Solar-assisted ground-source heat pump solutions for Dutch terraced houses

Abstract

In the last decades, the excessive increase in average global temperature related to a massive rise in greenhouse gas emissions showed the world how the fossil fuel society we live in today is drastically modifying and destroying the world we live in and is turning it in an un-habitable planet. Scientist all over the world made it clear that if we stay on the current patterns and we don't reduce drastically our greenhouse gas emissions, we are gonna end up with the extinction of the human species. The urgency of the problem seems to be clear to most people, what we need now are immediate actions to drastically reduce our greenhouse gas emissions. Among all different sectors, the residential sector is one of the biggest contributors to greenhouse gases (GHG) emissions and most of the energy is used for space heating (SH) and electrical appliances. In the specific case of the Netherlands, most energy provided to the residential sector is produced by means of natural gas, and the goal of the country is to replace natural gas with net-zero CO2 solutions. In this thesis work, a solar-assisted ground-source heat pump (SAGSHP) system for space heating for a typical Dutch terraced house is thoroughly investigated. In particular a 115 m2 house with 3 people living in it. The main different components of the system are investigate by looking at the state-of-the-art technology to understand what are the different system components that would be more convenient to use in the Netherlands in terms of efficiency, costs, etc. After the different system components have been selected and a general layout of the system is determined, the different components are designed and modelled using Matlab or Simulink environment. Finally, the whole system is assembled together and simulated in a Simulink environment. The simulation runs over a period of one year using a simulation time step of 6 minutes (0.1 hours). In particular two different cases have been used for the simulation. The base case used is an year where the ambient conditions used (ambient temperature and irradiance intensity) are values averaged over a period of twenty years (1991-2020). The second case is the simulation of a very cold year to see how the system performs in extreme cases. The simulated year is the year 2010. The obtained results are presented and discussed to draw conclusions and future work recommendations. The final goal of this work is to understand the competitiveness of the system with respect to a traditional gas boiler in terms of CO2 emission reduction, performance and costs. From this work it was possible to conclude that the chosen SAGSHP system performs slightly better in colder climates where a higher heat load requirement is needed. From the base case study used in this work, it was concluded that the modelled SAGSHP system can achieve a system seasonal coefficient of performance (SSCOP) of about 3.8 and it can significantly reduce the amount of CO2 emissions generated, up to about 2.8 ton of CO2 every year. From an economical point of view, the system levelized cost of energy (LCOE) is still higher than the LCOE of a traditional gas boiler system due to the high initial investment associated with SAGSHP systems.