Pelella, Francesco (2022) Electrical heat pumps: performance degradation under faulty conditions, fault evaluation and integration with renewable energy sources. [Tesi di dottorato]

Anteprima

Testo Pelella_Francesco_35.pdf Download (30MB) | Anteprima

Abstract

Heat pumps for domestic and residential heating and cooling will increase in number due to the ongoing Community regulations about decarbonization of energy intensive sectors and increase of renewable energy share. An interesting aspect of the research developments for heat pumps is the capacity, through models or data, to simulate the behaviour of the machine in normal and faulty conditions. This aspect results to be important considering that, with the spreading of digitalization, IoT and machine learning tools will allow a self-fault detection , diagnosis and evaluation with the aim of a better maintenance schedule. On the other hand, digital twins of heat pumps will be able to simulate the operation of an entire machine stock, to predict future energetic scenarios characterized by economic incentives or renewable energy integrations. In another direction instead, it exist a huge interest toward the possibility of integrating heat pumps with other multiple renewable energy sources such as ground, air and sun, in order to underline the energetic and economic convenience depending on different cost scenarios. Therefore, this thesis deepens these two opportunities of fault detection diagnosis and evaluation tools and of renewable energy integration on heat pumps. These topics are then analysed in two different sections of the work referred as Part 1 and Part 2. In Part 1, the effects of three common soft faults of refrigerant leakage, condenser and evaporator fouling on the thermodynamic cycle of a domestic air-to-air heat pump are analysed, both statically and dynamically considering several scenarios in terms of fault evolution, maintenance strategies and climate conditions. Moreover, by comparing different faulty thermodynamic cycles, it is found that a detection of a generic anomaly could be done with measure instruments commercially available on the market, whereas for a specific fault detection, diagnosis and evaluation, the effective possibility depends on the fault intensity levels and on the measuring equipment uncertainties. In Part 2 instead, the main aim is to evaluate the effective energetic and economic convenience in the exploitation of alternative sources of air such as the sun or the ground, for residential heat pump for space heating. Two different configurations are analysed, the first is a solar assisted direct expansion heat pump without a thermal storage, whereas the second is a multi-source (air, sun, ground) indirect expansion heat pump, with the employment of a thermal storage which can be sensible or latent. Results show that the direct expansion system is thermodynamically but not economically convenient compared with traditional air source heat pump, considering the actual cost scenario. The second system instead results to be both thermodynamically and economically convenient depending on the system configuration and on the energy prices and component costs, with more convenience for the usage of the solar source for warmer climates and of the ground source for colder cities.

Downloads

Actions (login required)

Modifica documento