelope. One way to do it is modelling the element as a resistors and capacitors network (RC), using the thermal-electrical analogy. In the hourly dynamic method introduced by the recently published standard EN ISO 52016-1:2017, each opaque element is modelled with a RC-network. Italy has implemented in the National Annex A of the Standard an alternative methodology for the definition of the number of nodes and position, based on the detailed layers' characteristics. In this work, the two methods are described and compared with the exact analytical solution for three cases under sinusoidal boundary conditions. In all the test cases, the results obtained applying the Italian Annex provide better results, with reduction of the error on the internal flux amplitude between 14% and 67%. In addition, it has been verified that the Italian model is actually well tuned. Indeed, the amplitude of the external flux is overestimated on average of only 3%, and the phase differences are limited (maximum ±1 hour). Lastly, also the effect of the change of number of nodes, and to move the nodes from the layers' mid-point to the interface, have been analysed, but none of these strategies were demonstrated able to increase significantly the model accuracy, which can be obtained only reducing the calculation timestep.

 Heat-transmission model based on the method of characteristics  Inclusion of the thermal capacity effect related to the turbulent boundary layer  Calculation 10 3 times faster than the finite-volume method at the same level of accuracy  Very good agreement with experimental data