• Energy Research

The current paper presents the design and energy performance analysis of a propane-based reversible Dual Source/Sink Heat Pump (DSHP). DSHPs offer an alternative to conventional water to water and air to water heat pumps, leveraging the strengths of both technologies in an efficient manner. The developed prototype incorporates an innovative Dual Source/Sink Heat eXchanger (DSHX), enabling the unit operating in various modes, including space heating, space cooling, and domestic hot water production using brine, air or both simultaneously as a source/sink. The DSHX serves as as both a condenser or an evaporator, directly rejecting or absorbing heat from air and/or brine. By eliminating secondary loops and defrost cycles, the DSHX minimizes energy losses. The main novelty of this work lies in the DSHX that integrates external units typically duplicated in DSHPs into a single component, eliminating the need for split refrigerant flow rates, thus avoiding maldistribution, refrigerant charge increase and draining valves. A steady state experimental campaign was conducted in a climatic chamber to characterize the DSHP prototype and validate the DSHX performance models. Heating capacity up to 11.2 kW and COP values up to 4.7 were achieved at nominal compressor speed by supplying hot water at 35 °C with an ambient temperature of 7 °C. Similarly, when producing cold water at 7 °C, cooling capacity and EER reached 9.8 kW and 3.6, respectively, at nominal compressor speed using air as heat sink at 35 °C. The effects of various operating parameters on the overall coefficient of performance and heat duty in both heating and cooling modes, considering air or brine as heat source/sink are analyzed in detail. Results demonstrate enhancements of approximately 15 % in capacity and efficiency compared to earlier work. Moreover, four deterministic models were created in order to predict the behaviour of the DSHX and validated against experimental results, reaching deviation values below 15 %. The authors would like to thank the support of the TRI-HP project (https://www.tri-hp.eu/project) funded by the European Union's Horizon 2020 research and innovation programme, Project No. 814888.

Hybrid Liquid Desiccant systems (HLDS) combine the liquid desiccant technology for dehumidification of air with conventional compression cycle technology for cooling. They are an alternative to conventional compression cooling systems, being more efficient and offering the possibility of independently control temperature and humidity. In this paper the design and operation of a HLDS is presented, for the air conditioning of a high latent load application with high ambient humidity levels. An analysis of the daily evolution of the performance of the system under different environmental conditions has been included. The innovative demonstration unit placed in Taiwan, in continuous operation since November 2015, achieved Energy efficiency Ratios (EER) up to 4.6. This work has been supported by the European Nanocool project (ref n. 314701) co-founded by the EC under FP7-2012-NMP-ENV-ENERGY-ICT-EeB. https://v2.sherpa.ac.uk/id/publication/12611

The Indus3Es project received funding under H2020-EE-18-2015: New technologies for utilization of heat recovery in large industrial systems, considering the whole energy cycle from heat production to transformation, delivery and end use. Funded under the Grant Agreement 680738, the main objective of the project is to develop an economically viable solution for industry, appropriate for existing plants and adaptable to various industrial processes, consisting on the technology of Absorption Heat Transformer. The developed system will be demonstrated in real environment in Tu¨pras, the main petrochemical industry in Turkey, enabling to analyze besides integration aspects, operational and business issues. Indus3Es System will be defined and optimized for different specificities in different sectors and industrial processes, for which up-scaling of the demonstrated technology and replication studies will be performed. Indus3Es is a project funded by the European Commission. This project has received funding from the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement n° 680738.

The integration of photovoltaic panels and heat pumps in domestic environments is a topic that has been studied extensively. Due to their electrical nature and the presence of elements that add thermal inertia to the system (water tanks and the building itself), the functioning of compression heat pumps can be manipulated to try to fulfill a certain objective. In this paper, following a rule-based control concept that has been identified in commercial solutions and whose objective is to improve the self-consumption of the system by actively modulating the heat pump compressor, a parametric analysis is presented. By making use of a lab-tested model, the performance of the implemented control algorithm is analyzed. The main objective of this analysis is to identify and quantify the effects of the main parameters in the performance of the system, namely the climate (conditioning both heating and cooling demands), the photovoltaic installation size, the thermal insulation of the building and the control activation criteria. A total of 168 yearly simulations have been carried out. The results show that the average improvement in self-consumption is around 13%, while the cost is reduced by 2.5%. On the other hand, the heat from the heat pump and the power consumed increase by 3.7% and 5.2%, respectively. Finally, a linear equation to estimate the performance of the controller is proposed.