A Spatially-Explicit Economic and Financial Assessment of Closed-Loop Ground-Source Geothermal Heat Pumps: A Case Study for the Residential Buildings of Valle d’Aosta Region

Antonio Novelli,Valentina D’Alonzo,Alessandro Casasso,Pietro Zambelli,Simon Pezzutto,Rubén Aarón Estrada Poggio

doi:10.3390/su132212516

Abstract

Ground Source Heat Pumps (GSHPs) take advantage of the high thermal inertia of the ground to achieve a higher energy efficiency compared to Air Source Heat Pumps. GSHPs, therefore, have the potential to reduce heating, cooling, and domestic hot water costs, however the high installation cost of borehole heat exchangers (BHEs) limits the growth of such installations. Nevertheless, GSHPs can be profitable under certain conditions (climate, expensive fuels, subsidies, etc.), which can be identified using geo-referenced data and Geographical Information Systems (GIS). The proposed work investigates the economic and financial ability of GSHPs to cover the heat demand of the residential building stock of the Italian region Valle d’Aosta. To identify the opportunities offered by GSHPs in the Valle d’Aosta region, more than 40,000 residential buildings were analyzed using a GIS-based method. The return on the investment was then assessed based on the occurrence of two conditions—the Italian subsidies of the “Conto Termico” and the installation of rooftop photovoltaic (PV) systems—which contribute to the reduction of the initial and operation costs, respectively. The life-cycle costs of the four resulting combinations were compared with conventional systems composed of an oil/gas boiler and an air-source chiller. One of the main findings of this study is that subsidies exert a key role in the financial feasibility of GSHPs, especially for replacing gas boilers, whereas the presence of a PV system has a minor influence on the financial analysis carried out.

Highlights

A large share of the global energy consumption is due to the buildings’ space heating and cooling (SH and SC) and the production of domestic hot water (DHW)
Heat pumps (HPs) are among the least carbon-intensive technologies for Heating, Ventilation and Air Conditioning (HVAC) technologies [6], the greenhouse gas (GHG) emissions related to their use strongly depend on the energy source used for the production of electricity [7,8]
To evaluate the suitability of the near-surface geothermal resource to cover the heating and cooling demand in the Valle D’Aosta region, spatially explicit analyses were performed over the whole residential building stock of the smallest Italian Region

Summary

Introduction

A large share of the global energy consumption is due to the buildings’ space heating and cooling (SH and SC) and the production of domestic hot water (DHW). SH and, to a lesser extent, DHW, and SC represent 75% of the energy demand of the building stock [1,2,3], and exceed 20% of the overall energy consumption and greenhouse gas (GHG) emissions [4]. These figures highlight the key role of the building sector in the mitigation of climate change through the massive introduction of low carbon technologies, which should be supported by economic and financial analyses. HPs are among the least carbon-intensive technologies for Heating, Ventilation and Air Conditioning (HVAC) technologies [6], the greenhouse gas (GHG) emissions related to their use strongly depend on the energy source used for the production of electricity [7,8].

Methods

Results

Conclusion