Energy analysis of a wood or pellet stove in a single-family house equipped with gas boiler and radiators

Marco Marigo,Giuseppe Emmi,Michele De Carli,Sara Bordignon,Fabio Zulli,Laura Carnieletto

doi:10.1007/s12273-022-0884-1

Abstract

In the residential sector, biomass appliances are widely used for space heating and often combined with other systems. This work aims at comparing the final and primary energy consumption of different configurations, including a conventional and a ducted pellet stove and a wood log stove using air as heat transfer fluid. A dynamic analysis of the interaction between biomass stoves and conventional heating systems, such as gas boilers and radiators, is carried out within a typical single-family house in a mild climate, using TRNSYS software. In addition, natural ventilation of the building is considered using CONTAM, with a focus on external infiltrations and internal air circulation due to the buoyancy effect. Results show that the biomass device in one room promotes the airflows between adjacent thermal zones, enhancing the heat distribution through door openings, in particular when an air ducted stove is present. The final energy consumption resulting from simulations with wood-burning stoves is 21% higher than pellet stoves. The pellet stove results in similar final energy and a 30% increase in overall primary energy, while the wood stove increases the final energy by 22% and approximately 40% of overall primary energy compared to the case of a traditional gas system coupled to radiators which is considered as reference. Nevertheless, non-renewable primary energy savings are higher than 50% with pellet stoves and 60% with wood-log stoves.

Highlights

The model proposed in this paper aims at comparing different plant configurations from the point of view of the energy consumption of the whole building, an issue where there was no evidence of an adequate background
The annual consumption presented in this paper was compared from an economic point of view to provide a comprehensive analysis of the different systems. Such analysis is reasonable as this work aims to compare an ordinary and average use of the biomass and gas boiler systems in a typical house archetype with regular energy performance, such as most houses where biomass devices are currently installed in the Italian scenario (Patti et al 2020)
The results concerning the operative temperature (Section 4.1) and the infiltration and air-coupling analysis (Section 4.2) are reported; despite the simplified model, the results shown in these sections highlight some significant aspects

Summary

Introduction

The problem of climate change has led, over the years, to an increasing number of policies aimed at saving energy and reducing greenhouse gases (GHG) emissions. Energy savings in households play a crucial role, accounting for 26% of the global final energy use and about 20% of the CO2 equivalent emissions. A recent revision of Directive 2009/28/EC (Renewable Energy Directive) encourages woody biomass use as a possible solution to reach the 32% renewable share. Despite the CO2 reduction, a consequence of biomass combustion is the emission of other pollutants. An incomplete combustion process, which is possible especially in the case of firewood, leads to the emission of pollutants such as CO, PM, SOx, NOx, NH3 (Li et al 2017)

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